Synthesis, Crystal Structures and NMR Spectroscopic Studies on Ruthenium Complexes with Phosphanylacetal and Phosphanylthioacetal Ligands

• Published in: European Journal of Inorganic Chemistry 2009-09, Vol.2009 (25), p.3807-3813
• Main Authors: Bayly, Simon R., Cowley, Andrew R., Dilworth, Jonathan R., Ward, Caroline V.
• Format: Article
• Language: English
• Subjects: Homogeneous catalysis; Mixed-donor li­gands; P ligands; Ruthenium; S ligands
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.200900451

The chemistry of the mixed P,S‐donor ligands [2‐(1,3‐dioxolan‐2‐yl)phenyl]diphenylphosphane (PhPOO, 1), and [2‐(1,3‐dithiolan‐2‐yl)phenyl]diphenylphosphane (PhPSS, 2) with the RuII precursors [RuCl2(PPh3)3] and [RuCl2(4‐cymene)]2 has been investigated. The structures of the resulting complexes were analysed by X‐ray crystallography and 1H, 13C and 31P NMR spectroscopy, and their activity as catalysts for hydrosilylation was examined. Reaction of 1 with [RuCl2(PPh3)3] in methanol solution produced [RuCl2(PhP(OMe)2)2] (3) {with [RuCl2(MeOH){PhP(OMe)2}(PPh3)] (3a) as a side product}, whereas the same reaction with [RuCl2(4‐cymene)]2 produced [RuCl2(PhPOO)2] (4). The dioxolane complex 4 showed fluxional behaviour by NMR spectroscopy, whereas 3 did not. Reaction of PhPSS with[RuCl2(PPh3)3] in methanol solution produced [RuCl2(PhPSS)2] (5), and reaction with [RuCl2(4‐cymene)]2 produced the cationic complex [RuCl(4‐cymene)(PhPSS)]+ (6) by precipitation with NaBPh4. In solution both 5 and 6 exist in two isomeric forms, and neither shows evidence of fluxionality at room temperature. Of the complexes tested only the acetal species 3 showed any significant hydrosilylation activity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) The chemistry of phosphanyl–dioxolane and phosphanyl–dithiolane mixed P,S‐donor ligands with the RuII precursors [RuCl2(PPh3)3] and [RuCl2(4‐cymene)]2 is reported. Full characterisation of the resulting complexes by 1H, 13C and 31P NMR spectroscopy and X‐ray crystallography is presented, and their activity as catalysts for hydrosilylation is examined.