Lewis Acid/Base Reactions of the Bis(amidinato)silylene [iPrNC(Ph)NiPr]2Si and Bis(guanidinato)silylene [iPrNC(NiPr2)NiPr]2Si with ElPh3 (El = B, Al)

Theoretical investigation on the effect of the ligand on bis-silylation of C(sp)–C(sp) by Ni complexes

Density functional theory is used to study the bis-silylation of alkyne catalysed by a transition metal nickel–organic complex. The active catalyst, organic ligand, reaction mechanism, and rate-determining step were discussed with regard to dynamics and thermodynamics. COD or SIPr (COD = cyclooctadiene, SIPr = 1,3-bis(2,6-diisopropyl-phenyl)-4,5-dihydroimidazol-2-ylidene) coordination with Ni will greatly reduce the energy barrier of the Si–Si insertion step, that is, ΔΔG reaches 15.5 kcal mol⁻¹. Furthermore, the structure of alkynes will change the energy barrier of the alkyne insertion step.

Density functional theory (DFT) is used to study the bis-silylation of alkynes catalyzed by a transition metal nickel–organic complex; the active catalyst, the organic ligand, the reaction mechanism, and rate-determining step are discussed in this paper.

(PhC(NtBu)2Al)2(SiH2)4 six-membered heterocycle: comparable in structure to cyclohexane

A (PhC(NtBu)₂Al)₂(SiH₂)₄ centrosymmetric six-membered heterocycle (LAl)₂(SiH₂)₄ (L = PhC(NtBu)₂) with chair conformation is prepared by reacting disilylene LSi–SiL with alane AlH₃·NEtMe₂. It is comparable in structure to cyclohexane containing four Si and two Al atoms as a core.

Reactivity of an NHC-stabilized pyramidal hydrosilylene with electrophilic boron sources

An NHC-stabilized three-coordinate hydrosilylene dehydrogenates ammonia borane and forms more stable complexes with BH₃, BPh₃, BBr₃ and BPhBr₂ but less stable ones with BF₃, and BCl₃ for which ligand scrambling occurs.

The effect of σ/π, σ and π donors on the basicity of silylene superbases: a density functional theory study

In this study, we examined computationally that the combination of π-and σ-donor substituents results in higher basicity of silylene compounds compared to the usage of π-donor substituents alone.

Iron(II), Cobalt(II), Nickel(II), and Zinc(II) Silylene Complexes: Reaction of the Silylene [iPrNC(NiPr2 )NiPr]2 Si with FeBr2 , CoBr2 , NiBr2 ⋅MeOCH2 CH2 OMe, ZnCl2 , and ZnBr2

Reaction of the donor-stabilized silylene [iPrNC(NiPr₂ )NiPr]₂ Si (1) with FeBr₂ , CoBr₂ , NiBr₂ ⋅MeOCH₂ CH₂ OMe, ZnCl₂ , and ZnBr₂ afforded the respective transition-metal silylene complexes 4-8, the formation of which can be described in terms of a Lewis acid/base reaction (4, 5, 7, 8) or a nucleophilic substitution reaction (6). However, the reactivity profile of silylene 1 is not only based on its strong Lewis base character; the different coordination modes of the two guanidinato ligands (4-6 vs. 7 and 8) add an additional reactivity facet. The paramagnetic compounds 4 and 5 and the diamagnetic compounds 6⋅THF, 7, and 8⋅0.5 Et₂ O were structurally characterized by single-crystal X-ray diffraction. In addition, compound 6⋅THF was studied by ¹⁵ N and ²⁹ Si solid-state NMR spectroscopy, and 7 and 8 were characterized by NMR spectroscopic studies in the solid state (¹⁵ N, ²⁹ Si) and in solution (¹ H, ¹³ C, ²⁹ Si). Compounds 4-8 represent very rare examples of Fe^II , Co^II , Ni^II , and Zn^II silylene complexes. Four-coordinate silicon(II) compounds with an SiN₃ M skeleton (M=Fe, Co, Ni) and M in the formal oxidation state +2 (4-6) have not yet been reported, and five-coordinate silicon(II) compounds with an SiN₄ Zn skeleton (7, 8) are also unprecedented.

Unprecedented solvent induced inter-conversion between monomeric and dimeric silylene–zinc iodide adducts

The reaction of silylene [PhC(NtBu)₂SiN(SiMe₃)₂] with ZnI₂leads to both monomeric [PhC(NtBu)₂Si{N(SiMe₃)₂} → ZnI₂]·THF (1) and dimeric [PhC(NtBu)₂Si{N(SiMe₃)₂} → ZnI₂]₂(2) adducts which are inter-convertible.

Bis(amidinato)- and bis(guanidinato)silylenes and silylenes with one sterically demanding amidinato or guanidinato ligand: synthesis and reactivity

Silylenes 1–4 have great synthetic potential for the synthesis of higher coordinate silicon(ii) and silicon(iv) complexes with unprecedented structural motifs.