PHYS 581 |
| [(3-methacryloxy)propyl]silsesquioxanes (MSSO) were prepared from the hydrolytic condensation of [(3-methacryloxy)propyl]trimethoxysilane (MPMS) in the presence of an acid catalyst (HCOOH). The proposed MSSO structures were characterized with FTIR and NMR (1H, 13C and 29Si), and were assigned by UV-MALDI-TOF MS. The large organic group connected to silicon was simplified for the quantum chemical calculation (QCC), and the correlation of the calculated total energies (ET) before and after simplification was analyzed by multiple linear regression, verifying no significant influence on the final conclusions of the research of structural formulas by a correlation coefficient (r). The geometric parameters (Si-O bond length and Si-O-Si, O-Si-O bond angle) and ET of the simplified MSSO were calculated by QCC to determine the relative stability of various SSO structures. The structural geometry (m-silicon ring) and the fraction of intramolecular cycles (f) were also employed to qualitatively determine the relative stability. The results of the calculation showed that almost all of the cage structures had a lower ET than the isomeric ladder structures; therefore, most MSSO molecular structures are of the cage type. |
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PHYS Poster Session - Computational Spectroscopy and Reaction Dynamics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster
Division of Physical Chemistry |