Isolation and Characterization of Lewis Base Stabilized Monomeric Parent Stibanylboranes

Abstract

The synthesis of the Lewis base stabilized monomeric parent compound of stibanylboranes, "H2 Sb-BH2 ", is reported. Through a salt metathesis route, the silyl-substituted compounds (Me3 Si)2 Sb-BH2 ⋅LB (LB=NMe3 , NHC(Me) ) were synthesized as representatives of derivatives with a Sb-B σ bond. Under very mild conditions, they could be transformed into the target compounds Me3 N⋅H2 B-HSb-BH2 ⋅NMe3 and H2 Sb-BH2 ⋅NHC(Me) , respectively. The products were characterized by X-ray structure analysis, NMR spectroscopy, IR spectroscopy, and mass spectrometry. DFT calculations give further insight into the stability and bonding of these unique compounds.

A Convenient Route to Mixed Pnictogenylboranes

“…[10] Rivard and co-workers succeeded in the preparation of H 3 B-H 2 NBH 2 -DMAP (DMAP = dimethylaminopyridine) and its conversion into borazine. [10a] In some cases,t he stabilization induced by the coordination of aL ewis base is sufficient for the isolation of such complexes.U sing this strategy,o ur group was able to synthesize the parent compounds of the phosphanylboranes, [11] the arsanylboranes, [12] and the stibanylboranes, [13] which are stabilized by aL ewis base only.E vidence that the free,u nstabilized phosphanylborane might exist was reported by Burg and coworkers with reference to the formation of H 2 PBMe 2 . [14, 15b] In contrast to the matrix-characterized H 2 NBH 2 , [6] the free parent phosphanylborane H 2 PBH 2 has not been observed experimentally thus far, but has been studied computationally.…”

“…Similar highly reactive compounds such as [H 2 N=BH 2 ] have been isolated under cryogenic conditions. [10a] In some cases,t he stabilization induced by the coordination of aL ewis base is sufficient for the isolation of such complexes.U sing this strategy,o ur group was able to synthesize the parent compounds of the phosphanylboranes, [11] the arsanylboranes, [12] and the stibanylboranes, [13] which are stabilized by aL ewis base only.E vidence that the free,u nstabilized phosphanylborane might exist was reported by Burg and coworkers with reference to the formation of H 2 PBMe 2 . [7] Thesame h 2 :h 2 coordination of [R 2 N=BH 2 ]w as observed within an Ir complex.…”

Ein Weg zu gemischten Pnictogenylboranen

“…[7] Eine ähnliche h 2 :h 2 -Koordination von [R 2 N=BH 2 ]w urde an einem Ir-Komplex beobachtet. Mithilfe dieser Strategie gelang es unserer Gruppe,d ie Stammverbindungen der Phosphanylborane, [11] Arsanylborane [12] und Stibanylborane [13] zu synthetisieren. In letzerem Fall wird das freie p-Orbital am Boratom durch eine Lewis-Base (LB) blockiert, während das freie Elektronenpaar des Pnictogenatoms an eine Lewis-Säure (LS) koordiniert.…”

A Sterically Encumbered 13/15 Cycle and its Cleavage with N‐heterocyclic Carbenes and other Lewis Bases

“…A lot of those adducts have been published over the last two decades, mostly for metal halogenides/hydrides like [(IMes)GaClH 2 ] or similar organosubstituted derivatives like [(I t Bu)AlMe 3 ] , . Moreover NHC stabilized 13/15 monomers are described, as well as a huge variety of such compounds where the electronic stabilization is realized with other Lewis bases like DMAP or amines …”