MIXED-METAL COMPLEXES CONTAINING UNUSUAL 8-COORDINATE [CU(CARBOXYLATO)4] CORES - STRUCTURES OF [LICU(BET)4]N(CLO4)3N AND [CACU(BET)4(NO3)2(H2O)]2[CA(NO3)4(H23)]2 (BET = ME3N+CH2CO2-)

The linkage of Li(I) and Ca(II) ions to the eight-coordinate [Cu(eta-Me3NCH2CO2-O,O')4] core results in the new complexes [LiCu(bet)4]n(ClO4)3n (2) and [CaCu(bet)4(NO3)2(H2O)]2[Ca(NO3)4(H2O)]2 (3) (bet = Me3N+CH2CO2-). X-ray structural analysis has revealed that 2 comprises an infinite cationic column with each pair of the eight-coordinate cores bridged by a Li(I) atom, featuring the shortest weak Cu-O(carboxylate) bond [2.705(5) angstrom] among its type, whereas 3 contains a heterodinuclear Cu-Ca cation consolidated by an uncommmon triple carboxylato-O,O' bridge with the Cu(II) atom surrounded by the four chelate groups in a three-up/one-down eight-coordinate arrangement. The dinuclear anion in 3 contains three kinds of nitrato ligands acting in bridging, bidentate chelate, and unidentate modes. Crystal data for 2 (21-degrees-C): tetragonal, space group P42mBAR (No. 111), a = 12.096(3) angstrom, c = 6.2330(7) angstrom, V = 911.8(3) angstrom3, Z = 1; R = 0.051 (R(w) = 0.060) for 613 data with I > 1.5sigma(I). Crystal data for 3 (21-degrees-C): monoclinic, space group P2(1)/n (No. 14), a = 12.105(2) A, b = 22.796(9) angstrom, c = 15.572(4) angstrom, = 90.63(1)degrees, V = 4297(2) angstrom3, Z = 2; R = 0.069 (R(w) = 0.053) for 4690 data with I > 3sigma(I).