Zerovalent ruthenium complexes of secondary alkoxyphosphines

Abstract

The reaction of [RuHCl(CO)L3] (L = PPh3) with cyclohexylphosphine (PH2Cy) affords [RuHCl(CO)L2(PH2Cy)], protonation of which in acetonitrile with HX affords [RuCl(NCMe)(CO)L2(PH2Cy)]X (X = ClO4, OTf, PF6) salts while HCl provides [RuCl2(CO)L2(PH2Cy)]. The labile chloride and/or acetonitrile ligands are replaced by CO, CNC6H2Me3-2,4,6, [Et2NCS2]– or [Tp]– (Tp = hydrotris(pyrazolyl)borate) to provide [RuCl(CO)2L2(PH2Cy)]+, [Ru[Cl(CO)(CNC6H2Me3-2,4,6)L2(PH2Cy)]+, [Ru(S2CNEt2)(CO)L2(PH2Cy)]+ and [Ru(CO)L(Tp)(PH2Cy)]+ salts. Deprotonation of [RuCl(CO)2L2(PH2Cy)]OTf in benzene affords [RuCl(PHCy)(CO)2L2], but in methanol the secondary methoxyphosphine complex [Ru(CO)2L2{PH(OMe)Cy}] is obtained, as is [Ru(CO)(CNC6H2Me3-2,4,6)L2{PH(OMe)Cy}] from [Ru[Cl(CO)(CNC6H2Me3-2,4,6)L2(PH2Cy)]OTf. The reactions of [Ru(CO)2L2{PH(OMe)Cy}] with CO, CNC6H2Me3-2,4,6 or dppe afford [Ru(CO)3L{PH(OMe)Cy}], [Ru(CO)2(CNC6H2Me3-2,4,6)L2{PH(OMe)Cy}] or [Ru(CO)2(dppe){PH(OMe)Cy}], resectively, in each case demonstrating a preference for dissociation of PPh3 rather than PH(OMe)Cy. Aerial oxidation of [Ru(CO)2L2{PH(OMe)Cy}] results in oxidation of one carbonyl ligand with formation of the carbonato complex [Ru(O2CO)(CO)L2{PH(OMe)Cy}]. The reaction of [Ru(CO)2L2{PH(OMe)Cy}] with ethynyl benzene provides two diastereomers of [RuH(CCPh)(CO)2L{PH(OMe)Cy}], while with anhydrous HCl, the cyclohexyl phosphine complex [RuCl2(CO)L2(PH2Cy)] is observed.