Cationic -Tricarbollide μ-10,11-H-10,11-H-7-MeN--7,8,9-CBH and Its Halogenated Derivatives: The Slow Iodination Process Occurring through Cationic Iodonium Tricarbollides.

A series of -tricarbollides based on 10,11-X-7-MeN--7,8,9-CBH (X = H, Cl, Br, I) and their protonated, i.e. cationic, counterparts, which have an extra H-bridge over the B10-B11 vector in the open pentagonal belt, were prepared. Their structures have been verified by the joint (DFT)/GIAO(ZORA)/NMR approach, MS and HR-MS spectroscopy, and X-ray diffraction techniques. The iodination process is quite slow and could be monitored by B NMR spectroscopy in conjunction with a computational search for the corresponding reaction pathway. These efforts have revealed the existence of monoiodo tricarbollide cationic motifs with an iodine atom in the positions that have features of an asymmetrical bridge over B10(H)-B11(H) in 10,11-H-7-MeN--7,8,9-CBH or B10(I)-B11(H) in 10,11-I,H-7-MeN--7,8,9-CBH. Interestingly, 1,2-(COOH)--1,2-CBH is one of the active acids, which confirms the earlier observation that a dicarboxylic acid based on -carborane acts as a superacid.