Free radicals, in organometallic chemistry

Free Radicals in Organometallic Chemistry, 14, 345 Heterocyclic Organoboranes, 2, 257... 

Fluxional and Nonrigid Behavior of Transition Metal Organometallic ir-Complexes, 16, 211 Free Radicals in Organometallic Chemistry, 14, 345 Functionally Substituted Cyclopentadienyl Metal Compounds, 21,1... 

Electronic Effects in Metallocenes and Certain Related Systems, 10, 79 Electronic Structure of Alkali Metal Adducts of Aromatic Hydrocarbons, 2, 115 Fast Exchange Reactions of Group I, II, and III Organometallic Compounds, 8, 167 Fluorocarbon Derivatives of Metals, I, 143 Free Radicals in Organometallic Chemistry, 14, 345 Heterocyclic Organoboranes, 2, 257... 

Free radicals in organometallic chemistry (M. F. Lappert and P. W. Lednor, Adv. Organometallic Chem., 14, 345). 

Advances in Carbocation Chemistry Advances in Carbohydrate Chemistry and Biochemistry Advances in Catalysis Advances in Cydoaddition Advances in Free Radical Chemistry Advances in Heterocyclic Chemistry Advances in Metal-Organic Chemistry Advances in Molecular Modeling Advances in Organometallic Chemistry Advances in Oxygenated Processes Advances in Photochemistry Advances in Physical Organic Chemistry Advances in Protein Chemistry Advances in Theoretically Interesting Molecules... 

Whereas homolytic ligand dissociation is not commonly observed for inorganic complexes, it has been identified as an important process in organometallic chemistry where it is favored by the characteristic weakness of transition metal-alkyl tr-bonds. Recent determinations yield metal alkyl band dissociation energies for CH3— Mn(CO)s (ca. 120 kJ/mol) and for several alkylcobalt complexes (ca. 80-100 kJ/mol) . Homolytic dissociation of such complexes results in the formation of free radicals and in the opening up of free radical catalytic pathways, e.g., for hydrogenation". Important biochemical examples of free radical catalytic mechanisms, initiated by the homolytic dissociation of a transition metal-carbon bond (i.e., the 5 -deoxyadenosy 1-cobalt bond of coenzyme 8,2) are provided by the coenzyme B,2-promoted rearrangements (see Section... 

T. V. RajanBabu, Functionalized Carbocyclic Derivatives from Carbohydrates Free Radical and Organometallic Methods, in Preparative Carbohydrate Chemistry (Ed. S. Hanessian), Marcel Dekker, 1997, Chap 25. 

The Period 1930-60. Following the work of Paneth (J ), there was a long period of active work on free radicals, mostly of importance in organic chemistry but with some relevance to organometallic chemistry. The radicals were generated by thermal, photochemical or discharge... 

His present interests include the development of new synthetic methodologies in carbohydrates, free radical chemistry, organometallic chemistry (Pauson-Khand reaction, transition metal (PtCl2, AuCl)-mediated cycloisomerization of polyunsaturated precursors), and synthesis/biologi-cal evaluation of heterocyclic systems (CSIC reaction, tacrine analogs). 

Additionally to the theoretical data and synthetic techniques for various metal complexes presented in Chaps. 2-A, we would like to pay special attention to three kinds of coordination compounds (complexes of phthalocyanines, quinones, and radioactive elements), whose syntheses, in our opinion, have been insufficiently generalized in monographs and textbooks on synthetic coordination chemistry. This choice is caused by the facts that phthalocyanines, as n-aromatic macrocyclic compounds, possess unusual thermal stability (nonstandard for organic and organometallic species) the quinone complexes have free-radical properties and coordination and organometallic compounds of radioactive elements are interesting at least for the reasons of necessity of special precautions in their syntheses and applications in the nuclear industry and nuclear medicine. So, this chapter is dedicated to the peculiarities of structure and properties and the main synthetic procedures for the complexes above. 

Bimolecular heterolytic substitution (SN2 and Se2) at a saturated center has been extensively investigated during the formative years of physical-organic chemistry, and the Se2 mechanism has an important role in the context of organometallic chemistry. The Sh2 mechanism involving a metal center M is defined by Eq. (1), and has been established for main group elements M since 1966. The well-known free radical process of atom (H or Hal) abstraction is an example of the SH2 mechanism at a terminal... 

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