A Novel Approach to the Molecular Imprinting of Polychlorinated Aromatic Compounds

Abstract

The aim of this investigation was to determine whether relatively weak interactions, such as hydrogen bonds to aromatic chlorine atoms and interactions involving aromatic π electrons could be exploited within artificial receptors, constructed using the technique of molecular imprinting. For the purposes of this investigation we chose 2,3,7,8-tetrachlorodibenzodioxin (TCDD) as the model target. Imprinted polymers have been prepared with two new templates designed to create recognition sites for TCDD. The first of these, the bis-N-(4-vinylphenyl)urea derivative of 2,8-dichloro-3,7-diaminodibenzodioxin, employed a carbonyl spacer to introduce aromatic amines into the polymer after reductive cleavage of the template. The second, N-(2-(3,7,8-trichlorodibenzodioxinyl))-2-methacryloyloxybenzamide, incorporated a salicylic acid spacer and introduced a methacrylic acid residue into the polymer following hydrolysis. Both amine and acid groups were positioned in such a way as to interact with TCDD through the formation of weak hydrogen bonds to aromatic chlorine atoms. A second recognition element was introduced into the binding sites by the inclusion of a polymerizable, electron-rich, aromatic ether capable of forming π−π interactions with the electron-deficient dioxin molecule. Polymers imprinted with either template showed significantly higher uptake of TCDD than the corresponding nonimprinted controls, even at concentrations as low as 2 nM.

Molecular imprinting science and technology: a survey of the literature for the years up to and including 2003

“…Another method for the introduction of amine functionality is the use of a urea linkage, with the carbonyl acting as spacer. 505 The role of the sacrificial spacer can also be filled by larger molecules such as salicylic acid. This is a useful approach for the imprinting of molecules with amine functionality.…”

“…Intramolecular hydrogen bonding positions the carboxylic acid functionality in the binding site, and after cleavage hydrogen bonding between the carboxylic acid and the amine functionality of the template can be re-established. 505,506 Silyl ether-based chemistry was employed in a template analogue approach for the imprinting of aromatic N-heterocycles. In this case the dimethyl silyl group acted as the spacer to introduce a 4-vinylphenol residue capable of H-bonding to an aromatic N-heterocycle.…”

Preparation of chiral stationary phase for HPLC based on immobilization of cellulose 3,5‐dimethylphenylcarbamate derivatives on silica gel

“…4-Vinylphenyl isocyanate was prepared from 4-vinylbenzoic acid by the conventional method using sodium azide. 20,21 Macroporous silica gel (Daiso gel SP-1000, pore size 100 nm, particle size 7 µm) was kindly supplied by Daiso Chemical. Solvents used in the chromatographic experiments were of HPLC grade.…”

One‐pot synthesis of polysaccharide 3,5‐dimethylphenylcarbamates having a random vinyl group for immobilization on silica gel as chiral stationary phases

“…1. Among them, (b) and (c) were commercially available, while (a) was made in our laboratory from 10-undecylenic acid using a modified Curtius rearrangement as follows [30].…”