Synthesis of molecularly imprinted polymers using a functionalized initiator for chiral-selective recognition of propranolol.

Weifeng Liu,Clovia Holdsworth,Lei Ye

doi:10.1002/chir.23167

Abstract

We present a new concept of synthesis for preparation of molecularly imprinted polymers using a functionalized initiator to replace the traditional functional monomer. Using propranolol as a model template, a carboxyl‐functionalized radical initiator was demonstrated to lead to high‐selectivity polymer particles prepared in a standard precipitation polymerization system. When a single enantiomer of propranolol was used as template, the imprinted polymer particles exhibited clear chiral selectivity in an equilibrium binding experiment. Unlike the previous molecular imprinting systems where the active free radicals can be distant from the template‐functional monomer complex, the method reported in this work makes sure that the actual radical polymerization takes place in the vicinity of the template‐associated functional groups. The success of using functional initiator to synthesize molecularly imprinted polymers brings in new possibilities to improve the functional performance of molecularly imprinted synthetic receptors.

Highlights

Owing to the specific molecular recognition capability, molecularly imprinted polymers (MIPs) have attracted enormous interest in applied science and technology areas
We present a new concept of synthesis for preparation of molecularly imprinted polymers using a functionalized initiator to replace the traditional functional monomer
Unlike the previous molecular imprinting systems where the active free radicals can be distant from the template-functional monomer complex, the method reported in this work makes sure that the actual radical polymerization takes place in the vicinity of the template-associated functional groups

Summary

| INTRODUCTION

Owing to the specific molecular recognition capability, molecularly imprinted polymers (MIPs) have attracted enormous interest in applied science and technology areas. Taking precipitation polymerization into account, under a standard molecular imprinting condition, one can expect that a significant portion of cross-linking reaction can lead to nonspecific particles, because the active radicals generated from the initiator have no affinity for the template (Figure 1A). When an active radical reacts with the template-bound functional monomer, an imprinted molecular binding site will start to form (Figure 1A). Based on this consideration, we propose that a functionalized initiator may be used to prepare MIPs without requiring commonly used functional monomers. We use a well-investigated molecular template propranolol to demonstrate the feasibility of non-covalent molecular imprinting using functionalized initiator (Figure 2). The polymer particles were purified following standard workup procedures before the molecular recognition characteristics were investigated

| MATERIALS AND METHODS

| RESULTS AND DISCUSSION

| CONCLUSIONS