Showing papers by "Milan Melnik published in 2001"

Copper(II) clofibriates, Part II. A two-dimensional coordination polymer of Cu(clofibriate)2(3-pyridylmethanol)2

Abstract: A two-dimensional coordination polymer of [Cu(clof)2(3-pymeth)2]n1 (clof = clofibriate anion and 3-pymeth = 3-pyridylmethanol) has been synthesized and characterized by single crystal structural analysis. The coordination environment about the copper(II) atom is tetragonal bipyramidal. The compound crystallizes in the monoclinic system, space group P21/c with a = 15.206(3), b = 8.029(2), c = 14.338(3) A, β = 113.64(3)°, V = 1603.6(6) A3 and Z = 2.

Heterometallic tin compounds: classification and analysis of crystallographic and structural data: part ii. trimeric to polymeric derivatives

Abstract: ABSTRACT Over 380 heterometallic tin compounds include 130 trimers, 100 tetramers, 30 pentamers. 45 hexamers. 15 heptamers, 12 octamers, 20 oligomers and 30 polymers. In these the Sn atom is found in oxidation states of 0, +2 and +4, with geometries including trigonal planar, tetrahedral. trigonal bipyramidal, octahedral and seven coordinate, with varying degrees of distortion. Of these, the first only exhibits Sn(0) and Sn(II) and the last only Sn(II) oxidation states, with tetrahedral geometry the most common overall. Examples of distortion isomersim are reported, with many being exhibited within the same crystal. The heterometal atoms include the transition and lanthanide metals along with the non-transition metals. Outside the dimers. the shortest Sn-M(non-transition) bond distances are found in the tetramers and hexamers. Both Sn(IV) and Sn(II) are found bonded to a variety of \"hard\" and \"soft\" heterometal atoms. Comparisons are made with the much less rich chemistry of Pb

Crystal structure, spectral and magnetic behavior of copper(ii)(5-chlorosalicylato)2 (aqua)2

Abstract: The synthesis and characterization of Cu(5-Clsal)2(H2O)2 (5-Clsal = 5-chlorosalicylate) are reported. Characterization of the compound was based on elemental analysis, electronic and EPR spectra, and magnetic susceptibility measurement over a temperature range 93–239 K. An X-ray analysis of Cu(5-Clsal)2(H2O)2 was carried out, showing a polymeric chain of copper(II) atoms bridged by pairs of water molecules with Cu-O(bridge) bond lengths of 1.970(2) and 2.718(2)A. The coordination sphere about each copper(II) atom is completed (on the X-axis) by a trans-pair of unidentate 5-chlorosalicylate anions. The bridging oxygen atoms arrange a planar Cu2O2 rhombus. The relationship between degree of distortion and g-values from EPR spectra is also discussed.

Germanium coordination compounds: classification and analysis of crystallographic and structural data

Abstract: ABSTRACT This review covers the ciystallographic and structural data for almost two hundred coordination compounds of germanium. In the majority the oxidation number of germanium is +4, with about one quarter being +2. Up to ten Ge atoms are found in anionic clusters. Coordination numbers from four to six with geometries of letrahedral. trigonal bipyramidal, square pyramidal, octahedral and pseudo-octahedral for the Ge(IV) derivatives, and two to four with geometries governed by a lone pair of electrons. The most common donor atoms are Ν and O. Distortion or configurational isomerism is reported in about 10% of the derivatives. Relationships between ligands. bond distances and bond angles are discussed in terms of steric and electronic influences.