Isolation of a planar 1,2-dilithio-disilene and its conversion to a Si–B hybrid 2π-electron system and a planar tetraboryldisilene

Abstract

Lithium reagents have long played important roles in synthetic chemistry. However, unsaturated organosilicon lithium reagents are rare in number. Herein, we describe the first isolation of a 1,2-dilithiodisilene: [(boryl)SiLi]2 (2)...

Synthesis of an N‐Heterocylic Boryl‐Stabilized Disilyne and Its Application to the Activation of Dihydrogen and C−H Bonds

“…To probe the mechanism for the activation of benzylic C−H bond, a solution of 3 in toluene was monitored by UV/Vis spectroscopy at room temperature. As shown in Figure S11, the reaction initially yielded a species featuring an absorption maximum at 473 nm, which disappeared in 3 h. This absorption is very similar to those found for 5 (Figure S10) and other boryl‐substituted disilenes [7h, 10] . The results strongly support the initial cycloaddition of 3 with the π system of toluene.…”

“…[7] It has been shown that NHB [ArN-(CH) 2 NAr]B (Ar = 2,6-iPr 2 C 6 H 3 ) could effectively tune the HOMO-LUMO gaps of acyclic silylenes and germylenes (A in Scheme 1). [8] In addition, it allowed the isolation of the first digermavinylidene (B), [9] 1,2-dilithiodisilene (C) [10] and 1-magnesium-disilacyclopropene (D). [11] These significant advances demonstrated the remarkable steric and electronic perturbations of the NHB group for highly reactive lowcoordinate species.…”

Neutral Homoaromatic Diboradisilacyclobutene: Synthesis, Structure, and Reactivity

“…Accordingly, the Si1–Si2 bond distance of 2.2260(11) Å in 3 is comparable to those of 2.2700(5) Å and 2.2145(7) Å in the Lewis base coordinated cyclotrisilenes and falls in the upper range of those reported Si–Si double bonds (2.132–2.289 Å) . Moreover, this measured value is also longer than those reported aromatic disilaborirenes (2.133–2.147 Å) featuring three-coordinate silicon atoms . The B1–Si1 bond length of 1.951(3) Å in 3 is a bit shorter than the typical B–Si single bonds (1.975–2.139 Å), , but noticeably longer than that of 1.838 Å in the neutral silaborene .…”

“…14 Moreover, this measured value is also longer than those reported aromatic disilaborirenes (2.133−2.147 Å) featuring three-coordinate silicon atoms. 15 The B1−Si1 bond length of 1.951(3) Å in 3 is a bit shorter than the typical B−Si single bonds (1.975−2.139 Å), 11a,16 but noticeably longer than that of 1.838 Å in the neutral silaborene. 17 The relatively long Si−Si bond and short B−Si bond may be due to the 2π electrons delocalization over the BSi 2 moiety.…”

Sequential Reduction of Borylstibane to an Electronically Nonsymmetric Diboryldistibene Radical Anion

“…Lithium 1,3,2-diazaborolide (HCNDip) 2 BLi­(solv) (solv = THF, DME; Dip = 2,6- i Pr 2 C 6 H 3 ), subsequently referred to as boryllithium, is a nucleophilic boron source that is extensively used for the synthesis of novel compounds with element–boron bonds across the periodic table . Its large steric demand and the electropositive and electronically unsaturated nature of the boron center proved to be very effective for the stabilization of unusual structural motifs, i.e., group 13 element-centered radicals, metalloid In clusters, acyclic silylenes, and reduced Si 2 species as well as a digermavinylidene …”