A convenient cyanide-free “one-pot” synthesis of nido-Me3N-7-CB10H12 and nido-7-CB10H13−

Abstract

Reaction of nido-^tBuH₂N-7-CB₁₀H₁₂ with Na₂CO₃ and (MeO)₂SO₂ in THF results in mono-methylation to give nido-^tBuMeHN-7-CB₁₀H₁₂, whilst prolonged reaction at elevated temperatures results in a quantitative yield of the tri-methyl derivative nido-Me₃N-7-CB₁₀H₁₂, as a result of metathesis of the tert-butyl group. The ¹¹B NMR spectrum of nido-^tBuMeHN-7-CB₁₀H₁₂ is explored as a function of pH, demonstrating exchange with nido-^tBuMeN-7-CB₁₀H₁₂⁻. Reaction of B₁₀H₁₄ with CyNC gives nido-CyH₂N-7-CB₁₀H₁₂, which is methylated by Na₂CO₃ and (MeO)₂SO₂ 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-^tBuMeHN-7-CB₁₀H₁₂ and nido-CyMe₂N-7-CB₁₀H₁₂, determined by single crystal X-ray diffraction, are reported.