Lithium and aluminium carbamato derivatives of the utility amide 2,2,6,6-tetramethylpiperidide
作者:Alan R. Kennedy、Robert E. Mulvey、David E. Oliver、Stuart D. Robertson
DOI:10.1039/c0dt00118j
日期:——
Insertion of CO2 into the metal–N bond of a series of synthetically important alkali-metal TMP (2,2,6,6-tetramethylpiperidide) complexes has been studied. Determined by X-ray crystallography, the molecular structure of the TMEDA-solvated Li derivative shows a central 8-membered (LiOCO)2 ring lying in a chair conformation with distorted tetrahedral lithium centres. While trying to obtain crystals of a THF-solvated derivative, a mixed carbonato/carbamato dodecanuclear lithium cluster was formed containing two central (CO3)2− fragments and eight O2CTMP ligands with four distinct bonding modes. A bisalkylaluminium carbamato complex has also been prepared via two different methods (CO2 insertion into a pre-formed Al–N bond and ligand transfer from the corresponding lithium reagent) which adopts a dimeric structure in the solid state.
在研究一系列在合成上重要的碱金属TMP(2,2,6,6-四甲基哌啶基)配合物的金属-N键插入CO2的过程中,通过X射线晶体学确定了TMEDA溶剂化的锂衍生物分子结构,显示出一个中心的八元(LiOCO)2环,以椅式构象存在,并具有扭曲的四面体锂中心。在尝试获得THF溶剂化的衍生物晶体时,形成了一个混合的碳酸/氨基甲酸十二核锂簇,包含两个中心的(CO3)2−片段和八个具有四种不同配位方式的O2CTMP配体。此外,通过两种不同的方法(预形成的Al-N键插入CO2和从相应的锂试剂转移配体)制备了一种双烷基铝氨基甲酸酯配合物,该配合物在固态下具有二聚结构。