Готові списки джерел за темами / Crystal Engineering - Ligand Molecules

Добірка наукової літератури з теми "Crystal Engineering - Ligand Molecules"

Автор: Grafiati
Опубліковано: 7 вересня 2023

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Статті в журналах з теми "Crystal Engineering - Ligand Molecules"

1

Chopra, Deepak, and Dhananjay Dey. "Computational approaches towards crystal engineering in molecular crystals." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C642. http://dx.doi.org/10.1107/s2053273314093577.

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Анотація:
The investigation of a large number of crystal structures has resulted in the development of the area of crystal engineering, which involves the study of intermolecular interactions in crystalline solids [1]. It is now of importance to understand the nature and energetics associated with different interactions [2] which influence the crystal packing. In this regard, different computational approaches (utilizing PIXEL and TURBOMOLE) have been developed which aid in the understanding of intra- and intermolecular interactions (for example, hydrogen and halogen bonding) in molecular crystals. This approach has been successfully applied in different classes of molecules [3]. These approaches can be combined with topological analysis of the electron density using the quantum theory of atoms in molecules (QTAIM) (in absence of high quality crystals for experimental electron density studies). In order to validate the above-mentioned methodology, we have performed a comprehensive analysis of a series of synthesized fluoro-derivatives of N'-phenylbenzimidamide to gain quantitative insights into different interactions which accompany crystal formation. The packing of the molecules has contributions from strong N-H...N, weak N-H...π [Fig 1], C-H...N, C-H...F, and C-H...π intermolecular interactions along with π-π stacking. In addition to that, ubiquitous H...H contacts are also present in the solid state. This methodology can be extended to include cocrystals, polymorphs (including solvates) and protein-ligand interactions at the active site.
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2

Guo, Yanmei, Yunhui Hao, Lei Gao, and Hongxun Hao. "Photomechanical Molecular Crystals of an Azopyridine Derivative and Its Zinc(II) Complex: Synthesis, Crystallization and Photoinduced Motion." Crystals 10, no. 2 (February 6, 2020): 92. http://dx.doi.org/10.3390/cryst10020092.

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Анотація:
In this work, photomechanical molecular crystals of 4-(4-(6-Hydroxyhexyloxy) phenylazo) pyridine (6cazpy) and its zinc(II) organic complex (complex-I) were synthesized and crystallized. DSC and TGA were used to characterize and compare properties of 6cazpy and its complex-I crystals. Photoinduced motions of 6cazpy crystals and its complex-I crystals were investigated and compared by UV/Vis irradiation. Bending away motions from the light source were observed from both 6cazpy crystals and its complex-I crystals. The bending away motion was attributed to the trans-to-cis photoisomerization of azopyridine derivatives in the crystalline phase. It is worth noting that the photomechanical properties of complex-I were enhanced by the formation of the ligand, which might be caused by the looser packing of molecules inside complex-I crystal. In addition, because of the existence of ligand, which combined two photoactive groups in each complex-I molecule, the isomerization reactions of these two photoactive groups in the molecules can increase the photomechanical movement ability of the crystal. It was also found that the crystal size and shape will affect the photoinduced movement of the crystals. PXRD and AFM were used to investigate the molecular mechanism and the surface topological change upon photoisomerization. The corresponding mechanism was proposed.
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3

Tai, Xi Shi, and Lin Tong Wang. "Synthesis, Fluorescence Properties of 2-Acetyl-2'-Chloroacetanilide with Rare Earth Nitrates Complexes." Advanced Materials Research 219-220 (March 2011): 574–77. http://dx.doi.org/10.4028/www.scientific.net/amr.219-220.574.

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Анотація:
The reaction of 2-acetyl-2'-chloroacetanilide (L) with rare earth nitrates in CH3CH2OH followed by recrystallization in CH3CH2OH gave rise to colorless block crystals materials. The complexes and ligand were analyzed by FAB, elemental analysis(C, H, N), FT-IR spectra, TG-DTA, molar conductivity and X-ray single crystal diffraction. The fluorescence properties of ligand and the Eu (Ⅲ) complex also have been investigated. The results of crystal structure and spectral data show that the rare earth ions coordinated with oxygen and nitrogen atoms of the ligand, the nitrate and coordinated water molecules. The Eu (Ⅲ) complex material shows characteristic red emissions.
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4

May, Nóra Veronika, Kevin Nys, H. Y. Vincent Ching, Laura Bereczki, Tamás Holczbauer, Valerio B. Di Marco та Petra Bombicz. "Crystal structures of zinc(II) complexes with β-hydroxypyridinecarboxylate ligands: examples of structure-directing effects used in inorganic crystal engineering". Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 77, № 2 (27 лютого 2021): 193–204. http://dx.doi.org/10.1107/s2052520621000299.

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Анотація:
The coordination properties of four hydroxypyridinecarboxylates, designed for the treatment of iron-overloading conditions as bidentate O,O′-donor ligands, have been studied with ZnII in the solid state. The coordination compounds [Zn(A1)2(H2O)2] (1), [Zn(A2)2(H2O)] (2), [Zn(A3)2(H2O)]·2H2O (3) and [Zn2(B1)4(H2O)2]·4H2O (4), where the ligands are 1-methyl-4-oxidopyridinium-3-carboxylate (A1, C7H6NO3), 1,6-dimethyl-4-oxidopyridinium-3-carboxylate (A2, C8H8NO3), 1,5-dimethyl-4-oxido-pyridinium-3-carboxylate (A3, C8H8NO3) and 1-methyl-3-oxidopyridinium-4-carboxylate (B1, C7H6NO3), have been synthesized and analysed by single-crystal X-ray diffraction. The ligands were chosen to probe (i) the electronic effects of inverting the positions of the O-atom donor groups (i.e. A1 versus B1) and (ii) the electronic and steric effects of the addition of a second methyl group in different positions on the pyridine ring. Two axially coordinated water molecules resulting in a six-coordinated symmetrical octahedron complement the bis-ligand complex of A1. Ligands A2 and A3 form five-coordinated trigonal bipyramidal complexes with one additional water molecule in the coordination sphere, which is a rarely reported geometry for ZnII complexes. Ligand B1 shows a dimeric structure, where the two Zn2+ dications have slightly distorted octahedral geometry and the pyridinolate O atom of the neighbouring complex bridges them. The coordination spheres of the Zn2+ dications and the supramolecular structures are discussed in detail. The packing arrangements of 1–3 are similar, having alternating hydrophilic and hydrophobic layers, however the similarity is broken in 4. The obtained coordination geometries are compared with their previously determined CuII analogues. The study of the individual complexes is complemented with a comprehensive analysis of ZnII complexes with oxygen donor ligands with data from the Cambridge Structural Database.
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5

Pinto, Camila B., Leonardo H. R. Dos Santos, and Bernardo L. Rodrigues. "Understanding metal–ligand interactions in coordination polymers using Hirshfeld surface analysis." Acta Crystallographica Section C Structural Chemistry 75, no. 6 (May 20, 2019): 707–16. http://dx.doi.org/10.1107/s2053229619005874.

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Анотація:
Properties related to the size and shape of Hirshfeld surfaces provide insight into the nature and strength of interactions among the building blocks of molecular crystals. In this work, we demonstrate that functions derived from the curvatures of the surface at a point, namely, shape index (S) and curvedness (C), as well as the distances from the surface to the nearest external (d e) and internal (d i) nuclei, can be used to help understand metal–ligand interactions in coordination polymers. The crystal structure of catena-poly[[[(1,10-phenanthroline-κ2 N,N′)copper(II)]-μ-4-nitrophthalato-κ2 O 1:O 2] trihydrate], {[Cu(C8H3NO6)(C12H8N2)]·3H2O} n , described here for the first time, was used as a prototypical system for our analysis. Decomposition of the coordination polymer into its metal centre and ligand molecules followed by joint analysis of the Hirshfeld surfaces generated for each part unveil qualitative and semi-quantitative information that cannot be easily obtained either from conventional crystal packing analysis or from Hirshfeld surface analysis of the entire polymeric units. The shape index function S is particularly sensitive to the coordination details and its mapping on the surface of the metallic centre is highly dependent on the nature of the ligand and the coordination bond distance. Correlations are established between the shape of the Hirshfeld surface of the metal and the geometry of the metal–ligand contacts in the crystals. This could be applied not only to estimate limiting coordination distances in metal–organic compounds, but also to help establish structure–property relationships potentially useful for the crystal engineering of such materials.
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6

Wang, Li Hua, and Peng Fei Li. "Synthesis, Structure, and Catalytic Activity of A New Mn(II) Complex with 1,4-Phenylenediacetic Acid and 1,10-Phenanthroline." Bulletin of Chemical Reaction Engineering & Catalysis 13, no. 1 (April 2, 2018): 1. http://dx.doi.org/10.9767/bcrec.13.1.975.1-6.

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Анотація:
A new Mn(II) complex material has been synthesized by one-pot reaction of Mn(CH3COO)2·4H2O, 1,4-phenylenediacetic (H2L), 1,10-phenanthroline (phen), and NaOH in water/ethanol (v:v = 1:1) solution. The structure of Mn(II) complex was determined by elemental analysis, FTIR, and X-ray single-crystal diffraction analysis. The results reveal that Mn(II) complex was constructed by a monodentate 1,4-phenylenediacetate ligand, two phen ligands, a coordinated water molecule, 0.5 uncoordinated 1,4-phenylenediacetate ligand and six uncoordinated water molecules. The complex molecules form 1D chain structure by the π-π interaction of phen molecules. The catalytic activity of Mn(II) complex for coupling of benzaldehyde, phenylacetylene and piperidine in 1,4-dioxane has also been investigated and the maximum yield of propargylamine is up to 72.2 % after 12 h at 120 oC. Copyright © 2017 BCREC Group. All rights reservedReceived: 5th March 2017; Revised: 7th June 2017; Accepted: 12nd July 207; Available online: 22nd January 2018; Published regularly: 2nd April 2018How to Cite: Wang, L.H., Li, P.F. (2018). Synthesis, Structure, and Catalytic Activity of A New Mn(II) Complex with 1,4-Phenylenediacetic Acid and 1,10-Phenanthroline. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1): 1-6 (doi:10.9767/bcrec.13.1.975.1-6)
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7

Chen, Xiao-Ming. "Crystal Engineering and Applications of Functional Metal-Organic Frameworks." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C16. http://dx.doi.org/10.1107/s2053273314099835.

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Анотація:
As a new kind of molecular materials composed of metal ions (or clusters) and organic bridging ligands that are interconnected by coordination bonds, porous metal-organic frameworks (MOFs) have many useful characteristics, such as high crystallinity, high porosity, structural diversity, designable frameworks, framework flexibility, as well as unique and modifiable organic pore surface. Therefore, they exhibit very promising potential applications in molecular adsorption/separation, catalysis, and sensors, etc. For example, they can be used for selective adsorption and separation of different gas molecules, such as CO2 and N2, capture of CO2 [2], sensing of small organic molecules and gas molecules, such as O2 and CO2, as well as catalysts and devices for solid-phase microextraction. In this presentation, the design and synthesis, unique pore surface, interesting functionalities will be presented by selected examples, in particular those of metal-azolate frameworks (MAFs) and a few devices useful for practical applications, from our group [1-3]. This work was supported by MoST (973 project) and NSFC.
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8

Peng, Yun-Dong, Ruo-Yu Li, Peng Li, and Yin-Xia Sun. "Insight into Rare Structurally Characterized Homotrinuclear CuII Non-Symmetric Salamo-Based Complex." Crystals 11, no. 2 (January 26, 2021): 113. http://dx.doi.org/10.3390/cryst11020113.

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Анотація:
A rare homotrinuclear CuII salamo-based complex [Cu3(L)2(μ-OAc)2(H2O)2]·2CHCl3·5H2O was prepared through the reaction of a non-symmetric salamo-based ligand H2L and Cu(OAc)2·H2O, and validated by elemental analyses, UV-Visible absorption, fluorescence and infrared spectra, molecular simulation and single-crystal X-ray analysis techniques. It is shown that three CuII atoms and two wholly deprotonated ligand (L)2− moieties form together a trinuclear 3:2 (M:L) complex with two coordination water molecules and two bi-dentate briging μ-acetate groups (μ-OAc−). Besides, the Hirshfeld surface analysis of the CuII complex was investigated. Compared with other ligands, the fluorescent strength of the CuII complex was evidently lowered, showing that the CuII ions possess fluorescent quenching effect.
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9

Bruno, John G. "Potential Use of Antifreeze DNA Aptamers for the Cryopreservation of Human Erythrocytes." Advanced Science, Engineering and Medicine 12, no. 7 (July 1, 2020): 870–74. http://dx.doi.org/10.1166/asem.2020.2628.

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Анотація:
This article summarizes proof of concept experiments which clearly demonstrated the ability of DNA aptamers selected against a molecular mimic of early ice crystal nuclei to protect the integrity of human erythrocytes following a slow freeze-thaw cycle. Following 10 cycles of selection and DNA amplification of rare candidate DNA aptamers against a copper-organic ligand complex which holds water molecules in a conformation resembling early ice crystal nuclei, the aptamers were tested for their ability to preserve erythrocyte morphology by phase-contrast microscopy versus controls without aptamers and with the original randomized aptamer DNA library template following slow freezing and storage overnight at -20 °C with slow thawing at 25 °C. Those experiments revealed that a minimum of 32 μg/ml of the final selected aptamer pool of DNA molecules was required to completely protect nearly 100% of the erythrocytes. By contrast, the treatment groups without the aptamers or with the randomized aptamer template DNA at 32 μg/ml produced only fragmented erythrocytes and cellular debris (no intact cells), thus indicating that specifically selected DNA conformations were required to bind and limit the size of forming ice crystals to cryoprotect the erythrocytes.
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10

Bakheit, Ahmed H., Mohamed W. Attwa, Adnan A. Kadi, Hazem A. Ghabbour, and Hamad M. Alkahtani. "Exploring the Chemical Reactivity, Molecular Docking, Molecular Dynamic Simulation and ADMET Properties of a Tetrahydrothienopyridine Derivative Using Computational Methods." Crystals 13, no. 7 (June 27, 2023): 1020. http://dx.doi.org/10.3390/cryst13071020.

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Анотація:
This study investigates the crystal structure, physicochemical properties, and pharmacokinetic profile of Ethyl 2-amino-6-methyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate (EAMT) as a potential therapeutic agent. The crystal structure was analyzed using Hirshfeld surface analysis in conjunction with the quantum theory of atoms in molecules (QT-AIM). Non-covalent interactions were evaluated through reduced-density gradient reduction, revealing that the EAMT crystal is stabilized by hydrogen bonds between EAMT molecules in the crystal and between EAMT molecules and water molecules. The molecular electrostatic nature of interactions was examined using MESP, while global and local descriptors were calculated to assess the compound’s reactivity. Molecular docking with the Adenosine A1 receptor was performed and validated through a 50 ns molecular dynamics simulation (MDS). Results suggest that EAMT influences protein structure, potentially stabilizing specific secondary structure elements. The compactness analysis showed a slightly more compact protein conformation and a marginally increased solvent exposure in the presence of the EAMT ligand, as indicated by Rg and SASA values. The total binding free energy (ΔG total) was determined to be −114.56 kcal/mol. ADMET predictions demonstrated EAMT’s compliance with Lipinski’s and Pfizer’s rule of five, indicating good oral availability. The compound may exhibit low-potency endocrine activity. In conclusion, EAMT presents potential as a therapeutic candidate, warranting further exploration of its molecular interactions, pharmacokinetics, and potential safety concerns.
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Більше джерел

Дисертації з теми "Crystal Engineering - Ligand Molecules"

1

Tahier, Tayyibah. "Crystal engineering of mixed-ligand metal-organic frameworks." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/22913.

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Анотація:
Research of solid state complexes has grown and developed exponentially over the past few years in terms of supramolecular chemistry and crystal engineering. The synthesis and characterisation of metal organic frameworks (MOFs) have attracted widespread attention owing to their potential in various applications. This includes gas sorption, which could aid in alleviating serious environmental issues such as global warming by sequestrating greenhouse gases. Advances in the design of these materials using the mixed ligand approach add to variation in structures and thus provide a further means of tailoring of properties. A novel two dimensional, mixed ligand MOF has been synthesised based on 1,3,5 benzenetricarboxylic acid, 4,4' bipyridine N,N' dioxide and zinc sulfate with the formula [Zn3(BTC)(4,4' bpdo)(OH)(SO4)(H2O)3]n·n(H2O)2.33 (1). The 2D layers of 1 arrange in a polar fashion with adjacent layers forming isolated cavities. Variable temperature powder X ray diffraction (VT PXRD) analysis showed that the crystallinity of the compound was retained and the crystalline phase remained unchanged as the temperature was increased. Variable temperature single crystal X ray diffraction (VT SCXRD) analysis of 1 revealed that the dehydration and rehydration processes occur via single crystal to single crystal transformations. Water vapour sorption experiments showed a type I isotherm, typical of microporous materials. A two dimensional, interpenetrated, mixed ligand MOF has been synthesised based on 5 nitro 1,3 benzenedicarboxylic acid, 1,2 bis(4 pyridyl)ethane and cadmium nitrate with the formula [Cd(bpe)1.5nbdc]·DMF (2). VT PXRD analysis shows subtle differences in the compound as the temperature is increased. VT SCXRD experiments show that the most notable change in the structure occurs at 373 K. These changes include the removal of the guest molecule and a change in the crystal system, along with changes in the orientation of the pyridyl ring of the organic ligand. Carbon dioxide sorption experiments at 195 K showed a type IV isotherm, which is usually associated with mesoporous materials. Both 1 and 2 were synthesised using the solvothermal method and fully characterised using X ray diffraction studies (SCXRD, PXRD, VT SCXRD and VT PXRD), thermal analysis (thermogravimetric, differential scanning calorimetry, hot stage microscopy), elemental analysis and FT IR spectroscopy. The porosity of the compounds was tested using carbon dioxide (273 K and 193 K), nitrogen, water vapour and liquid sorption experiments.
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2

Morales, Leslie Ann. "Crystal Engineering of Binary Compounds Containing Pharmaceutical Molecules." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000166.

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3

Mutti, Marcello. "Crystal engineering of mixed-ligand metal-organic frameworks based on simple carboxylate and bipyridyl ligands." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29726.

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Анотація:
Over the last few decades research in supramolecular chemistry and crystal engineering have seen an exponential growth. The synthesis of metal-organic frameworks (MOFs) has attracted much interest worldwide due to the possibility of obtaining a large variety of structures with a wide range of applications in fields pertaining to storage, separation and catalysis. This work focuses on the crystal engineering of MOFs based on mixed ligands which may ultimately be used in the gas storage of pollutants, greenhouse gases or fuel. Two novel 2D mixed-ligand MOFs, both based on manganese, 4,4’-bipyridine and 1,3,5- benzenetricarboxylic acid, have been prepared and fully characterized. The employment of dimethylformamide or dimethylacetamide, as the solvent, results in two isostructural MOFs. Another novel MOF, similar in structure to the previous two, with 5-nitroisophthalic acid instead of 1,3,5-benzenetricarboxylic acid has been also prepared and characterized. This MOF has the same metal and ligand combination as, and is largely isostructural to, a literature example, but differs in method of preparation and solvent content. These Mnbased MOFs have potential voids in the structure making them candidates for gas sorption experiments. A novel 2D mixed-ligand MOF based on cobalt, 4,4’-bipyridine and 5-nitroisophthalic acid has been synthesized and fully characterized. Its structure is the same of another MOF, based on manganese, present in this work and like its manganese analogue it exhibits potential void spaces in the framework that make it a candidate for gas sorption experiments. Finally, a novel 2D MOF based on 1,3,5-benzenetricarboxylic acid and cadmium bromide has been synthesized and fully characterized. Dehydration and rehydration studies performed by combining powder X-ray diffraction with thermogravimetric analysis show that it can lose coordinated water, that comes from the reaction solvent, upon heating, and reabsorb water from the atmosphere, ultimately regaining its original structure. All MOFs were synthesized via the solvothermal method and characterized with X-ray diffraction (single crystal and powder) and thermal analyses (hot stage microscopy, differential scanning calorimetry and thermogravimetric analysis).
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4

Ren, He. "Crystal Engineering of Giant Molecules Based on Perylene Diimide Conjugated Polyhedral Oligomeric Silsesquioxane Nano-Atom." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1461014185.

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5

Ghiasi, Zahra. "Development of a Computational Mechanism to Generate Molecules with Drug-likeCharacteristics." Ohio University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou162861276157897.

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6

Mehlana, Gift. "Crystal engineering of dynamic metal organic frameworks for applications in chromic sensing and capturing of small molecules." Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/13360.

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Анотація:
Includes bibliographical references.
Crystal engineering of metal organic frameworks (MOFs) has developed rapidly over the years. This has been fuelled by useful properties endowed by these materials. MOFs present a unique platform to control chemical and physical properties through manipulation of the components that construct these materials. In this thesis a series of MOFs prepared from 3-(4-pyridyl)benzoate or 4-(4-pyridyl)benzoate with Co(ll), Zn(ll) and Ni(ll) are presented. Most materials were synthesised under solvothermal conditions. The link between the phenyl and pyridyl ring in the ligand allows for conformational change through varying the dihedral angles between these two parts. The carboxylate moiety can also rotate relative to the phenyl ring and its ability to assume different coordination modes under different environments is of utmost importance in achieving flexibility for the design. Structural elucidation of compounds was performed by single crystal X-ray diffraction. Topological analysis was performed on the networks formed by the compounds to have a better understanding of the network connectivity. Bulk material was characterised by thermal methods such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), variable temperature powder X-ray diffraction (PXRD) studies and by hot stage microscopy (HSM). Thermochromic and solvatochromic properties of the activated phases were investigated by spectroscopic techniques. Dynamic motion of the networks upon guest loss and absorption by activated phases were evaluated by single crystal X-ray diffraction studies using Pawley fitting methods. Standard kinetic models were used to analyse the kinetics of guest uptake from isothermal experiments. Non-isothermal experiments were conducted using the TGA and the activation energies were determined for guest desolvation using the Ozawa and Flynn method.
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7

Liang, Wenlang. "Imaging long-range orientational order in monolayers of amphiphilic molecules with scanning probe force microscope and liquid crystal optical amplification." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6231.

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Анотація:
Monolayers of amphiphilic molecules at interface provide a unique system for understanding the thermodynamic and rheological properties of quasi two-dimensional systems. They are also an excellent model accessible for studying cell membranes. The feature of long-range organization of molecular tilt azimuth in monolayers at the air/water interface is one of the most interesting findings over the past two decades, which leads to the formation rich and defined textures. By observing the changes in these textures, the transitions between tilted monolayer phases can be detected. We study the boojum and stripe textures formed in the liquid-condensed phase of pentadecanoic acid (PDA) monolayers at the air/water interface and find that they can be preserved after being transferred to glass substrates at low dipping speeds at a temperature lower than the room temperature. Frictional force microscopy confirms the long-range tilt order in the transferred boojums and stripes of PDA, implying the interaction of the PDA molecules with the glass surface does not change the tilt order. Polymerized stripe textures of pentacosadiynoic acid (PCA) monolayers can also be transferred onto solid substrates. Atomic force microscopy shows that the PCA stripe textures represent the regular variations of molecular packing densities in PCA monolayers. Furthermore, we find that the molecular orientation and packing density changes in monolayers can induce the local order of nematic liquid crystals. Due to the long-range orientation correlation of nematic liquid crystals, the boojum and stripe textures in monolayers can be observed by an optical microscope after liquid crystal optical amplification.
M.S.M.S.E.
Masters
Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
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8

Gunawardana, Chamara Abeywickramasinghe. "Crystal engineering with coordination, hydrogen- and halogen-bonds, and the construction of porous solids." Diss., 2018. http://hdl.handle.net/2097/39092.

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Анотація:
Doctor of Philosophy
Department of Chemistry
Christer B. Aakeröy
A set of multifunctional molecules [isomeric forms of 1-(pyridylmethyl)-2,2'-biimidazole] was synthesized and subjected to systematic co-crystallizations with selected hydrogen- and halogen-bond donors in order to explore the impact of interaction type, geometry and electrostatics on the resulting supramolecular architectures. The structural outcome with hydrogen-bond donors (carboxylic acids) is somewhat unpredictable because of the presence of the acid···biimidazole heterosynthon that can compete with biimidazole···biimidazole homosynthon. In contrast, the solid-state supramolecular behavior of those probe molecules is largely unchanged in halogen-bonded co-crystals. Only two types of primary interactions, the two-point hydrogen bonds responsible for pairing biimidazole moieties, and the single-point halogen bonds responsible for the co-crystal formation and structure extension, are present in these systems. The results highlight that, by incorporating geometric biases along with orthogonal interactions, one can effectively prevent synthon crossover which is of paramount importance in complex crystal engineering endeavors. Heterobifunctional ligands pave the way for elaborate metallo-supramolecular systems, and are also useful for combining metal-ligand bonding with other types of non-covalent interactions. Nine new acetylacetonate ligands featuring either pyridyl- or thiophenyl-heterocycles were successfully prepared, and their metal binding abilities were studied with selected di- and tri-valent transition metal ions. As expected, the acetylacetonate ligation to metal dications remains consistent. In each case, the metal is four-coordinate and resides in a square planar environment. Differences in the overall architectures arise from the role played by the terminal heterocycles and the solvent. In seven (out of nine) structures, the heterocyclic end is involved in a structure-directing interaction and it is more prevalent in ligands bearing 4-pyridinyl unit. Divergent molecules containing bulky substituents tend to produce porous materials via frustrated packing. Two rigid tetrahedral cores, tetraphenylmethane and 1,3,5,7-tetraphenyladamantane, grafted peripherally with four (trimethylsilyl)ethynyl moieties were found to have only isolated voids in their crystal structures. Hence, they were modified into tecton-like entities, tetrakis(4-(iodoethynyl)phenyl)methane [I₄TEPM] and 1,3,5,7-tetrakis(4-(iodoethynyl)phenyl)adamantane [I₄TEPA], and the effect of motif-forming characteristics of iodoethynyl units on molecular arrangement and crystal porosity was analyzed. I₄TEPM not only holds increased free volume compared to its precursor, but also forms one-dimensional channels. Furthermore, it readily co-crystallizes with Lewis basic solvents to afford two-component porous materials even though they suffer from stability issues. As the binding sites in I₄TEPM and I₄TEPA are tetrahedrally-predisposed, they can be further utilized for the modular assembly of highly symmetric, three-dimensional extended architectures. With that in mind, these two building blocks were subsequently allowed to react with various halide salts, and it was found that the reactions between I₄TEPM and tetraphenylphosphonium halides readily yield four-fold interpenetrated diamondoid networks sustained by C–I⋯X⁻ (X⁻ = chloride, bromide, iodide) halogen-bonding interactions. The halide anions exhibit mutual-induced fitting of their coordination and act as four-connecting tetrahedral nodes, while the tetraphenylphosphonium cations render essential templating information and structural support.
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9

Kumar, Vineet. "Crystal engineering of multicomponent solids of pharmaceutically important molecules (Orotic acid, isoorotc acid,nsaids and sulfa drugs) with pyridine and aminopyridine based coformers." Thesis, 2018. http://localhost:8080/iit/handle/2074/7548.

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10

Gamekkanda, Gamaethige Janaka Chaminda. "Hydrogen- and halogen-bond driven supramolecular architectures from small molecules to cavitands, and applications in energetic materials." Diss., 2018. http://hdl.handle.net/2097/39133.

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Doctor of Philosophy
Department of Chemistry
Christer B. Aakeröy
A family of six β-diketone based ligands capable of simultaneously acting as halogen-bond (XB) donors (each of para and meta substituted chloro, bromo and iodo functionalities) and chelating ligands was synthesized. Four ligands were characterized by X-ray diffraction to identify the structural behavior of the ligand itself. The free ligands bearing bromine and iodine show XB interactions (C-X···O) whereas the ligand containing chlorine did not show XB interactions. The corresponding Cu(II) complexes for ligands were also synthesized in different solvents such as acetonitrile, ethyl acetate and nitromethane. Both acetonitrile and ethyl acetate participate in XB interactions with XB donors (Br or I) although nitromethane does not participate in such interaction. Metal-ligand complexes with iodine as XB donor in the para position engage in XB interactions to make extended supramolecular architecture when the solvent is nitromethane. When the XB donor attached in the meta position of the ligand, formation of extended supramolecular architecture was seen even in the presence of a strongly coordinating solvent such as acetonitrile. Two tetra functionalized molecules bearing hydrogen-bond (HB) donors (-OH) and XB donors (-C≡C-I) and one tetra functionalized molecule which has only HB donors (-OH and -C≡C-H) were synthesized. The donor molecules themselves show potential for making HB and XB interactions with the available acceptor sites present in the system. The competition between intermolecular HB and XB was explored by co-crystallizing with suitable nitrogen based acceptors. HB and XB donors showed equal competitiveness toward common acceptors when making HB/ XB interactions. Furthermore, the geometry and relative positioning of the donor sites can, in certain cases, change the balance between the competing interactions by favoring HB interactions. A series of cavitands functionalized with XB donors, HB/XB donors and β-diketone have been synthesized. Binding preferences of XB and HB/XB cavitands towards a series of suitable HB/XB acceptors were studied in solid state and they have confirmed the presence of interactions between donor and acceptors. Cavitands with β-diketone functionality were subjected to binding studies with metal ions in solution as well as in the solid state. Successful metal-ligand complexation in solid state as well as in solution state based on UV/Vis titrations have been confirmed. In order to stabilize chemically unstable energetic compound, pentaerythritol tetranitrocarbamate (PETNC), a co-crystallization approach targeting the acidic protons was employed. A co-crystal, a salt and a solvate were obtained and the acceptors were identified as supramolecular protecting groups leading to reduced chemical reactivity and improved stability of PETNC with minimal reduction of desirable energetic properties. Several potential tetrazole based explosives which are thermal and impact sensitive and solid propellants which are impact sensitive were subjected to co-crystallization experiment to stabilize and enhance their properties. Co-crystals and salts of the explosives were obtained with suitable nitrogen based and oxygen based acceptors. The impact sensitivity and thermal instability of the explosives were improved with the introduction of co-formers. Oxygen based acceptors have shown more favorable explosive property improvements compared to nitrogen based acceptors with significant retention of explosive nature of the parent explosives.
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Книги з теми "Crystal Engineering - Ligand Molecules"

1

T, Tiekink Edward R., Vittal Jagadese J, and Zaworotko Michael, eds. Organic crystal engineering: Frontiers in crystal engineering. Hoboken, N.J: Wiley, 2010.

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2

The importance of Pi-interactions in crystal engineering: Frontiers in crystal engineering. Hoboken, NJ: Wiley, 2012.

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3

Braga, Dario, Fabrizia Grepioni, and A. Guy Orpen, eds. Crystal Engineering: From Molecules and Crystals to Materials. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4505-3.

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4

Dario, Braga, Grepioni Fabrizia, Orpen A. Guy, and North Atlantic Treaty Organization. Scientific Affairs Division., eds. Crystal engineering: From molecules and crystals to materials. Dordrecht: Kluwer Academic Publishers, 1999.

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5

Braga, Dario. Crystal Engineering: From Molecules and Crystals to Materials. Dordrecht: Springer Netherlands, 1999.

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6

1944-, Langone John J., ed. Molecular design and modeling: Concepts and applications. Part A, Proteins, peptides, and enzymes. San Diego: Academic Press, 1991.

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7

J, Langone John, ed. Molecular design and modeling: Concepts and applications. San Diego: Academic Press, 1991.

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8

Williams, Jeffrey H. Crystal Engineering: How Molecules Build Solids. Iop Concise Physics, 2017.

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9

Williams, Jeffrey H. Crystal Engineering: How Molecules Build Solids. Morgan & Claypool Publishers, 2017.

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10

Williams, Jeffrey H. Crystal Engineering: How Molecules Build Solids. Morgan & Claypool Publishers, 2017.

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Частини книг з теми "Crystal Engineering - Ligand Molecules"

1

Jorgensen, William L., Erin M. Duffy, Jonathan W. Essex, Daniel L. Severance, James F. Blake, Nora A. McDonald, and Julian Tirado-Rives. "Computational Studies of Molecular Recognition from Alkane Dimers to Protein-Ligand Complexes." In Crystal Engineering The Design and Application of Functional Solids, 113–25. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-015-9105-8_7.

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2

Erk, P. "Crystal Design." In Crystal Engineering: From Molecules and Crystals to Materials, 143–61. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4505-3_9.

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3

Sharma, C. V. Krishnamohan. "Crystal Engineering: Functionality and Aesthetics." In Crystal Engineering: From Molecules and Crystals to Materials, 481–500. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4505-3_28.

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4

Lipkowski, J., G. Szymanski, A. Chen, I. Burgess, D. Bizzotto, X. Cai, M. Hoon-Khosla, and C. Jeffrey. "Spectroscopic and Electrochemical Studies of Coordination of Organic Molecules to Gold Single Crystal Surfaces." In Metal-Ligand Interactions in Chemistry, Physics and Biology, 155–81. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-011-4245-8_7.

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5

Braga, Dario, and Fabrizia Grepioni. "Crystal Engineering: From Molecules and Crystals to Materials." In Crystal Engineering: From Molecules and Crystals to Materials, 421–41. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4505-3_24.

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6

Desiraju, Gautam R. "Diversity and Certainty — Database Research in Crystal Engineering." In Crystal Engineering: From Molecules and Crystals to Materials, 229–41. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4505-3_13.

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7

Geiser, U. "Toward Crystal Design in Organic Conductors and Superconductors." In Crystal Engineering: From Molecules and Crystals to Materials, 279–94. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4505-3_16.

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8

Williams, D. E. "Theoretical Prediction of Crystal Structures of Rigid Organic Molecules." In Crystal Engineering: From Molecules and Crystals to Materials, 295–310. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4505-3_17.

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9

Lynden-Bell, R. M. "The Chemical Bond in Molecules and Solids." In Crystal Engineering The Design and Application of Functional Solids, 29–48. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-015-9105-8_2.

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10

Hosseini, Mir Wais. "An Approach to the Crystal Engineering of Coordination Networks." In Crystal Engineering: From Molecules and Crystals to Materials, 181–208. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4505-3_11.

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Тези доповідей конференцій з теми "Crystal Engineering - Ligand Molecules"

1

Barker, Alex J., Brant Cage, Stephen Russek, Ruchira Garg, Robin Shandas, and Conrad R. Stoldt. "Tailored Nanoscale Contrast Agents for Magnetic Resonance Imaging." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81503.

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Two potential molecular imaging vectors are investigated for material properties and magnetic resonance imaging (MRI) contrast improvement. Monodisperse magnetite (Fe3O4) nanocrystals ranging in size from 7 to 22 nm are solvothermally synthesized by thermolysis of Fe(III) acetylacetonate (Fe(AcAc)3) both with and without the use of heptanoic acid (HA) as a capping ligand. For the resulting Fe3O4 nanocrystals, X-Ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and superconducting quantum interference device magnetometry (SQUID) is used to identify the average particle size, monodispersity, crystal symmetry, and magnetic properties of the ensembles as a function of time. The characterization study indicates that the HA synthesis route at 3 hours produced nanoparticles with the greatest magnetic anisotropy (15.8 × 104 J/m3). The feasibility of Fe8 single molecule magnets (SMMs) as a potential MRI contrast agent is also examined. SQUID magnetization measurements are used to determine anisotropy and saturation of the potential agents. The effectiveness of the Fe3O4 nanocrystals and Fe8 as potential MRI molecular probes is evaluated by MRI contrast improvement using 1.5 mL phantoms dispersed in de-ionized water. Results indicate that the magnetically optimized Fe3O4 nanocrystals and Fe8 SMMs hold promise for use as contrast agents based on the reported MRI images and solution phase T1/T2 shortening.
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2

Brewer, Bryson M., Yandong Gao, Rebecca M. Sappington, and Deyu Li. "Microfluidic Molecular Trap: Probing Extracellular Signaling by Selectively Blocking Exchange of Specific Molecules in Cell-Cell Interactions." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64489.

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Communication among cell populations is achieved via a wide variety of soluble, extracellular signaling molecules [1]. In order to investigate the role of specific molecules in a cellular process, researchers often utilize in vitro cell culture techniques in which the molecule under question has been removed from the signaling pathway. Traditionally, this has been accomplished by eliminating the gene in the cell that is responsible for coding the targeted ligand/receptor by using modern DNA technology such as gene knockout; however, this process is expensive, time-consuming, and labor intensive. Previously, we have demonstrated a microfluidic platform that uses a semi-permeable barrier with embedded receptor-coated nanoparticles to selectively remove a specific molecule or ligand from the extracellular signaling pathway in a cell co-culture environment [2]. This initial proof-of-principle was conducted using biotinylated nanoparticles and fluorescently tagged avidin molecules, as the avidin/biotin complex is the strongest known non-covalent interaction between a protein and a ligand (Dissociation constant kd = 10−15 M). Also, the trap was only effective for short time periods (<15 min) because the high concentration of fluorescently tagged avidin molecules required for visualization quickly saturated the barrier. However, nearly all biologically relevant ligand-receptor interactions have lower binding affinities than the avidin-biotin complex, with dissociation constants that are larger by several orders of magnitude. In addition, many in vitro cell culture experiments are conducted over multiple hours or days. Thus, a practically useful molecular trap device must be able to operate in a lower binding affinity regime while also lasting for extended time periods. Here we present results in which a biotinylated-particle barrier was used to successfully block lower concentrations of fluorescently tagged avidin for multiple days, showcasing the applicability of the device for long term experiments. In addition, we introduce a modified molecular trap in which the protein A/goat IgG complex was used to demonstrate the effectiveness of the platform for lower binding affinity protein-ligand interactions. These results indicate the potential usefulness of the microfluidic molecular trap platform for probing extracellular signaling pathways.
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3

Xiaochuan, Zeng, Li Xuejun, He Cuizhu, and Hu Qiaodan. "First-Principles Study on Adsorption Reaction of Oxygen Molecules on Fe (110) Crystal Surface." In 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-92890.

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Abstract The adsorption reaction between oxygen (O2) molecule and ferrum (Fe) (110) crystal surface in the oxidation process of Fe surface was studied by using the first-principles method. The differential charge density analysis of the adsorption sites of oxygen molecule on Fe (110) crystal surface, the calculation of adsorption energy at different sites and the analysis of electronic density of states showed that the stable adsorption position of oxygen molecule was parallel to Fe (110) crystal surface, and the oxygen atom tended to adsorb at the triangular gap of Fe atoms. The electronic structure of the adsorption system showed that the 2p electron orbital of oxygen atom plays a major role in the adsorption, and only O-Fe electron interaction exists when oxygen molecule is adsorbed in the parallel orientation, which makes the whole Fe (110) crystal surface lose electrons, increase the system potential and the risk of electrochemical corrosion. The research conclusions can provide theoretical support for the further insight in the oxidation corrosion mechanism of nuclear metal surface.
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4

Piper, James W., Robert A. Swerlick, and Cheng Zhu. "A Novel Method for Determination of Affinity of Surface Bound Receptor-Ligand Binding." In ASME 1996 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/imece1996-1134.

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Abstract Cell-cell and cell-substrate adhesion is an integral component of many biological processes. These adhesive interactions are mediated by binding of cell adhesion molecules to their specific receptors. An important determinant of the receptor-ligand interaction is their binding affinity. Existing bulk chemistry approaches for measuring binding affinity require at least one of the reactants to be in solution. Therefore, at least one molecular species is able to move in three dimensions, and there is no force acting on the bond. This kind of binding affinity is referred to as 3-D affinity in the present paper. In contrast, in the case of cell adhesion, the motions of both molecular species are restricted to two-dimensional because both receptor and ligand are anchored to a surface (and the binding affinity is thereby referred to as 2-D affinity). In addition, dislodging forces usually exist which affect the binding reaction. This coupling between chemistry and mechanics requires that the binding affinity be a function of the bond force instead of a constant. Because of these differences, the (3D) binding affinity measured via traditional approaches cannot be directly applied to the analysis of receptor-ligand binding in cell adhesion. There is a lack of methods for the direct measurement of binding affinity when both receptor and ligand are bound to a surface and subject to a force. It is this gap that the present paper intends to fill.
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5

Chesla, Scott E., Bryan T. Marshall, and Cheng Zhu. "Measuring the Probability of Receptor Extraction From the Cell Membrane." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0262.

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Abstract Recently, there has been an increasing interest in measuring the interaction forces between cell adhesion receptors and their ligands [1–3]. These molecules are either anchored on the membrane of a cell or coated on the surface of a substratum. The two surfaces are joined together as a result of the formation of non-covalent bonds between the receptors and ligands. The forces are measured when the two surfaces are separated. In a theoretical paper published nineteen years ago, George Bell estimated the force required to break a receptor-ligand bond and that required to uproot the receptor from the cell membrane to be of the same order of magnitude [4]. The interpretation of the force data therefore requires the knowledge of detachment mode, i.e., via adhesive mechanism if the receptor-ligand bond is dissociated or via cohesive mechanism if the receptor-membrane anchor is disrupted.
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6

Jomeh, Sina, and Mina Hoorfar. "Numerical Investigation of the Effect of Geometric and Physiochemical Parameters on Biomolecule Capture Efficiency." In ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30531.

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This paper presents and compares three different designs including open channel, circular pillar and screen-plate microreactors for capturing and detection of biomolecules in a buffer liquid. In general, these capturing/detection devices consist of a flow cell containing one or several reactive surfaces loaded with ligand molecules. The critical issue in the design of an efficient device is the proximity of the biomolecules to the ligands in the capturing stage since the latter is immobilized on the reactive surface and the former is freely moving in the flow. The flow pattern and the geometry of the device are the key factors in this regard. The presented designs are numerically modeled and compared in terms of capture efficiency. Immersed biomolecules are assumed to behave like a continuum medium. The Navier-Stokes and advection-diffusion equations are solved in two dimensions and the concentration profile is found after a certain sampling period. The chemical reaction between the ligand and the biomolecule is included in the model through solving the first order kinetic equation at the boundaries. The average surface concentrations of the adsorbed molecules are plotted and compared for all the geometries to determine the most efficient one. Considering the performance, ease of fabrication, and detection, the screen plates are found to be the best option for the purpose of biomolecule removal. The effects of the change in the geometric parameters (e.g., the flow path width in the microchannels) and physicochemical parameters (e.g., the diffusion constant, ligand surface density, and forward and backward reaction rates) involved in the problem on the adsorbed concentration are thoroughly inspected and the corresponding results are plotted.
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Dai, Guoliang, and Gen Sazaki. "The Adsorption of Protein Molecules at a Crystal/solution Interface Observed by an Improved TIRFM." In 2009 3rd International Conference on Bioinformatics and Biomedical Engineering (iCBBE). IEEE, 2009. http://dx.doi.org/10.1109/icbbe.2009.5163569.

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8

Wang, Qi. "Couette Flows of Liquid Crystal Polymers." In ASME 1996 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/imece1996-0237.

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Abstract Using the BMAB theory with the Doi closure approximation and a biaxial representation of the orientation tensor, we demonstrate that the steady states of liquid crystal polymeric Couette flows between two concentric, circular cylinders in relative rotation exhibit biaxial symmetries. Therefore, two order parameters and a triad of directors must be employed to model average molecular orientation in the flow. With two directors confined to the plane orthogonal to the axis of rotation, stable steady states may exhibit flow-aligning, log-rolling and mixed flow-aligning and log-rolling behavior depending on the initial orientation between the two cylinders. The orientational pattern and the degree of orientation is sensitive to the value of the polymer concentration, the anisotropic drag coefficient and the ratio of the radius of the two cylinders. Molecules achieve higher degree of orientation at the wall of the inner cylinder than at that of the outer cylinder in the flow-aligning regime, and vice versa in the log-rolling regime.
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Grandum, Svein, Yasunori Kobayashi, Akira Yabe, Sohei Matsumoto, Fumio Takemura, Kazuya Nakagomi, and Per-Erling Frivik. "Molecular Dynamics Simulation of Ice Crystal Growth From a Surface Containing Adsorbed Antifreeze Protein." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0957.

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Abstract In order to develop advanced low temperature storage systems based on slurry ice, resistant to recrystallization, Antifreeze Protein (AFP) has been introduced as an effective additive. In this paper, the mechanism of crystal growth when AFPs are adsorbing to the surface of ice has been investigated by Molecular Dynamics simulation. Liquid water molecules were located above the adsorption plane, containing a simplified model of the AFP and the growth potential, corresponding to a supercooling of approximately 40 K was applied. Growth was not easily occurring close to the AFP but at sites where the molecules easily could generate at least two hydrogen bonds to the crystal lattice. This resulted in a curved ice surface, similar to the previously observations using a Scanning Tunneling Microscope.
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10

Tballad, V. R., S. Brasselet, G. R. Desiraju, and J. Zyss. "Octupolar Crystalline Structures for Quadratic Nonlinear Optics : A Dual Crystal and Propagative Engineering Approach." In The European Conference on Lasers and Electro-Optics. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/cleo_europe.1998.ctuj4.

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Crystal engineering is increasingly turning towards functional materials. Octupolar . NLO active substances are expected to overcome many of the disadvantages posed by dipolar species. While octupolar non-linearity has been demonstrated at the molecular level, its demonstration in supramolecular crystalline systems remains a challenge. Trigonal, non- centrosymmetric assemblies of trigonal molecules lead to supramolecular octupolar networks. However, most trigonal molecules do not assemble into trigonal networks. In this work, the principles of crystal engineering have been used in the carry-over of molecular symmetry into the crystals structures of six related compounds. Supramolecular retrosynthesis of a trigonal network based on herringbone interactions leads to 2,4,6-triaryloxy-l,3,5-triazines as the starting materials. Six triazines are analyzed and their molecular non-linearities are measured by HLS experiments.
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Звіти організацій з теми "Crystal Engineering - Ligand Molecules"

1

Pisani, William, Dane Wedgeworth, Michael Roth, John Newman, and Manoj Shukla. Exploration of two polymer nanocomposite structure-property relationships facilitated by molecular dynamics simulation and multiscale modeling. Engineer Research and Development Center (U.S.), March 2023. http://dx.doi.org/10.21079/11681/46713.

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Polyamide 6 (PA6) is a semi-crystalline thermoplastic used in many engineering applications due to good strength, stiffness, mechanical damping, wear/abrasion resistance, and excellent performance-to-cost ratio. In this report, two structure-property relationships were explored. First, carbon nanotubes (CNT) and graphene (G) were used as reinforcement molecules in simulated and experimentally prepared PA6 matrices to improve the overall mechanical properties. Molecular dynamics (MD) simulations with INTERFACE and reactive INTERFACE force fields (IFF and IFF-R) were used to predict bulk and Young's moduli of amorphous PA6-CNT/G nanocomposites as a function of CNT/G loading. The predicted values of Young's modulus agree moderately well with the experimental values. Second, the effect of crystallinity and crystal form (α/γ) on mechanical properties of semi-crystalline PA6 was investigated via a multiscale simulation approach. The National Aeronautics and Space Administration, Glenn Research Center's micromechanics software was used to facilitate the multiscale modeling. The inputs to the multiscale model were the elastic moduli of amorphous PA6 as predicted via MD and calculated stiffness matrices from the literature of the PA6 α and γ crystal forms. The predicted Young's and shear moduli compared well with experiment.
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