Bis(diphosphino)methanide and hydride derivatives of Ir4(CO)12

Abstract

The reaction of [Ir 4 (CO) 10 (µ-(Ph 2 P) 2 CH 2 )] with dried KOH forms [Ir 4 (CO) 10 (µ-(Ph 2 P) 2 CH)] Ϫ which subsequently converts into [Ir 4 (CO) 9 (µ 3 -(Ph 2 P) 2 CH)] Ϫ , a rare example of an Ir cluster with an Ir-C bond (average 2.274(8) Å). The same reaction with the weaker base 1,8-diazobicyclo[5.4.0]undec-7-ene or with K 2 CO 3 in wet CH 2 Cl 2 under CO affords the anion [HIr 4 (CO) 9 (µ-(Ph 2 P) 2 CH 2 )] Ϫ , a hydride-cluster with an unusually long Ir-H distance (2.08(6) Å at 90 K). Intramolecular CO scrambling is observed in CD 2 Cl 2 solution above 200 K, preserving the terminal-axial position of the hydride ligand.