Multisite Magnetization Transfer Studies of Metal Migration in (η3-C7H7)Re(CO)4, (η3-C7H7)Os(CO)3SnPh3, (η3-C7H7)Re(CO)3PMe3, (η5-C7H7)Re(CO)3, (η5-C7H7)Fe(CO)2SnPh3, (η5-C7H7)Os(CO)2SnPh3, and (η5-C7H7)Ru(CO)2SnPh3
Citations Over TimeTop 21% of 2002 papers
Abstract
Multisite magnetization transfer (MMT) studies of metal migration around the C7H7 rings in (η3-C7H7)Re(CO)4 (1), (η3-C7H7)Os(CO)3SnPh3 (2), (η3-C7H7)Re(CO)3PMe3 (3), (η5-C7H7)Re(CO)3 (4), (η5-C7H7)Fe(CO)2SnPh3 (5), (η5-C7H7)Os(CO)2SnPh3 (6), and (η5-C7H7)Ru(CO)2SnPh3 (7) are reported. The possible presence of 1,2-, 1,3-, and/or 1,4-metal shifts in the ring fluxionality was investigated in all compounds, and it was shown that both 1,2- and 1,3-shifts occur concurrently in 5 and 6, but that only 1,2-shifts occur in 1, 2, 3, and 4, and only 1,3-shifts in 7. Several of the compounds exist as mixtures of isomers, and the application of MMT was crucial in unraveling the fluxionality of one isomer in the presence of the other. Thus, MMT experiments allowed the study of the rate of metal migration in the symmetric isomer of 2, which occurs in the presence of more rapid exchange in the asymmetric isomer. The symmetric isomer of 3 was found to exchange faster than the asymmetric isomer. MMT study of the exchange between symmetric and asymmetric isomers of 7 at low temperatures showed that the two enantiomers of the asymmetric isomer exchange directly with the symmetric isomer, but not with each other. MMT experiments allowed the study of metal migration in 7 in the presence of the isomer interchange process. The rate constants and free energies of activation for the metal shifts and for the isomer interchange are reported. It was concluded that orbital symmetry considerations do not provide useful predictions about the mechanisms of metal migration in compounds containing η1-, η3-, or η5-C7H7 rings.
Related Papers
- → Investigation of racemisation of the enantiomers of glitazone drug compounds at different pH using chiral HPLC and chiral CE(2007)49 cited
- → First order magnetization process in Pr2Fe14B single crystal(1987)58 cited
- → Three-dimensional magnetization process in HoFe11Ti(2002)3 cited
- → Analysis of reversible magnetization-dependent Preisach models for recording media(1992)28 cited
- → A Study on Intial Susceptibility for the Prediction of Vertical Magnetization in Flash D Demagnetization(2014)