(446b) Evaluation of Separation Techniques for Ddsq Based Nanostructured Chemicals

Double Decker Polyhedral Oligomeric Silsesquioxanes or DDSQâ??s are building blocks that have been used with success in several applications. The synthesis of DDSQâ??s results in unavoidable production of mixtures containing cis and trans isomers when two different moieties (Y and X) are located in each deck. In this work DDSQ cages were synthesized making the Y moiety methyl, isobutyl, or cyclochexyl and the X moiety p-phenylamine or m-phenylamine. The cis and trans isomers were isolated by preparatory chromatography aid by TLC. A common absorption wavelength of 254nm was obtained for all the evaluated isomers by UV-vis spectroscopy. However, significant differences were obtained in the absorption peak height between para and meta moieties in the Y position at the same concentration. The individual isomers as well as the cis/trans mixtures were analyzed by adsorption normal phase HPLC and by partition HPLC. From these experiments was found that for cis/trans mixtures the trans peak showed lower retention times than cis peak. Also, an inverse relation was observed between the retention time and the size of the Y group.