Cage-closing reactions of the nido-carborane anion 7,9-C2B9H12− and derivatives; formation of neutral 11-vertex carboranes by acidification†
Abstract
Reactions of the nido-carborane salts (Bu4N)(nido-7,9-R,R′-7,9-C2B9H10) (R,R′
= H; R,R′
= Me; R,R′
= Ph; R = Ph, R′
= Me) with H2SO4 at ambient temperature give the 11-vertex closo-carboranes 2,3-R,R′-2,3-C2B9H9 in high yields (R,R′
= H; R,R′
= Me; R,R′
= Ph; R = Ph, R′
= Me). Halogenated derivatives of closo-carboranes, 10-X-2,3-C2B9H10 (X = Cl, I), are formed from reactions of salts containing 1(6)-X-7,9-C2B9H11− anions with H2SO4, and 4-F-2,3-(p-FC6H4)2-2,3-C2B9H8 is formed from (Bu4N)(3-F-7,9-(p-FC6H4)2-7,9-C2B9H9) and F3CSO3H. Elimination of the