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The paper reports the methods for the synthesis of new cluster compounds of trans-tetrachlorodi-μ-carboxylates of dirhenium(III) with dipeptides of the glycyl series. The compositions and the structures were determined by electron absorption and IR spectroscopies as well as by elemental analysis for the following newly synthesized compounds: trans-[Re2(H3N+- CH2-CO-NH-CH(COO)-CH2-CH(CH3)-CH3)2Cl4·2CH3CN]Cl2 (I) and trans-[Re2(H3N+-CH2-CO-NH-CH(COO)-CH2-C6H5)2Cl4·2CH3CN]Cl2 (II). Analysis of the electronic absorption spectra of the solutions of the synthesized substances showed the presence of a doublet pattern (12500 and 16129 cm-1), which corresponds to the δ→δ*-electronic transition of the Re-Re quadruple bond characteristic of solutions of trans-tetrachlorodi-μ-carboxylates of dirhenium (III). The appearance of oscillations at 1485 cm-1 for I and 1486 cm-1 for II, characteristic of the νs(CO) of the coordinated carboxylate group, was detected on the IR spectra, which indicates the bridging coordination of this group to the ... binuclear fragment. The protonation of the amino group is indicated by the appearance of a wide band of valence oscillations ... in the range of 3400-3350 cm-1 and deformation oscillations ... at 1557 cm-1 and 1614 cm-1 for I and II, respectively. The stability of the obtained complex compounds in aqueous solutions was determined. It was shown that the hydrolysis of the synthesized substances takes place in 4-5 days, which is accompanied by a decrease in the pH of the reaction solution. [ABSTRACT FROM AUTHOR]

Density functional theory studies of structural and electronic properties of small clusters were performed. For each cluster an optimization of structure and the basic properties of the band structure were conducted. It was determined that with increasing (n) energetically more efficient in the small clusters is stabilization from the ring to fulleren-like structures containing tetragonal and hexagonal faces and all atoms have coordination number equal three. Among the clusters (ZnO)12 with doped atoms most stable are clusters where Zn was replaced by Mn, Cu and Co atoms. Band gap in the electronic spectrum of doped clusters decreases due to p-d hybridization orbitals of the impurity atom with the orbitals of the oxygen atom. [ABSTRACT FROM AUTHOR]