14655-23-3Relevant academic research and scientific papers
Photofragmentation Kinetics of Some Triruthenium Carbonyl Clusters
Brodie, Nacy M. J.,Huq, Rokeya,Malito, John,Markiewicz, Stan,Poe, Anthony J.,Sekhar, Vasu C.
, p. 1933 - 1940 (2007/10/02)
The photokinetics of fragmentation reactions of with L=PPh3, P(OPh)3, AsPh3, CO, 1-octene, and methyl acrylate in a variety of solvents have been studied.Quantum yields increase to limiting values at high but the limiting values vary significantly with the nature of L.The low efficiency of photochlorination in chlorocarbon solvents, the absence of inhibition by CO of reactions with L=PPh3, and the absence of appropriate effects of varying incident light intersity all suggest that the first kinetically significant product is a non-radical reactive isomer of .This can revert to or react with L to form which itself can revert to or undergo fragmentation.The former choice governs the rate of increase with to a limiting quantum yield whereas the latter choice governs the dependence of the values of the limiting quantum yield on the nature of L.This scheme is also applicable to photoreactions of and the quantitative behaviour of the two clusters is not significantly different.Only lower limits for quantum yields for formation of the reactive isomers can be deduced from the data and it remains possible that the primary photophysical process is the formation of a very short-lived diradical by homolysis of a metal-metal bond.Photokinetic studies of reactions of with L (L=PPh3 or PBun3) are also reported.
Systematic substituent effects on dissociative substitution kinetics of Ru(CO)4L complexes (L = P-, As-, and Sb-donor ligands)
Chen, Lezhan,Po?, Anthony J.
, p. 3641 - 3647 (2008/10/08)
The kinetics of dissociation of CO from Ru(CO)4L (L = a wide variety of P-, As-, and Sb-donor ligands) have been studied, and the values of the rate constants can be resolved quantitatively into electronic and steric effects. The curved steric profile obtained shows that steric effects are quite small for small substituents such as P(OCH2)3CEt and P(OEt)3, but they increase steadily and substantially as the size of the substituent increases. A similar analysis of data in the literature for CO dissociative reactions of other substituted carbonyl complexes is also successful in resolving electronic and steric effects, and a clear dependence of steric effects on the coordination number of the complexes is shown. The analysis can be applied to some methyl migration reactions that involve CO loss, and the results can help to indicate the relative importance of CO loss and methyl migration in the transition states. Trends in the C-O stretching frequencies in the axial Ru(CO)4L and diaxial Ru(CO)3L2 complexes are described.
