Showing papers by "Milan Melnik published in 1993"
24 citations
TL;DR: In this article, the coordination polyhedron around Cu(II) is a highly deformed octahedron, formed by four carboxylate oxygen atoms from two salicylate ligands [Cu − O bond lengths are 1.935(6) (2 ×) and 2.609 (6) A (2)
Abstract: Dark violet crystals of Cu(C 6 H 4 OHCOO) 2 (NC 5 H 4 CONH 2 ) 2 crystallize in the orthorhombic system, group Pbca (No. 61), with unit cell parameters a = 14.625(7), b = 9.572(5), c = 18.671(9) A, V = 2613.76 A 3 Z = 4. The structure was solved using direct methods, and refined by the least-squares method. Final R = 0.055 for 1361 independent reflexions. The coordination polyhedron around Cu(II) is a highly deformed octahedron, formed by four carboxylate oxygen atoms from two salicylate ligands [Cu − O bond lengths are 1.935(6) (2 ×) and 2.609(6) A (2 ×)] and two nitrogen atoms from two nicotinamides [Cu − N bond lengths: 1.994(7) A (2 ×)]. Molecular structural units in the crystal are interlinked by hydrogen bonds of nitrogen and oxygen atoms of nicotinamides
16 citations
TL;DR: In this article, the synthesis and characterisation of Cu(niflumate)2 and 3-pyridylcarbnol (3-Pyrinol)2 is reported based on elemental analyses, electronic and EPR spectra and magnetic susceptibility measurements over a temperature range (4.2 to 295K).
Abstract: The synthesis and characterisation of Cu(niflumate)2 and Cu(niflumate)2(3-pyridylcarbnol)2 is reported. Characterisation of the compounds were based on elemental analyses, electronic and EPR spectra and magnetic susceptibility measurements over a temperature range (4.2 to 295K). ESR of powdered solids were typical for S = 1/2, with well resolved perpendicular and parallel hyperfine splitting. Magnetic susceptibilities obey the Curie-Weiss law. Both compounds have a probable polymeric structure with a pseudo-octahedral environment about the Cu(II) centre.
6 citations
TL;DR: In this paper, the spectra of dimeric copper(II) carboxylate complexes of the type Cu(CH3COO)2L with the biologically important ligand L = nicotinamide are reported.
Abstract: ESR studies of dimeric copper(II) carboxylate complexes of the type Cu(CH3COO)2L.2H2O and Cu(CH3CH2COO)2L with the biologically important ligand L = nicotinamide are reported. The spectra show features corresponding to dimeric copper(II) complexes, and which at low temperatures are well resolved. Seven lines from hyperfine splitting Az2 (high-field side) and six of seven lines from hyperfine splitting Az1 (low-field side) are found. The observed resonances are used to calculate the zero-field splitting parameters D and E. Spin-Hamiltonian and zero-field splitting parameters are used to estimate the antiferromagnetic interaction; for Cu(CH3CH2COO)2L.2H2O-2J = 320 cm−1 and for Cu(CH3CH2COO)2L - 2J = 332 cm−1.
5 citations
Journal Article•
4 citations
TL;DR: In this article, the synthesis and characterization of the complexes CuX2(nia)2 (where X=ClCH2COO−, Cl2CHCOO+, Cl3CCOO− and CH3CHClCOO+) is reported.
Abstract: The synthesis and characterization of the complexes CuX2(nia)2 (where X=ClCH2COO−, Cl2CHCOO−, Cl3CCOO−, CH3CHClCOO− or CH3CCl2COO−, and nia=nicotinamide) is reported. Characterization of the compounds was based on elemental analysis, electronic and EPR spectra, and magnetic susceptibility measurements over a temperature range. Available evidence supports a pseudo−octahedral environment around copper(II). The magnetic properties for the compounds indicate the presence of weak antiferromagnetic interactions. EPR spectra of finely ground polycrystalline samples are consistent with an essentially dx2−y2 ground state.
2 citations