From Unsymmetrically Substituted Benzamidinato and Guanidinato Dichlorohydridosilanes to Novel Hydrido N-Heterocyclic Silylene Iron Complexes

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• 作者：Burgert Blom ; Markus Pohl ; Gengwen Tan ; Daniel Gallego ; Matthias Driess
• 刊名：Organometallics
• 出版年：2014
• 出版时间：October 13, 2014
• 年：2014
• 卷：33
• 期：19
• 页码：5272-5282
• 全文大小：533K
• ISSN：1520-6041

文摘

Starting from the unsymmetric N,N鈥?substituted thiourea compounds (R)N(H)C(鈺怱)N(H)(^tBu) (1, R = Dipp: 2,6-ⁱPr₂-C₆H₃; 2, R = 1-adamantyl), the corresponding asymmetric carbodiimines (R)N鈺怌鈺怤(^tBu) (3, R = Dipp; 4, R = 1-adamantyl) are readily accessible in high yields upon reduction with LiHMDS (Li[N(SiMe₃)₂]). The reaction of compound 3 with PhLi followed by SiCl₄ afforded, in a one-pot reaction, the asymmetric benzamidinato-stabilized trichlorosilane [PhC{(N^tBu)(NDipp)}]SiCl₃ (5). Similarly, silanes [PhC{(N^tBu)(NDipp)}]SiHCl₂ (6), [(NMe₂)C{(N^tBu)(NDipp)}]SiHCl₂ (7), and [PhC{(N^tBu)(NAd)}]SiHCl₂ (8) could also be isolated. All novel trichloro- or dichlorohydridosilanes were fully spectroscopically characterized and studied by single-crystal X-ray diffraction analyses, the latter revealing in all cases a distorted-trigonal bipyramidal five-coordinate silicon center. The reactions of silanes 5鈥?b>8 with K₂[Fe(CO)₄] were also explored: In the case of the reaction of silane 5 with K₂[Fe(CO)₄], no reaction was observed even after prolonged heating. However, in the case of the silanes 6鈥?b>8, the selective formation of the corresponding hydrido Si^II:鈫扚e⁰ complexes [[R¹C{(N^tBu)(NR²)}](H)Si:鈫扚e(CO)₄] (9, R¹ = Ph, R² = Dipp; 10, R¹ = NMe₂, R² = Dipp; 11, R¹ = Ph, R² = 1-adamantyl) could be achieved. Complexes 9鈥?b>11 represent unprecedented hydrido-N-heterocyclic silylene complexes, bearing asymmetric ligand backbones. Complexes 9鈥?b>11 were fully spectroscopically characterized, and in addition the single-crystal X-ray structure analysis of compound 10 is reported.