Synthesis of Boronated Amidines by Addition of Amines to Nitrilium Derivative of Cobalt Bis(Dicarbollide).

A series of novel cobalt bis(dicarbollide) based amidines were synthesized by the nucleophilic addition of primary and secondary amines to highly activated B-N≡C-R triple bond of the propionitrilium derivative [8-EtC≡N-3,3'-Co(1,2-CBH)(1',2'-CBH)]. The reactions with primary amines result in the formation of mixtures of and isomers of amidines, whereas the reactions with secondary amines lead selectively to the -isomers. The crystal molecular structures of -[8-EtC(NMe)=HN-3,3'-Co(1,2-CBH)(1',2'-CBH)], -[8-EtC(NEt)=HN-3,3'-Co(1,2- CBH)(1',2'-CBH)] and -[8-EtC(NCH)=HN-3,3'-Co(1,2-CBH)(1',2'-CBH)] were determined by single crystal X-ray diffraction.