Unique properties of ruthenium(II) phosphole complexes

Article abstract of DOI:10.1021/ic00319a017

Several ruthenium(II) complexes of Ph₃P, 1-phenyldibenzophosphole (DBP), and 1-phenyl-3,4-dimethylphosphole (DMPP) have been synthesized. A more general synthesis of ttt-RuCl₂(CO)₂(PR₃)₂ has been developed. These complexes were characterized by infrared and NMR (¹H, ¹³C{¹H}, ³¹P{¹Hi}) spectroscopy, and their solution behavior, including redox properties, was studied. The ttt-RuCl₂(CO)₂(phosphole)₂ complexes undergo ligand-redistribution reactions to form mer-trans-RuCl₂(CO)(phosphole)₃ and, presumably, a phosphole-deficient compound. These compounds were also investigated for their ability to catalyze the homogeneous hydrogenation and/or isomerization of allylbenzene at 100°C and a hydrogen pressure of 100 psi in a 50/50 ethanol/benzene solution. Each of the complexes catalyzed both the hydrogenation of allylbenzene to propylbenzene and its isomerization to one or both of the internal isomers, cis- and trans-β-methylstyrene. The turnover numbers for these processes are a function of the precatalyst geometry, the nature of the phosphorus ligand, and the presence or absence of coordinated carbon monoxide.