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Struktur von α‐(Dimethylamino)benzyllithium in Lösung: Dynamisches Gleichgewicht zwischen einer η 1 ‐ und einer η 3 ‐Spezies
Author(s) -
Ahlbrecht Hubertus,
Harbach Jürgen,
Hauck Tim,
Kalinowski HansOtto
Publication year - 1992
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.19921250730
Subject(s) - chemistry , mndo , equilibrium constant , solvation , tetrahydrofuran , solvent , lewis acids and bases , computational chemistry , molecule , organic chemistry , catalysis
Structure of α‐(Dimethylamino)benzyllithium in Solution: Dynamic Equilibrium between an η 1 and an η 3 Species Temperature‐dependent 1 H‐ and 13 C‐NMR‐spektroscopic shifts observed in tetrahydrofuran are indicative of an equilibrium between a high‐temperature η 3 and a low‐temperature η 1 species. MNDO calculations are in accord with this view, and HOESY experiments proof it, too. The equilibrium is controled by solvation or complexation, low Lewis basicity of the solvent or bidentate ligands favoring the η 3 , high Lewis basicity or tridentate ligands the η 1 species. Equilibrium as well as rate constants have been estimated, and from their temperature dependence the thermodynamics of the equilibrium and the activation barriers were calculated.