Dynamics and structure of some rhodium-acetylene derivatives

• Published in: Journal of organometallic chemistry Vol. 101; no. 1; pp. 133 - 138
• Main Authors: Todd, L.J., Wilkinson, J.R., Rausch, M.D., Gardner, S.A., Dickson, R.S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.1975
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/S0022-328X(00)88541-1

The acetylene ligand of (C 5H 5) 3Rh 3(CO)(Ph 13CCPh) is fluxional in solution at room-temperature but static at −87°C. The acetylene ligand of (C 5H 5) 3- RH 3(Ph 13CCPh) is fluxional even at −127°C. The acetylene carbon signal is very deshielded suggesting the possibility of carbenoid-type bonding for this ligand According to C NMR evidence the derivative [(C 5H 5)Rh(PhC 2Ph)] 2 does not have a metallocyclopentadiene structure but an unsymmetrical four-carbon ligand. The complex [(C 5H 5)Rh(CO)] 2CF 3C 2CF 3 possesses a static bridging acetylene ligand. However the carbonyl groups appear to be scrambling at room temperature and in a static terminal position at −60°C.