New 8-aryl-8´-iodo derivatives of cobalt bis(1,2-dicarbollide)

Reactions of 8,8´-μ-iodo-3-commo-3-cobalta[bis(1,2-dicarba-closo-dodecaborane)] (8,8´-μI-3,3´-Co(1,2-C2B9H10)2) with aryl halides (fluoro-, chloro-, bromo-, iodo-, and o-dichlorobenzenes) were studied. The reaction of 8,8´-μ-I-3,3´-Co(1,2-C2B9H10)2 with these reagents proceeded only in the presence of sterically hindered Lewis bases with the cleavage of the bridging B—I bond and the formation of the corresponding anionic 8-aryl-8´-iodo derivatives of cobalt bis(1,2-dicarbollide). X-ray diffraction studies were carried out for the charge-compensated 8´-iodo-8-(4,1-oxathian-1-ium)icosahydro-1,1´,2,2´-tetracarba-3-commo-cobaltacloso-tricosaborate and the anionic tetramethylpiperidinium 8´-(3,4-dichlorophenyl)-8-iodoicosahydro-1,1´,2,2´-tetracarba-3-commo-cobalta-closo-tricosaborate. The X-ray diffraction data showed that the molecule of the former compound has the gauche conformation, whereas the anionic complex is in the trans conformation.