Crystal structure of {Mn11(1,10-C12H8N2)3]2+ [(B9C2H11)Co111(B8C2H10)Co111(B9C2H10)Co111(B9C2H11)]2-.CH3CN

A novel compound, [MnPhen(3)][(B9C2H11)Co(B8C2H10)Co(B9C2H)].CH3CN (Phen= 1,10-phenantroline), comprising a Co(III) dicobaltacarborane cluster anion has been prepared and characterized by single crystal X-ray diffraction. Crystal data are the following: C44H59B26N7Co2Mn, M= 1139.84, triclinic, space group P 1, unit cell parameters: a = 13.2465(11) angstrom, b = 14.521(2) angstrom, c = 15.2536(15) angstrom; alpha = 77.027(9)degrees, beta = p = 88.500(8)degrees, gamma=77.274(9)degrees; V=2788.5(5)angstrom, Z=2, d(calc)= 1.358 g/cm(3), T= 295 K, F(000)=1162, mu=0.853 mm(-1). The structure was solved by the direct and Fourier methods and refined anisotropically (isotropically for hydrogen atoms) using the full-matrix technique to final factors R-1 = 0.0374, wR(2) = 0.0915 for 7397 I-hkl >= 2 sigma(I) of 9779 I-hkl measured (diffractometer Enraf-Nonius CAD-4, lambda MoK alpha, graphite monochromator, theta/2 theta-scanning). The structure is formed from [MnPhen(3)](2+) cations, [(B9C2H11)x Co(B8C2H10)Co(B9C2H11)](2-) anions, and acetonitrile molecules CH3CN. Central Mn atom in the cation has a distorted octahedral coordination environment formed by six nitrogen atoms of three bi-dentate Phen ligands, average Mn-N bond length being 2.263(2) angstrom. The anion has a chain-like structure built from three icosahedra sharing common vertices occupied by the cobalt atoms. The central icosahedron including ten light atoms (8B, 2C) provides two vertices for the cobalt atoms shared with the other icosahedra having 11 light atoms (9B, 2C). The arrangement of -C-2- groups in the anion corresponds to a quasi-gauche-configuration of asymmetric sandwich complexes of both cobalt atoms.