Three ZnII complexes containing bispicam ligands (bispicam = bis(2-pyridylmethyl)amine), [Zn(bispicam)2](NO3) 2·2CH3OH 4A, [Zn(bispicam)(NO3) 2] 4B, and [Zn(bispicam)2](OTf)2 6, were obtained, and their structures were determined by X-ray crystallography. Complexes of the general formulation [Zn(bispicam)2]X2 (X = Cl- (1), Br- (2), I- (3), NO3 - (4A), ClO4- (5), and OTf- (6)) show fac geometric isomers (a) or enantiomers (c) and (d) according to anions. Moreover, complexes 4-6 could carry out the catalytic transesterification of a range of esters with methanol under the mild conditions. Importantly, the catalyst 4B with an unsaturated structure has shown better efficiency than the catalysts, 4A, 5, and 6, having saturated structures. To explain this reactivity difference, two different reaction mechanisms have been proposed (metal-based vs. amide N-H-based).
Bibliographical noteFunding Information:
Financial support from South Korea Ministry Environment “ET-Human Resource Development Project”, the Korean Science & Engineering Foundation ( R01-2008-000-20704-0 and 2009-0074066 ), the Converging Research Center Program through the National Research Foundation of South Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2009-0082832 ), and South Korea University Grant is gratefully acknowledged.
- Geometric isomers
- Zinc(II) complexes
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry