Chemistry of coordinatively unsaturated organoruthenium amidinates as entry to homogeneous catalysis
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- 作者：Nagashima ; Hideo ; Kondo ; Hideo ; Hayashida ; Taizo ; Yamaguchi ; Yoshitaka ; Gondo ; Mitsuru ; Masuda ; Satoshi ; et. al.
- 关键词：Coordinative unsaturation ; Ruthenium amidinates ; Redox processes ; Catalysis ; Carbenes ; Silyl group migration
- 刊名：Coordination Chemistry Reviews
- 出版年：2003
- 出版时间：October, 2003
- 年：2003
- 卷：245
- 期：1-2
- 页码：177-190
- 全文大小：358 K
文摘
The chemistry of coordinatively unsaturated organoruthenium complexes is reviewed in this article. In particular, the subject is focused on neutral and cationic organoruthenium amidinates, which formally have 16 valence electrons and show signs of coordinative unsaturation. The ruthenium amidinates, (η5-C5Me5)Ru(η-amidinate) (1), and their isoelectronic analogues, [(η6-arene)Ru(η-amidinate)]+ (2), are synthesized and characterized; a possible stabilizing factor of the unsaturated metal center is weak coordination of π-electrons in the amidinates ligands. Reactions of various two-electron donor ligands with 1 or 2 reveal the strong π-donor property of 1 and Lewis acid nature of 2. One or two-electron redox processes of 1 in the reactions with organic halides are studied by isolation of the corresponding Ru(III) and Ru(IV) products; the results lead to their catalysis for the Tsuji–Trost reaction and the intramolecular Kharasch reaction. The treatment of 2 with trimethylsilyldiazomethane results in the formation of cationic amidinato-carbene complexes, which involve unusual reversible metal-to-carbon silyl group migration.