Institute of Chemistry, Metalorganics and Inorganic Materials, Technische Universität Berlin, Strasse des 17. Juni 135, Sekr. C2, D-10623 Berlin, Germany.
J Am Chem Soc. 2010 Mar 10;132(9):3038-46. doi: 10.1021/ja910305p.
The strikingly different behavior of the ylide-like, N-heterocyclic silylene LSi: (5: L = CH[(C horizontal lineCH(2))CMe(NAr)(2)]; Ar = 2,6-(i)PrC(6)H(3)) versus its LSi-->Ni(CO)(3) complex 13 to activate E-H bonds (E = S, N) of small molecules is reported. Remarkably, conversion of 5 with hydrogen sulfide leads exclusively to the first isolable silathioformamide, L'Si( horizontal lineS)H (16: L' = CHC(Me)NAr; Ar = 2,6-(i)PrC(6)H(3)) with a donor-supported Si horizontal lineS double bond and four-coordinate silicon. The latter result demonstrates the unusual ambivalent reactivity of 5 by combining two modes of reactivity involving S-H bond activation and subsequent 1,4- and 1,1-addition, respectively. In addition, 5 can serve as a ligand with well-balanced sigma-donor and pi-acceptor capabilities toward transition metals. This has been demonstrated by the isolable [Ni(0)(arene)] complexes 12a-e (arene = Me(n)C(6)H(6-n), n = 0-3), which are ideal precursors for the formation of the corresponding Ni(CO)(3) complex 13. The latter activates a S-H bond in hydrogen sulfide, too, but the presence of the Ni(CO)(3) moiety governs the formation of the complex 17, bearing an unprecedented beta-diketiminate silicon(II) thiol ligand: L'Si(SH): (L' = CHC(Me)NAr; Ar = 2,6-(i)PrC(6)H(3)). Likewise, the Si(II)-->Ni(CO)(3) coordination in 13 steers exclusively 1,4-addition of ammonia, isopropylamine, and phenylhydrazine onto the silylene ligand 5, leading to the corresponding beta-diketiminate silicon(II) amide or hydrazide complexes L'Si(NHR)-->Ni(CO)(3) (23a-c: R = H, (i)Pr, N(H)Ph). IR measurements reveal that the carbonyl stretching frequencies of the Ni(CO)(3) moiety in 23a-c are shifted to even lower wavenumbers in comparison to those of NHCs or phosphines. In other words, the beta-diketiminate silicon(II) amide ligands in 23a-c represent the strongest donors in the series of N-heterocyclic silylenes reported as yet.
报告了类似叶立德的、N-杂环硅烯 LSi：（5：L = CH[(C 水平线 CH(2))CMe(NAr)(2)]；Ar = 2,6-(i)PrC(6)H(3))与它的 LSi-->Ni(CO)(3) 配合物 13 激活小分子的 E-H 键（E = S，N）的截然不同的行为。值得注意的是，5 与硫化氢的转化仅导致第一个可分离的硅硫代甲酰胺，L'Si(水平线 S)H（16：L' = CHC(Me)NAr；Ar = 2,6-(i)PrC(6)H(3)）具有供体支持的 Si 水平线 S 双键和四配位硅。后者的结果证明了 5 的不寻常的两亲反应性，通过结合两种涉及 S-H 键活化和随后的 1,4-和 1,1-加成的反应模式。此外，5 可以作为配体，对过渡金属具有良好平衡的 sigma-供体和 pi-受体能力。这已经通过可分离的[Ni(0)(芳烃)]配合物 12a-e（芳烃= Me(n)C(6)H(6-n)，n = 0-3）证明，这些配合物是形成相应的 Ni(CO)(3)配合物 13 的理想前体。后者也能激活硫化氢中的 S-H 键，但 Ni(CO)(3)部分的存在控制着配合物 17 的形成，其具有前所未有的β-二酮亚胺硅(II)硫醇配体：L'Si(SH)：（L' = CHC(Me)NAr；Ar = 2,6-(i)PrC(6)H(3)）。同样，在 13 中，Si(II)-->Ni(CO)(3)配位专一地使氨、异丙胺和苯肼与硅烯配体 5 进行 1,4-加成，得到相应的β-二酮亚胺硅(II)酰胺或酰肼配合物 L'Si(NHR)-->Ni(CO)(3)（23a-c：R = H，(i)Pr，N(H)Ph）。IR 测量表明，23a-c 中 Ni(CO)(3)部分的羰基伸缩频率与 NHCs 或膦相比，向更低的波数移动。换句话说，在报告的 N-杂环硅烯系列中，23a-c 中的β-二酮亚胺硅(II)酰胺配体代表最强的供体。
