Molecular engineering of phase transition temperatures in dodecasil-3C clathrasils

Single crystals of the dodecasil-3C clathrasils 17SiO₂- M (M=cyclohexane, cyclopentane, piperidine, pyrrolidine, cyclopentylamine, and cyclobutylamine) were grown using hydrothermal techniques. The influence that the organic guest molecule in a given silica host framework has on the bulk properties of the clathrasil was demonstrated. Each material displayed two phase transitions, one between 59 and 180°C and the other between -110 and -1°C. These phase transition temperatures could be systematically varied by varying the size of the guest molecule