Lithium and aluminium carbamato derivatives of the utility amide 2,2,6,6-tetramethylpiperidide.
Insertion of CO(2) 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 (CO(3))(2-) fragments and eight O(2)CTMP ligands with four distinct bonding modes. A bisalkylaluminium carbamato complex has also been prepared via two different methods (CO(2) 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.
Kennedy
Alan R
AR
WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
Mulvey
Robert E
RE
Oliver
David E
DE
Robertson
Stuart D
SD