(166b) Separation of Double-Decker-Shaped-Silsesquioxanes Condensed with Multiple Functional Groups

Tetrasilanol double decker shaped silsesquioxanes (DDSQ(OH)₄) were condensed in this study by the addition of equimolar fractions of DDSQ-tetrasilanol, methyltrichlorosilane, and A-methyldichlorosilane, where A stands for hydrogen (H), methyl (Me), or vinyl (Vi). Adsorption HPLC experiments were run for the condensation products and four peaks were identified. The remaining Cl groups were hydrolyzed passing the products through a Si-gel column where three fractions were separated from the mixture. Each fraction was characterized by ²⁹Si-NMR, adsorption HPLC, and mass spectroscopy. It was found that the first fraction obtained by LC was always a DDSQ cage with the A-Me-siloxane attached to both sides. ²⁹Si-NMR presented trans and cis isomers in the spectrum. A single peak with t_R = 2.43 min was resolved in the chromatogram. The second LC fraction was DDSQ cages with a A-Me-siloxane attached to one side and OH-Me-siloxane attached to the opposite side. Trans and cis orientations were identified in the ²⁹Si-NMR spectrum. After HPLC experiments, both isomers were in a single peak located in t_R = 4.21 min. Finally, the third fraction had trans and cis DDSQ molecules with OH-Me-siloxanes in both sides. Two peaks corresponding to trans and cis isomers of Me-OH-DDSQ-Me-OH were identified in this fraction by HPLC. Trans isomers were detected after t_R = 8.02 min and cis isomers after tR = 8.55 min. Mass spectroscopy for separated cages showed the expected molecular weights for each molecule. 100g/day batch separation were simulated by finding the adsortion isotherms and the mass transfer coefficient for the three main materials obtained at the end of the synthesis. The material produced and separated in this study can be further reacted taking advantage of the multiple moieties in the cages. It can be used in different applications such as drug delivery, block copolymers, compatibilizers, among others.