Reductive coupling, metal atom-organic

Abstraction, reductive coupling, electron transfer, bond activation, oxidative addition, n-complexation, disproportionation and metal cluster formation are some of the reactions that occur when metal atoms interact with organic polymers and small molecules. Examples of these reactions are provided from the literature on the organometallic chemistry of free atoms and coordination-deficient molecules. Past uses of model compound studies to understand the early stages of chromium metallization on polyimide are critiqued. New evidence for reactions of chromium atoms with compounds related to polyimides is given. 

Insertion of carbon monoxide followed by reductive coupling is an old reaction that continues to be studied and developed. Examples of this reaction are the carbonylation of nickel dialkyl complexes to give ketones, " alkyl-alkoxides to yield esters, and alkyl-amides to give organic amides (Equation (79)). The carbonylation of the binuclear complex 145 leads to the formation of an isoquinolone ring with the elimination of one of the two Ni atoms, but no GO insertion occurs at the second metal moiety. Hydrolytic cleavage of the remaining Ni-G bond provides the free heterocyclic base (Scheme 45). ... 

When metallo-enzymes effect the oxidation or reduction of organic substrates or simple molecules such as H2O, N2 or O2, they often function as multielectron donors or acceptors with two or more metals at the active site. The electronic coupling between the metals is often accompanied by unique spectroscopic features such as electron spin-spin coupling. The metal-metal electronic coupling may facilitate the multi-electron-transfer reactions with the substrates. In simpler molecular systems, two electron-transfer processes most often require substrate binding , as in an inner-sphere, group (or atom ) transfer process. ... 

The formation of C—N bonds is an important transformation in organic synthesis, as the amine functionality is found in numerous natural products and plays a key role in many biologically active compounds [1]. Standard catalytic methods to produce C—N bonds involve functional group manipulations, such as reductive amination of carbonyl compounds [2], addition of nucleophiles to imines [3], hydrogenation of enamides [4—8], hydroamination of olefins [9] or a C—N coupling reaction [10, 11]. Recently, the direct and selective introduction of a nitrogen atom into a C—H bond via a metal nitrene intermediate has appeared as an attractive alternative approach for the formation of C—N bonds [12-24]. 

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