Showing papers by "Milan Melnik published in 2012"

Platinum organometallic compounds: classification and analysis of crystallographic and structural data. Monomeric Pt compounds with PtC2AB, PtA2BC and PtABCD compositions

Abstract: Abstract This review covers almost 350 four-coordinated monomeric organoplatinum complexes with PtC2AB, PtA2BC and PtABCD compositions, and there is wide variability of chromophores. The most common ligands in addition to the C donor are PPh3 and chlorine. Platinum(II) is found only in a square-planar environment involving cis- as well as trans-configurations with a different degree of distortion, especially when bi- or terdentate ligands are present. The trans-effect decreases in the order of the atoms in which the effect dominates, H>C>P>Si>S. There are at least two types of isomerism, cis-trans and distortion. The data strongly suggest that distortion isomerism is, for platinum chemistry, more common than cis- and trans-isomerism.

Structural characterization of heterometallic platinum complexes with non-transition metals. Part II: heterotrimeric complexes

Abstract: Abstract We analyzed and classified almost 100 heterotrimers of platinum with non-transition metals of the composition Pt2M (42 examples), PtM2 (48 examples), and PtMM' (6 examples). These trimers crystallized in five crystal classes: rhombohedral and tetragonal, each 1.5%; orthorhombic, 4%; triclinic, 35%; and monoclinic, 58%. There are 15 non-transition metals: Ge, Sn, Pb, Zn, Cd, Hg, Li, Na, K, Ga, In, Tl, Al, Sb, and Bi, which are partners to Pt for the creation of their respective heterotrimers. The three metal atoms form a wide variety of frameworks, with triangular and linear the most common. There is a rich variety of Pt-M bond lengths, with the mean values following the order: 2.326 Å (M=Al)<2.351 Å (Ga)<2.450 Å (Ge)<2.549 Å (Sn)<2.560 Å (Sb)<2.562 Å (In)<2.582 Å (Li)<2.658 Å (Hg)<2.738 (Pb)<2.770 Å (Tl). In the series Pt2M, the mean Pt-Pt bond distance is 2.803 Å. Correlations between structural parameters, heterometals, and donor ligands were developed and discussed.

Platinum organometallic compounds: classification and analysis of crystallographic and structural data. Part I. Monomeric Pt(0) and partly of Pt(II) with PtC4, PtA3B and PtC2A2 chromophores

Abstract: Abstract This review covers over 110 monomeric Pt(0) organometallics and 220 monomeric Pt(II) organometallics. The predominant geometry for Pt(0) is square planar, with some examples of two-, five-, and six-coordinated. The monomeric Pt(II) organometallics in the review covers only those with the chromophores PtC4, PtA3B and PtC2A2. The most common ligand, besides C donor ligands, which are of a wide variety, is PPh3. At least two types of isomerism occur in the platinum organometallics analysed in this review: cis-trans and distortion. Relations between Pt-ligand bond distances, bond angles and transeffect are discussed regarding steric and electronic influence.

Structural characterization of heteropolymeric iron and main group metal complexes

Abstract: Abstract This review summarizes almost 40 structures of polymeric Fe(M), where M=Mg, Ca, Sr, Ba, In, Te, Ge, Sn, Bi, Zn, Cd and Hg complexes. The complexes crystallized in the monoclinic, tetragonal, orthorhombic and triclinic classes, from which the monoclinic by far prevails (∼50%). The most common ligands are with O, N and C donor atoms. The iron atoms are found in the oxidation states 0, +2 and +3, with +3 being the most common. In most complexes the iron(0) is 5-, iron(II) and iron(III) are 6-coordinated, but there are examples of 3-, 5- and even 7-coordinated complexes. The inner coordination spheres about the M atoms range from 3 to 11. The structures are discussed in terms of the coordination about the metal atoms, and correlations are outlined between donor atoms, bond lengths and interbond angles.