Reactivity of molecules containing element-element bonds. Part 3. Reduction of halo-organometallics of antimony(III) and bismuth(III); crystal and molecular structure of CoCp2[SbPh2Cl2]

Tetraphenyldibismuthine has been prepared by reducing BiPh2I with bis(cyclopentadienyl)-cobalt(II), CoCp2, the former being produced in situ in THF solution from BiPh3 and BiI3 (2:1 molar ratio) or from BiPh3 and I2; also, bis(pentamethylcyclopentadienyl)cobalt(II), CoCp2*, reduces BiPh2Cl to Bi2Ph4 in THF solution. The bismuth(III) bromides Bi(p-tolyl)2Br or BiMe2Br have been reduced by CoCp2 to the corresponding dibismuthines, Bi2(p-tolyl)4 or Bi2Me4. Reduction by CoCp2 of the chloro derivatives of bismuth(III) and antimony(III), EPh2Cl produces E2Ph4 and the ionic CoCp2[EPh2Cl2] complexes as by-products. The crystal and molecular structure of the antimony derivative CoCp2[SbPh2Cl2] was solved by X-ray diffraction methods. Crystal data: monoclinic, space group P2(1), a = 8.856(3), b = 16.245(5), c = 7.770(3) angstrom, beta = 109.67(5)-degrees, Z = 2, R = 0.0396. Similar to Bi2Ph4, Sb2Ph4 undergoes reactions across the element-element bond with p-benzoquinone and diazomethane to the corresponding insertion products (Ph2Sb)2O2C6H4 and (Ph2Sb)2CH2, respectively.