2 research outputs found
Probing the Structural and Binding Mechanism Heterogeneity of Molecularly Imprinted Polymers
We devised a strategy, using a de
novo building approach, to construct
model molecularly imprinted polymers (MIPs) and assess their ability
at binding various target molecules. While our models successfully
reproduce the gross experimental selectivities for two xanthines,
our atomistic models reveal in detail the considerable heterogeneity
of the structure and binding mechanisms of different imprints within
such a material. We also demonstrate how nonimprinted regions of a
MIP are also responsible for much of binding of target molecules.
High levels of cross-linking are shown to produce less specific imprints
Calculation of the <sup>29</sup>Si NMR Chemical Shifts of Aqueous Silicate Species
A DFT methodology for calculating <sup>29</sup>Si NMR
chemical
shifts of silicate species typically present prior to nucleation in
zeolite synthesis solutions, incorporating solvent effects through
an implicit representation is presented. We demonstrate how our methodology
can reproduce the experimentally observed spectra and, by comparison
to well characterized peaks in two different experimental studies,
demonstrate the transferability and robustness of the methodology.
We discuss certain cases in which caution must be exercised when implicit
solvent representations are used for calculating silicate cluster
geometries: those cases in which intramolecular hydrogen bonding can
play a significant role in the geometry. A number of reassignments
of previous tentative experimental assignments are proposed, and we
also make assignments for the challenging substituted four-ring species.
We present all of our computed chemical shift for previously observed
species together with a number of other viable silicate clusters to
serve as a reference point for future experimental studies