The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform
Lenka Piknová-findoráková - One of the best experts on this subject based on the ideXlab platform.
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The physicochemical and biological properties of zinc(II) complexes
Journal of Thermal Analysis and Calorimetry, 2007Co-Authors: Erika Szunyogová, Dagmar Mudroňová, Katarína Györyová, Radomíra Nemcová, Jana Kovářová, Lenka Piknová-findorákováAbstract:Spectroscopic (IR), thermoanalytical (TG/DTG, DTA) and biological methods were applied to investigate physicochemical and biological properties of seven zinc(II) complex compounds of the following formula Zn(HCOO)_2·2H_2O (I), Zn(HCOO)_2·tph (II), Zn(CH_3COO)_2·2H_2O (III), Zn(CH_3COO)_2·tph (IV), Zn(CH_3COO)_2·2phen (V), Zn(CH_3CH_2COO)_2·2H_2O (VI), Zn(CH_3CH_2CH_2COO)_2·2H_2O (VII), where tph=theophylline, phen=phenazone. The formation of various intermediates during thermal decomposition suggests the dependence on the length of aliphatic carboxylic chain and type of N-Donor Ligand (tph, phen). The final product of the thermal decomposition was ZnO. The antimicrobial activity of these complexes were tested against G^+ and G^– bacteria. Strong inhibitive effect was observed towards E. coli , salmonellae and Staph. aureus .
Tatsuo Yajima - One of the best experts on this subject based on the ideXlab platform.
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attractive Ligand Ligand interactions involving aromatic rings in five coordinate ternary copper ii complexes with a dipeptide and a bidentate n donor Ligand
Inorganica Chimica Acta, 2002Co-Authors: Tatsuo Yajima, Maki Okajima, Akira Odani, Osamu YamauchiAbstract:Structures and stabilities of ternary copper(II) complexes, Cu(DP)(DA), where DP and DA denote dipeptides with an aromatic amino acid residue and bidentate nitrogen donor Ligands, respectively, have been studied by synthetic, crystallographic, potentiometric, and spectroscopic methods. The X-ray crystal structure analysis of [Cu(gly/L-tyr)(bzp)] (gly/L-tyr� /glycyl-Ltyrosinate, bzp� /N -benzyl-N -2-pyridylmethylamine) revealed that the complex has a distorted square-pyramidal structure exhibiting an intramolecular edge-to-face stacking interaction between the pyridine ring of bzp and the phenol ring of gly/L-tyr around the Cu(II) center. [Cu(gly/L-tyr)(bzmp)] (bzmp � /N -benzyl-N -6-methyl-2-pyridylmethylamine) was also revealed to hav ea similar structure and an intramolecular CH-p-type interaction between the methyl group of bzmp and the phenol ring of gly/L-tyr. The absorption spectra of the ternary Cu(II) � /DP � /DA systems in water showed that the ternary complexes have a shoulder peak near 900 nm, supporting that the Cu(II) center has a square-pyramidal geometry. From the stability constants for the ternary Cu(II) complexes determined by pH titration at 25 8C and I� /0.1 M (KNO3), Cu(gly/L-tyr)(DA) and Cu(gly/L-trp)(DA) (DA � /Ligands with one or two aromatic rings) were found to be stabilized relative to Cu(gly/gly)(DA) (gly/gly� /glycylglycinate), which has been concluded to be due to the contribution of the edge-to-face or CH-p interactions within the complexes in solution. # 2002 Elsevier Science B.V. All rights reserved.
Osamu Yamauchi - One of the best experts on this subject based on the ideXlab platform.
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attractive Ligand Ligand interactions involving aromatic rings in five coordinate ternary copper ii complexes with a dipeptide and a bidentate n donor Ligand
Inorganica Chimica Acta, 2002Co-Authors: Tatsuo Yajima, Maki Okajima, Akira Odani, Osamu YamauchiAbstract:Structures and stabilities of ternary copper(II) complexes, Cu(DP)(DA), where DP and DA denote dipeptides with an aromatic amino acid residue and bidentate nitrogen donor Ligands, respectively, have been studied by synthetic, crystallographic, potentiometric, and spectroscopic methods. The X-ray crystal structure analysis of [Cu(gly/L-tyr)(bzp)] (gly/L-tyr� /glycyl-Ltyrosinate, bzp� /N -benzyl-N -2-pyridylmethylamine) revealed that the complex has a distorted square-pyramidal structure exhibiting an intramolecular edge-to-face stacking interaction between the pyridine ring of bzp and the phenol ring of gly/L-tyr around the Cu(II) center. [Cu(gly/L-tyr)(bzmp)] (bzmp � /N -benzyl-N -6-methyl-2-pyridylmethylamine) was also revealed to hav ea similar structure and an intramolecular CH-p-type interaction between the methyl group of bzmp and the phenol ring of gly/L-tyr. The absorption spectra of the ternary Cu(II) � /DP � /DA systems in water showed that the ternary complexes have a shoulder peak near 900 nm, supporting that the Cu(II) center has a square-pyramidal geometry. From the stability constants for the ternary Cu(II) complexes determined by pH titration at 25 8C and I� /0.1 M (KNO3), Cu(gly/L-tyr)(DA) and Cu(gly/L-trp)(DA) (DA � /Ligands with one or two aromatic rings) were found to be stabilized relative to Cu(gly/gly)(DA) (gly/gly� /glycylglycinate), which has been concluded to be due to the contribution of the edge-to-face or CH-p interactions within the complexes in solution. # 2002 Elsevier Science B.V. All rights reserved.
Alan E. Rowan - One of the best experts on this subject based on the ideXlab platform.
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2. The multiple phenyl embrace as a synthon in cu(i)/pph(3)/N-Donor Ligand coordination polymers
Crystal Growth & Design, 2011Co-Authors: Femke F. B. J. Janssen, R. De Gelder, Alan E. RowanAbstract:The multiple phenyl embrace is a supramolecular motif comprised of phenyl-phenyl interactions, which can, like hydrogen bonds, form extended networks between molecules in the solid state. The analysis of 23 crystal structures of coordination polymers based on the M/PPh3/N-Donor Ligand system (M = Cu(I) or Ag(I)) showed that 71% of the independent M-PPh 3 groups are involved in a 6-fold phenyl embrace (6PE). Strong 6PE interactions are obtained when the geometry of the PPh3 group can be described as a rotor. The analysis of these groups showed that 83% of the PPh3 groups have their phenyl groups in the rotor conformation. It is shown, however, that these good rotors are not necessarily involved in the 6PE and that the 6PE can also be formed by nonrotors. In the Cu(I)/PPh 3/N-Donor Ligand system, the 6PE interactions form an independent connection (often) perpendicular to the backbone of the coordination polymer. In many cases, the 6PE increases the dimensionality of the network formed between Cu(I) and N-Donor Ligands. Therefore, the multiple phenyl embrace seems to be a useful synthon in crystal engineering of stable networks.
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1. Solvent, linker, and anion effects on the formation, connectivity, and topology of cu(i)/pph(3)/N-Donor Ligand coordination polymers
Crystal Growth & Design, 2011Co-Authors: Femke F. B. J. Janssen, Laurens P. J. Veraart, Jan M. M. Smits, René De Gelder, Alan E. RowanAbstract:The effect of linker, anion, and solvent on the formation, topology, and connectivity of coordination polymers was investigated for polymers resulting from reactions between [Cu(MeCN)2(PPh3)2][X] (X = BF4–, ClO4–, and PF6–) and nitrogen donor Ligands (pyrazine, 4,4′-bipyridine, and 3,4′-bipyridine) in three solvents (CH2Cl2, CHCl3, tetrahydrofuran (THF)). The 18 crystallization experiments with linear N-Donor Ligands yielded seven crystal structures of one-dimensional (1D) and five crystal structures of two-dimensional (2D) coordination polymers. The nine crystallization experiments with the nonlinear N-Donor Ligand yielded four crystal structures showing 1D coordination polymers. The isolated compounds with linear N-Donor Ligands were characterized by X-ray diffraction techniques, elemental analysis, and 1H NMR. The compounds with 3,4′-bipyridine were analyzed with single-crystal diffraction. The thermal properties of several coordination polymers were investigated by thermal gravimetric analysis (TGA) a...
Erika Szunyogová - One of the best experts on this subject based on the ideXlab platform.
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The physicochemical and biological properties of zinc(II) complexes
Journal of Thermal Analysis and Calorimetry, 2007Co-Authors: Erika Szunyogová, Dagmar Mudroňová, Katarína Györyová, Radomíra Nemcová, Jana Kovářová, Lenka Piknová-findorákováAbstract:Spectroscopic (IR), thermoanalytical (TG/DTG, DTA) and biological methods were applied to investigate physicochemical and biological properties of seven zinc(II) complex compounds of the following formula Zn(HCOO)_2·2H_2O (I), Zn(HCOO)_2·tph (II), Zn(CH_3COO)_2·2H_2O (III), Zn(CH_3COO)_2·tph (IV), Zn(CH_3COO)_2·2phen (V), Zn(CH_3CH_2COO)_2·2H_2O (VI), Zn(CH_3CH_2CH_2COO)_2·2H_2O (VII), where tph=theophylline, phen=phenazone. The formation of various intermediates during thermal decomposition suggests the dependence on the length of aliphatic carboxylic chain and type of N-Donor Ligand (tph, phen). The final product of the thermal decomposition was ZnO. The antimicrobial activity of these complexes were tested against G^+ and G^– bacteria. Strong inhibitive effect was observed towards E. coli , salmonellae and Staph. aureus .
