Syntheses, structure characterisation and X-ray structures of the complexes Ru 3(CO) 11L [L = Ph 2P(C 6H 4Me- p), Ph 2PC 6F 5, P(C 6H 4Cl- p) 3, P(3,5-CF 3–C 6H 3) 3 and P(C 6H 4Me- p) 3

Abstract

Five trinuclear monosubstituted complexes of the type Ru 3(CO) 11L were synthesised by the reaction of Ru 3(CO) 12 with phosphine ligands (L) using the radical anion catalysed method. The structures of the resulting clusters were elucidated by means of elemental analyses and spectroscopic methods, including IR, 1H NMR, 13C NMR and 31P NMR spectroscopy. 31P NMR spectra of the complexes Ru 3(CO) 11P(C 6H 4Me- p) 3 and Ru 3(CO) 11P(C 6H 4Cl- p) 3 showed splitting of the phosphorus signals into triplets. X-ray crystallographic studies of all five complexes were carried out. Out of the three unidentate tertiary phosphine complexes, Ru 3(CO) 11P(C 6H 4Me- p) 3 and Ru 3(CO) 11P(C 6H 4Cl- p) 3 are ordered while the complex Ru 3(CO) 11P(3,5-CF 3–C 6H 3) 3 exhibits disorder with respect to the trifluoromethyl groups. In all the five monosubstituted complexes, the ligand occupies the equatorial position due to steric reasons and coordination of the ligands are only at the phosphorus atom. The effect of substitution resulted in significant differences in the Ru–Ru distances. Out of the three Ru–Ru bonds, the one which is cis to the ligand is noticeably longer and the mean value for this longest Ru–Ru bond is 2.889 Å, while the mean value for the two shorter Ru–Ru bonds is 2.841 Å. The P–C distances are in the range 2.333(6)–2.354(6) Å. The equatorial Ru–CO moieties are almost linear and the average value for all the five complexes studied range from 176.3 to 177.6°, while the axial CO groups are slightly bent, ranging from 173.8 to 174.1°.