Efficient generation of stable adducts of Si(ii) dihydride using a donor–acceptor approach

Abstract

A stable Si(II) dihydride complex, IPr·SiH(2)·BH(3) (IPr = [(HCNDipp)(2)C:]; Dipp = 2,6-(i)Pr(2)C(6)H(3)), was synthesized and preliminary reactivity involving this source of encapsulated silylene is reported.

On the Reactivity of the Silylene PhC(NtBu)2SiNPh2 toward Organic Substrates

“…LSiNPh 2 [15] (1) was prepared as reported in the literature. 1 H, 13 C, and 29 Si NMR spectra were recorded with a Bruker Avance DRX 500 spectrometer, using C 6 D 6 as a solvent. Chemical shifts δ are given relative to SiMe 4 .…”

“…[7][8][9] Many important reactivity studies of stable silylenes toward a variety of substrates have been reported. [10][11][12][13][14] Recently we synthesized a functionalized silylene LSiNPh 2 (1) [L = PhC(NtBu) 2 ] by the facile metathesis reaction of LiNPh 2 with LSiCl. [15] Reactions of stable silylenes with organo isothiocyanates are not reported in the literature.…”

Recent Advances in the N-Heterocyclic Carbene-Supported Chemistry of Silicon

“…Based on the energies of the frontier orbitals in the EH 2 series (E ¼ Si, Ge, Sn and Pb), SiH 2 is predicted to be both the strongest Lewis base and Lewis acid in the series, and concurrently IPr•SiH 2 •BH 3 (23) is stable in refluxing toluene and only decomposes at ca. 230 C in the solid state under N 2 [66]. For comparison, the previously reported Ge(II) congener IPr•GeH 2 •BH 3 (24) [43] decomposes completely in refluxing toluene to yield IPr•BH 3 and Ge metal (with H 2 evolution).…”

“…Later the Rivard group noted that the hydride source Li[AlH 4 ] converted IPr•SiCl 2 •BH 3 (22) into IPr•SiH 2 •BH 3 (23) when short reaction times coupled with an Et 2 O/toluene solvent mixture were employed [66] (Scheme 4); prolonged reaction times led to the formation of copious amounts of the known alane adduct IPr•AlH 3 [67], presumably via a carbene exchange reaction between 23 and the AlH 3 byproduct. Based on the energies of the frontier orbitals in the EH 2 series (E ¼ Si, Ge, Sn and Pb), SiH 2 is predicted to be both the strongest Lewis base and Lewis acid in the series, and concurrently IPr•SiH 2 •BH 3 (23) is stable in refluxing toluene and only decomposes at ca.…”

“…In addition, IPr•SiCl 2 has been shown to be an effective two-electron donor to a wide range of mid-to-late transition metal complexes as exemplified by the synthesis of complexes such as [(IPr•SiCl 2 ) 2 Ni(CO) 2 ] (30) [73], [(IPr•SiCl 2 ) 2 Co (CO) 3 ] + [CoCl 3 (THF)] À (31) [74], [(IPr•SiCl 2 )V(CO) 3 Cp] (32) [75], and the Rh(I) salt all-trans-[(IPr•SiCl 2 ) 2 Rh(CO) 2 ] + [Rh(CO) 2 Cl 2 ] À (33) by the Rivard group [66]. Moreover Roesky and coworkers have discovered that efficient [1 + 2] cycloaddition chemistry can transpire between IPr•SiCl 2 (15) and Ph 2 CO [76] to give 34 (Scheme 6), which highlights the ability of the silicon center in 15 to act both as an electrophile and as a nucleophile in reacting with benzophenone.…”