The Solid Channel Structure Inclusion Complex Formed Between Guest Styrene and Host γ-Cyclodextrin

Abstract

The solid complex of guest styrene included inside the channels of host γ-cyclodextrin (styrene/γ-CDchannel-IC) was formed in order to perform polymerization of styrene in a confined environment (γ-CD channels). The experimental molar ratio of styrene to γ-CD in styrene/γ-CDchannel-IC was found to be 2:1, which is consistent with molecular modeling studies, utilizing Quantum Mechanics PM3 parameters that indicate the γ-CD/two styrene molecular complex is the most energetically favorable. Consistent with modeling of the γ-CD/two styrene molecular complex, no experimental indication of intermolecular π–π interactions between the pairs of included styrene molecules inside the γ-CD channels was observed. Once included in the host γ-CD cavities, the thermal stability of normally volatile bulk styrene to elevated temperatures (much above its boiling point) was observed until the γ-CD host molecules themselves began to degrade at ∼ ∼300 °C. In addition, the thermal degradation of host γ-CD from the styrene/γ-CDchannel-IC was observed to be different from that of pure γ-CD due to co-degradation of styrene and γ-CD.