Volume 41, Issue 1-2

An analysis of the structural parameters of PtM, Pt 2 M, PtM 2 and PtMM′ (M = non-transition metals) derivatives shows that each complex contains two crystallographically independent molecules within the same crystal. The respective molecules differ by the degrees of distortion and exemplify the distortion isomerism. These are discussed in terms of the coordination with the platinum and the M atoms and the correlations are drawn among the metal atoms, donor atoms, bond lengths and bond angles. A wide variety of non-transition metals (Sn, Ga, In, Tl, Zn, Cd, Hg, Sb) exist, among which the most prevalent is Sn.

Substances like 3-aminopropyltriethoxysilane are often used as adhesive promoters in various formulations for coatings or to adjust the properties of siloxanes and other polymers. Cyclisation of similar substances is also interesting because of the formation of the Si-N bond. 1-Aza-2-silacyclopentanes were synthesised from 3-aminopropylalkoxysilanes by intramolecular condensation reactions and substitution reactions at the silicon atom. The products tend to undergo ring-opening polymerisation. In contrast to literature reports, they can only be isolated as N -substituted derivatives. Phenylisocyanate inserts into the Si-N bonds of cyclic aminosilanes to form seven-membered heterocycles. Furthermore, phenylisocyanate reacts with N-H bonds in the same molecule. Two insertion products were isolated, and their crystal structures were determined.

The Zinc oxide-cerium oxide (ZnO-CeO 2 ) nanocomposite was prepared by a coprecipitation method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and particle size distribution analysis. The XRD pattern shows the cubic phase of cerium oxide as the dominant phase. The FE-SEM images show the homogeneity distribution of zinc and cerium oxides in the sample. The mean particle size of the nanocomposite determined by dynamic light scattering technique was 58 nm. The catalytic activity of ZnO-CeO 2 nanocomposite was examined on the synthesis of thieno[2,3- d ]pyrimidin-4(3 H )-one derivatives. In all cases, the products were obtained in good to excellent yields.

The new diorganotin(IV) complexes of composition [Me 2 Sn(C 6 H 5 OCH 2 CONHO) 2 ](I) and [ n -Bu 2 Sn(C 6 H 5 OCH 2 CONHO) 2 ](II) have been synthesized by the reactions of Me 2 SnCl 2 and n -Bu 2 SnCl 2 with potassium phenoxyacetohydroxamate (PhOAHK=C 6 H 5 OCH 2 CONHOK) in 1:2 molar ratio in methanol and benzene solvent medium and characterized by elemental analyses and spectroscopic techniques (infrared, 1 H nuclear magnetic resonance and mass spectrometry). The [O,O coordination] through carbonyl and hydroxamic oxygen atoms and distorted octahedral geometry around the mononuclear tin has been inferred. The electrochemical behavior of complexes studied by the cyclic voltammetric technique has shown quasi-irreversible two-step reduction from tin (IV) to tin (II). Thermal behavior of complexes studied by the thermogravimetric technique in N 2 atmosphere has yielded SnO as the decomposition product. The in vitro antimicrobial activity assays against various pathogenic Gram-negative bacteria, namely, Salmonella typhi , Escherichia coli ; Gram-positive Bacillus cereus and Staphylococcus aureus and fungi Aspergillus niger and Alternaria alternata by the minimum inhibitory concentration method have shown their potential as promising antimicrobial agents compared to the respective standard chloramphenicol and nystatin drugs.

Geometries and electronic properties of PdWSi n ( n =10–20) clusters are investigated by density functional methods. According to our calculated results, it is obvious that tungsten (W)-encapsulated silicon frame determines the final PdWSi n ( n =10–20) forms because W and silicon (Si) interactions are stronger than palladium (Pd)-Si interactions. The electronic charges are transferred from the Si frame to W firstly and Pd finally, which is completely different from the homoatomic transition metal (TM) 2 -doped silicon clusters. The calculated highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps exhibit that PdWSi 12 has the biggest HOMO-LUMO gap.

Reaction of [Al(OPr i ) 3 ] with K(OPr i ), in 1:1 molar ratio in refluxing anhydrous tetrahydrofuran yields a polymeric complex [(THF)K(μ-OPr i ) 2 Al(μ-OPr i ) 2 ] n . The complex is characterized by spectroscopic studies and single crystal X-raydiffraction analysis.