The intramolecularly bridged alkyl cobaltic complexes are one of important coenzyme B12 model coplexes. In this paper, study on the thermolytic reaction of aqua(3 bromopropyl)cobaloximes in solution revealed that a new intramolecularly bridged alkyl cobaloximes complex was formed and the reaction is influenced by tempertature and solvent. Adding cyclodxtrin has no obvious effect to the rate of the reaction, but various products with different axial bases were obtained. The intramolecularly bridged alkyl cobaloxime complex (bromo(O trimethylene dimethy lglyoxime)(dimethylglyoximate)cobalt?) was characterized by EA and ESI MS. Thermogravimetric analysis of this complex found that a carbon radical that from homolysis of the Co C bond is retained in the proximity of CoⅡ complex, which is very similar to the behavior of coenzyme B12.
