Transition metals reaction mechanisms

R. G. WiUdns, Kinetics andMechanism of Reactions of Transition Metal Complexes, 2nd ed., VCH, Weinheim, Germany, 1991. A critical and selected compilation of kinetics and mechanism data. 

In terms of gross features of mechanism, a redox reaction between transition metal complexes, having adjacent stable oxidation states, generally takes place in a simple one-equivalent change. For the post-transition and actinide elements, where there is usually a difference of two between the stable oxidation states, both single two-equivalent and consecutive one-equivalent changes are possible. 

As indicated by the mechanism, carboalumination is a syn addition. The resulting vinylalanes react with electrophiles with net retention of configuration. The electrophiles that have been used successfully include iodine, epoxides, formaldehyde, and ethyl chloroformate.229 We will also see in Chapter 8 that the vinylalanes can undergo exchange reactions with transition metals, opening routes for formation of carbon-carbon bonds. 

The methods of organic synthesis have continued to advance rapidly and we have made an effort to reflect those advances in this Fifth Edition. Among the broad areas that have seen major developments are enantioselective reactions and transition metal catalysis. Computational chemistry is having an expanding impact on synthetic chemistry by evaluating the energy profiles of mechanisms and providing structural representation of unobservable intermediates and transition states. 

Wilkins, R. G. Substitution Reactions. In Kinetics and Mechanism of Reactions of Transition Metals, 2nd ed. VCH Weinheim, Germany, 1991 Chapter 4. 

Wilkins, R. G. (1991). Kinetics and Mechanisms of Reactions of Transition Metal Complexes. VCH Publishers, New York. Contains a wealth of information on reactions of coordination compounds. 

Henderson, R. A. The Mechanisms of Reactions at Transition Metal Sites Oxford University Press Oxford, 1994. 

Rate Constants for the Reactions of Transition Metal Salts and Complexes with Peroxyl Radicals in Systems with a Cyclic Mechanism of Chain Termination (Experimental Data)... 

Many more examples have been collected for the reaction of transition metal hydride complexes with 1,3-dienes, which appear to proceed via radical pair mechanisms, even without photochemical activation72-77. The following general mechanism has been assumed to be operative for the reaction of HMn(CO)572,73, HFe(CO)4SiCl374,75, HFe(CO)2Cp76 and HCo(CO)4 (H-[M]) (equation 18)77. 

As the above discussion indicates, assigning mechanisms to simple anation reactions of transition metal complexes is not simple. The situation becomes even more difficult for a complex enzyme system containing a metal cofactor at an active site. Methods developed to study the kinetics of enzymatic reactions according to the Michaelis-Menten model will be discussed in Section 2.2.4. 

Studies related to the mechanisms of nitric oxide reactions with transition metal complexes in this laboratory were supported by grants from the U.S. National Science Foundation, by a Collaborative UC/Los Alamos National Laboratory Research grant, by a grant from the U.S. Japan Cooperative Research Program (Photoconversion/ Photosynthesis) (NSF INT 9116346), and by a grant from the ACS Petroleum Research Fund. We thank the students and postdoctoral fellows at UC Santa Barbara who participated in this research and acknowledge collaborative studies with Dr. David Wink (National Cancer Institute, Bethesda MD, USA), Dr. Mikio Hoshino (RIKEN, Wako-shi, Japan) and Dr. Jon Schoonover (Los Alamos National Laboratory). 

Ralph G. Wilkins. Kinetics and Mechanisms of Reactions of Transition Metal Complexes. VCH 1991... 

Kinetics and mechanism of reactions of transition metal complexes / Ralph G. Wilkins. - 2., thoroughly rev. ed. -Weinheim New York Basel Cambridge VCH, 1991 ISBN 3-527-28389-7 (Weinheim. ..) brosch. 

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