Synthesis, Structural Analysis, and Functional Group Interconversion in the [closo-B10H8-1,10-X2]2-(X = CN, [OCRNMe2]+, OCOR, and [OH2]+) Derivatives

Derivatives [closo-B10H8-1,10-(CN)(2)](2-)and [closo-B10H8-1,10-(OCHNMe2)(2)], efficiently obtained from [closo-B10H8-1,10-(IPh)(2)] by nucleophilic substitution with CN(-)and DMF, were envisioned as precursors to diacid [closo-B10H8-1,10-(COOH)(2)](2-)and to dihydroxy derivative [closo-B10H8-1,10-(OH)(2)](2-), respectively. Attempts at hydrolysis or reduction of the dinitrile gave no reaction or complex mixtures of products. In contrast, the DMF adduct was cleanly hydrolyzed to diformate [closo-B10H8-1,10-(OCHO)(2)](2-)and subsequently to protonated dihydroxy [closo-B10H8-1,10-(OH2)(2)]. The latter was O-acylated with PhCOCl. Crystal and molecular structures of five derivatives were established by single crystal XRD methods and compared to those for other [closo-B10H8-1,10-X-2](2-)derivatives. Trends in molecular geometry in the series and also reactivity of the dinitrile and intermediates were corroborated and correlated with DFT results (B3LYP/TZVP) by analysis of bonding, charge distribution and vibrational frequencies.