Osmium and Ruthenium Complexes Containing an N-Heterocyclic Carbene Ligand Derived from Benzo[h]quinoline
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- 作者：Miguel A. Esteruelas ; Francisco J. Ferná ; ndez-Alvarez ; Enrique Oñ ; ate
- 刊名：Organometallics
- 出版年：2007
- 出版时间：October 8, 2007
- 年：2007
- 卷：26
- 期：21
- 页码：5239 - 5245
- 全文大小：151K
- 年卷期：v.26,no.21(October 8, 2007)
- ISSN：1520-6041
文摘
Benzo[h]quinoline (Hbq) undergoes 1,2-hydrogen shift from the carbon at the 2-position to the nitrogenin the presence of the complexes MH2Cl2(PiPr3)2 (M = Os (1), Ru (1a)). The coordination of the undressedcarbon atom of the resulting NH tautomer (HNbq) to the metal center of the osmium and rutheniumcomplexes gives rise to the formation of the osmium-elongated dihydrogen species OsCl2{-C-[HNbq]}(2-H2)(PiPr3)2 (2; H-H = 1.22 Å) and to the five-coordinate ruthenium derivative RuCl2{-C-[HNbq]}(PiPr3)2 (3), respectively. Under a hydrogen atmosphere, complex 3 is in equilibrium with the dihydrogenRuCl2{-C-[HNbq]}(2-H2)(PiPr3)2 (4; H-H = 0.91 Å). The X-ray structure of 2 and the 1H NMR spectraof 2-4 suggest that a hydrogen bond involving the NH group of the heterocycle and a chloride ligandplays an important role in the stabilization of these complexes. Both 2 and 4 undergo deprotonation toafford species containing the usual metalated benzo[h]quinoline group (bq). Treatment of 2 with Et3Ngives OsCl{2-N,C-[bq]}(2-H2)(PiPr3)2 (5; H-H = 1.29 Å), whereas the reaction of 4 with the amineleads to RuCl{2-N,C-[bq]}(2-H2)(PiPr3)2 (6; H-H = 1.01 Å). Complexes 5 and 6, which have beencharacterized by X-ray diffraction analysis, can be directly obtained by reaction of the correspondingdihydride-dichloro starting materials with benzo[h]quinoline in the presence of Et3N.