Simple Access to the Heaviest Alkaline Earth Metal Hydride: A Strongly Reducing Hydrocarbon‐Soluble Barium Hydride Cluster

Abstract

Abstract Reaction of Ba[N(SiMe 3 ) 2 ] 2 with PhSiH 3 in toluene gave simple access to the unique Ba hydride cluster Ba 7 H 7 [N(SiMe 3 ) 2 ] 7 that can be described as a square pyramid spanned by five Ba 2+ ions with two flanking BaH[N(SiMe 3 ) 2 ] units. This heptanuclear cluster is well soluble in aromatic solvents, and the hydride 1 H NMR signals and coupling pattern suggests that the structure is stable in solution. At 95 °C, no coalescence of hydride signals is observed but the cluster slowly decomposes to undefined barium hydride species. The complex Ba 7 H 7 [N(SiMe 3 ) 2 ] 7 is a very strong reducing agent that already at room temperature reacts with Me 3 SiCH=CH 2 , norbornadiene, and ethylene. The highly reactive alkyl barium intermediates cannot be observed and deprotonate the (Me 3 Si) 2 N − ion, as confirmed by the crystal structure of Ba 14 H 12 [N(SiMe 3 ) 2 ] 12 [(Me 3 Si)(Me 2 SiCH 2 )N] 4 .