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Condis Crystals of Small Molecules III. Thermal Analysis of Plastic and Condis Crystals of some Cyclosilanes |
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| Authors: | Miaoyong Cao John Wesson Kyriakos Loufakis Bernhard Wunderlich Martin Möller |
| Affiliation: | 1. Department of Chemistry , Rensselaer Polytechnic Institute , Troy, New York, 12180, USA;2. Institut für Makromolekulare Chemie der Universit?t Freiburg , 7800, Freiburg, Federal Republic of Germany;3. Department of Chemistry , Rensselaer Polytechnic Institute , Troy, New York, 12180, USA |
| Abstract: | Three cyclic methyl and ethyl substituted silanes were synthesized and their thermal properties analyzed. All show a plastic crystalline state which permits also ring and/or side-chain conformational motion as judged from the enthalpies of transition to the isotropic state. Heat capacity data and entropies of disordering into the plastic crystal leave open the possibility of a condis (conformationally disordered) state below the plastic crystal state with a continuous, transitionless freezing of the conformational motion at lower temperature. |
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