Dirhenium and dimolybdenum complexes of di(isopropylphosphino)methane

The first multiply bonded dimetal complexes that contain the bridging phosphine ligand Pr2iPCH2PPr2i (dippm) have been isolated and structurally characterized. The dimolybdenum(II) and dirhenium(III,II) complexes Mo2Cl4(μ-dippm)2 and [trans-Re2(μ-O2CCH3)2Cl2(μ-dippm)2]Cl0.74(ReO4)0.26 have MM distances of 2.1699(3) and 2.2705(3) Å, respectively, in accord with and bond orders. Attempts to isolate Re2Cl4(μ-dippm)2 led instead to the dirhenium(V) complex Re2O3Cl4(μ-dippm)2, structurally analogous to the previously isolated Re2O3Cl4(μ-dppm)2 (dppm=Ph2PCH2PPh2).