Crystalline Neutral Aluminum Selenide/Telluride: Isoelectronic Aluminum Analogues of Carbonyls

Abstract

Neutral aluminum chalcogenides (R−Al(L)�Ch; L = ligand, Ch = chalcogen), stabilized by a Lewis base ligand, represent isoelectronic counterparts to carbonyl compounds and have long been pursued for isolation. Herein, we present the synthesis of an aluminum selenide, [N]−Al( i Pr 2 -bimy)�Se, and an aluminum telluride, [N]−Al( i Pr 2 -bimy)�Te, under ambient conditions ([N] = 1,8-bis(3,5-di-tert-butylphenyl)-3,6-di-tert-butylcarbazolyl; i Pr 2 -bimy = 1,3-diisoproplylbenzimidazole-2-ylidene). These compounds arise from the oxidation reaction of [N]−Al( i Pr 2 -bimy) with Se and ( n Bu) 3 P�Te, respectively. One notable characteristic of the Al and Ch interaction is the presence of an Al−Ch σ bond, strengthened by the electrostatic attraction between the Al + and Ch − centers as well as the donation of lone pairs from Ch into vacant orbitals at Al. This results in an Al−Ch multiple bond with an ambiphilic nature. Preliminary investigations into their reactivity unveil their remarkable propensity for facile (cyclo)addition reactions with diverse substrates, including PhCCH, PhCN, AdN 3 , MeI, PhSiH 3 , and C 6 F 6 , leading to the formation of unprecedented main group heterocycles and alumachalcogenides.

Recent advances in the chemistry of isolable carbene analogues with group 13–15 elements

“…135,136 In a recent exploration, we discovered that subjecting 16 to reactions with Se and ( n Bu) 3 P = Te leads to the synthesis of the first neutral tricoordinate aluminum chalcogenides, namely aluminum selenide 21-P4 and aluminum telluride 21-P5 . 137…”