PREPARATION AND CHARACTERIZATION OF L-TARTARIC ACID SILICA COMPOSITESRECOGNIZING MOLECULAR ASYMMETRY

L-Tartaric acid-silica composites have been prepared by the sol-gel me thod in which tetraethoxysilane is hydrolysed after reacting with L-ta rtaric acid. Optical resolution of tris(pentane-2,4-dionato) metal com plexes was performed using sol-gel derived composites and composites p repared using a conventional impregnation technique. The composites pr epared through the sol-gel process showed much higher optical resoluti on abilities when the composite was used for packing in chromatography . X-Ray diffraction and NMR results suggested that L-tartaric acid in the sol-gel derived composites is highly dispersed because it bonds to silicon atoms. The silica gel support was observed by scanning electr on microscopy to be composed of small particles whose diameters are be low 30 nm. The asymmetry recognition ability of the composites was fou nd to arise from the combined effect of the silica support and the hig hly dispersed optically active compound.