Reactions of [RuCl2(PPh3)4] with mixed anhydrides of diphenylphosphinous and acrylic acids; structure of [RuCl{(Ph2PO)2H}(PPh3)(O2CCH2CH2PPh3)]·C4H8O

Abstract

Reactions of [RuCl₂(PPh₃)₄] with 1 mol equivalent of Ph₂PO₂CCHCR′R″ produce [RuCl₂(PPh₃)₂(Ph₂PO₂CCHCR′R″)](R′, R″= H or Me), although for R′= H, R″= H or Me the major product is [RuCl{(Ph₂PO)₂H}(PPh₃)(O₂CCH₂CHR″PPh₃)], which for R″= H has been crystallographically characterized. Using 2 mol equivalents of Ph₂PO₂CCRCR′R″ the products are [RuCl₂(Ph₂PO₂CCRCR′R″)₂](R = H, R′= R″= Me; R = Me, R′= H, R″= Ph) or [RuCl₂(PPh₃)(Ph₂PO₂CCHCH₂)(Ph₂POPPh₂)]. The complexes have all been characterized spectroscopically and the mixed anhydride ligands are generally co-ordinated through P and O, apparently for steric reasons. Binding through P and the CC appears to occur in [RuCl₂(PPh₃)₂(Ph₂POCH₂CHCMe₂)], prepared from [RuCl₂(PPh₃)₄] and Ph₂POCH₂CHCMe₂, whilst unidentate binding via the P atom is observed for the mixed anhydride in [RuCl₂(PPh₃)(Ph₂PO₂CCHCH₂)(Ph₂POPPh₂)]. Crystal data for [RuCl{(Ph₂PO)₂H}(PPh₃)(O₂CCH₂CH₂PPh₃)]: orthorhombic, space group P2₁2₁2₁, with a= 15.16(3), b= 23.05(3), c= 17.08(4)Å and Z= 4. The structure was obtained from 6558 reflections measured on an automatic diffractometer and refined to an R value of 0.076. The main features of the structure include the zwitterionic triphenylphosphoniopropionate betaine ligand binding via the carboxylate in a chelating fashion and the planar RuPOHPO ring of the bis(diphenylphosphinito)hydrogenate ligand. The O ⋯ O distance in this ligand is 2.382(12)Å indicative of strong hydrogen bonding.