Synthesis of Group 13 element metallacarboranes and related structure-reactivity correlations

Synthesis, reactivity, and structural characterization studies of a number of group 13 metallacarborane species are described. These include studies of the icosahedral aluminacarborane closo-3-Et-3,1,2-AlC 2 B 9 H 11 (1a). Compound 1a reacts with Lewis bases to form adducts of the type 2L•1a (L=Lewis base). The reaction of 1a with excess PEt 3 results in the rapid formation of endo-10-{AlEt(PEt 3 ) 2 }-7,8-C 2 B 9 H 11 (3). The novel sandwich species commo-3,3'-Al[{exo-8,9-(μ-H) 2 -AlEt 2 -3,1,2-AlC 2 B 9 H 9 )}(3,1,2-AlC 2 B 9 H 11 )] (4) results from thermal dimerization of 1a. The related sandwich anions [commo-3,3'-Al(3,1,2-AlC 2 B 9 H 11 ) 2 ] − ([5] − ) and [commo-3,3'-Ga(3,1,2-GaC 2 B 9 H 11 ) 2 ] − ([6] − ) have been prepared. The full details of the synthesis and structural characterization of σ-bonded species nido-6,9-(μ-AlEt-(OEt 2 ))-6,9-C 2 B 8 H 10 (8), [Al(η 2 -6,9-C 2 B 8 H 10 ) 2 ] − ([10] − ), and [Al(η 2 -2,7-C 2 B 6 H 8 ) 2 ] − ([11] − ) are reported