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Affinity capillary electrophoresis and quantum mechanical calculations applied to the investigation of hexaarylbenzene‐based receptor binding with lithium ion
Author(s) -
Ehala Sille,
Toman Petr,
Rathore Rajendra,
Makrlík Emanuel,
Kašička Václav
Publication year - 2011
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201100092
Subject(s) - chemistry , capillary electrophoresis , electrophoresis , lithium (medication) , ionic strength , density functional theory , binding constant , electrolyte , ion , analytical chemistry (journal) , stability constants of complexes , computational chemistry , chromatography , binding site , organic chemistry , aqueous solution , medicine , biochemistry , electrode , endocrinology
In this study, two complementary approaches, affinity capillary electrophoresis (ACE) and quantum mechanical density functional theory (DFT) calculations, have been employed for quantitative characterization and structure elucidation of the complex between hexaarylbenzene (HAB)‐based receptor R and lithium ion Li + . First, by means of ACE, the apparent binding constant of Li R + complex ( K LiR +) in methanol was determined from the dependence of the effective electrophoretic mobilities of Li R + complex on the concentration of lithium ions in the 25 mM Tris/50 mM chloroacetate background electrolyte (BGE) using non‐linear regression analysis. Prior to regression analysis, the effective electrophoretic mobilities of the Li R + complex were corrected to reference temperature 25°C and constant ionic strength 25 mM. The apparent binding constant of the Li R + complex in the above methanolic BGE was evaluated as log K LiR += 1.15±0.09. Second, the most probable structures of nonhydrated Li R + and hydrated Li R + ·3H 2 O complexes were derived by DFT calculations. The optimized structure of the hydrated Li R + ·3H 2 O complex was found to be more realistic than the nonhydrated Li R + complex because of the considerably higher binding energy of Li R + ·3H 2 O complex (500.4 kJ/mol) as compared with Li R + complex (427.5 kJ/mol).