Preparation and catalytic property of cyclodextrin-ferrocenylamine inclusion compounds

Abstract

Ferrocenylamines : N, N-dimethylaminomethylferrocene, N, N-dimethylaminomethyl ferrocene methiodide, α-methylferrocenylmethylamine, ferrocenylethylamine, N,N-diphenylamino methylferrocene, Schiff base derivative, reduced Schiff base derivative, 6-ferrocenyl-2,2'-dipyridine, 2-(α, α-diphenylhydroxylmethyl) dimethylaminomethylferrocene and other ferrocenyl derivatives: acetylferrocene, ferrocenylmethylalcohol, α-hydroxyethylferrocene were prepared and characterized by FTIR and 1H NMR technique. The inclusion compounds of the above complexes with beta-cyclodextrin can be easily prepared 60-75 percent yields by adding ferrocenyl derivatives directly to an aqueous beta-cyclodextrin solution at 60°C. The inclusion compounds were characterized by 1H NMR, IR and X-ray diffraction techniques. Stoichiometries were determined by elemental analyses to be 1:1. Thermogravimetric analyses showed that inclusion compounds are thermally stable. 1H NMR data indicate that the interaction between cyclodextrin and ferrocenyl derivative is a real inclusion phenomenon. X-ray diffractograms of the inclusion compounds were different from those of the corresponding mixtures. The synthesized ferrocenylamine derivatives were studied for the catalytic activity in the alkylation of benzaldehyde with diethylzinc. Moderate to high yields (45-96%) but low enantioselectivities were obtained. On the contrary, the inclusion compounds gave lower yields (37-54%) with higher enantioselectivities.