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Title: Solid-state {sup 31}P NMR study of phosphonate binding sites in guanidine-functionalized, molecular imprinted silica xerogels

Abstract

Phosphonate binding sites in guanidine and ammonium surface-functionalized silica xerogels were prepared via the molecular imprinting technique and characterized using solid-state {sup 31}P MAS NMR. One-point, two-point, and nonspecific host-guest interactions between phenylphosphonic acid (PPA) and the functionalized gels were distinguished by characteristic chemical shifts of the observed absorption peaks. Using solid-state as well as solution-phase NMR analyses, absorptions observed at 15.5 and 6.5 ppm were identified as resulting from the 1:1 (one-point) and 2:1 (two-point) guanidine to phosphonate interactions, respectively. Similar absorptions were observed with the ammonium functionalized gels. By examining the host-guest interactions within the gels, the efficiency of the molecular imprinting procedure with regard to the functional monomer-to-template interaction could be readily assessed. Template removal followed by substrate adsorption studies conducted on the guanidine-functionalized gels provided a method to evaluate the binding characteristics of the receptor sites to a phosphonate substrate. During these experiments, {sup 29}Si and {sup 31}P MAS NMR acted as diagnostic monitors to identify structural changes occurring in the gel matrix and at the receptor site from solvent-mediated processes.

Authors:
;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
20080268
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Journal Article
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 12; Journal Issue: 5; Other Information: PBD: May 2000; Journal ID: ISSN 0897-4756
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; PHOSPHONATES; GUANIDINES; GELS; SILICATE MINERALS; ADSORPTION

Citation Formats

Sasaki, D.Y., and Alam, T.M. Solid-state {sup 31}P NMR study of phosphonate binding sites in guanidine-functionalized, molecular imprinted silica xerogels. United States: N. p., 2000. Web. doi:10.1021/cm990737r.
Sasaki, D.Y., & Alam, T.M. Solid-state {sup 31}P NMR study of phosphonate binding sites in guanidine-functionalized, molecular imprinted silica xerogels. United States. doi:10.1021/cm990737r.
Sasaki, D.Y., and Alam, T.M. Mon . "Solid-state {sup 31}P NMR study of phosphonate binding sites in guanidine-functionalized, molecular imprinted silica xerogels". United States. doi:10.1021/cm990737r.
@article{osti_20080268,
title = {Solid-state {sup 31}P NMR study of phosphonate binding sites in guanidine-functionalized, molecular imprinted silica xerogels},
author = {Sasaki, D.Y. and Alam, T.M.},
abstractNote = {Phosphonate binding sites in guanidine and ammonium surface-functionalized silica xerogels were prepared via the molecular imprinting technique and characterized using solid-state {sup 31}P MAS NMR. One-point, two-point, and nonspecific host-guest interactions between phenylphosphonic acid (PPA) and the functionalized gels were distinguished by characteristic chemical shifts of the observed absorption peaks. Using solid-state as well as solution-phase NMR analyses, absorptions observed at 15.5 and 6.5 ppm were identified as resulting from the 1:1 (one-point) and 2:1 (two-point) guanidine to phosphonate interactions, respectively. Similar absorptions were observed with the ammonium functionalized gels. By examining the host-guest interactions within the gels, the efficiency of the molecular imprinting procedure with regard to the functional monomer-to-template interaction could be readily assessed. Template removal followed by substrate adsorption studies conducted on the guanidine-functionalized gels provided a method to evaluate the binding characteristics of the receptor sites to a phosphonate substrate. During these experiments, {sup 29}Si and {sup 31}P MAS NMR acted as diagnostic monitors to identify structural changes occurring in the gel matrix and at the receptor site from solvent-mediated processes.},
doi = {10.1021/cm990737r},
journal = {Chemistry of Materials},
issn = {0897-4756},
number = 5,
volume = 12,
place = {United States},
year = {2000},
month = {5}
}