Iron(II), Cobalt(II), Nickel(II), and Zinc(II) Silylene Complexes: Reaction of the Silylene [iPrNC(NiPr₂)NiPr]₂Si with FeBr₂, CoBr₂, NiBr₂⋅MeOCH₂CH₂OMe, ZnCl₂, and ZnBr₂

Abstract

Reaction of the donor-stabilized silylene [iPrNC(NiPr )NiPr] Si (1) with FeBr , CoBr , NiBr ⋅MeOCH CH OMe, ZnCl , and ZnBr 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 Et O were structurally characterized by single-crystal X-ray diffraction. In addition, compound 6⋅THF was studied by N and Si solid-state NMR spectroscopy, and 7 and 8 were characterized by NMR spectroscopic studies in the solid state ( N, Si) and in solution ( H, C, Si). Compounds 4-8 represent very rare examples of Fe , Co , Ni , and Zn silylene complexes. Four-coordinate silicon(II) compounds with an SiN 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 SiN Zn skeleton (7, 8) are also unprecedented.

Access to Silicon(II)– and Germanium(II)–Indium Compounds

“…However, in recent years, attention has shifted to silicon compounds, where the formal oxidation state of silicon is +2, popularly known as silylenes . Examples of carbonyl-free silylene complexes of 3d transition metals in the formal oxidation state +2 are now too frequent to be comprehensively listed, thanks to extensive investigations by the groups of H. Roesky, P. Roesky, Stalke, Driess, Tacke, Inoue, Khan, and many others. − The coverage of the s and p blocks is also expanding and is supplemented by examples of bonding to s-/p-block Lewis acids such as boron, aluminum, calcium, germanium, tin, and lead . However, when it comes to indium, there has only been one reaction reported between a Si­(II) compound and an indium derivative.…”

A cyclopentadienyl functionalized silylene – a flexible ligand for Si- and C-coordination

“…Silylenes are known for their ability to bind to, among others, low-valent transition metal complexes. 6,20,28,41,[50][51][52][53][54][55][56] For this purpose, compound 1 was treated with group 9 dimers [RhCl Compound 6 crystallizes in the monoclinic space group P2 1 / n with one molecule in the asymmetric unit (Fig. 6).…”

Amidinato Germylene‐Zinc Complexes: Synthesis, Bonding, and Reactivity

“…The group of P. Roesky reported the first silylene‐zinc complexes, [ZnCl( η 2 ‐C 5 Me 5 ){Si(PhC(N t Bu) 2 )(C 5 Me 5 )}], [Zn 2 ( μ‐ Cl) 2 Ph 2 {Si(PhC(N t Bu) 2 )Ph} 2 ] and [ZnCl 2 {Si(PhC(N t Bu) 2 )Et} 2 ] (Chart 1), using PhC(N t Bu) 2 SiCl . Subsequently, the same group as well as the group of Tacke reported few more examples of silylene‐zinc complexes using PhC(N t Bu) 2 Si( η 5 ‐C 5 Me 5 ) and [ i PrNC(N i Pr 2 )N i Pr] 2 Si as ligands. In our part, we have showed that amido silylene, [PhC(N t Bu) 2 SiN(SiMe 3 ) 2 ] forms both monomeric [PhC(N t Bu) 2 Si{N(SiMe 3 ) 2 }→ZnI 2 ]⋅THF and dimeric [{PhC(N t Bu) 2 }(N(SiMe 3 ) 2 )SiZnI( μ ‐I)] 2 adducts upon reaction with ZnI 2 and these adducts are interconvertible simply by changing the solvents …”