P 41 Pentanuclear pivalate Ni(II) and Co(II) clusters: Modulation of molecular structures and magnetic properties // Journal of Molecular Structure. - 2003. - Vol. 656, № 1-3. - P207-224 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): CLUSTER -- MAGNETIC PROPERTIES -- TRANSITION METAL Аннотация: Reaction of nickel cluster Ni9(HOOCCMe3) 4(?4-OH)3(?3-OH) 3(?n-OOCCMe3)12 (1) or cobalt pivalate polymer [Co(OH)n(OOCCMe3)2-n] x (7) with bis[3,5-(dimethylpyrazolyl)]-1,2,4,5-tetrazine (3) in MeCN solution was found as a result in the formation of isostructural pentanuclear clusters of composition M5(?3-OH) 2(?-OOCCMe3)4(?-N,N?,N? -3,5-Me2C3HN2C2(O)N 4)4(MeCN)2 (M = Ni (4), Co (8)) with a planar spirane metal core. Reaction of cobalt complex 7 with 3 in benzene gives rise to a pentanuclear cluster Co5(?3-OH)2(?-OOCCMe 3)4(?-N,N?,N?-3,5-Me2C 3HN2C2(O)N4)4(C 5N2H8)2 (9), containing coordinated pyrazole molecules as terminating ligands instead of labile MeCN ligands in 8. The reaction of cluster 8 with 2,6-diaminopyridine (T = 85 °C) in MeCN results in the substitution of MeCN ligands and formation of a new cluster Co5(?3-OH)2(?-OOCCMe3) 4(?-N,N?,N?-3,5-Me2C3HN 2C2(O)N4)4(C5H 7N3)2 (10) with two 2,6-diaminopyridine ligands instead of MeCN molecules. The reactions of 4 and 8 with NiCl 2·6H2O in MeCN/EtOH solution (3: 1) give rise to isostructural ferromagnetic pentanuclear chloro-bridged clusters M 5(?3-OH)2(?-CI)2(? -OOCCMe3)2(?-N,N?,N?-3,5-Me 2C3HN2C2 (O)N4) 2(?-N,N?,N?,O-3,5-Me2C3HN 2C2(O)N4)2(MeCN)2 (M = Co (11), Ni (12)). The reaction of 8 with solid COCl2·6H 2O in MeCN results in new seven-nuclear ferromagnetic cluster CO 5(?3-OH)2(?-CI)2(? -OOCCMe3)2(?-N,N?,N?-3,5-Me 2C3HN2- C2(O)N4) 2(?-N,N?,N?,O-3,5-Me2C3HN 2C2(O)N4)2(MeCN) 2[Co(CH3CN)CI2]2 (13). The molecular structures of 4, 8, 9, 10, 12 and 13 established by X-ray diffraction studies and magnetic behavior of new nickel and cobalt pivalate clusters are discussed. |