UNUSUAL ISOMERS OF EDGE-SHARING BIOCTAHEDRAL COMPLEXES

The edge-sharing bioctahedral complexes 1,2,5,6-W2Cl6(dmpe)2 (1),1,2,5,6-MOWC16(dmpe)2 (2),1,3,5,7-MoWCl6-(dmpe)2 (3), 1,2,5,8-MOWC16(TETRAPHOS-1) (4), and 1,3,5,7-W2Cl6(dmpe)2 (5) are formed as the oxidative addition products of reactions between the corresponding quadruply bonded complexes and PhlC12 or CH2Cl2. Complexes 1, 2, and 4 represent new isomeric forms for the MM'X6P4 core. Complex 4 cocrystallizes with small amounts of 1,2,5,8-Mo2Cl6(TETRAPHOS-1) to form a solid solution. The apparent Mo-W distance is 2.718(2) angstrom for 1,2,5,8-MOWC16(TETRAPHOS-1). Complexes 2 and 3 are free from contamination by their dimolybdenum analogs and the Mo-W distances are 2.695 (i) A for 1,2,5,6- MOWC16(dmpe)2 and 2.7028 (5) A for 1,3,5,7-MOWCl6-(dmpe)2. Complex 1 is isostructural with complex 2 and has a W-W distance of 2.6726(8) angstrom. The crystal structures of 1-4 are fully described. Crystallographic data for these compounds are as follows: Compound 1, Pbca with a = 13.417(3) angstrom, b = 14.629(4) angstrom, c = 13.111(3) angstrom, V = 2573(1) angstrom3, and Z = 4; compound 2, Pbca with a = 13.517(5) angstrom, b = 14.615(5) angstrom, c = 13.124(4) angstrom, V = 2593(1) angstrom3, and Z = 4; compound 3, P2(1)/n with a = 9.2905(1) A, b = 13.106(2) angstrom, c = 10.495(2) angstrom, beta = 96.13(1)-degrees, V = 1270.7(3) angstrom3, and Z = 2; compound 4 I23 with a = b = c = 25.36[2] angstrom, V = 16322(15) angstrom3, and Z = 12.