
TY  - JOUR
A1  - Goldfuss, Bernd 
A1  - Eisenträger, Frank 
T1  - Chiral ligand induced distortions: the origin of pyramidal three-coordinated lithium ions in the X-ray crystal structure of Lithium (1<emph type="2">R</emph>,2<emph type="2">R</emph>,4<emph type="2">S</emph>)-<emph type="2">exo</emph>- 2-[<emph type="2">o</emph>-(dimethylaminomethyl)phenyl]-1,3,3-trimethylbicyclo[2.2.1]heptan-<emph type="3">endo</emph>-2-olate
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 2000
VL  - 53
IS  - 3
SP  - 209
EP  - 212
KW  - Lithium; alkoxides; chiral ligands; X-ray crystal analysis; ONIOM computations; ab initio computations.
UR  - https://doi.org/10.1071/CH99184 
N2  - The X-ray crystal structure of dimeric lithium (1R,2R,4S)-exo-2-&#91;o-(dimethylaminomethyl)phenyl&#93;-1,3,3-trimethylbicyclo&#91;2.2.1&#93;heptan-endo-2-olate (2-Li)2 exhibits lithium ions with pyramidal environments of oxygen and nitrogen atoms. Ab initio (RHF/6-31+G*) computations of dimeric trimethylamine-coordinated lithium methoxide show that electrostatics disfavour the pyramidal distortions at lithiums in (2-Li)2 by 5.0 kJ/mol. ONIOM(B3LYP/6-31+G*:UFF) computations of (2-Li)2 as well as of (2-Li-b)2 and (2-Li-c)2, with one or two planar constrained lithium ion environments, reveal destabilizations of 32.2 and 97.5 kJ/mol, respectively, upon planarization at lithium. The destabilizations of planar coordinated lithiums in (2-Li-b)2 and (2-Li-c)2 arise from repulsions between methylamino groups and bicycloheptane moieties and give rise to the observed pyramidal environments at the lithiums in the X-ray crystal structure of (2-Li)2. 
ER  -

