A convenient cyanide-free 'one-pot' synthesis of nido-Me3N-7-CB10H12 and nido-7-CB10H13.

Abstract

Reaction of nido-(BuH2N)-Bu-t-7-CB10H12 with Na2CO3 and (MeO)(2)SO2 in THF results in mono-methylation to give nido-(BuMeHN)-Bu-t-7-CB10H12, whilst prolonged reaction at elevated temperatures results in a quantitative yield of the trimethyl derivative nido-Me3N-7-CB10H12, as a result of metathesis of the tert-butyl group. The B-11 NMR spectrum of nido-(BuMeHN)-Bu-t-7-CB10H12 is explored as a function of pH, demonstrating exchange with nido-(BuMeN)-Bu-t-7-CB10H12-. Reaction of B10H14 with CyNC gives nido-CyH2N-7-CB10H12, which is methylated by Na2CO3 and (MeO) 2SO(2) in THF to give nido-CyMe2N-7-CB10H12. Deprotonation of nido-Me3N-7-CB10H12 and nido-CyMe2N-7-CB10H12 yields Na[nido-Me3N-7-CB10H11] and Na[nido-CyMe2N-7-CB10H11] respectively. Both trialkyl( amino) carboranes can be converted to Na[nido-CB10H13], itself a precursor to the poorly coordinating anion closo-CB11H12-. The molecular structures of nido-(BuMeHN)-Bu-t-7-CB10H12 and nido-CyMe2N-7-CB10H12, determined by single crystal X-ray diffraction, are reported.