RuCl2[(2,6-Me2C6H3)PPh2]2: A New Precursor for Cyclometalated Ruthenium(II) Complexes
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- 作者：Walter Baratta ; Alessandro Del Zotto ; Gennaro Esposito ; Alessandra Sechi ; Micaela Toniutti ; Ennio Zangrando ; and Pierluigi Rigo
- 刊名：Organometallics
- 出版年：2004
- 出版时间：December 20, 2004
- 年：2004
- 卷：23
- 期：26
- 页码：6264 - 6272
- 全文大小：172K
- 年卷期：v.23,no.26(December 20, 2004)
- ISSN：1520-6041
文摘
The five-coordinate complex RuCl{(2-CH2-6-MeC6H3)PPh2}(CO)(L*) (2; L* = (2,6-Me2C6H3)PPh2) was prepared in high yield by reaction of the 14-electron complex RuCl2(L*)2 (1) withformaldehyde in the presence of NEt3 via cyclometalation of an ortho methyl group andaldehyde decarbonylation. Alternatively, 2 can be obtained from RuCl3 hydrate, L*, H2CO,and amine in a one-pot reaction. Treatment of 2 with CO affords the cis-dicarbonyl derivativeRuCl{(2-CH2-6-MeC6H3)PPh2}(CO)2(L*) (3), whereas reaction with phosphines leads to thefive- and six-coordinate complexes RuCl{(2-CH2-6-MeC6H3)PPh2}(CO)(L)n (n = 1, L = PCy3(4), Ph2P(CH2)3PPh2 (6); n = 2, L = PMePh2 (5)) by displacement of L*, according to thesteric requirement of the incoming ligand. Similarly, complex 2 reacts with the bidentatenitrogen ligands 2-(aminomethyl)pyridine and ethylenediamine, affording the six-coordinatederivatives RuCl{(2-CH2-6-MeC6H3)PPh2}(CO)(L) (L = 2-(aminomethyl)pyridine (7), ethylenediamine (8)) in high yield. The related iodide derivative RuI{(2-CH2-6-MeC6H3)PPh2}(CO)(L*) (9) has been prepared from 2 and NaI by chloride displacement. Treatment of 2with Na[BArf4] in the presence of 2,2'-bipyridine or 2-(aminomethyl)pyridine gives the cationiccomplexes [Ru{(2-CH2-6-MeC6H3)PPh2}(CO)(L*)(L)][BArf4] (L = 2,2'-bipyridine (10), 2-(aminomethyl)pyridine (11)), while with 3 equiv of pyridine the derivative [Ru{(2-CH2-6-MeC6H3)PPh2}(CO)(Py)3][BArf4] (12) is obtained. The structure of the 
-agostic complex 2 has beenestablished through an X-ray crystal study, whereas the structure for 7 is supported by 2DNMR experiments in solution. Complexes 7 and 8 are active catalysts for transfer hydrogenation of ketones in 2-propanol, displaying TOF values up to 63 000 h-1.
-agostic complex 2 has beenestablished through an X-ray crystal study, whereas the structure for 7 is supported by 2DNMR experiments in solution. Complexes 7 and 8 are active catalysts for transfer hydrogenation of ketones in 2-propanol, displaying TOF values up to 63 000 h-1.