THE REACTIONS OF DIRHENIUM COMPLEXES WITH TRIS(DIPHENYLPHOSPHINO)METHANE - THE CONVERSION OF THE DIRHENIUM(III) COMPLEX CIS-RE-2(O2CCH3)(2)CL-4(PY)(2) TO MONONUCLEAR TRANS-RECL2[ETA(2)-HC(PPH(2))(3)](2)

The reaction of tris(diphenylphosphino)methane (HC(PPh(2))(3), abbrevi ated tripod) with Re2Cl4(PMe(3)), in hot ethanol leads to the formatio n of Re2Cl4(mu-dppm)(PMe(3))(2) as the major product (dppm=Ph(2)PCH(3) PPh(2)). The compound trans-ReCl2[eta(2)-HC(PPh(2))(3)](2) was obtaine d as a minor product from the reaction of cis-Re-2(O2CCH3)(2)Cl-4(py)( 2) with HC(PPh(2))(3). This complex, which was structurally characteri zed by X-ray crystallography, is an example of a small but growing cla ss of mononuclear rhenium(II) complexes that have a trans-ReCl2P4 octa hedral geometry. Crystal data at + 20 degrees C: triclinic space group P ($) over bar 1 (No. 2), a=10.867(1), b=13.157(1), c=13.4060(9) Angs trom, alpha=109.279(6), beta=98.477(5), gamma=112.198(6)degrees, V=159 1.9(6) Angstrom(3), Z=1. The structure was refined by full-matrix]east -squares to R=0.034 (R(W)=0.043) for 5005 data with I > 3 sigma(I).