[Co4(ν3-NPEt3)2(HNPEt3)2(O2C-CH3)2-(ν-OSiMe2OSiMe2O)2] -: a tetranuclear cobalt(II) complex with ladder structure

The title compound has been prepared from cobalt(II) acetate and Me3SiNPEt3 in boiling toluene in the presence of silicon grease and traces of water as blue single crystals which were characterized by IR spectroscopy and by a crystal structure determination. Space group Pbca, Z = 8, lattice dimensions at -50 degrees C: a = 1449.3(1), b = 1724.9(1), c = 2356.6(2) pm, R = 0.0548. [CO4(v(3)-NPEt3)(2)(HNPEt3)(2)(O2C-CH3)(2)- (v-OSiMe2OSiMe2O)(2)] has a centrosymmetric structure. The four cobalt atoms which are coordinated tetrahedrally are v(3)-bridged via the N atoms of the two (NPEt3-) groups and v(2)-bridged by the O atoms of the chelating (OSiMe2OSiMe2O2-) units. The core atoms are arranged in three four-membered rings which are connected in a stair-like way.