Artykuły w czasopismach: „Non-transition Metals - Poly-dentate Ligands”

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Mattoussi, Hedi, Liang Du, Neda Arabzadeh Nosratabad i Zhicheng Jin. "(Keynote) N-Heterocyclic Carbene-coated Gold Nanoparticles and Luminescent Quantum Dots". ECS Meeting Abstracts MA2022-02, nr 20 (9.10.2022): 904. http://dx.doi.org/10.1149/ma2022-0220904mtgabs.

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N-heterocyclic carbenes (NHCs) have generated much interest for use as versatile metal-coordinating groups, since they were first synthesized by Arduengo and coworkers in 1991. NHC molecules can be considered as L-type ligands, because they share their non-bonding electron pairs with the σ-accepting orbital of transition metals, and this endows them with strong coordination interactions. NHC-appended molecules have recently been actively exploited as potentially effective ligands for the surface passivation of various colloidal nanomaterials. We investigate the coordination interactions between a few representative colloidal nanocrystals, including gold nanoparticles (AuNPs) and luminescent quantum dots (QDs), and a NHC-based polymer ligand. The latter presents multiple NHC groups and several short poly (ethylene glycol) (PEG) chains as solubilizing blocks. We find that our NHC-decorated ligands rapidly coordinate onto both sets of nanocrystals, which we attribute to their soft Lewis base nature. These ideally match the soft Lewis acid character of transition metal colloid surfaces, promoting strong coordination bonding through soft‐soft interaction. We combine NMR spectroscopy, fluorescence spectroscopy, high-resolution transmission electron microscopy supplemented with dynamic light scattering to characterize the nature of the binding interactions. Furthermore, the long-term stability of the NHC-stabilized nanocolloids have been tested after phase transfer to water, a highly challenging chemical venue for such groups, due to the moisture sensitive nature of NHC molecules. Data show that our NHC-polymer-stabilized AuNPs and QDs exhibit long-term colloidal stability in buffer media while preserving their optical and fluorescing properties, with no sign of degradation or aggregation build up for at least one year of storage. We will discuss the ligand design and synthesis, characterization of the polymer-stabilized nanocrystals under various conditions, with a particular focus on the beneficial effects of ligand multi-coordination interactions onto the nanocolloid surfaces.

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Prananto, Yuniar P., Aron Urbatsch, Boujemaa Moubaraki, Keith S. Murray, David R. Turner, Glen B. Deacon i Stuart R. Batten. "Transition Metal Thiocyanate Complexes of Picolylcyanoacetamides". Australian Journal of Chemistry 70, nr 5 (2017): 516. http://dx.doi.org/10.1071/ch16648.

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A variety of transition metal complexes involving picolylcyanoacetamides (pica = NCCH2CONH-R; R = 2-picolyl- (2pica), 3-picolyl- (3pica), 4-picolyl- (4pica)) and thiocyanate have been synthesised and their solid-state structures have been determined. The complexes were all obtained from reactions between the corresponding metals salts and pica ligands with sodium thiocyanate under ambient conditions. Both 3pica and 4pica coordinate to the metal solely through the nitrogen atom of the picolyl group and form discrete tetrahedral [M(NCS)2(pica)2] (3pica; M = Mn, Zn; 4pica; M = Co) and octahedral [M(NCS)2(3pica)4] (M = Co, Fe, Ni) complexes. In addition, one-dimensional N,S-thiocyanate-bridged coordination polymers poly-[M(µ-NCS)2(pica)2] (3pica; M = Cd; 4pica; M = Co, Cd) were obtained. The ligand 2pica gave the discrete octahedral complexes [Co(NCS)2(2pica)2] and [Cd(NO3)2(2pica)2] in which 2pica chelates in a bidentate fashion through its picolyl and carbonyl groups. Magnetic susceptibility measurements on the cobalt(ii) complexes were performed and showed short-range antiferromagnetic coupling for the [Co(NCS)2(4pica)2]n 1D polymer.

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Matsumoto, Fukashi, i Yoshiki Chujo. "Synthesis of transition-metal-containing poly(pyrazabole)s". Pure and Applied Chemistry 78, nr 7 (1.01.2006): 1407–11. http://dx.doi.org/10.1351/pac200678071407.

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Novel organoboron polymers containing transition metals (Ni, Pd, Pt) and pyrazaboles in the main chain were prepared by Cu-catalyzed coupling polymerization. The Ni- and Pt-containing polymers showed MLCT (metal-to-ligand charge transfer) absorption, whereas the Pd-containing polymer did not demonstrate the absorption. Only the Pd-containing polymer exhibited the emission spectrum with a vibronic structure. These differences in the optical properties were studied in detail.

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Liu, Yang, Yong-Lan Feng i Wei-Wei Fu. "A two-dimensional zinc(II) coordination polymer based on mixed dimethyl succinate and bipyridine ligands: synthesis, structure, thermostability and luminescence properties". Acta Crystallographica Section C Structural Chemistry 72, nr 4 (16.03.2016): 308–12. http://dx.doi.org/10.1107/s2053229616003211.

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From the viewpoint of crystal engineering, the construction of crystalline polymeric materials requires a rational choice of organic bridging ligands for the self-assembly process. Multicarboxylate ligands are of particular interest due to their strong coordination activity towards metal ions, as well as their various coordination modes and versatile conformations. The structural chemistry of dicarboxylate-based coordination polymers of transition metals has been developed through the grafting of N-containing organic linkers into carboxylate-bridged transition metal networks. A new luminescent two-dimensional zinc(II) coordination polymer containing bridging 2,2-dimethylsuccinate and 4,4′-bipyridine ligands, namely poly[[aqua(μ2-4,4′-bipyridine-κ2N:N′)bis(μ3-2,2-dimethylbutanedioato)-κ4O1,O1′:O4:O4′;κ5O1:O1,O4:O4,O4′-dizinc(II)] dihydrate], {[Zn2(C6H8O4)2(C10H8N2)(H2O)]·2H2O}n, has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction and elemental, IR and thermogravimetric analyses. In the structure, the 2,2-dimethylsuccinate ligands link linear tetranuclear ZnIIsubunits into one-dimensional chains along thecaxis. 4,4′-Bipyridine acts as a tethering ligand expanding these one-dimensional chains into a two-dimensional layered structure. Hydrogen-bonding interactions between the water molecules (both coordinated and free) and carboxylate O atoms strengthen the packing of the layers. Furthermore, the luminescence properties of the complex were investigated. The compound exhibits a blue photoluminescence in the solid state at room temperature and may be a good candidate for potential hybrid inorganic–organic photoactive materials.

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Tandon, Santokh S., Laurence K. Thompson, John N. Bridson i John C. Dewan. "Dinuclear cobalt(II) complexes of a polyhydroimidazole ligand. Dinuclear (2:1) non-metallocyclic derivatives and dinuclear (1:1) metallocyclic complexes with a large, unoccupied central cavity". Canadian Journal of Chemistry 70, nr 11 (1.11.1992): 2771–76. http://dx.doi.org/10.1139/v92-352.

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The ligand BTIM (1,2,4,5-tetrakis(4,5-dihydro-imidazol-2-yl)benzene) reacts with cobalt(II) salts to form two series of complexes. The 1:1, dinuclear, metallocyclic derivatives [Co2(BTIM)2X2]X2 (X = Cl (I), Br (II)) involve two bis-dentate ligands in a metallocyclic structure with a large unoccupied cavity. The 2:1, binuclear derivatives [Co2(BTIM)X4] (X = Cl (III), Br (IV)) involve two metals bound to a single, bis-bidentate ligand. The crystal and molecular structures of II and III are reported. Compound II crystallized in the monoclinic system, space group P21/c, with a = 13.642(6) Å, b = 11.560(3) Å, c = 18.406(7) Å, β = 101.73(3)° and four formula units per unit cell. Refinement by full-matrix least squares gave final residuals of R = 0.060 and Rw = 0.062. Compound III crystallized in the triclinic system, space group [Formula: see text], with a = 8.367(2) Å, b = 14.254(3) Å, c = 7.649(2) Å, α = 100.99(2)°, β = 101.44(2)°, γ = 106.85(1)° and one formula per unit cell. Refinement by full-matrix least squares gave final residuals of R = 0.052 and Rw = 0.045. In the metallocyclic structure (II) the square-pyramidal cobalt(II) centres are separated by 7.599(4) Å, while in the 2:1 derivative the two tetrahedral cobalt(II) centres have a much larger separation (8.736(3) Å).

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K. Dawood, Saad, i Sahbaa A. Al-Sabaawi. "Investigation of New Tetra Dentate Macrocyclic [N4] Ligand and it's Complexes with Transition Metal's". JOURNAL OF EDUCATION AND SCIENCE 24, nr 2 (30.11.1999): 22–27. http://dx.doi.org/10.33899/edusj.1999.58727.

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Kucera, Benjamin E., Robert E. Jilek, William W. Brennessel i John E. Ellis. "Bis(pyrene)metal complexes of vanadium, niobium and titanium: isolable homoleptic pyrene complexes of transition metals". Acta Crystallographica Section C Structural Chemistry 70, nr 8 (4.07.2014): 749–53. http://dx.doi.org/10.1107/s2053229614015290.

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Reduction of VCl3(THF)3(THF is tetrahydrofuran) and NbCl4(THF)2by alkali metal pyrene radical anion salts in THF affords the paramagnetic sandwich complexes bis[(1,2,3,3a,10a,10b-η)-pyrene]vanadium(0), [V(C16H10)2], and bis[(1,2,3,3a,10a,10b-η)-pyrene]niobium(0), [Nb(C16H10)2]. Treatment of tris(naphthalene)titanate(2−) with pyrene provides the isoelectronic titanium species, isolated as an (18-crown-6)potassium salt, namelycatena-poly[[(18-crown-6)potassium]-μ-[(1,2-η:1,2,3,3a,10a,10b-η)-pyrene]-titanate(−I)-μ-[(1,2,3,3a,10a,10b-η:6,7-η)-pyrene]], {[K(C12H24O6)][Ti(C16H10)2]}n. The first two compounds have very similar packing, with neighboring molecules arranged orthogonally to one another, such that aromatic donor–acceptor interactions are likely responsible for the specific arrangement. The asymmetric unit contains a half-occupancy metal center η6-coordinated to one pyrene ligand, with the fullM(pyrene)2molecule generated by a crystallographic inversion center. In the titanium compound, the cations and anions are in alternating contact throughout the crystal structure, in one-dimensional chains along the [101] direction. As in the other two compounds, the asymmetric unit contains a half-occupancy Ti atom η6-coordinated to one pyrene ligand. Additionally, the asymmetric unit contains one half of an (18-crown-6)potassium cation, located on a crystallographic inversion center coincident with the K atom. The full formula units are generated by those inversion centers. In all three structures, the pyrene ligands are eclipsed and sandwich the metals in one of two inversion-related sites. These species are of interest as the first isolable homoleptic pyrene transition metal complexes to be described in the scientific literature.

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Suzuki, Seigo, Toshiki Sawada, Takashi Ishizone i Takeshi Serizawa. "Bioinspired structural transition of synthetic polymers through biomolecular ligand binding". Chemical Communications 54, nr 85 (2018): 12006–9. http://dx.doi.org/10.1039/c8cc06232c.

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Rahman, Md Lutfor, Bablu Hira Mandal, Shaheen M. Sarkar, Nor Asiken Abdul Wahab, Mashitah Mohd Yusoff, Sazmal E. Arshad i Baba Musta. "Synthesis of poly(hydroxamic acid) ligand from polymer grafted khaya cellulose for transition metals extraction". Fibers and Polymers 17, nr 4 (kwiecień 2016): 521–32. http://dx.doi.org/10.1007/s12221-016-6001-2.

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Gupta, Lokesh Kumar, i Sulekh Chandra. "Physicochemical and Biological Characterization of Transition Metal Complexes with a Nitrogen Donor Tetra-dentate Novel Macrocyclic Ligand". Transition Metal Chemistry 31, nr 3 (kwiecień 2006): 368–73. http://dx.doi.org/10.1007/s11243-005-0002-0.

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Krinchampa, Pattiya, Kittipong Chainok, Siriporn Phengthaisong, Sujittra Youngme, Filip Kielar i Nanthawat Wannarit. "A novel one-dimensional double-chain-like ZnIIcoordination polymer: poly[bis(1-benzyl-1H-imidazole-κN3)tris(μ-cyanido-κ2C:N)(cyanido-κC)disilver(I)zinc(II)]". Acta Crystallographica Section C Structural Chemistry 72, nr 12 (7.11.2016): 960–65. http://dx.doi.org/10.1107/s2053229616017502.

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One of most interesting systems of coordination polymers constructed from the first-row transition metals is the porous ZnIIcoordination polymer system, but the numbers of such polymers containingN-donor linkers are still limited. The title double-chain-like ZnIIcoordination polymer, [Ag2Zn(CN)4(C10H10N2)2]n, presents a one-dimensional linear coordination polymer structure in which ZnIIions are linked by bridging anionic dicyanidoargentate(I) units along the crystallographicbaxis and each ZnIIion is additionally coordinated by a terminal dicyanidoargentate(I) unit and two terminal 1-benzyl-1H-imidazole (BZI) ligands, giving a five-coordinated ZnIIion. Interestingly, there are strong intermolecular AgI...AgIinteractions between terminal and bridging dicyanidoargentate(I) units and C—H...π interactions between the phenyl rings of BZI ligands of adjacent one-dimensional linear chains, providing a one-dimensional linear double-chain-like structure. The supramolecular three-dimensional framework is stabilized by C—H...π interactions between the phenyl rings of BZI ligands and by AgI...AgIinteractions between adjacent double chains. The photoluminescence properties have been studied.

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Rahman, Md Lutfor, Bablu Hira Mandal, Shaheen M. Sarkar, Mashitah M. Yusoff, Sazmal Arshad i Baba Musta. "Synthesis of poly(hydroxamic acid) ligand from polymer grafted corn-cob cellulose for transition metals extraction". Polymers for Advanced Technologies 27, nr 12 (20.06.2016): 1625–36. http://dx.doi.org/10.1002/pat.3840.

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Nasir, H. M., T. A. Saki i M. Y. Al-Luaibi. "Synthesis, identification and thermal study of some new inorganic polymers based on bis-dithiocarbamate ligands with silicone, tellurium and some transition metals". Innovaciencia Facultad de Ciencias Exactas Físicas y Naturales 7, nr 1 (25.10.2019): 1–13. http://dx.doi.org/10.15649/2346075x.507.

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Introduction: In recent years, there has been considerable interest in dithiocarbamate complexes because of its diverse biological roles, very few reports have been made on polymeric bis- dithiocarbamate compounds with carbon chain of n-propyl or hexamethelene with transition metals in addition of the absence of any report of organosilicone or tellurium halides with such compounds Our interest in this report based on the preparation of new series of polymers with an expected activity as a fungi side compounds followed by the using of prepared amino compound as a hardners for epoxy paints Materials and Methods: A new polymers of the general structures –(MS2CNH(CH2)6NHCS2M-)n where [M= Cu, Cd, Mn and Zn] and –(M(R)2S2CNH(CH2)nNHCS2MR2-)m where [M= Si,R=CH 3 , n= 2 ,3 and 6 ; M=Te , R= Br , n= 2 ,3 and 6 ; M=Co, Ni R=Cl ; n= 6] have been prepared by reaction of MX2 where M= Ni ,Co, Cd , Mnor Zn , X= Cl ; M=Cu , X= SO4 , and dimethyl dichloro silane, tellurium tetrabromide with the corresponding sodium salts of bis-dithiocarbamateligands. Results and Discussion: Dimethyldichloro silane is a very sensitive material to O-H group, in addition to that, TeBr4 decomposed rapidlyin water so, a series solvents may be useful with such sensitive chemicals to water , in the other hand, dithiocarbamate ligands which is usually prepared in aqueous and alcoholic solution , must be prepared and isolated carefully to apply the other steps of synthesis using a chloroform solution as a solvent. It seems for the first view for dithiocarbamato ligands it may act as a bi dentate ligands using two sulphur donating atoms that is clearly appeared in common complexes such as diethyl dithiocarbamato or pipyridyl, morpholino dithiocarbamato with representation metal elements, even in such type of elements a sulfur bridges may formed. In this study, it showed clearly that Zinc and Cadimium polymers are diamagnetic polymers that is mean that these polymers are with oxidation state equal to (II) and a tetrahedral configuration Conclusions: The study showed that the new silicone polymers act as a stable polymers compared with others. All new polymers are of a high stability with large values of char contain with commercial epoxy. Among silicone polymers, the polymerwith carbon chain equal to 3 is more stable than that with 2 carbon atoms while the silicone polymer with 6 carbon atoms is the less stable one, may thermal treatment caused decomposition combined.

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Black, David T., Alan R. Kennedy i Kiara M. Lobato. "Disulfonated azo dyes: metal coordination and ion-pair separation in twelve M II compounds of Ponceau Xylidine and Crystal Scarlet". Acta Crystallographica Section C Structural Chemistry 75, nr 6 (15.05.2019): 633–42. http://dx.doi.org/10.1107/s2053229619005540.

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The structures of seven divalent metal cation compounds of Ponceau Xylidine {PX; systematic name of dication: 4-[2-(3,4-dimethylphenyl)hydrazin-1-ylidene]-3-oxo-3,4-dihydronaphthalene-2,7-disulfonate}, also known as Acid Red 26, CI 16150, and of five divalent metal cation compounds of Crystal Scarlet {CS; systematic name of dication: 8-[2-(naphthalen-1-yl)hydrazin-1-ylidene]-7-oxo-7,8-dihydronaphthalene-1,3-disulfonate}, also known as Acid Red 44, CI 16250, are presented. These are hexaaquamagnesium(II) PX dimethylformamide (DMF) monosolvate, [Mg(H2O)6](C18H14N2O7S2)·C3H7NO, (I); heptaaquacalcium(II) PX 2.5-hydrate, [Ca(H2O)7](C18H14N2O7S2)·2.5H2O, (II); catena-poly[aqua(μ-DMF)tris(DMF)bis(μ3-PX)distrontium(II)], [Sr(C18H14N2O7S2)(C3H7NO)2(H2O)0.5] n , (III); the transition-metal series hexaaquametal(II) PX DMF monosolvate, [M(H2O)6](C18H14N2O7S2)·C3H7NO, where M (metal) = Co, (IV), Ni, (V), Cu, (VI), and Zn, (VII); heptaaquacalcium(II) CS monohydrate, [Ca(H2O)7](C20H13N2O7S2)·H2O, (VIII); octaaquastrontium(II) CS monohydrate, [Sr(H2O)8](C20H13N2O7S2)·H2O, (IX); catena-poly[[triaqua(DMF)barium(II)]-μ-CS], [Ba(C20H13N2O7S2)(C3H7NO)(H2O)3] n , (X); tetrakis(DMF)(CS)copper(II) monohydrate, [Cu(C20H13N2O7S2)(C3H7NO)4]·H2O, (XI); and catena-poly[[[aquatris(DMF)zinc(III)]-μ-CS] diethyl ether hemisolvate], {[Zn(C20H13N2O7S2)(C3H7NO)3(H2O)]·0.5C4H10O} n , (XII). In all cases, the structures obtained were solvates with dimethylformamide (DMF) and/or water present. The disulfonated naphthalene-based azo anions adopt hydrazone tautomeric forms. The structures of the Mg salt and of four transition-metal forms (M = Co, Ni, Cu and Zn) of PX are found to form an isostructural series. All have solvent-separated ion-pair (SSIP) type structures and the formula [M(H2O)6][PX]·DMF. The Ca salt of PX also has an SSIP structure, but has a higher hydration state, [Ca(H2O)7][PX]·2.5H2O. In contrast, the Sr salt of PX, [Sr(PX)(DMF)2(H2O)0.5] n forms a one-dimensional coordination polymer. Both the Ca and the Sr salt of CS have an SSIP structure, namely [Ca(H2O)7][CS]·H2O and [Sr(H2O)8][CS]·H2O, whilst the heavier Ba analogue, [Ba(CS)(DMF)(H2O)3] n , forms a one-dimensional coordination polymer. Unlike PX, two CS structures containing transition metals are found to be coordination complexes, [Cu(CS)(DMF)4]·H2O and {[Zn(CS)(DMF)3(H2O)]·0.5Et2O} n . This suggests that CS is a better ligand than PX for transition metals. The Cu complex forms discrete molecules with Cu in a square-pyramidal environment, whilst the Zn species is a one-dimensional coordination polymer based on octahedral Zn centres.

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González-Belman, Oscar, Artur Brotons-Rufes, Michele Tomasini, Laura Falivene, Lucia Caporaso, Jose Jiménez-Halla i Albert Poater. "Towards Dual-Metal Catalyzed Hydroalkoxylation of Alkynes". Catalysts 11, nr 6 (2.06.2021): 704. http://dx.doi.org/10.3390/catal11060704.

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Poly (vinyl ethers) are compounds with great value in the coating industry due to exhibiting properties such as high viscosity, soft adhesiveness, resistance to saponification and solubility in water and organic solvents. However, the main challenge in this field is the synthesis of vinyl ether monomers that can be synthetized by methodologies such as vinyl transfer, reduction of vinyl phosphate ether, isomerization, hydrogenation of acetylenic ethers, elimination, addition of alcohols to alkyne species etc. Nevertheless, the most successful strategy to access to vinyl ether derivatives is the addition of alcohols to alkynes catalyzed by transition metals such as molybdenum, tungsten, ruthenium, palladium, platinum, gold, silver, iridium and rhodium, where gold-NHC catalysts have shown the best results in vinyl ether synthesis. Recently, the hydrophenoxylation reaction was found to proceed through a digold-assisted process where the species that determine the rate of the reaction are PhO-[Au(IPr)] and alkyne-[Au(IPr)]. Later, the improvement of the hydrophenoxylation reaction by using a mixed combination of Cu-NHC and Au-NHC catalysts was also reported. DFT studies confirmed a cost-effective method for the hydrophenoxylation reaction and located the rate-determining step, which turned out to be quite sensitive to the sterical hindrance due to the NHC ligands.

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Chirvony, Vladimir S. "Primary photoprocesses in cationic 5,10,15,20-meso-tetrakis(4-N-methylpyridiniumyl)porphyrin and its transition metal complexes bound with nucleic acids". Journal of Porphyrins and Phthalocyanines 07, nr 11 (listopad 2003): 766–74. http://dx.doi.org/10.1142/s108842460300094x.

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Photophysical properties of meso-tetrakis(4-N-methylpyridiniumyl)porphyrin ( TMpyP 4) and its metallocomplexes M (II) TMpy P4 ( M = Zn , Cu , Ni , Co ) bound to natural DNA and synthetic poly-, oligo- and mononucleotides are considered with a primary emphasis placed upon intermolecular interaction of the photoexcited porphyrins with the nearest environment. Quenching of the fluorescent S 1 (but not triplet T 1) state due to guanine to porphyrin electron transfer is observed for TMpyP 4 intercalated between GC base pairs of the double-strand helixes, whereas in the case of TMpyP 4 complexed with guanosine monophosphate (GMP) both S 1 and T 1 states of the porphyrin are quenched. Furthermore, a dependence of the efficiency of TMpyP 4 triplet state quenching by the dissolved molecular oxygen from air on the porphyrin localization enables one to readily distinguish porphyrin groove binding mode from intercalation. Excited states of the TMpyP 4 complexes with transition metals, in spite of their very short lifetimes, also interact with nucleic acid components by means of an axial ligand binding/release to/from the metal. A possible structure of the five-coordinate excited complex (“exciplex”) formed in case of CuTMpyP 4 groove binding to some single- and double-strand polynucleotides is discussed.

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Tolbatov, Iogann, Alessandro Marrone, Cecilia Coletti i Nazzareno Re. "Computational Studies of Au(I) and Au(III) Anticancer MetalLodrugs: A Survey". Molecules 26, nr 24 (15.12.2021): 7600. http://dx.doi.org/10.3390/molecules26247600.

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Owing to the growing hardware capabilities and the enhancing efficacy of computational methodologies, computational chemistry approaches have constantly become more important in the development of novel anticancer metallodrugs. Besides traditional Pt-based drugs, inorganic and organometallic complexes of other transition metals are showing increasing potential in the treatment of cancer. Among them, Au(I)- and Au(III)-based compounds are promising candidates due to the strong affinity of Au(I) cations to cysteine and selenocysteine side chains of the protein residues and to Au(III) complexes being more labile and prone to the reduction to either Au(I) or Au(0) in the physiological milieu. A correct prediction of metal complexes’ properties and of their bonding interactions with potential ligands requires QM computations, usually at the ab initio or DFT level. However, MM, MD, and docking approaches can also give useful information on their binding site on large biomolecular targets, such as proteins or DNA, provided a careful parametrization of the metal force field is employed. In this review, we provide an overview of the recent computational studies of Au(I) and Au(III) antitumor compounds and of their interactions with biomolecular targets, such as sulfur- and selenium-containing enzymes, like glutathione reductases, glutathione peroxidase, glutathione-S-transferase, cysteine protease, thioredoxin reductase and poly (ADP-ribose) polymerase 1.

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Mohamed, Amira A., Fatma M. Ahmed, Wael A. Zordok, Walaa H. El-Shwiniy, Sadeek A. Sadeek i Hazem S. Elshafie. "Novel Enrofloxacin Schiff Base Metal Complexes: Synthesis, Spectroscopic Characterization, Computational Simulation and Antimicrobial Investigation against Some Food and Phyto-Pathogens". Inorganics 10, nr 11 (25.10.2022): 177. http://dx.doi.org/10.3390/inorganics10110177.

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Condensation of the reaction between enrofloxacin and ethylenediamine in the existence of glacial acetic acid produced a new N,N-ethylene (bis 1-cyclopropyl-7-(4-ethylpiperazin-1-yl)-6-fluoro-1,4-dihydroquinoline-3-carboxylic acid Schiff base (H2Erx-en). H2Erx-en was used as a tetra-dentate ligand to produce novel complexes by interacting with metal ions iron(III), yttrium(III), zirconium(IV), and lanthanum(III). The synthetic H2Erx-en and its chelates had been detected with elemental analysis, spectroscopic methods, mass spectrometry, thermal studies, conductometric and magnetic measurements experiments. The calculated molar conductance of the complexes in 1 × 10−3 M DMF solution shows that iron(III), yttrium(III) and lanthanum(III) are 1:1 electrolytes, however the zirconium(IV) complex is non-electrolyte. The infrared spectra of H2Erx-en chelates indicated that the carboxylic group is deprotonated and H2Erx-en is associated with metals as a tetra-dentate through nitrogen and oxygen atoms. The disappearance of the carboxylic proton in all complexes corroborated information concerning H2Erx-en deprotonation and complexation with metal ions, according to 1H NMR data. Thermal analysis revealed the abundance of H2O particles in the chelates’ entrance and outlet spheres, indicating the disintegration pattern of H2Erx-en and their chelates. The Coats–Redfern and Horowitz–Metzeger approaches were utilized to calculate the thermodynamic items (Ea, ΔS *, ΔH *, and ΔG *) at n = 1 and n ≠ 1. The resulting data reveal better organized chelate building activation. Density functional theory (DFT) was created to properly grasp the optimal architecture of the molecules. The chelates are softer than H2Erx-en, with estimates varying between 95.23 eV to 400.00 eV, compared to 31.47 eV for H2Erx-en. The disc diffusion technique was utilized to assess H2Erx-en and their chelates in an antimicrobial assay against various food and phytopathogens. The zirconium(IV) chelate has the most potent antibacterial action and is particularly efficient against Salmonella typhi.

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Sandic, Zvjezdana, i Aleksandra Nastasovic. "Functionalized macroporous copolymer of glycidyl methacrylate: The type of ligand and porosity parameters influence on Cu(II) ion sorption from aqueous solutions". Chemical Industry 63, nr 3 (2009): 269–73. http://dx.doi.org/10.2298/hemind0903269s.

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The removal of heavy metals from hydro-metallurgical and other industries' wastewaters, their safe storage and possible recovery from waste- water streams is one of the greater ecological problems of modern society. Conventional methods, like precipitation, adsorption and biosorption, electrowinning, membrane separation, solvent extraction and ion exchange are often ineffective, expensive and can generate secondary pollution. On the other hand, chelating polymers, consisting of crosslinked copolymers as a solid support and functional group (ligand), are capable of selectively loading different metal ions from aqueous solutions. In the relatively simple process, the chelating copolymer is contacted with the contaminated solution, loaded with metal ions, and stripped with the appropriate eluent. Important properties of chelating polymers are high capacity, high selectivity and fast kinetics combined with mechanical stability and chemical inertness. Macroporous hydrophilic copolymers of glycidyl methacrylate and ethylene glycol dimethacrylate modified by different amines show outstanding efficiency and selectivity for the sorption of precious and heavy metals from aqueous solutions. In this study poly(GMA-co-EGDMA) copolymers were synthesized with different porosity parameters and functionalized in reactions with ethylene diamine (EDA), diethylene triamine (DETA) and triethylene tetramine (TETA). Under non-competitive conditions, in batch experiments at room temperature, the rate of sorption of Cu(II) ions from aqueous solutions and the influence of pH on it was determined for four samples of amino-functionalized poly(GMA-co-EGDMA). The sorption of Cu(II) for both amino-functionalized samples was found to be very rapid. The sorption half time, t1/2, defined as the time required to reach 50% of the total sorption capacity, was between 1 and 2 min. The maximum sorption capacity for copper (2.80 mmol/g) was obtained on SGE-10/12-deta sample. The sorption capacity of Cu(II) ions increases with increasing pH and has maximum at pH ~5. In the experimental pH range, the maximum sorption capacity of Cu(II) ions again is reached on SGE-10/12-deta. By comparing literature data and obtained results it is possible to conclude that amino-functionalized macroporous copolymers based on glycidyl methacrylate are efficient for sorption of Cu(II) ions from aqueous solutions and sorption capacity for copper mostly depends on type of amine with which the basic copolymer is functionalized.

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Liu, Feng-Yi, Dong-Mei Zhou, Xiao-Lan Zhao i Jun-Feng Kou. "Complexes of nickel(II) and copper(II) with 1,2,4-triazole-3-carboxylic acid and of cobalt(III) with 3-amino-1,2,4-triazole-5-carboxylic acid". Acta Crystallographica Section C Structural Chemistry 73, nr 11 (24.10.2017): 1010–16. http://dx.doi.org/10.1107/s2053229617012943.

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Because of their versatile coordination modes and strong coordination ability for metals, triazole ligands can provide a wide range of possibilities for the construction of metal–organic frameworks. Three transition-metal complexes, namely bis(μ-1,2,4-triazol-4-ide-3-carboxylato)-κ3 N 2,O:N 1;κ3 N 1:N 2,O-bis[triamminenickel(II)] tetrahydrate, [Ni2(C3HN3O2)2(NH3)6]·4H2O, (I), catena-poly[[[diamminediaquacopper(II)]-μ-1,2,4-triazol-4-ide-3-carboxylato-κ3 N 1:N 4,O-[diamminecopper(II)]-μ-1,2,4-triazol-4-ide-3-carboxylato-κ3 N 4,O:N 1] dihydrate], {[Cu2(C3HN3O2)2(NH3)4(H2O)2]·2H2O} n , (II), (μ-5-amino-1,2,4-triazol-1-ide-3-carboxylato-κ2 N 1:N 2)di-μ-hydroxido-κ4 O:O-bis[triamminecobalt(III)] nitrate hydroxide trihydrate, [Co2(C3H2N4O2)(OH)2(NH3)6](NO3)(OH)·3H2O, (III), with different structural forms have been prepared by the reaction of transition metal salts, i.e. NiCl2, CuCl2 and Co(NO3)2, with 1,2,4-triazole-3-carboxylic acid or 3-amino-1,2,4-triazole-5-carboxylic acid hemihydrate in aqueous ammonia at room temperature. Compound (I) is a dinuclear complex. Extensive O—H...O, O—H...N and N—H...O hydrogen bonds and π–π stacking interactions between the centroids of the triazole rings contribute to the formation of the three-dimensional supramolecular structure. Compound (II) exhibits a one-dimensional chain structure, with O—H...O hydrogen bonds and weak O—H...N, N—H...O and C—H...O hydrogen bonds linking anions and lattice water molecules into the three-dimensional supramolecular structure. Compared with compound (I), compound (III) is a structurally different dinuclear complex. Extensive N—H...O, N—H...N, O—H...N and O—H...O hydrogen bonding occurs in the structure, leading to the formation of the three-dimensional supramolecular structure.

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Rahman, Md Lutfor, Shaheen M. Sarkar, Mashitah Mohd Yusoff i Mohd Harun Abdullah. "Optical detection and efficient removal of transition metal ions from water using poly(hydroxamic acid) ligand". Sensors and Actuators B: Chemical 242 (kwiecień 2017): 595–608. http://dx.doi.org/10.1016/j.snb.2016.11.007.

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Weiß, Dana, Annette Schier i Hubert Schmidbaur. "2-Diphenylphosphino-phenoI as a Ligand for Mono- and Poly-Nuclear Complexes of Manganese, Cobalt, Nickel, Zinc, and Cadmium". Zeitschrift für Naturforschung B 53, nr 11 (1.11.1998): 1307–12. http://dx.doi.org/10.1515/znb-1998-1112.

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2-Diphenylphosphino-phenol was chosen as an ambivalent (hard/soft) chelating ligand for biologically important first row transition metals. The expected mode of complexation is relevant to trapping of metal ions in humic acids and related environmental ion exchange systems with phenolate functions. The 1:2 complex with nickel(II) is known to have a standard mononuclear square-planar structure, and experimental evidence suggests that the new cobalt(II) complex is analogous. By contrast, zinc and cadmium were found to give novel trinulear complexes [M3(2- Ph2P-C6H4O)6], M = Zn, Cd. In a chain of three metal atoms, the octahedrally coordinated central atom resides on a center of inversion and is solely oxygen-bound [MO6], while the two peripheral metal atoms are in a mixed coordination environment [fac-MO3P3], The analogous manganese(II) complex crystallizes as a net trihydrate, where two different trinuclear units are present in the lattice. One is of a new type and represents a centrosymmetrical hexahydrate [Mn3(2-Ph2P-C6H4 0)6(OH2)6]. The central part is an octahedral [Mn(OH2)6]2+ dication, which is hydrogen-bonded to two [Mn(2 -Ph2P-C6H4O)3]- anions. The nickel(II) complex was found to form 1:1 adducts with ZnCl2 or ZnBr2. The two complexes are isomorphous. In the adduct structure the zinc atom is attached to the two oxygen atoms of the nickel compound leaving the remainder of the molecular geometry largely unchanged. Together with the two halogen atoms a tetrahedral environment [ZnO2X2] is formed (X = Cl, Br), while the nickel atom retains its square planar [NiO2P2] environment.

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Venkatramaiah, Nutalapati, Ricardo F. Mendes, Artur M. S. Silva, João P. C. Tomé i Filipe A. Almeida Paz. "A ladder coordination polymer based on Ca2+and (4,5-dicyano-1,2-phenylene)bis(phosphonic acid): crystal structure and solution-state NMR study". Acta Crystallographica Section C Structural Chemistry 72, nr 9 (25.08.2016): 685–91. http://dx.doi.org/10.1107/s2053229616012328.

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The preparation of coordination polymers (CPs) based on either transition metal centres or rare-earth cations has grown considerably in recent decades. The different coordination chemistry of these metals allied to the use of a large variety of organic linkers has led to an amazing structural diversity. Most of these compounds are based on carboxylic acids or nitrogen-containing ligands. More recently, a wide range of molecules containing phosphonic acid groups have been reported. For the particular case of Ca2+-based CPs, some interesting functional materials have been reported. A novel one-dimensional Ca2+-based coordination polymer with a new organic linker, namely poly[[diaqua[μ4-(4,5-dicyano-1,2-phenylene)bis(phosphonato)][μ3-(4,5-dicyano-1,2-phenylene)bis(phosphonato)]dicalcium(II)] tetrahydrate], {[Ca2(C8H4N2O6P2)2(H2O)2]·4H2O}n, has been prepared at ambient temperature. The crystal structure features one-dimensional ladder-like∞1[Ca2(H2cpp)2(H2O)2] polymers [H2cpp is (4,5-dicyano-1,2-phenylene)bis(phosphonate)], which are created by two distinct coordination modes of the anionic H2cpp2−cyanophosphonate organic linkers: while one molecule is only bound to Ca2+cationsviathe phosphonate groups, the other establishes an extra single connectionviaa cyano group. Ladders close pack with water molecules through an extensive network of strong and highly directional O—H...O and O—H...N hydrogen bonds; the observed donor–acceptor distances range from 2.499 (5) to 3.004 (6) Å and the interaction angles were found in the range 135–178°. One water molecule was found to be disordered over three distinct crystallographic positions. A detailed solution-state NMR study of the organic linker is also provided.

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Bitterwolf, Thomas E. "Evidence for metal to solvent charge transfer photooxidation of iron, cobalt, nickel and copper dithiocarbamato derivatives in poly(vinylchloride) matrices at ca. 90K: New insights into the bonding of late transition metals with dithiocarbamate ligands through DFT modeling". Inorganica Chimica Acta 361, nr 5 (kwiecień 2008): 1319–26. http://dx.doi.org/10.1016/j.ica.2007.08.017.

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Jabbar, Araf Ismael, Mahmoud Najim Al-jibouri i Ahmad H. Ismail. "Synthesis and Structural Studies of Transition Metals Complexes with Poly dentate Azo dye ligand Derived from Coumarine11". Egyptian Journal of Chemistry, 5.06.2021, 0. http://dx.doi.org/10.21608/ejchem.2021.78215.3826.

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Wehmeyer, Frerk-Ulfert, i Robert Langer. "A hampered oxidative addition of pre-coordinated pincer ligands can favour alternative pathways of activation". Chemical Communications, 2023. http://dx.doi.org/10.1039/d3cc00874f.

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Pre-coordination to a transition metal by the terminal donor groups of a tri-dentate ligand is a common strategy to stabilise elusive groups, to achieve unprecedented bond activation and to develop...

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Ojha, Smriti, Preeti Verma, Sushil Kumar i Sudhanshu Mishra. "Synthesis characterization and biological activity of 4-methyl-benzene sulfonohydrazide derivatives". Letters in Drug Design & Discovery 20 (24.10.2022). http://dx.doi.org/10.2174/1570180820666221024141247.

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Background: A Schiff base is generally bi- or tri-dentate ligands capable of forming very stable complexes with transition metals. Schiff base complexes have synthetic flexibilities and biological activity against various diseases. Objective: In the current study, Schiff bases compounds [PV1 – PV5] were synthesized from 4-methyl-1-benzene sulfonyl chloride. Subsequently, the synthesized products were analyzed for their antibacterial activity. Methods: Schiff base is a nitrogen analog with a carbonyl group. The reaction that results in the formation of new complexes involves the condensation of carbonyl compounds with an amine group. Furthermore, thin layer chromatography, FT-IR spectroscopy, and 1H-NMR were performed for product characterization. Results: All five complexes were successfully synthesized and some of the compounds demonstrated antibacterial, antifungal, anti-inflammatory and analgesic properties. Conclusion: The results confirmed the structure and presence of functional groups as per the scheme of synthesis. These synthesized compounds have the potential to treat the studied diseases and could be used as a therapeutic candidate if further research is done.

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Ali, Tamer Awad, Samy B. El-Henawy i Gehad G. Mohamed. "Electroanalytical determination of Al(III) ion in petroleum water samples using symmetric 1,3-diamine-based Schiff base as a carrier". Journal of the Iranian Chemical Society, 18.04.2022. http://dx.doi.org/10.1007/s13738-022-02549-0.

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AbstractThe capacity of a synthetic (N1E, N3E)-N1,N3-bis(quinolin-2-ylmethylene)benzene-1,3-diamine Schiff base ligand to operate as a cation carrier in a poly(vinylchloride) (PVC) membrane (electrode I) and screen-printed ion-selective electrode (SPE) (electrode II) was investigated. The screen-printed and the fabricated poly(vinylchloride) membrane (PVC) electrodes displayed outstanding response properties for Al(III) ions. The electrodes had linear potential response with a slope of 17.95 ± 0.14 and 19.80 ± 0.46 mV decade−1 in the concentration range of 1.0 × 10−5–1.0 × 10−1 and 1.0 × 10−7–1.0 × 10−1 mol L−1 for electrode I and electrode II, respectively. The detection limit of the proposed sensors is 2.1 × 10−6 and 6.3 × 10−8 mol L−1, and it can be used over a period of 35 and 190 days for electrode I and electrode II, respectively. The suggested sensors showed strong selectivity against a wide range of other cations, including alkali, alkaline earth, heavy, and transition metals, and could be employed in pH ranges of 3.0–6.0 and 2.5–6.5 for electrode I and electrode II, respectively. The effect of several plasticizers has been studied. These electrodes had been successfully used to determine Al(III) in aqueous solution and various real water samples. They used as an indicator electrodes in aluminum ion potentiometric titration against standard EDTA solution. The devised approach was used to determine the concentration of Al(III) in several real water samples with high percentage recoveries and low standard and relative standard deviation values. The results were in good agreement with those obtained using atomic absorption spectrometry as indicated from the calculated t- and F-test values.

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