Pincer CNN Ruthenium(II) Complexes with Oxygen-Containing Ligands (O2CR, OAr, OR, OSiR3, O3SCF3): Synthesis, Structure, and Catalytic Activity in Fast Trans

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• 作者：Walter Baratta ; Maurizio Ballico ; Alessandro Del Zotto ; Eberhardt Herdtweck ; Santo Magnolia ; Riccardo Peloso ; Katia Siega ; Micaela Toniutti ; Ennio Zangrando ; Pierluigi Rigo
• 刊名：Organometallics
• 出版年：2009
• 出版时间：August 10, 2009
• 年：2009
• 卷：28
• 期：15
• 页码：4421-4430
• 全文大小：933K
• 年卷期：v.28,no.15(August 10, 2009)
• ISSN：1520-6041

文摘

The pincer complexes [RuX(CNN)(dppb)] (5−11: X = carboxylate, phenoxide, alkoxide, silanolate, triflate; HCNN = 1-[6-(4′-methylphenyl)pyridin-2-yl]methanamine; dppb = Ph₂P(CH₂)₄PPh₂), containing the Ru−NH₂ functionality and a monodentate oxygen donor ligand, have been prepared in high yield starting from [RuCl(CNN)(dppb)] (1) via substitution of the chloride with sodium or thallium compounds or protonation of the alkoxide [Ru(OiPr)(CNN)(dppb)]·n(iPrOH) (3). In the solid state the formate 5 shows intermolecular NH···O hydrogen bonds, whereas the acetate 6 displays an intramolecular interaction, as inferred from X-ray studies. Addition of phenol and alcohol compounds to the phenoxide and alkoxide complexes leads to fast ligand exchange through hydrogen bond interactions. The corresponding pincer complexes [RuX(CNN′)(dppb)] (12, 13b: X = phenoxide, alkoxide; HCNN′ = N,N-dimethyl-1-[6-(4′-methylphenyl)pyridin-2-yl]methanamine), containing the Ru−NMe₂ moiety, have been obtained from [RuCl(CNN′)(dppb)] (4) and sodium phenoxide or alkoxide. All the NH₂ complexes 5−11 are highly active catalysts in the transfer hydrogenation of ketones in 2-propanol with NaOiPr, affording complete conversion in a few minutes and achieving TOF values of up to 3.8 × 10p>6p> hp>−1p> with 0.005 mol % of catalyst.