Dirhenium and dimolybdenum complexes of di(isopropylphosphino)methane

The first multiply bonded dimetal complexes that contain the bridging phosp hine ligand (Pr2PCH2PPr2i)-P-i (dippm) have been isolated and structurally characterized. The dimolybdenum(II) and dirhenium(III,II) complexes Mo2Cl4( mu -dippm)(2) and [trans-Re-2( mu -O2CCH3)(2)Cl-2(mu -dippm)(2)]Cl-0.74(ReO 4)(0.26) have M-M distances of 2.1699(3) and 2.2705(3) Angstrom, respective ly, in accord with Mo -(4) Mo and Re-Re-3.5 bond orders. Attempts to isolat e Re2Cl4(mu -dippm)(2) led instead to the dirhenium(V) complex Re2O3Cl4(mu- dippm)(2), structurally analogous to the previously isolated Re2O3Cl4(mu - dppm)(2) (dppm = Ph2PCH2PPh2). (C) 2001 Elsevier Science BN. All rights res erved.