Artículos de revistas: "Intramolecular interactions through space"

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Wang, Jiaobing, Lili Hou, Wesley R. Browne y Ben L. Feringa. "Photoswitchable Intramolecular Through-Space Magnetic Interaction". Journal of the American Chemical Society 133, n.º 21 (junio de 2011): 8162–64. http://dx.doi.org/10.1021/ja202882q.

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Michinobu, Tsuyoshi, Manabu Tanaka, Jun Inui y Hiroyuki Nishide. "Intramolecular Through-Space Antiferromagnetic Interactions of Cross-Conjugated Aromatic Polyaminium Radical Gels". Journal of Nanoscience and Nanotechnology 9, n.º 1 (1 de enero de 2009): 514–21. http://dx.doi.org/10.1166/jnn.2009.j020.

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3

Kishimoto, Naoki, Hideyuki Ogasawara y Koichi Ohno. "Anisotropic Intermolecular Interactions and Through-Space/Through-Bond Intramolecular Interactions Observed by Collision-Energy-Resolved Penning Ionization Electron Spectroscopy". Bulletin of the Chemical Society of Japan 75, n.º 7 (julio de 2002): 1503–13. http://dx.doi.org/10.1246/bcsj.75.1503.

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4

Rathore, Rajendra y Jay K. Kochi. "Vicinal-diaryl interactions in stilbenoid hydrocarbons as observed in the through-space charge delocalization of their cation radicals". Canadian Journal of Chemistry 77, n.º 5-6 (1 de junio de 1999): 913–21. http://dx.doi.org/10.1139/v99-081.

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The conformational preference of vicinal or 1,2-phenyl groups is probed in two classes of ring-substituted 1,2-diphenylbicyclooctene (stilbenoid) hydrocarbons 1a-1d and 2a-2c. UV-vis spectroscopy reveals, and X-ray crystallography verifies, the intramolecular (edge-to-face) orientation for the phenyl-phenyl interaction in stilbenoids 1a-1d. Most importantly, when two pairs of ortho-methyl substituents are present, the cofacial phenyl groups in the stilbenoid donors are established by X-ray crystallography and spectrally observed in the cation radicals (2a+.-2c+.) by the appearance of new bands with strong absorptions in the near IR with λmax = 1100-1315 nm, analogous to those previously observed in intermolecular (aromatic) interactions of aromatic cation radicals.Key words: stilbenoid hydrocarbon, cation radical, aryl-aryl interaction.

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5

Figueira-Duarte, Teresa M., Vega Lloveras, José Vidal-Gancedo, Aline Gégout, Béatrice Delavaux-Nicot, Richard Welter, Jaume Veciana, Concepció Rovira y Jean-François Nierengarten. "Changes in electronic couplings of mixed-valence systems due to through-space intramolecular interactions". Chemical Communications, n.º 42 (2007): 4345. http://dx.doi.org/10.1039/b707522g.

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6

Bhandary, Subhrajyoti, Yarabhally R. Girish, Katharigatta N. Venugopala y Deepak Chopra. "Crystal structure analysis of [5-(4-methoxyphenyl)-2-methyl-2H-1,2,3-triazol-4-yl](thiophen-2-yl)methanone". Acta Crystallographica Section E Crystallographic Communications 74, n.º 8 (31 de julio de 2018): 1178–81. http://dx.doi.org/10.1107/s2056989018010654.

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The title compound, C15H13N3O2S, crystallizes in the monoclinic space group P21/n and its molecular conformation is stabilized via intramolecular C—H...O and C—H...N contacts. The supramolecular structure is mainly governed by C—H...N hydrogen-bonded centrosymmetric dimers, C—H...O and C—H...S hydrogen bonds and S...π and π–π stacking interactions which, together, lead to the formation of a layered crystal packing. The intermolecular interactions were further evaluated through the molecular electrostatic potential map and Hirshfeld fingerprint analysis.

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7

Hijji, Yousef, Belygona Barare, Gilbert Wairia, Ray J. Butcher y Jan Wikaira. "Crystal structure of (E)-2-{[(6-methoxy-1,3-benzothiazol-2-yl)imino]methyl}phenol". Acta Crystallographica Section E Crystallographic Communications 71, n.º 4 (21 de marzo de 2015): 385–87. http://dx.doi.org/10.1107/s2056989015005228.

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The title compound, C15H12N2O2S, crystallizes in the orthorhombic space groupPna21, with two molecules in the asymmetric unit (Z′ = 2). Each molecule consists of a 2-hydroxy Schiff base moiety linked through a spacer to a 2-aminobenzothiazole moiety. Each molecule contains an intramolecular hydrogen bond between the –OH group and imine N atom, forming a six-membered ring. The two independent molecules are linked by a pair of C—H...O hydrogen bonds, forming dimers with anR22(20) ring motif. These dimers are further lined into sheets in theabplane by weak intermolecular C—H...N interactions. The structure was refined as an inversion twin

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8

Mossine, Valeri V., Steven P. Kelley y Thomas P. Mawhinney. "Intramolecular 1,5-S...N σ-hole interaction in (E)-N′-(pyridin-4-ylmethylidene)thiophene-2-carbohydrazide". Acta Crystallographica Section E Crystallographic Communications 76, n.º 4 (17 de marzo de 2020): 557–61. http://dx.doi.org/10.1107/s2056989020003011.

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The title compound, C11H9N3OS, (I), crystallizes in the monoclinic space group P21/n. The molecular conformation is nearly planar and features an intramolecular chalcogen bond between the thiophene S and the imine N atoms. Within the crystal, the strongest interactions between molecules are the N—H...O hydrogen bonds, which organize them into inversion dimers. The dimers are linked through short C—H...N contacts and are stacked into layers propagating in the (001) plane. The crystal structure features π–π stacking between the pyridine aromatic ring and the azomethine double bond. The calculated energies of pairwise intermolecular interactions within the stacks are considerably larger than those found for the interactions between the layers.

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9

Dhanalakshmi, G., Velu Saravanan, Arasambattu K. Mohanakrishnan y S. Aravindhan. "Synthesis, Crystal Structure, Hirshfeld Surface, Energy Framework and Molecular Docking Analysis of Two Novel Carbazole Derivatives". Asian Journal of Chemistry 31, n.º 12 (16 de noviembre de 2019): 3017–28. http://dx.doi.org/10.14233/ajchem.2019.22430.

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Carbazole derivatives are important compounds from medicinal point of view because of their widespread biological significance. In the present work two compounds 7-(4-chlorophenyl)-5-methyl- 12-(phenylsulfonyl)-12H-naphtho[1,2-b]carbazole (I) and 7-ethyl-5-methyl-12-(phenylsulfonyl)-12Hnaphtho[ 1,2-b]carbazole (II) have been synthesized and characterized by XRD, Hirshfeld surface, energy framework and docking analysis. Single crystal X-ray diffraction analysis shows that the compound I crystallizes in monoclinic system with space group P21/n whereas compound II crystallizes in triclinic with space group P-1. In both compounds there are two intramolecular C-H···O hydrogen bonds, which generates two S (6) ring motifs. The crystal packing is stabilized through weak C-H···O and C-H···Cl interactions. The molecules also features C-H···π interactions. The intermolecular interactions of both compounds were analyzed using Hirshfeld surface analysis and two dimensional fingerprint plots, which was confirmed by the XRD data. Energy frameworks were used to calculate the intermolecular interaction energies and their distribution over the crystal structure. Molecular docking studies show that the compounds exhibits antitumor activity.

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10

Kukhta, Nadzeya A., Heather F. Higginbotham, Tomas Matulaitis, Andrew Danos, Aisha N. Bismillah, Nils Haase, Marc K. Etherington et al. "Revealing resonance effects and intramolecular dipole interactions in the positional isomers of benzonitrile-core thermally activated delayed fluorescence materials". Journal of Materials Chemistry C 7, n.º 30 (2019): 9184–94. http://dx.doi.org/10.1039/c9tc02742d.

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Rather than donor–acceptor dihedral angles, the TADF performance of DMAC–BZN positional isomers is instead controlled by differences in acceptor strength arising from π-system electron density – along with a through-space dipole interaction.

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11

Jiang, Chenglin, Jingsheng Miao, Danwen Zhang, Zhenhua Wen, Chuluo Yang y Kai Li. "Acceptor-Donor-Acceptor π-Stacking Boosts Intramolecular Through-Space Charge Transfer towards Efficient Red TADF and High-Performance OLEDs". Research 2022 (25 de junio de 2022): 1–12. http://dx.doi.org/10.34133/2022/9892802.

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Organic push-pull systems featuring through-space charge transfer (TSCT) excited states have been disclosed to be capable of exhibiting thermally activated delayed fluorescence (TADF), but to realize high-efficiency long-wavelength emission still remains a challenge. Herein, we report a series of strongly emissive orange-red and red TSCT-TADF emitters having (quasi)planar and rigid donor and acceptor segments which are placed in close proximity and orientated in a cofacial manner. Emission maxima (λem) of 594−599 nm with photoluminescence quantum yields (PLQYs) of up to 91% and delayed fluorescence lifetimes of down to 4.9 μs have been achieved for new acceptor-donor-acceptor (A-D-A) molecules in doped thin films. The presence of multiple acceptors and the strong intramolecular π-stacking interactions have been unveiled to be crucial for the efficient low-energy TSCT-TADF emissions. Organic light-emitting diodes (OLEDs) based on the new A-D-A emitters demonstrated electroluminescence with maximum external quantum efficiencies (EQEs) of up to 23.2% for the red TSCT-TADF emitters. An EQE of 18.9% at the brightness of 1000 cd m-2 represents one of the highest values for red TADF OLEDs. This work demonstrates a modular approach for developing high-performance red TADF emitters through engineering through-space interactions, and it may also provide implications to the design of TADF emitter with other colours.

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12

Kratochvíl, Bohumil, Jiří Novotný, Svatava Smrčková y Jiří Krechl. "Structure determination of N,N'-diphenylacetamidinium oxalate". Collection of Czechoslovak Chemical Communications 55, n.º 2 (1990): 479–84. http://dx.doi.org/10.1135/cccc19900479.

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The structure of N,N'-diphenylacetamidinium oxalate was solved by direct methods and refined anisotropically to R = 0.036 for 1 551 unique observed reflections. The compound (C16H16N2O4) crystallizes in the P21/c space group with the lattice parameters a = 17.672(2), b = 8.263(3), c = 10.771(2) Å, β = 104.64(1)°, Z = 4. Intra- and intermolecular hydrogen bonds between amidinium nitrogens and oxalate oxygens of the N-H···O and O-H···O types form infinite chains parallel to the [010] direction in the structure. Mutual interactions between the chains are mediated by the van der Waals forces. Planes of the phenyl rings bisect at the dihedral angle of 55.8(1)°. In contrast to similar model structures benzamidinium pyruvate, benzamidinium bromoacetate and p-methylbenzamidinium formate monohydrate, the structure of N,N'-diphenylacetamidinium oxalate does not exhibit the amidine-carboxyl interaction through two parallel intramolecular N-H···O bonds.

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13

King, Andrew T., Hugh G. Hiscocks, Lidia Matesic, Mohan Bhadbhade, Roger Bishop y Alison Thavary Ung. "Formation of an unexpected 3,3-diphenyl-3H-indazole through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate". Beilstein Journal of Organic Chemistry 15 (19 de junio de 2019): 1347–54. http://dx.doi.org/10.3762/bjoc.15.134.

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The one-pot reaction of 2,6-bis(diphenylmethyl)-4-methoxyaniline with tert-butylnitrite, BTEAC and DABSO in the presence of CuCl2 provided an unexpected 3H-indazole product 8. The structure of the compound was determined by HRMS, IR, NMR and further confirmed by single crystal X-ray crystallography. The compound crystallises in the triclinic P-1 space group, with unit cell parameters a = 9.2107 (4), b = 10.0413 (5), c = 14.4363 (6) Å, α = 78.183 (2), β = 87.625 (2), γ = 71.975 (2)°. The formation of 8 proceeded through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate 9. The molecules of 8 are organised by edge–face Ar–H···π, face–face π···π, and bifurcated OCH2–H···N interactions. In addition to these, there are Ar–H···H–Ar close contacts, (edge–edge and surrounding inversion centres) arranged as infinite tapes along the a direction.

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14

Tang, Chao, Hui Xu, Feng Liu, Yi-Jie Xia y Wei Huang. "Isolated large π systems in pyrene–fluorene derivatives for intramolecular through-space interaction in organic semiconductors". Organic Electronics 14, n.º 3 (marzo de 2013): 782–89. http://dx.doi.org/10.1016/j.orgel.2012.12.035.

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15

Voronkov, M. G., E. A. Zel’bst y V. V. Belyaeva. "Intramolecular inductive through-space interaction between nitrogen and oxygen atoms in silatranes, quasisilatranes, protatranes, triethanolamine, and diethanolamine". Doklady Chemistry 455, n.º 1-2 (marzo de 2014): 49–52. http://dx.doi.org/10.1134/s001250081403001x.

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16

Mokin, Yakov I., Anastasia A. Gavrilova, Anna S. Fefilova, Irina M. Kuznetsova, Konstantin K. Turoverov, Vladimir N. Uversky y Alexander V. Fonin. "Nucleolar- and Nuclear-Stress-Induced Membrane-Less Organelles: A Proteome Analysis through the Prism of Liquid–Liquid Phase Separation". International Journal of Molecular Sciences 24, n.º 13 (2 de julio de 2023): 11007. http://dx.doi.org/10.3390/ijms241311007.

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Radical changes in the idea of the organization of intracellular space that occurred in the early 2010s made it possible to consider the formation and functioning of so-called membrane-less organelles (MLOs) based on a single physical principle: the liquid–liquid phase separation (LLPS) of biopolymers. Weak non-specific inter- and intramolecular interactions of disordered polymers, primarily intrinsically disordered proteins, and RNA, play a central role in the initiation and regulation of these processes. On the other hand, in some cases, the “maturation” of MLOs can be accompanied by a “liquid–gel” phase transition, where other types of interactions can play a significant role in the reorganization of their structure. In this work, we conducted a bioinformatics analysis of the propensity of the proteomes of two membrane-less organelles, formed in response to stress in the same compartment, for spontaneous phase separation and examined their intrinsic disorder predispositions. These MLOs, amyloid bodies (A-bodies) formed in the response to acidosis and heat shock and nuclear stress bodies (nSBs), are characterized by a partially overlapping composition, but show different functional activities and morphologies. We show that the proteomes of these biocondensates are differently enriched in proteins, and many have high potential for spontaneous LLPS that correlates with the different morphology and function of these organelles. The results of these analyses allowed us to evaluate the role of weak interactions in the formation and functioning of these important organelles.

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17

Samanta, Pralok K. y Ramprasad Misra. "Intramolecular charge transfer for optical applications". Journal of Applied Physics 133, n.º 2 (14 de enero de 2023): 020901. http://dx.doi.org/10.1063/5.0131426.

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Tuning of intramolecular charge transfer (ICT) in a molecule could be used to modulate its linear and nonlinear optical (NLO) response properties. Over the years, the ICT process in the so-called “push–pull” molecules in which electron donor (D) and acceptor (A) groups are connected either directly or through a π-electron bridge has been used for emission color tuning, modulating absorption maxima, optimizing first or higher order hyperpolarizabilities, and two-photon absorption (TPA), among others. As ICT is the functional basis of many optoelectronic and semiconductor devices, optimizing the parameters involved in this process as well as modeling the effect of the environment and intermolecular interaction are crucial for these applications. NLO processes such as second harmonic generation, sum-frequency generation, and TPA have been used extensively for numerous technological applications, such as optical switching, optical limiting, bioimaging, and biophotonics. Recently, through-bond and through-space ICT have been employed to tune the reverse intersystem crossing that facilitates thermally activated delayed fluorescence for fabricating next-generation organic light-emitting diodes. Aggregation-induced emission of ICT molecules either alone or in combination with the other phenomenon, such as TPA, could be useful in many optical applications. In this perspective, the state-of-the-art and challenges in designing ICT-based molecules and materials for optical applications will be discussed. The underlying theories used to quantify the magnitude of ICT and NLO response are mentioned, followed by a discussion on the latest development and scope of using these molecules and materials for optical applications.

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18

Itoh, Hiroki, Yasuhisa Senda, Hirochika Sakuragi y Katsumi Tokumaru. "Intramolecular Through-Space Interaction in 2-(p-Methoxyphenyl)-2-butenyl 9-Phenanthrenecarboxylate as Evidenced by Their Isomerization Behavior". Bulletin of the Chemical Society of Japan 66, n.º 4 (abril de 1993): 1312–15. http://dx.doi.org/10.1246/bcsj.66.1312.

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19

Jyothi, K. L., M. K. Hema, Karthik Kumara y N. K. Lokanath. "Gallic acid-butyramide monohydrate cocrystal: Crystal growth, Structural insights, Theoretical calculations and Molecular docking studies against COVID-19 main protease". Current Chemistry Letters 12, n.º 1 (2023): 235–48. http://dx.doi.org/10.5267/j.ccl.2022.6.004.

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Single crystal X-ray diffraction is the only experimental technique available to elucidate the complete three-dimensional structure of the samples at molecular and atomic levels. But this technique demands defect-free single crystals. Growing good quality single crystals which are suitable to collect X-ray intensity data is an art rather than science. Among the various crystal growth methods, the most effective and commonly used is the slow evaporation method. Using this method, defect-free single crystals of the ground mixture of gallic acid (GA) and butyramide (BU) taken in a 1:1 molar ratio are obtained. The compound was subjected to experimental characterizations like; PXRD, FTIR, SCXRD, and TGA. Further, these results were utilized in the computational characterizations namely, Hirshfeld surface analysis, interaction energy calculations, DFT studies, and docking studies. Structural characterization revealed that the GA-BU compound was crystallized as a cocrystal hydrate with 2:1:1 stoichiometry in a monoclinic crystal system and P21/n space group. Structural studies exposed the presence of various inter and intramolecular hydrogen bond interactions, ring synthons, DDAA environment of the water molecule, and π ... π stacking interactions. The contribution of the several close contacts to the crystal structure, the influence of different interaction energies in the packing, the HOMO-LUMO energy gap, and the location of reactive sites were realized through computational studies. Further, a molecular docking study has been performed to check the antiviral activity of the title compound against COVID-19.

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20

Gelan, J., P. Adriaensens, D. Vanderzande, D. Declercq, E. Hermans y F. C. De Schryver. "Full 1H and 13C NMR Chemical Shift Assignment of 1-Pyrenyl Substituted Oligosilanes as a Tool to Differentiate between Intramolecular "Through Space" and "Through Bond" Ground State Interactions". Journal of the American Chemical Society 116, n.º 17 (agosto de 1994): 7877–84. http://dx.doi.org/10.1021/ja00096a051.

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21

Marfo-Owusu, Prof Emmanuel y Dr Amber Thompson. "Hydrogen Bonded Charge Transfer Complex of Chloranilic Acid With Benzimidazole". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 de agosto de 2014): C1826. http://dx.doi.org/10.1107/s2053273314081741.

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The crystal structure of 1:1:1 complex of chloranilic acid with benzimidazole and water determined by X-ray diffraction methods is reported. It crystallizes in the monoclinic (space group, P21/c) crystal system. Both chloranilic acid and benzimidazole molecules adopt a face-to-face stacking arrangement along the b-axis. An interaction beween adjacent layers is a π...π stacking interactions between chloranilic acid molecules. The dihedral angle between the interacting chloranilic acid ring planes is only 1.22 (7)0with an interplanar spacing between C10...C12 (3.383 (16) Å) and C13...C15 (3.351 (14) Å ). Water influences proton transfer in the hydrogen bonded charge transfer complex, and contributes to generating increased number of hydrogen bonds utilized in the stabilzaation of the crystal structure of the complex. Water serves as an efficient bridge between the chloranilic acid molecules through O-H...O intermolecular hydrogen bonds to form a zigzag channel, as well as directly linking chloranilic acid molecules with benzimidazole molecules which are strongly entrapped within the zigzag channel by intermolecular hydrogen bonding network involving the N-H...O, C-H...O, and C-H...Cl interactions. In the chloranilate anion structure, an intramolecular hydrogen bonding involving O2-H7 and O1 (dO2... O1 and dH7... O1 = 2.670 (12) and 2.25 Å) occurs. The supramolecular architecture of the hydrogen bonded charge complex exhibits a three-dimensional hydrogen bonding network

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22

Donlevy, TM, LR Gahan, TW Hambley, GR Hanson, A. Markiewicz, KS Murray, IL Swann y SR Pickering. "Synthesis, X-Ray Crystal Structure and Magnetic Studies of a Biscopper(II) Complex of a C-Spiro Binucleating Linear Octadentate Ligand". Australian Journal of Chemistry 43, n.º 8 (1990): 1407. http://dx.doi.org/10.1071/ch9901407.

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Reaction of the binucleating ligand 5,5-bis(4-amino-2-thiabutyl)-3,7- dithianonane-1,9-diamine (L1) with a copper(II) salt in aqueous solution, and in the presence of lithium dithionate, results in the isolation of a dark blue crystalline solid identified as [Cu2(L1)](S2O6)2.4H2O. Crystals of the complex are triclinic, space group Pī , a 8.227(2), b 13.103(3), c 16.423(4) Ǻ, α 68.68(2), β 86.68(2), γ 75.50(2)°, Z 2, R 0.026 (5039 F). The structure consists of two copper(II) atoms each of which is coordinated through two thioether and two primary amine atoms. The two copper sites are linked through a saturated spiro carbon atom. Each copper atom is also coordinated to one water molecule; one of the copper atoms is coordinated to an oxygen atom of one dithionate anion. Thus, one copper atom is six-coordinate (4+2 tetragonally distorted), and the other is five-coordinate. The intramolecular Cu...Cu distance is 7.127 Ǻ; the shortest intermolecular Cu...Cu distance is 6.591 Ǻ. The angle between the two N2S2 planes is 92.2°. Low-temperature magnetic studies indicate weak intra- and inter-molecular antiferromagnetic interactions with a singlet-triplet splitting 2J of -10 cm-1 and a θ of -5 K. E.p.r. studies indicate a magnetic dipole-dipole interaction between the two copper(II) sites and a weak intermolecular antiferromagnetic interaction.

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23

Etse, Koffi Senam, Guillermo Zaragoza y Bernard Pirotte. "Crystal structure and Hirshfeld surface analysis of N-(2-(N-methylsulfamoyl)phenyl)formamide: Degradation product of 2-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide". European Journal of Chemistry 10, n.º 3 (30 de septiembre de 2019): 189–94. http://dx.doi.org/10.5155/eurjchem.10.3.189-194.1903.

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The hydrolysis of 2-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide (2) during crystallization under humidity (85 %) conditions, lead to N-(2-(N-methylsulfamoyl)phenyl)formamide as second step hydrolysis product, identified in the proposed degradation mechanism. Crystal of N-(2-(N-methylsulfamoyl)phenyl)formamide C8H10N2O3S (4), was obtained and characterized. The molecular structure determination was carried out with MoKα X-ray and data measured at 100 K. The compound 4 crystallizes in triclinic P͞1 space group with unit cell parameters a = 4.8465(4) Å, b = 8.1942(9) Å, c = 11.8686(13) Å, α = 77.080(4)°, β = 82.069(4)°, γ = 80.648(4)°, V = 450.76 (8) Å3 and Z = 2. The crystal structure is stabilized by intramolecular N-H···O and intermolecular C-H···O and N-H···O hydrogen bonds that extended as infinite 1D chain along [100]. Stabilization is also ensured by oxygen-π stacking interaction between the aromatic ring and oxygen of the sulfonamide group. The analysis of intermolecular interactions through the mapping of dnorm and shape-index revel that the most significant contributions to the Hirshfeld surface 40.6 and 33.9% are from H···H and O···H contacts, respectively.

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Bader, Mamoun M. y Phuong-Truc Pham. "Crystal structure of 1-{4-[bis(4-methylphenyl)amino]phenyl}ethene-1,2,2-tricarbonitrile". Acta Crystallographica Section E Crystallographic Communications 80, n.º 3 (29 de febrero de 2024): 339–42. http://dx.doi.org/10.1107/s2056989024001804.

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The title compound, C25H18N4, crystallizes in the centrosymmetric orthorhombic space group Pbca, with eight molecules in the unit cell. The main feature noticeable in the structure is the impact of the tricyanovinyl (TCV) group in forcing partial planarity of the portion of the molecule carrying the TCV group and directing the molecular packing in the solid state, resulting in the formation of π-stacks of dimers within the unit cell. Short π–π stack closest atom-to-atom distances of 3.444 (15) Å are observed. Such motif patterns are favorable as they are thought to be conducive for better charge transport in organic semiconductors, which results in enhanced device performance. Intramolecular charge transfer is evident from the shortening in the observed experimental bond lengths. The nitrogen atoms (of the cyano groups) are involved in extensive short contacts, primarily through C—H...NC interactions with distances of 2.637 (17) Å.

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Bosch, Eric, Nathan P. Bowling y Shalisa M. Oburn. "Conformational control through co-operative nonconventional C—H...N hydrogen bonds". Acta Crystallographica Section C Structural Chemistry 77, n.º 8 (26 de julio de 2021): 485–89. http://dx.doi.org/10.1107/s2053229621007427.

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We report the design, synthesis, and crystal structure of a conjugated aryleneethynyl molecule, 2-(2-{4,5-dimethoxy-2-[2-(2,3,4-trifluorophenyl)ethynyl]phenyl}ethynyl)-6-[2-(pyridin-2-yl)ethynyl]pyridine, C30H17F3N2O2, that adopts a planar rhombus conformation in the solid state. The molecule crystallizes in the space group P-1, with Z = 2, and features two intramolecular sp2 -C—H...N hydrogen bonds that co-operatively hold the arylethynyl molecule in a rhombus conformation. The H atoms are activated towards hydrogen bonding since they are situated on a trifluorophenyl ring and the H...N distances are 2.470 (16) and 2.646 (16) Å, with C—H...N angles of 161.7 (2) and 164.7 (2)°, respectively. Molecular electrostatic potential calculations support the formation of C—H...N hydrogen bonds to the trifluorophenyl moiety. Hirshfeld surface analysis identifies a self-complementary C—H...O dimeric interaction between adjacent 1,2-dimethoxybenzene segments that is shown to be common in structures containing that moiety.

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Kimura, Takeshi, Yasuhiro Ishikawa, Kensaku Ueki, Yoji Horie y Naomichi Furukawa. "Effect of Through-Space Interaction on the Photolytic Desulfurization or Deselenization and Intramolecular Cyclization Reactions of 1,9-Disubstituted Dibenzochalcogenophenes". Journal of Organic Chemistry 59, n.º 23 (noviembre de 1994): 7117–24. http://dx.doi.org/10.1021/jo00102a043.

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27

Mzozoyana, Vuyisa, Fanie R. van Heerden y Craig Grimmer. "Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds". Beilstein Journal of Organic Chemistry 16 (10 de febrero de 2020): 190–99. http://dx.doi.org/10.3762/bjoc.16.22.

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4-(2-Fluorophenyl)-7-methoxycoumarin (6) was synthesized by Pechmann reaction under mild conditions via a three-step reaction. The solution-state 1H NMR spectra of 6 showed a strong intramolecular interaction between F and H5 (J FH = 2.6 Hz) and 13C NMR suggested that this C–F···H–C coupling is a through-space interaction. The 2D 19F-{1H} HOESY and 1H-{19F} 1D experiments were done to confirm this F···H interaction. The single crystal X-ray structure and the DFT-optimized structure showed that the fluorinated phenyl ring favors the orientation with the fluorine atom closer to H5 than H3. The X-ray structure also showed the existence of the intermolecular C–F···H–C interaction.

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Schutte-Smith, Marietjie, Andreas Roodt, Roger Alberto, Linette Twigge, Hendrik Gideon Visser, Leo Kirsten y Renier Koen. "Structures of rhenium(I) complexes with 3-hydroxyflavone and benzhydroxamic acid as O,O′-bidentate ligands and confirmation of π-stacking by solid-state NMR spectroscopy". Acta Crystallographica Section C Structural Chemistry 75, n.º 4 (4 de marzo de 2019): 378–87. http://dx.doi.org/10.1107/s2053229619002717.

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The synthesis and crystal structures of two new rhenium(I) complexes obtained utilizing benzhydroxamic acid (BHAH) and 3-hydroxyflavone (2-phenylchromen-4-one, FlavH) as bidentate ligands, namely tetraethylammonium fac-(benzhydroxamato-κ2 O,O′)bromidotricarbonylrhenate(I), (C8H20N)[ReBr(C7H6NO2)(CO)3], 1, and fac-aquatricarbonyl(4-oxo-2-phenylchromen-3-olato-κ2 O,O′)rhenium(I)–3-hydroxyflavone (1/1), [Re(C15H9O3)(CO)3(H2O)]·C15H10O3, 3, are reported. Furthermore, the crystal structure of free 3-hydroxyflavone, C15H10O3, 4, was redetermined at 100 K in order to compare the packing trends and solid-state NMR spectroscopy with that of the solvate flavone molecule in 3. The compounds were characterized in solution by 1H and 13C NMR spectroscopy, and in the solid state by 13C NMR spectroscopy using the cross-polarization magic angle spinning (CP/MAS) technique. Compounds 1 and 3 both crystallize in the triclinic space group P\overline{1} with one molecule in the asymmetric unit, while 4 crystallizes in the orthorhombic space group P212121. Molecules of 1 and 3 generate one-dimensional chains formed through intermolecular interactions. A comparison of the coordinated 3-hydroxyflavone ligand with the uncoordinated solvate molecule and free molecule 4 shows that the last two are virtually completely planar due to hydrogen-bonding interactions, as opposed to the former, which is able to rotate more freely. The differences between the solid- and solution-state 13C NMR spectra of 3 and 4 are ascribed to inter- and intramolecular interactions. The study also investigated the potential labelling of both bidentate ligands with the corresponding fac-99mTc-tricarbonyl synthon. All attempts were unsuccessful and reasons for this are provided.

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Jiao, Ti Feng y Jing Xin Zhou. "Research on Hydrogen Bonding Interaction of Trigonal Schiff Base Compound with Barbituric Acid in Organized Molecular Films". Materials Science Forum 694 (julio de 2011): 528–32. http://dx.doi.org/10.4028/www.scientific.net/msf.694.528.

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In order to investigate the supramolecular assembly and intermolecular hydrogen bonding of special amphiphile, a trigonal Schiff base compound was designed and synthesized, and it supramolecular assembly and interaction properties were investigated by spectral measurements. It was found that the Schiff base compound can be spread on water surface to form stable monolayer. When it was spread on the subphase containing barbituric acid, it can show hydrogen bonding interaction with barbituric acid. Due to the directionality and strong matching of hydrogen bond, two barbituric acid molecules can be encapsulated into intramolecular space of the trigonal Schiff base compound through intermolecular H-bonding to form a 1:2 complex. A rational complex mode was proposed.

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30

Jiao, Ti Feng y Jing Xin Zhou. "Investigation of Coordination Interaction of Trigonal Schiff Base Compound with Zn(II) Ions in Organized Molecular Films". Applied Mechanics and Materials 236-237 (noviembre de 2012): 815–18. http://dx.doi.org/10.4028/www.scientific.net/amm.236-237.815.

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In order to investigate the supramolecular assembly and coordination interaction of special amphiphile, a trigonal Schiff base compound with long alkyl chains was designed and synthesized, and its supramolecular assembly and interaction properties were investigated by spectral and morphological measurements. It was found that the Schiff base compound can be spread on water surface to form stable monolayer. When on the Zn(II) ions subphase, an in situ coordination can occur for all ligands. As a result, a 1:2 complex was formed for the trigonal chain Schiff base with Zn(II) ions through the coordination interaction. Due to the directionality and strong matching of coordination, two Zn(II) ions can be encapsulated into intramolecular space of the trigonal Schiff base compound.

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31

Bogdanov, Georgii, John P. Tillotson y Tatiana Timofeeva. "Crystal structures, syntheses, and spectroscopic and electrochemical measurements of two push–pull chromophores: 2-[4-(dimethylamino)benzylidene]-1H-indene-1,3(2H)-dione and (E)-2-{3-[4-(dimethylamino)phenyl]allylidene}-1H-indene-1,3(2H)-dione". Acta Crystallographica Section E Crystallographic Communications 75, n.º 11 (3 de octubre de 2019): 1595–99. http://dx.doi.org/10.1107/s205698901901329x.

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The title pull–push chromophores, 2-[4-(dimethylamino)benzylidene]-1H-indene-1,3(2H)-dione, C18H15NO2 (ID[1]) and (E)-2-{3-[4-(dimethylamino)phenyl]allylidene}-1H-indene-1,3(2H)-dione, C20H17NO2 (ID[2]), have donor–π-bridge–acceptor structures. The molecule with the short π-bridge, ID[1], is almost planar while for the molecule with a longer bridge, ID[2], is less planar. The benzene ring is inclined to the mean plane of the 2,3-dihydro-1H-indene unit by 3.19 (4)° in ID[1] and 13.06 (8)° in ID[2]. The structures of three polymorphs of compound ID[1] have been reported: the α-polymorph [space group P21/c; Magomedova & Zvonkova (1978). Kristallografiya, 23, 281–288], the β-polymorph [space group P21/c; Magomedova & Zvonkova (1980). Kristallografiya, 25 1183–1187] and the γ-polymorph [space group Pna21; Magomedova, Neigauz, Zvonkova & Novakovskaya (1980). Kristallografiya, 25, 400–402]. The molecular packing in ID[1] studied here is centrosymmetric (space group P21/c) and corresponds to the β-polymorph structure. The molecular packing in ID[2] is non-centrosymmetric (space group P21), which suggests potential NLO properties for this crystalline material. In both compounds, there is short intramolecular C—H...O contact present, enclosing an S(7) ring motif. In the crystal of ID[1], molecules are linked by C—H...O hydrogen bonds and C—H...π interactions, forming layers parallel to the bc plane. In the crystal of ID[2], molecules are liked by C—H...O hydrogen bonds to form 21 helices propagating along the b-axis direction. The molecules in the helix are linked by offset π–π interactions with, for example, a centroid–centroid distance of 3.9664 (13) Å (= b axis) separating the indene rings, and an offset of 1.869 Å. Spectroscopic and electrochemical measurements show the ability of these compounds to easily transfer electrons through the π-conjugated chain.

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32

Cotelle, Yoann, Marie Hardouin-Lerouge, Stéphanie Legoupy, Olivier Alévêque, Eric Levillain y Piétrick Hudhomme. "Glycoluril–tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests". Beilstein Journal of Organic Chemistry 11 (17 de junio de 2015): 1023–36. http://dx.doi.org/10.3762/bjoc.11.115.

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Glycoluril-based molecular clips incorporating tetrathiafulvalene (TTF) sidewalls have been synthesized through different strategies with the aim of investigating the effect of electrochemical and spatial properties for binding neutral accepting guests. We have in particular focused our study on the spacer extension in order to tune the intramolecular TTF···TTF distance within the clip and, consequently, the redox behavior of the receptor. Carried out at different concentrations in solution, electrochemical and spectroelectrochemical experiments provide evidence of mixed-valence and/or π-dimer intermolecular interactions between TTF units from two closed clips. The stepwise oxidation of each molecular clip involves an electrochemical mechanism with three one-electron processes and two charge-coupled chemical reactions, a scheme which is supported by electrochemical simulations. The fine-tunable π-donating ability of the TTF units and the cavity size allow to control binding interaction towards a strong electron acceptor such as tetrafluorotetracyanoquinodimethane (F4-TCNQ) or a weaker electron acceptor such as 1,3-dinitrobenzene (m-DNB).

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33

Noor, Awal. "Crystallographic Evidence of η1-Coordination of Bulky Aminopyridine in Halide-Containing Iron (II) Complexes". Crystals 12, n.º 5 (14 de mayo de 2022): 697. http://dx.doi.org/10.3390/cryst12050697.

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Reaction of N-(2,6-diisopropylphenyl)-[6-(2,4,6-triisopropylphenyl)-pyridine-2-yl]-amine (ApH) in equimolar ratio with anhydrous FeBr2 and FeI2 in tetrahydrofuran (THF) afforded, after workup in toluene, the first examples of mono(aminopyridine) Fe(II) complexes, [ApHFeBr(µ-Br)]2 (1) and [ApHFeI2(thf)] (2), respectively. X-ray analysis shows 1 to be dimeric, whereas compound 2 is monomeric. In both cases, aminopyridine ligands show rare η1-coordination to Fe through pyridine nitrogen atom. Compound 1 exhibits intramolecular N–H⋯Br hydrogen bonds [3.363 Å] with an N–H⋯Br angle of 158.84°. Hirshfeld surface and fingerprint plots identify the significant intermolecular interactions in the crystal network. Both compounds crystallized in the monoclinic space group. For compound 1, C2/c, the cell parameters are: a = 25.5750(5) Å, b = 10.5150(5) Å, c = 18.9610(8) Å, β = 97.892(5)°, V = 5050.7(3) A3, Z = 4. For compound 2, P21/c, the cell parameters are: a = 10.3180(7) Å, b = 16.1080(10) Å, c = 18.6580(11) Å, β = 102.038(5)°, V = 3032.8(3) A3, Z = 4.

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34

Sharma, Ruchika, Sandeep Ashok Sankpal, Pradeep Jangonda Patil, Saminathan Murugavel, Sonachalam Sundramoorthy y Rajni Kant. "Synthesis, X-ray crystal structure, DFT, Hirshfeld surfaces, energy frameworks, and molecular docking analysis of a bicyclic ortho-aminocarbonitrile derivative". European Journal of Chemistry 13, n.º 2 (30 de junio de 2022): 135–44. http://dx.doi.org/10.5155/eurjchem.13.2.135-144.2225.

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2-Amino-4-(2, 5-dimethoxyphenyl)-4a,5,6,7-tetrahydronaphthalene-1,3,3(4H)-tricarbonitrile has been synthesized and characterized by conventional spectroscopic techniques (FT-IR and 1H NMR) and the three-dimensional structure elucidated by single crystal X-ray diffraction studies (SC-XRD). It exists in monoclinic crystal system with space group P21/c and lattice parameters: a = 14.641(13) Å, b = 8.653(4) Å, c = 16.609(10) Å, β = 116.34(3)°, and Z = 4. In the crystal packing, molecules are connected through N-H···O and N-H···N intermolecular and intramolecular C-H···O interactions. The N1-H11···N2 interaction results in the formation of a dimer corresponding to R22(12) graph-set motif. The molecular structure has been theoretically optimized by using density functional theory (DFT) with the basis set B3LYP/6-311G (d,p). The optimized bond geometry shows consistency with the SC-XRD data. Besides this, the molecular electrostatic potential (MEP), Mulliken charges, and frontier molecular orbital analysis have been described. The dnorm, shape index, curvedness, crystal voids, 2D fingerprint (FP) plots, and 3D energy frameworks using Hirshfeld surface (HS) studies have also been computed and investigated. The molecular docking studies for 2-amino-4-(2, 5-dimethoxyphenyl)-4a,5,6,7-tetrahydronaphthalene-1,3,3(4H)-tricarbonitrile with DNA gyrase/lanosterol 14α-demethylase suggest that the compound may act as an active antimicrobial drug.

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35

Murthy, T. N. Sanjeeva, Zeliha Atioğlu, Mehmet Akkurt, M. K. Veeraiah, Ching Kheng Quah, C. S. Chidan Kumar y B. P. Siddaraju. "Crystal structure and Hirshfeld surface analysis of (E)-3-(2-chlorophenyl)-1-(2,5-dichlorothiophen-3-yl)prop-2-en-1-one". Acta Crystallographica Section E Crystallographic Communications 75, n.º 2 (4 de enero de 2019): 124–28. http://dx.doi.org/10.1107/s2056989018018066.

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The molecular structure of the title compound, C13H7Cl3OS, consists of a 2,5- dichlorothiophene ring and a 2-chlorophenyl ring linked via a prop-2-en-1-one spacer. The dihedral angle between the 2,5-dichlorothiophene and 2-chlorophenyl rings is 9.69 (12)°. The molecule has an E configuration about the C=C bond and the carbonyl group is syn with respect to the C=C bond. The molecular conformation is stabilized by two intramolecular C—H...Cl contacts and one intramolecular C—H...O contact, forming S(5)S(5)S(6) ring motifs. In the crystal, the molecules are linked along the a-axis direction through van der Waals forces and along the b axis by face-to-face π-stacking between the thiophene rings and between the benzene rings of neighbouring molecules, forming corrugated sheets lying parallel to the bc plane. The intermolecular interactions in the crystal packing were further analysed using Hirshfield surface analysis, which indicates that the most significant contacts are Cl...H/ H...Cl (28.6%), followed by C...H/H...C (11.9%), C...C (11.1%), H...H (11.0%), Cl...Cl (8.1%), O...H/H...O (8.0%) and S...H/H...S (6.6%).

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Burlov, Anatoliy S., Valery G. Vlasenko, Pavel V. Dorovatovskii, Yan V. Zubavichus y Victor N. Khrustalev. "Crystal structure of bis{1-phenyl-3-methyl-4-[(quinolin-3-yl)iminomethyl-κN]-1H-pyrazol-5-olato-κO}zinc methanol 2.5-solvate from synchrotron X-ray diffraction". Acta Crystallographica Section E Crystallographic Communications 73, n.º 8 (18 de julio de 2017): 1208–12. http://dx.doi.org/10.1107/s2056989017010441.

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The title compound, [Zn(C20H15N4O)2]·2.5CH3OH, I, was synthesized via the reaction of zinc acetate with the respective ligand and isolated as a methanol solvate, i.e., as I·2.5CH3OH. The crystal structure is triclinic (space group P-1), with two complex molecules ( A and B ) and five methanol solvent molecules in the asymmetric unit. One of the five methanol solvent molecules is disordered over two sets of sites, with an occupancy ratio of 0.75:0.25. Molecules A and B are conformers and distinguished by the conformations of the bidentate 1-phenyl-3-methyl-4-[(quinolin-3-yl)iminomethyl]-1H-pyrazol-5-olate ligands. In both molecules, the zinc cations have distorted tetrahedral coordination spheres, binding the monoanionic ligands through the pyrazololate O and imine N atoms. The two ligands adopt slightly different conformations in terms of the orientation of the terminal phenyl and quinoline substituents with respect to the central pyrazololate moiety. The molecular geometries of A and B are supported by intramolecular C—H...O and C—H...N hydrogen bonds. In the crystal of I, molecules form dimers both by secondary intermolecular Zn...O [3.140 (2)–3.553 (3) Å] and π–π stacking interactions. The dimers are linked by intermolecular hydrogen bonds through the solvent methanol molecules into a three-dimensional network.

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37

Minyaev, Mikhail E., Ilya E. Nifant'ev, Alexander N. Tavtorkin, Sof'ya A. Korchagina, Shadana Sh Zeynalova, Ivan V. Ananyev y Andrei V. Churakov. "Isomorphous rare-earth bis[bis(2,6-diisopropylphenyl)phosphate] complexes and their self-assembly into two-dimensional frameworks by intramolecular hydrogen bonds". Acta Crystallographica Section C Structural Chemistry 73, n.º 10 (29 de septiembre de 2017): 820–27. http://dx.doi.org/10.1107/s2053229617012979.

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The crystal structures of rare-earth diaryl- or dialkylphosphate derivatives are poorly explored. Crystals of bis[bis(2,6-diisopropylphenyl)phosphato-κO]chloridotetrakis(methanol-κO)neodymium methanol disolvate, [Nd(C24H34O4P)Cl(CH4O)4]·2CH3OH, (1), and of the lutetium, [Lu(C24H34O4P)Cl(CH4O)4]·2CH3OH, (2), and yttrium, [Y(C24H34O4P)Cl(CH4O)4]·2CH3OH, (3), analogues have been obtained by reactions between lithium bis(2,6-diisopropylphenyl)phosphate and LnCl3(H2O)6 (in a 2:1 ratio) in methanol. Compounds (1)–(3) crystallize in the C2/c space group. Their crystal structures are isomorphous. The molecule possesses C 2 symmetry with a twofold crystallographic axis passing through the Ln and Cl atoms. The bis(2,6-diisopropylphenyl)phosphate ligands all display a κ1 O-monodentate coordination mode. The coordination polyhedron for the metal atom [coordination number (CN) = 7] is a distorted pentagonal bipyramid. Each [Ln{O2P(O-2,6-iPr2C6H3)2}2Cl(CH3OH)4] molecular unit exhibits two intramolecular O—H...O hydrogen bonds, forming six-membered rings, and two intramolecular O—H...Cl interactions, forming four-membered rings. Intermolecular O—H...O hydrogen bonds connect each unit via four noncoordinating methanol molecules with four other units, forming a two-dimensional hydrogen-bond network. Crystals of bis[bis(2,6-diisopropylphenyl)phosphato-κO]tetrakis(methanol-κO)(nitrato-κ2 O,O′)neodymium methanol disolvate, [Nd(C24H34O4P)(NO3)(CH4O)4]·2CH3OH, (4), have been obtained in an analogous manner from NdCl3(H2O)6. Compound (4) also crystalizes in the C2/c space group. Its crystal structure is similar to those of (1)–(3). The κ2 O,O′-bidentate nitrate anion is disordered over a twofold axis, being located nearly on it. Half of the molecule is crystallographically unique (CNNd = 8). Unlike (1)–(3), complex (4) exhibits disorder of all three methanol molecules, one isopropyl group of the phosphate ligand and the NO3 − ligand. The structure of (4) displays intra- and intermolecular O—H...O hydrogen bonds similar to those in (1)–(3). Compounds (1)–(4) represent the first reported mononuclear bis[bis(diaryl/dialkyl)phosphate] rare-earth complexes.

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38

Nishide, Kiyoharu, Yuri Hagimoto, Hiroaki Hasegawa, Motoo Shiro y Manabu Node. "ChemInform Abstract: A Novel Intramolecular Through-Space Interaction Between F and CN: A Strategy for the Conformational Control of an Acyclic System." ChemInform 33, n.º 9 (22 de mayo de 2010): no. http://dx.doi.org/10.1002/chin.200209028.

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Fall, Serigne Abdou Khadir, Sara Hajib, Younas Aouine, Rachid Ouarsal, Anouar Alami, Mohamed El Omari, Abderrazzak Assani, Mohamed Saadi y Lahcen El Ammari. "X-ray Structure Determination of Naphthalen-2-yl 1-(Benzamido(diethoxyphosphoryl)methyl)-1H-1,2,3-triazole-4-carboxylate". Molbank 2022, n.º 2 (10 de mayo de 2022): M1360. http://dx.doi.org/10.3390/m1360.

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We have previously published on a new triazolic phosphonic α-amino ester in position 4 on the triazole ring of a naphthalene ester. The aim of the present paper was to describe its crystallographic study by XRD. The crystal structure of naphthalen-2-yl 1-(benzamido(diethoxyphosphoryl)methyl)-1H-1,2,3-triazole-4-carboxylate was determined by single-crystal X-ray diffraction. This compound crystallizes in the monoclinic system, space group P21/c. The naphthalene system is almost planar and makes dihedral angles of 67.1(2)° and 63.9(2)° with the triazole ring and the phenyl cycle, respectively. The phosphorus atom is surrounded by three oxygen atoms and one carbon atom building a distorted tetrahedron. It is also noted, that one of the two ethyl groups is disordered. In the crystal, the molecules are connected through C-H…O and N-H…O hydrogen bonds to build dimers that are linked together by C-H…O hydrogen bonds, in addition to C-H…π interactions. The presence of an intramolecular hydrogen bond contributes to the stability of the molecular conformation by completing the S(5) cycle.

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40

Cheng, Jin-Feng, Ze-Hui Pan, Kai Zhang, Yue Zhao, Chuan-Kui Wang, Lei Ding, Man-Keung Fung y Jian Fan. "Interrupted intramolecular donor-acceptor interaction compensated by strong through-space electronic coupling for highly efficient near-infrared TADF with emission over 800 nm". Chemical Engineering Journal 430 (febrero de 2022): 132744. http://dx.doi.org/10.1016/j.cej.2021.132744.

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41

H Gurlhosur, Dr Shrikrishna. "Investigating the Structural and Electronic Characteristics of a Novel Hybrid Material: Single Crystal Analysis and DFT Studies of a Compound Based on 2-Hydroxypyridine and Selenic Acid." INTERNATIONAL RESEARCH JOURNAL OF ENGINEERING & APPLIED SCIENCES 9, n.º 1 (31 de marzo de 2021): 38–42. http://dx.doi.org/10.55083/irjeas.2021.v09i01007.

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A novel hybrid material, denoted as [(2-OH-pyH+)]2SeO4, has been skillfully synthesized using a precise slow evaporation technique, showcasing crystalline attributes within the monoclinic system. The compound adopts the centrosymmetric space group C2/c, revealing distinctive structural features. Comprehensive investigations into the molecular structure, vibrational spectra, and optical properties of [(2-OH-pyH+)]2SeO4 have been conducted through theoretical studies at the B3LYP/6–31 + G* level, providing valuable insights. This study significantly advances our understanding of the material’s properties and explores potential applications. The synthesis of [(2-OH-pyH+)]2SeO4 is accompanied by a multifaceted theoretical approach, including TD-DFT calculations to simulate the HOMO and LUMO, determining the frontier orbital gap, and computing the UV–visible spectrum in the gas phase. These computational insights establish a crucial link between experimental and theoretical realms, offering a holistic comprehension of the material’s electronic properties. The investigation further delves into intermolecular and intramolecular charge interactions through Natural Bond Orbital (NBO) analysis, unraveling the compound’s bonding nature. Molecular Electrostatic Potential (MEP) calculations contribute to the research, shedding light on the charge distribution and electrostatic features of [(2-OH-pyH+)]2SeO4. This comprehensive research not only successfully synthesizes and characterizes the novel hybrid material but also provides a detailed exploration of its electronic and optical properties through a synergistic combination of experimental and computational approaches, opening potential applications in diverse fields such as catalysis and materials science.

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42

Asciutto, Eliana K., Timothy Gaborek y Jeffry D. Madura. "Sodium versus potassium effects on the glutamic acid side-chains interaction on a heptapeptide". Journal of Theoretical and Computational Chemistry 13, n.º 03 (mayo de 2014): 1440004. http://dx.doi.org/10.1142/s0219633614400045.

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Equilibrium peptide conformations in solution, especially in the presence of salts, has been of interest for several decades. The fundamental interactions that determine the dominant peptide conformations in solution have been experimentally and computationally probed; however, a unified understanding has not yet emerged. In a previous study, we performed metadynamics simulations on the heptapeptide AEAAAEA in Sodium Chloride ( NaCl ) and Potassium Chloride ( KCl ) solutions at concentrations ranging from 0.5–2.0 M. Using a three-dimensional collective variable coordinate system, we computed the free energy landscapes in each saline environment as well as in pure water. We found that the presence of Na + and K + ions induces some changes in the stability of the conformers that define the state space, but does not alter the overall energetics between conformers and does not favor helical conformations. We investigate here, how the presence of salts ( NaCl and KCl ) affects the glutamic–glutamic interaction and its consequences on the stability of each equilibrium conformation. We perform this study through fixed backbone simulations for the most populated conformations identified in our previous work: the α-helix, 310-helix, π-helix, the extended polyproline II (PPII) and 2.51-helix conformations. It was found that for each conformation, there exists stable substates determined by the glutamic acid side-chains distance and orientation, and that Na + and K + cations (de)stabilize preferentially each conformation. It was also found that intramolecular single water mediated hydrogen bonds play a crucial role in the observed (de) stabilization of each equilibrium conformation.

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43

Xie, Wendi, Junwen Deng, Yunhao Bai, Jinsheng Xiao y Huiliang Wang. "Hydrogen-Bonding-Driven Nontraditional Photoluminescence of a β-Enamino Ester". Molecules 28, n.º 16 (8 de agosto de 2023): 5950. http://dx.doi.org/10.3390/molecules28165950.

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Nontraditional luminogens (NTLs) do not contain any conventional chromophores (large π-conjugated structures), but they do show intrinsic photoluminescence. To achieve photoluminescence from NTLs, it is necessary to increase the extent of through-space conjugation (TSC) and suppress nonradiative decay. Incorporating strong physical interactions such as hydrogen bonding is an effective strategy to achieve this. In this work, we carried out comparative studies on the photoluminescence behaviors of two β-enamino esters with similar chemical structures, namely methyl 3-aminocrotonate (MAC) and methyl (E)-3-(1-pyrrolidinyl)-2-butenoate (MPB). MAC crystal emits blue fluorescence under UV irradiation. The critical cluster concentration of MAC in ethanol solutions was determined by studying the relationship between the photoluminescence intensity (UV–visible absorbance) and concentration. Furthermore, MAC exhibits solvatochromism, and its emission wavelength redshifts as the solvent polarity increases. On the contrary, MPB is non-emissive in both solid state and solutions. Crystal structures and theoretical calculation prove that strong inter- and intramolecular hydrogen bonds lead to the formation of large amounts of TSC of MAC molecules in aggregated states. No hydrogen bonds and thus no effective TSC can be formed between or within MPB molecules, and this is the reason for its non-emissive nature. This work provides a deeper understanding of how hydrogen bonding contributes to the luminescence of NTLs.

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Curran, Sean P., Danielle Leuenberger, Einhard Schmidt y Carla M. Koehler. "The role of the Tim8p–Tim13p complex in a conserved import pathway for mitochondrial polytopic inner membrane proteins". Journal of Cell Biology 158, n.º 6 (9 de septiembre de 2002): 1017–27. http://dx.doi.org/10.1083/jcb.200205124.

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Tim23p is imported via the TIM (translocase of inner membrane)22 pathway for mitochondrial inner membrane proteins. In contrast to precursors with an NH2-terminal targeting presequence that are imported in a linear NH2-terminal manner, we show that Tim23p crosses the outer membrane as a loop before inserting into the inner membrane. The Tim8p–Tim13p complex facilitates translocation across the intermembrane space by binding to the membrane spanning domains as shown by Tim23p peptide scans with the purified Tim8p–Tim13p complex and crosslinking studies with Tim23p fusion constructs. The interaction between Tim23p and the Tim8p–Tim13p complex is not dependent on zinc, and the purified Tim8p–Tim13p complex does not coordinate zinc in the conserved twin CX3C motif. Instead, the cysteine residues seemingly form intramolecular disulfide linkages. Given that proteins of the mitochondrial carrier family also pass through the TOM (translocase of outer membrane) complex as a loop, our study suggests that this translocation mechanism may be conserved. Thus, polytopic inner membrane proteins, which lack an NH2-terminal targeting sequence, pass through the TOM complex as a loop followed by binding of the small Tim proteins to the hydrophobic membrane spanning domains.

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Parrish, Jonathan C., J. Guy Guillemette y Carmichael JA Wallace. "A tale of two charges: Distinct roles for an acidic and a basic amino acid in the structure and function of cytochrome c". Biochemistry and Cell Biology 79, n.º 1 (1 de enero de 2001): 83–91. http://dx.doi.org/10.1139/o00-083.

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Cytochrome c is a small electron transport protein found in the intermembrane space of mitochondria. As it interacts with a number of different physiological partners in a specific fashion, its structure varies little over eukaryotic evolutionary history. Two highly conserved residues found within its sequence are those at positions 13 and 90 (numbering is based on the standard horse cytochrome c); with single exceptions, residue 13 is either Lys or Arg, and residue 90 is either Glu or Asp. There have been conflicting views on the roles to be ascribed to these residues, particularly residue 13, so the functional properties of a number of site-directed mutants of Saccaromyces cerevisiae iso-1 cytochrome c have been examined. Results indicate that the two residues do not interact specifically with each other; however, residue 13 (Arg) is likely to be involved in interactions between cytochrome c and other electro statically oriented physiological partners (intermolecular), whereas residue 90 (Asp) is involved in maintaining the intrinsic structure and stability of cytochrome c (intramolecular). This is supported by molecular dynamics simulations carried out for these mutants where removal of the negative charge at position 90 leads to significant shifts in the conformations of neighboring residues, particularly lysine 86. Both charged residues appear to exert their effects through electrostatics; however, biological activity is significantly more sensitive to substitutions of residue 13 than of residue 90.Key words: cytochrome c, structure-function studies, molecular modelling, surface electrostatics.

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46

Murthy, T. N. Sanjeeva, Zeliha Atioğlu, Mehmet Akkurt, C. S. Chidan Kumar, M. K. Veeraiah, Ching Kheng Quah y B. P. Siddaraju. "Crystal structure and Hirshfeld surface analysis of (2E)-3-(2,4-dichlorophenyl)-1-(2,5-dichlorothiophen-3-yl)prop-2-en-1-one". Acta Crystallographica Section E Crystallographic Communications 74, n.º 9 (10 de agosto de 2018): 1201–5. http://dx.doi.org/10.1107/s2056989018010976.

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The molecular structure of the title compound, C13H6Cl4OS, consists of a 2,5-dichlorothiophene ring and a 2,4-dichlorophenyl ring linked via a prop-2-en-1-one spacer. The dihedral angle between the 2,5-dichlorothiophene ring and the 2,4-dichlorophenyl ring is 12.24 (15)°. The molecule has an E configuration about the C=C bond and the carbonyl group is syn with respect to the C=C bond. The molecular conformation is stabilized by intramolecular C—H...Cl contacts, producing S(6) and S(5) ring motifs. In the crystal, the molecules are linked along the a-axis direction through face-to-face π-stacking between the thiophene rings and the benzene rings of the molecules in zigzag sheets lying parallel to the bc plane along the c axis. The intermolecular interactions in the crystal packing were further analysed using Hirshfield surface analysis, which indicates that the most significant contacts are Cl...H/ H...Cl (20.8%), followed by Cl...Cl (18.7%), C...C (11.9%), Cl...S/S...Cl (10.9%), H...H (10.1%), C...H/H...C (9.3%) and O...H/H...O (7.6%).

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47

Taylor, Laurence J., Emma E. Lawson, David B. Cordes, Kasun S. Athukorala Arachchige, Alexandra M. Z. Slawin, Brian A. Chalmers y Petr Kilian. "Synthesis and Structural Studies of peri-Substituted Acenaphthenes with Tertiary Phosphine and Stibine Groups". Molecules 29, n.º 8 (18 de abril de 2024): 1841. http://dx.doi.org/10.3390/molecules29081841.

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Two mixed peri-substituted phosphine-chlorostibines, Acenap(PiPr2)(SbPhCl) and Acenap(PiPr2)(SbCl2) (Acenap = acenaphthene-5,6-diyl) reacted cleanly with Grignard reagents or nBuLi to give the corresponding tertiary phosphine-stibines Acenap(PiPr2)(SbRR’) (R, R’ = Me, iPr, nBu, Ph). In addition, the Pt(II) complex of the tertiary phosphine-stibine Acenap(PiPr2)(SbPh2) as well as the Mo(0) complex of Acenap(PiPr2)(SbMePh) were synthesised and characterised. Two of the phosphine-stibines and the two metal complexes were characterised by single-crystal X-ray diffraction. The peri-substituted species act as bidentate ligands through both P and Sb atoms, forming rather short Sb-metal bonds. The tertiary phosphine-stibines display through-space J(CP) couplings between the phosphorus atom and carbon atoms bonded directly to the Sb atom of up to 40 Hz. The sequestration of the P and Sb lone pairs results in much smaller corresponding J(CP) being observed in the metal complexes. QTAIM (Quantum Theory of Atoms in Molecules) and EDA-NOCV (Energy Decomposition Analysis employing Naturalised Orbitals for Chemical Valence) computational techniques were used to provide additional insight into a weak n(P)→σ*(Sb-C) intramolecular bonding interaction (pnictogen bond) in the phosphine-stibines.

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48

Shen, Tanxiao, Nan Jiang, Xiao’a Zhang, Lirong He, Xian Hua Lang, Jing Zhi Sun y Hui Zhao. "Pyrene-Functionalized Polyacetylenes: Synthesis and Photoluminescence Property". Polymers 11, n.º 8 (19 de agosto de 2019): 1366. http://dx.doi.org/10.3390/polym11081366.

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Four pyrene-functionalized polyacetylenes were designed and prepared through a typical post-polymerization modification route, which is the highly efficient reaction between activated ester and primary anime groups. The chemical structures of the resultant polymers were characterized with multiple spectroscopic techniques and the data indicated the successful functionalization of the polyacetylenes. The introduction of the pyrene moieties into the polymer structure allowed us to investigate the interactions between the polymer backbone and side chains. For the mono-substituted polyacetylenes, both the monomer and excimer emission features of the pyrene groups could be recorded, while for the di-substituted polyacetylenes, the fluorescence from the pyrene excimer vanished and the fluorescence intensity from the pyrene monomer decreased, the fluorescence from the polymer chain predominated the emission features. The concomitant energy transfer from the pyrene monomer and excimer to poly(diphenylacetylene) backbone was associated with the underlying mechanism. In addition to the substitution modes, the linkage between the poly(diphenylacetylene) backbone and the pyrene moiety also played a significant role in the determination of the emission species. A long alkyl spacer was beneficial to the pyrene monomer emission while a short one may be helpful to the formation of the excimer and intramolecular energy transfer.

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49

Zhao, Tingting, Nischal Karki, Brian D. Zoltowski y Devin A. Matthews. "Allosteric regulation in STAT3 interdomains is mediated by a rigid core: SH2 domain regulation by CCD in D170A variant". PLOS Computational Biology 18, n.º 12 (21 de diciembre de 2022): e1010794. http://dx.doi.org/10.1371/journal.pcbi.1010794.

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Signal Transducer and Activator of Transcription 3 (STAT3) plays a crucial role in cancer development and thus is a viable target for cancer treatment. STAT3 functions as a dimer mediated by phosphorylation of the SRC-homology 2 (SH2) domain, a key target for therapeutic drugs. While great efforts have been employed towards the development of compounds that directly target the SH2 domain, no compound has yet been approved by the FDA due to a lack of specificity and pharmacologic efficacy. Studies have shown that allosteric regulation of SH2 via the coiled-coil domain (CCD) is an alternative drug design strategy. Several CCD effectors have been shown to modulate SH2 binding and affinity, and at the time of writing at least one drug candidate has entered phase I clinical trials. However, the mechanism for SH2 regulation via CCD is poorly understood. Here, we investigate structural and dynamic features of STAT3 and compare the wild type to the reduced function variant D170A in order to delineate mechanistic differences and propose allosteric pathways. Molecular dynamics simulations were employed to explore conformational space of STAT3 and the variant, followed by structural, conformation, and dynamic analysis. The trajectories explored show distinctive conformational changes in the SH2 domain for the D170A variant, indicating long range allosteric effects. Multiple analyses provide evidence for long range communication pathways between the two STAT3 domains, which seem to be mediated by a rigid core which connects the CCD and SH2 domains via the linker domain (LD) and transmits conformational changes through a network of short-range interactions. The proposed allosteric mechanism provides new insight into the understanding of intramolecular signaling in STAT3 and potential pharmaceutical control of STAT3 specificity and activity.

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50

Wang, Li-Hua, Mohammad Azam, Xi-Hai Yan y Xi-Shi Tai. "Synthesis, Structural Characterization, and Hirschfeld Surface Analysis of a New Cu(II) Complex and Its Role in Photocatalytic CO2 Reduction". Molecules 29, n.º 9 (24 de abril de 2024): 1957. http://dx.doi.org/10.3390/molecules29091957.

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A new Cu(II) complex, [CuL1L2(CH3COO)2(H2O)]·H2O, was synthesized by the reaction of Cu(CH3COO)2·H2O, 6-phenylpyridine-2-carboxylic acid (HL1), and 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine (L2) in ethanol-water (v:v = 1:1) solution. The Cu(II) complex was characterized using elemental analysis, IR, UV-vis, TG–DTA, and single-crystal X-ray analysis. The fluorescence properties of the copper complex were also evaluated. The structural analysis results show that the Cu(II) complex crystallizes in the triclinic system with space group P-1. The Cu(II) ion in the complex is five-coordinated with one O atom (O2) and one N atom (N1) from one 6-phenylpyridine-2-carboxylate ligand (L1), one N atom (N2) from 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine ligand (L2), one O atom (O4) from acetate, and one O atom (O5) from a coordinated water molecule, and it adopts a distorted trigonal bipyramidal geometry. Cu(II) complex molecules form a two-dimensional layer structure through intramolecular and intermolecular O-H…O hydrogen bonding. The two-dimensional layer structures further form a three-dimensional network structure by π-π stacking interactions of aromatic rings. The analysis of the Hirschfeld surface of the Cu(II) complex shows that the H…H contacts made the most significant contribution (46.6%) to the Hirschfeld surface, followed by O…H/H…O, N…H/H…N and C…H/H…C contacts with contributions of 14.2%, 13.8%, and 10.2%, respectively. In addition, the photocatalytic CO2 reduction using Cu(II) complex as a catalyst is investigated under UV-vis light irradiation. The findings reveal that the main product is CO, with a yield of 10.34 μmol/g and a selectivity of 89.4% after three hours.

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