Sandwiched Metallacarboranes of f-Block Elements

Abstract The dilithium complexed “carbons adjacent” nido-carborane anions of the type [2-(SiMe3)-3-(R)-2,3-C2B4H4]2- [R = SiMe3, Me, H], as well as the disodium and dilithium complexed “carbons apart” nido-carborane anions [2-(SiMe3)-4-(R)-2,4-C2B4H4]2- [R = SiMe3, Me] have exhibited different reactivity patterns toward various lanthanide halides, depending upon the solvents used in the reactions and the nature of the group 1 metal. Both the tetrahydofuran (THF) and N,N,N,N-tetramethylethylenediamine (TMEDA)-solvated closo-dilithiacarboranes have been found to be important synthons in the production of novel metallacarboranes of f-block elements. Several unprecedented examples of lanthanide-carborane complexes have been synthesized, their structures determined and reactivity studied.