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Optical resolution of tris (acetylacetonato) aluminium(III) by low temperature chromatography

1976; Elsevier BV; Volume: 12; Issue: 1 Linguagem: Inglês

10.1016/0020-1650(76)80116-x

1878-3473

Bengt Nordén, Ivan Jonáš,

Advanced Chemical Physics Studies

Al(acac)3 was resolved into optical isomers with a high yield by chromatography on D-lactose/Al2O3 at 210 K and the circular dichroism (CD) spectra of the enantiomers were measured. The absolute configuration was established both by using a locally excited transition in the ligand and by correlating the retention order due to the adsorption with that of an equivalent complex with known configuration. The nomenclature (CD+)303-Al(acac)3 is suggested for the enantiomer exhibiting positive CD at 303 nm. This enantiomer has the absolute configuration From the observed racemisation rate constants at elevated temperatures activation parameters were estimated: Eα = 131 ± 5 kJ mol−1, ΔH★ = 130 ± 5 kJ mol−1, ΔS★ = 220 ± 16 J K−1 mol−1. Al(acac)3 is the first example of a compound that has been optically resolved by low temperature chromatography (LTC).