Synthesis and spectral properties of the novel dicationic bimetallic phosphine-bridged compounds [W 2I 2(μ-LL)(CO) 2(dppm) 2(η 2-MeC 2Me) 2] [BF 4] 2 {dppm = Ph 2P(CH 2)PPh 2; LL = Ph 2P(CH 2) n PPh 2, n = 1–6 or [Fe(η 5-C 5H 4PPh 2) 2

Abstract

Two equivalents of the cationic monobut-2-yne complex [WI(CO)(NCMe) (dppm)(η 2-MeC 2Me)][BF 4] react with one equivalent of the bidentate phosphine ligands L L {LL = Ph 2P(CH 2) n PPh 2, n = 1–6 or [Fe(η 5-C 5 H 4PPh 2) 2]} in CH 2Cl 2 at room temperature, to rapidly afford the bimetallic phosphine-bridged compounds [W 2I 2(μ-LL)(CO) 2(dppm) 2(η 2-MeC 2Me) 2][BF 4] 2 ( 1– 7) in high yield. Equimolar quantities of [WI(CO)(NCMe)(dppm) (η 2-MeC 2Me)][BF 4] and dppm react in CH 2Cl 2 at room temperature to afford a mixture of [W 2I 2(μ-dppm)(CO) 2(dppm) 2(η 2-MeC 2Me) 2][BF 4] 2, [WI(CO)(η 1-dppm)(dppm)(η 2MeC 2Me)][BF 4] and unreacted dppm. 13 C NMR spectroscopy shows that each but-2-yne ligand in these bimetallic complexes are utilizing both their filled pπ-orbitals and donating four electrons to the tungsten in these compounds.