Polyhedral Monocarbaborane Chemistry. A Review of Recent Developments Among C -Aryl Monocarbaborane Systems
The Brellochs Reactions, of nido-B 1 0 H 1 4 with aromatic aldehydes to give [6-Ar-nido-6-CB 9 H 1 1 ] - anions in high yield, now permits excellent entries into C-aryl monocarbaborane chemistry, which is reviewed. From [6-Ar-nido-6-CB 9 H 1 1 ] - , one-step cluster-closure, cluster-Aufbau, or cluster-dismantling reactions yield [1-Ph-closo-1-CB 1 1 H 1 1 ] - , [7-Ph-nido-7-CB 1 0 H 1 2 ] - , [1-Ph-closo-1-CB 9 H 9 ] - , [2-Ph-closo-2-CB 9 H 9 ] - , [4-close-4-PhCB 8 H 8 ] - and [6-Ph-arachno-6-CB 8 H 1 3 ]. Second-step reactions involving these products yield [2-Ph-closo-2-CB 1 0 H 1 0 ] - , [6-Ph-nido-6-CB 8 H 1 1 ], [1-Ph-closo-1-CB 7 H 7 ] and [4-Ph-closo-4-CB 8 H 8 ] - , as well as alternative routes to [1-Ph-closo-1-CB 1 1 H 1 1 ] - and [1-Ph-closo-1-CB 9 H 9 ] - . This readier access to this extensive suite of C-aryl monocarbaboranes permits a readier examination of their derivative chemistry. Monohalogenated and poly-halogenated species [1-Ph-close-1-CB 9 H 9 - n X n ] - and [1-Ph-close-1-CB 1 1 H 1 1 - n X n ] - have been formed as well as (SMe 2 )-substituted {CB 1 1 } and {CB 1 0 } systems. Coupling reactions with para-substituted [XC 6 H 4 CB 1 1 H 1 0 X] - systems give rod-like anions, and with poly-iodinated [PhCB 1 1 H 5 I 6 ] - and [PhCB 9 H 4 I 5 ] - give the globular [PhCB 1 1 H 5 Ar 5 I] - and [PhCB 9 H 4 Ar 4 I] - anions. Additional interesting species include [PhCB 1 1 H 1 0 CH=CHCH 3 ] - , [PhCB 1 1 H 1 0 SMe(CH 2 ) 4 OH] - and [PhCB 9 H 8 -6-OH] - . A review with 49 references.