Polyhedral monocarbaborane chemistry. A review of recent developments among C-aryl monocarbaborane systems

The Brellochs Reactions, of nido-B10H14 with aromatic aldehydes to give [6-Ar-nido-6-CB9H11] - anions in high yield, now permits excellent entries into C-aryl monocarbaborane chemistry, which is reviewed. From [6-Ar-nido-6-CB9H11](-), one-step cluster-closure, clusterAufbau, or cluster-dismantling reactions yield [1-Ph-closo-1-CB11H11](-), [7-Ph-nido-7-CB10H12](-), [1-Ph-closo-1-CB9H9](-), [2-Ph-closo-2-CB9 H-9](-),[4-closo-4-PhCB8H8](-) and [6-Ph-arachno6- CB8 H-13]. Second-step reactions involving these products yield [2-Ph-closo-2-CB10H10](-), [6-Ph-nido-6-CB8H11], [1-Ph-closo-1-CB7H7](-) and [4-Ph-closo-4-CB8H8](-), as well as alternative routes to [1-Ph-closo-1-CB11 H-11](-) and [1-Ph-closo-1-CB9H9](-). 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-closo-1-CB9H9-nXn](-) and [1-Ph-closo-1-CB11H11-nXn](-) have been formed as well as (SMe2)- substituted {CB11} and {CB10} systems. Coupling reactions with para-substituted [XC6H4CB11H10X](-) systems give rod-like anions, and with poly-iodinated [PhCB11H5I6](-) and [PhCB9H4I5](-) give the globular [PhCB11H5Ar5I](-) and [PhCB9H4Ar4I](-) anions. Additional interesting species include [PhCB11H10CH=CHCH3](-), [PhCB11H10SMe(CH2)(4)OH](-) and [PhCB9H8-6-OH](-). A review with 49 references.