Formation of alkaline earth metal-arsenic cages via the metalation of triisopropylsilylarsane with calcium, strontium, and barium bis[bis(trimethylsilyl)amide] in tetrahydrofuran

The metalation of triisopropyisilylarsane with the alkaline earth metal bis [bis(trimethylsilyl)amides] in tetrahydrofuran yields the THF complexes of calcium (1), strontium (2), and barium-bis(triisopropylsilylarsanide) (3). Dissolving of these compounds in toluene leads to the elimination of triiso propylsilylarsane and the formation of the THF complexes of tetraalkaline e arth metal hexakis( triisopropylsilylarsanide)-triisopropylsilylarsanediide of calcium (4), strontium (5), and barium (6), respectively. The central p olyhedron of compound 4 can be described as two trigonal bipyramids with th e metal atoms in apical positions, connected via the arsanediide substituen t as a common corner. The central moieties of the compounds 5 and 6 consist of four trigonal bipyramids which are connected by common edges as well as common faces.