Complexes derived from the reactions of diphenylphosphinoacetic acid. Part 3 . Dimetal complexes from [Mo 2Cl 8] 4− and [Re 2Cl 8] 2−

Abstract

Diphenylphosphinoacetic acid ( 1) reacts with K 4Mo 2Cl 8 in refluxing methanol to afford the centrosymmetric dimolybdenum(II) complex Mo 2Cl 4(μ-Ph 2PCH 2CO 2Me) 2 ( 2) that contains two trans P,O bridging phosphine–ester ligands, an eclipsed rotational geometry, and a MoMo quadruple bond distance of 2.1450(8) Å. The corresponding reactions of 1 with (n-Bu 4N) 2Re 2Cl 8 in refluxing methanol and ethanol yield the paramagnetic, dirhenium(III,II) complexes Re 2Cl 5(Ph 2PCH 2CO 2R) 3 (R=Me ( 3) or Et ( 4)) in which the phosphine–ester ligands are P-bound. A crystal structure determination of 3 shows it to have the 1,3,6-structure with a ReRe bond length of 2.2318(3)Å in accord with a ReRe bond order of 3.5.