Division of Chemistry and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore.
Chemistry. 2010 Sep 3;16(33):10250-4. doi: 10.1002/chem.201000089.
The synthesis and characterization of novel monomeric silylsilylenes [{PhC(NtBu)(2)}Si--Si{(NtBu)(2)C(H)Ph}R] (R=Cl (2), H (4)) are described. Compound 2 was prepared by the treatment of [{PhC(NtBu)(2)}SiHCl(2)] (1) with two equivalents of potassium graphite, whereas compound 4 was synthesized by the treatment of 1 with four equivalents of potassium graphite. The results suggest that silicon(II) hydride intermediate [{PhC(NtBu)(2)}SiH] was formed in the reduction, which underwent a hydrosilylation with the amidinate ligand of [{PhC(NtBu)(2)}SiR] (R=Cl or H) to form 2 and 4, respectively. The existence of [{PhC(NtBu)(2)}SiH] in solution was demonstrated by the treatment of [{PhC(NtBu)(2)}SiCl] (3) with [K{HB(iBu)(3)}]. Compounds 2 and 4 have been characterized by X-ray crystallography and NMR spectroscopy. The results show that compounds 2 and 4 are stable in solution or the solid state, and do not dimerize to form the corresponding disilene. DFT calculations show that the Si--Si bonds in 2 and 4 do not have multiple-bond character.
新型单体硅亚硅基 [{PhC(NtBu)(2)}Si--Si{(NtBu)(2)C(H)Ph}R]（R=Cl（2），H（4））的合成与表征。化合物 2 通过 [{PhC(NtBu)(2)}SiHCl(2)]（1）与两当量的钾石墨反应制备得到，而化合物 4 通过 1 与四当量的钾石墨反应合成得到。结果表明，硅（II）氢化物中间体 [{PhC(NtBu)(2)}SiH] 是在还原过程中形成的，它与 [{PhC(NtBu)(2)}SiR]（R=Cl 或 H）的酰胺化物配体发生氢硅烷化反应，分别形成 2 和 4。通过 [{PhC(NtBu)(2)}SiCl]（3）与 [K{HB(iBu)(3)}] 反应证明了 [{PhC(NtBu)(2)}SiH] 在溶液中的存在。化合物 2 和 4 通过 X 射线晶体学和 NMR 光谱进行了表征。结果表明，化合物 2 和 4 在溶液或固态中稳定，不会二聚形成相应的二硅烯。DFT 计算表明，2 和 4 中的 Si--Si 键不具有多重键性质。
