Reaction of 13-Vertex Carborane μ‑1,2-(CH2)4‑1,2‑C2B11H11 with Nucleophiles: Linkage Effect on Product Formation

The length of C,C′-linkage has a great influence on the reactivity of 13-vertex carboranes. Reaction of 1,2-(CH2)4-1,2-C2B11H11 (1a) with Et2NH gave a 1:1 adduct nido-7-NEt2H-μ-1,3-(CH2)4-1,3-C2B11H11 (2). Compound 1a reacted with Me2NLi or Et2NLi to afford nido-[9-Nu-μ-7,8,10-(CH2)4CCH-B11H10]− (Nu = NMe2, [3]−; Nu = NEt2, [4]−). Complex [4]− was also obtained by deprotonation of 2. Treatment of 1a with MeOH/base generated nido-[3-OMe-μ-1,2-(CH2)4-1,2-C2B11H11]− ([5]−) at room temperature, which was converted to nido-[μ-7,8-(CH2)4CHB­(OMe)2-7-CB10H11]− ([6]−) upon heating in the presence of Et3N. Complex [6]− was oxidized by H2O2 to the corresponding alcohol [μ-7,8-(CH2)4CHOH-7-CB10H11]− ([7]−) or hydrolyzed to the boronic acid [μ-7,8-(CH2)4CHB­(OH)2-7-CB10H11]− ([8]−). Reaction of 1a with (4-MeC6H4)­SNa produced a CB11– anion closo-[μ-1,2-(CH2)4CHS­(4-MeC6H4)-1-CB11H10]− ([9]−). The above complexes were fully characterized by 1H, 13C, and 11B NMR spectroscopic data and elemental analyses. Molecular structures of 1–[7]− and [9]− were further confirmed by single-crystal X-ray analyses.