RESUMO
An interaction of M(hfac)2 (M = Mn or Ni) with N-(bis(4,4,5,5-tetramethyl-3-oxido-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)methylene)-2-methyl-propan-2-amine oxide (a nitronyl nitroxide diradical with the >C[double bond, length as m-dash]N(O)-tert-Bu coupler) was investigated under various conditions. It was found that prolongation of reaction time caused transformation of the initial diradical into new diradicals with the unique >C[double bond, length as m-dash]N-OH coupling unit and formation of binuclear Mn(ii) and Ni(ii) complexes, which were characterized by X-ray diffraction analysis. The resulting binuclear heterospin complexes have a complicated magnetic structure with six paramagnetic centers and a number of exchange interaction channels between them, as well as between neighboring complexes. To adequately describe the magnetic properties of these complexes, high-level ab initio calculations of their electronic structure and parameters of the spin-Hamiltonian were carried out. The accuracy of the conventional broken-symmetry density functional theory approach in the calculation of the exchange interaction parameters was also verified.
RESUMO
A sequence of stages in the syntheses of isomeric bisamino acid complexes of Pt(II) with beta-aminopropionic acid (beta-alanine = beta-AlaH) has been studied by the (195)Pt NMR spectroscopy. The techniques have been developed of the synthesis of the cis- and trans-bischelates of Pt(II) and Pd(II) with beta-alanine as well as of the halide complexes of trans-[M(beta-AlaH)(2)Cl(2)] (M = Pt, Pd) and trans-K(2)[Pt(beta-Ala)(2)I(2)] types. The NMR spectroscopy and IR spectroscopy (in the nuclei of (195)Pt,(13)C,(1)H) and X-ray diffraction analysis have been used to examine the structures of the synthesized compounds.
