Premium
Crystal Structure of a Representative Mixed Adduct of Trimethylaluminium and a Lithium Amide and a Theoretical MO Study on Model Systems
Author(s) -
Armstrong David R.,
Craig Fiona J.,
Kennedy Alan R.,
Mulvey Robert E.
Publication year - 1996
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19961291024
Subject(s) - chemistry , adduct , lithium (medication) , lithium amide , amide , crystal structure , transmetalation , endothermic process , monomer , stereochemistry , medicinal chemistry , crystallography , organic chemistry , catalysis , enantioselective synthesis , endocrinology , polymer , adsorption , medicine
Abstract Reaction of the simple alane adduct [Me 3 Al · HN(CH 2 Ph) 2 ] ( 2 ) with the lithium amide [(PhCH 2 ) 2 NLi] leads to the formation of the mixed adduct [Me 3 Al · (PhCH 2 ) 2 NLi · HN(CH 2 Ph) 2 ] ( 1 ). The crystal structures of 1 and 2 are reported. Exhibiting a four‐membered, mixed‐metal, mixedanion ring‐core, the structure of 1 is unusual in containing a monomeric lithium dibenzylamide fragment. Such fragments generally convert to aza‐allyl derivatives, so its existence here can be attributed to the stabilising effect of the attached Me 3 Al ligand. Crystalline 2 adopts the classical, distorted‐tetrahedral arrangement of simple monomeric alane adducts. Ab initio MO calculations on model systems show that mixed adduct formation from Me 3 Al and Me 2 NLi is exothermic, while further reaction to give Me 2 AlNMe 2 and MeLi (i.e., complete transmetallation) is endothermic.