Synthesis of boronated amidines by addition of amines to nitrilium derivative of cobalt bis(Dicarbollide)†

Abstract

A series of novel cobalt bis(dicarbollide) based amidines were synthesized by the nucle-ophilic 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-C2 B9 H10 )(1′,2′-C2 B9 H11 )]. The reactions with primary amines result in the formation of mixtures of E and Z isomers of amidines, whereas the reactions with secondary amines lead selectively to the E-isomers. The crystal molecular structures of E-[8-EtC(NMe2 )=HN-3,3′-Co(1,2-C2 B9 H10 )(1′,2′-C2 B9 H11 )], E-[8-EtC(NEt2 )=HN-3,3′-Co(1,2-C2 B9 H10 )(1′,2′-C2 B9 H11 )] and E-[8-EtC(NC5 H10 )=HN-3,3′-Co(1,2-C2 B9 H10 )(1′,2′-C2 B9 H11 )] were determined by single crystal X-ray diffraction.