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Title: Computational studies of polyelectrolytes containing zeolite fragments.

Abstract

The structures and sodium affinities of a series of zeolitic fragments [H{sub 3}Al(OCH{sub 3}){sub x}(OSiH{sub 3}){sup -}{sub 1-x}, 2T, H{sub 2}Al(OCH{sub 3}){sub x}(OSiH{sub 3}){sup -}{sub 2-x}, 3T, Al(OCH3){sub x}(OSiH{sub 3}){sup -}{sub 4-x}, 5T] that mimic the charge sites in polyelectrolytes are calculated by ab initio molecular orbital methods at different levels of theory. At the HF/6-31G* level, the decrease in the sodium affinity due to the substitution of an OCH{sub 3} group by an OSiH{sub 3} group is about 8 kcal/mol in the 2T and 3T systems. In the 5T systems, the replacement of a sodium-coordinated OCH{sub 3} group by an OSiH{sub 3} group causes a decrease of 7 kcal/mol in the sodium affinity, while the substitution for a non-sodium-coordinated OCH{sub 3} group results in a 2.7 kcal/mol decrease. The lower sodium affinity indicates a weaker Coulombic interaction, suggesting an enhanced ionic conductivity with the substitution of carbon by silicon, consistent with experimental results. Natural bond orbital (NBO) analyses show that silicon-bonded oxygen atoms have smaller lone-pair dipole moments, resulting in a lower sodium affinity. The substitution of aluminum by boron leads to a higher sodium affinity, although the effect of replacing an OCH{sub 3} group by an OSiH{sub 3}more » group still reduces the sodium affinity. The effect of the sodium cation on the bond angles in these systems is also investigated.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
942495
Report Number(s):
ANL/CHM/JA-32027
Journal ID: ISSN 1089-5647; JPCBFK; TRN: US200916%%504
DOE Contract Number:  
DE-AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
J. Phys. Chem. B
Additional Journal Information:
Journal Volume: 103; Journal Issue: 31 ; Aug. 5, 1999; Journal ID: ISSN 1089-5647
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ELECTROLYTES; POLYMERS; MORPHOLOGY; AFFINITY; MOLECULAR ORBITAL METHOD; IONIC CONDUCTIVITY; SODIUM; ZEOLITES; MATERIAL SUBSTITUTION; SILICON; CARBON; DIPOLE MOMENTS; ALUMINIUM; BORON

Citation Formats

Lee, Y.-C., Curtiss, L. A., Ratner, M. A., Shriver, D. F., and Northwestern Univ. Computational studies of polyelectrolytes containing zeolite fragments.. United States: N. p., 1999. Web. doi:10.1021/jp990649u.
Lee, Y.-C., Curtiss, L. A., Ratner, M. A., Shriver, D. F., & Northwestern Univ. Computational studies of polyelectrolytes containing zeolite fragments.. United States. doi:10.1021/jp990649u.
Lee, Y.-C., Curtiss, L. A., Ratner, M. A., Shriver, D. F., and Northwestern Univ. Thu . "Computational studies of polyelectrolytes containing zeolite fragments.". United States. doi:10.1021/jp990649u.
@article{osti_942495,
title = {Computational studies of polyelectrolytes containing zeolite fragments.},
author = {Lee, Y.-C. and Curtiss, L. A. and Ratner, M. A. and Shriver, D. F. and Northwestern Univ.},
abstractNote = {The structures and sodium affinities of a series of zeolitic fragments [H{sub 3}Al(OCH{sub 3}){sub x}(OSiH{sub 3}){sup -}{sub 1-x}, 2T, H{sub 2}Al(OCH{sub 3}){sub x}(OSiH{sub 3}){sup -}{sub 2-x}, 3T, Al(OCH3){sub x}(OSiH{sub 3}){sup -}{sub 4-x}, 5T] that mimic the charge sites in polyelectrolytes are calculated by ab initio molecular orbital methods at different levels of theory. At the HF/6-31G* level, the decrease in the sodium affinity due to the substitution of an OCH{sub 3} group by an OSiH{sub 3} group is about 8 kcal/mol in the 2T and 3T systems. In the 5T systems, the replacement of a sodium-coordinated OCH{sub 3} group by an OSiH{sub 3} group causes a decrease of 7 kcal/mol in the sodium affinity, while the substitution for a non-sodium-coordinated OCH{sub 3} group results in a 2.7 kcal/mol decrease. The lower sodium affinity indicates a weaker Coulombic interaction, suggesting an enhanced ionic conductivity with the substitution of carbon by silicon, consistent with experimental results. Natural bond orbital (NBO) analyses show that silicon-bonded oxygen atoms have smaller lone-pair dipole moments, resulting in a lower sodium affinity. The substitution of aluminum by boron leads to a higher sodium affinity, although the effect of replacing an OCH{sub 3} group by an OSiH{sub 3} group still reduces the sodium affinity. The effect of the sodium cation on the bond angles in these systems is also investigated.},
doi = {10.1021/jp990649u},
journal = {J. Phys. Chem. B},
issn = {1089-5647},
number = 31 ; Aug. 5, 1999,
volume = 103,
place = {United States},
year = {1999},
month = {8}
}