Ten-vertex closo-carboranes react with “wet” fluoride: A direct closo-to-arachno transformation as a result of a hydride transfer

On the basis of the experimentally observable transformation of closo-1,6-C2B8H10 to arachno-4,6-C2B7H12− with NBu4F, the DFT computational protocol has been used to examine the corresponding reaction pathway. Therefore, this work is a joint synthetic/computational attempt to describe the formation of such a 9-vertex arachno cluster. Analogous experimental transformations of closo-1,2-C2B8H10 and closo-1,10-C2B8H10 have been attempted and the corresponding arachno clusters have been afforded only computationally as the results of energetically demanding processes. For comparison, the identical reaction of icosahedral carboranes provided the fluoroborate anions BF4− and BHxF4−x− (x = 1–3) similarly as in the course of the reactions under scrutiny, but in the case of the 1,2- and 1,10-isomers as the only detectable products. The negative charge of the arachno-4,6-C2B7H12− product with respect to the neutral arachno-4,6-C2B7H13 is caused by a CH group instead of two CH2, detected for the latter.