Synthesis, Characterization, and Reactivity of Ruthenium Diene/Diamine Complexes Including Catalytic Hydrogenation of Ketones

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• 作者：M. Esther Morilla ; Pilar Rodrí ; guez ; Tomá ; s R. Belderrain ; Claudia Graiff ; Antonio Tiripicchio ; M. Carmen Nicasio ; Pedro J. P&eacute ; rez
• 刊名：Inorganic Chemistry
• 出版年：2007
• 出版时间：October 29, 2007
• 年：2007
• 卷：46
• 期：22
• 页码：9405 - 9414
• 全文大小：181K
• 年卷期：v.46,no.22(October 29, 2007)
• ISSN：1520-510X

文摘

Thermal reactions between [RuCl₂(diene)]_n (diene = 2,5-norbornadiene, nbd; 1,5-cyclooctadiene, cod) with anexcess of N,N,N',N'-tetramethylethylene diamine (tmeda) afforded derivatives [RuCl₂(diene)(tmeda)] (diene = nbd,1; cod, 2) as a mixture of cis and trans isomers. When thermolysis was performed under H₂ mixtures of hydridespecies [RuCl(H)(diene)(tmeda)] (diene = nbd, 3; cod, 4) and the bis-tmeda adduct trans-[RuCl₂(tmeda)₂] (5) wereobtained in different ratios depending upon the reaction conditions and reaction times. Heating polymeric Ru(II)precursors in toluene in the presence of a 5-fold excess of the bulkier N,N,N',N'-tetraethylethylene diamine (teeda)resulted in a rare diamine dealkylation process with formation of trans-[RuCl₂(nbd)(Et₂NCH₂CH₂NHEt)] (6) andtrans-[RuCl₂(cod)(EtHNCH₂CH₂NHEt)] (7) in high yields. The presence of N-H functionalities in the coordinateddiamine ligands of 6 and 7 was unambiguously established by single-crystal X-ray diffraction studies. The dealkylationprocess of the teeda ligand seems to proceed intramolecularly as shown by solution NMR studies performed withthe soluble Ru(II) precursors trans-[RuCl₂(amine)₂(diene)] (diene = nbd, amine = morpholine, 9; diene = cod,amine = Et₂NH, 10). The above complexes [RuCl₂(diene)(diamine)] have been tested as precatalysts in thehydrogenation of ketones both for transfer as well as direct hydrogenation, the latter route being the most effective.