Alkyl carbonyl complexes, structures

The groups of Philipsborn [84], Heaton [85-88] and Mann [89-91] have used ° Rh NMR extensively to elucidate structural and mechanistic aspects of a wide variety of metal carbonyl and metal cluster complexes. Further, Zamaraevl [92] has shown that NMR studies on several quadrupolar nuclei, e. g. Mo, help with the characterization of the alkyl peroxo-complexes, which are thought to be inter-... 

Nishinaga and co-workers isolated a series of stable cobalt(III)-alkyl peroxide complexes such as (170) and (171) in high yields from the reaction of the pentacoordinated Co"-Schiff base complex with the corresponding phenol and 02 in CH2C12. Complex (170 R=Bu ) has been characterized by an X-ray structure. These alkyl peroxide complexes presumably result from the homolytic addition of the superoxo complex Co111—02 to the phenoxide radical obtained by hydrogen abstraction from the phenolic substrate by the CoUI-superoxo complex. The quinone product results from / -hydride elimination from the alkyl peroxide complex (172)561,56,565,566 The quinol (169) produced by equation (245) has been shown to result from the reduction of the CoIU-alkyl peroxide complex (170) by the solvent alcohol which is transformed into the corresponding carbonyl compound (equation 248).561... 

The reactivity of carbonyls of Cr, Mo, and W with alkyl lithium is somewhat lower than that of nickel and iron carbonyls. The most interesting reaction of these metal carbonyls, found and studied extensively by Fischer and his coworkers, is the formation of carbene complexes 98-"). Phenyl or methyl lithium adds readily to W(CO)6 at room temperature to form carbonylate complexes. The tetramethyl ammonium salt of the complex is treated with acid and then with diazomethane to give a neutral complex whose structure was found to be that of a carbene complex. In this way a series of carbene complexes of Cr, Mo, and Mn were synthesized. 

Aldehydes are the class of carbonyl compounds where one substituent is an alkyl, alkenyl, or aryl group, and the other is a hydrogen atom, 4.34. The suffix for aldehydes is -al added to the hydrocarbon skeleton name, so if R = CH3, 4.34 would be ethanal (the old name, which is still commonly used, was acetaldehyde). In formal nomenclature, the aldehyde carbon is designated as C-1. When R = H, the name is methanal, but this compound is almost invariably known by its common name, formaldehyde. With more complex structures, the longest chain starting at C-1 is discerned, numbered, and the substituents put in as usual. So 4.35 is 2,3-dimethylpentanal. 

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