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New copper(II) complexes with 8-hydroxyquinoline-2-carbaldehyde-N-methylnitrone (HL1) (1) and pyridine-2-carbaldehyde-N-methylnitrone (L2) (2) have been synthesized. The crystal structure of compound 1 consists of binuclear molecules Cu2(L1)2(NO3)2 with the oxygen atoms of the hydroxy groups acting as bridges between the copper ions. The nitrone ligand in 1 is coordinated in a tridentate fashion forming five-and six-membered chelate rings, and the copper ions have a square-pyramidal environment with the bridging oxygen atoms in apical positions. In compound 2 Cu(L2)2(NO3)2, the copper atom adopts a distorted octahedral environment with bidentately coordinated nitrone ligands. In both cases the nitrone groups are involved in coordination via the oxygen atom. Compounds 1 and 2 have been studied by EPR, UV-VIS and IR spectroscopy. The free nitrone HL1 has also been studied by X-ray diffraction as well as by IR and UV spectroscopy.

Silver, Triphenylphosphine, Triphenylstibine, Cyanoximes, X-Ray Data Silver(I) cyanoximate complexes Ag{ONC(CN)-R} (R = COPh, {L1}; COC(CH3)3, {L2}; benzothiazol-2-yl, {L3}) with triphenylphosphine and -stibine of compositions Ag(PPh3)n{L} (n = 2, 4) and Ag(SbPh3)n{L} (n = 3 for {L1} and {L2}, n = 2 for {L3}) were synthesized by the reaction of the components in acetonitrile solution and characterized by elemental analyses and IR spectroscopy. The crystal structures of Ag(SbPh3)3{L} (L = {L } (1), { L2} (2), Ag(SbPh3)2{L3} CH3CN (3) and Ag(PPh3)2{L '}C H 3CN (4), have been determined by X-ray diffraction. For all the compounds examined the coordination environment of the silver atom has the geometry of a distorted terahedron ([AgP2NO] (4); [AgSb3N] (1), (2); [AgSb2N2] (3)). The bis adducts Ag(EPh3)«{L} adopt molecular structures, in which the organic anions are coordinated in bidentate chelate fashion via the nitroso nitrogen atom and the oxygen (nitrogen for { L3}) atom of the substituent R. In the fm-stibino complexes (Ag-Sb 2.670(4) -2.7748(8) A; Sb-Ag-Sb 108.87(4) -115.00(2)°) the cyanoximates are unidentate ligands and coordinated via the nitroso nitrogen atoms (Ag-N ca. 2.35(1) A). The different behaviour of N ,0 and N,N chelating cyanoximes under the same conditions suggests, that the Sb donor triphenylstibine is able to substitute the oxygen atoms in the silver(I) coordination sphere, but not the nitrogen ones. This causes the formation of 1:

The bipyridine-based ligand 6,6'-bis{[methyl(oxido)imino]methyl}-2,2' -bipyridine (L) reacts with copper(II) chloride in methanol to produce a tetrachlorocuprate(II) salt [CuL][CuCl4] (1). Reactions of equimolar quantities of Ni(NO3)2 · 6H2O and Co(NO3)2 · 6H2O with L in methanol produce compounds [ML(NO3)2] (M = Ni (2), M = Co (3). Reaction of Cr(NO3)3 · 6H2O with L affords [Cr(L)(H2O)2](NO3)3 · 0.5H2O (4). The structures of compounds 1 - 4 were determined by X-ray diffraction. In all four complexes L exhibits the tetradentae chelating mode of coordination.