Pedrosa Sergio, Vidal Fernando, Lee Lucia Myongwon, Vargas-Baca Ignacio, Gómez-Sal Pilar, Mosquera Marta E G
Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, Campus Universitario, E-28871 Alcalá de Henares, Spain.
Dalton Trans. 2015 Jun 28;44(24):11119-28. doi: 10.1039/c5dt01320h. Epub 2015 May 22.
The reaction of lithiated picolines and [TiCl3(η(5)-C5Me5)] leads to several bridging or terminal imido compounds, each of which can be selectively formed by controlling the stoichiometry and temperature. Specifically, the dinuclear imido-bridged [TiCl(η(5)-C5Me5)(μ-NR)]2 (1a, NR = 2-imido-3-picoline; 1b, NR = 2-imido-5-picoline) species and the unusual Ti-Li imido-amido heterobimetallic complex [{Li(THF)}{Ti(η(5)-C5Me5)(NR)(NHR)2}] (2a, NR = 2-imido-3-picoline; 2b, NR = 2-imido-5-picoline) were isolated. Compounds 2 are in effect the first structurally characterized examples of titanium(IV) coordinated to terminal imido-pyridines. DFT-D calculations for 2a denote a multiple bond character between titanium and the imido ligand and a strong polarization of the electron density by the alkali cation in spite of the lack of intermetallic bonding.
锂化甲基吡啶与[TiCl3(η(5)-C5Me5)]反应生成了几种桥联或端基亚胺化合物，通过控制化学计量比和温度可选择性地生成每种化合物。具体而言，分离得到了双核亚胺桥联的[TiCl(η(5)-C5Me5)(μ-NR)]2（1a，NR = 2-亚胺基-3-甲基吡啶；1b，NR = 2-亚胺基-5-甲基吡啶）物种以及不寻常的Ti-Li亚胺-酰胺异双金属配合物[{Li(THF)}{Ti(η(5)-C5Me5)(NR)(NHR)2}]（2a，NR = 2-亚胺基-3-甲基吡啶；2b，NR = 2-亚胺基-5-甲基吡啶）。化合物2实际上是首例结构表征的与端基亚胺吡啶配位的钛(IV)化合物。对2a的DFT-D计算表明，尽管缺乏金属间键合，但钛与亚胺配体之间存在多重键特征，且碱金属阳离子使电子密度发生强烈极化。
