Fabrication of Chiral Stationary Phases via Continuous Assembly of Polymers for Resolution of Enantiomers by Liquid Chromatography

Abstract

Precise stereochemical determination of chiral molecules is highly important, especially in the pharmaceutical industry where one enantiomer may have a therapeutic effect while the other has detrimental effects. Herein, the continuous assembly of polymers (CAP) mediated via ringopening metathesis polymerization (ROMP) is used to fabricate immobilized-type chiral stationary phases (CSPs) -as cross-linked thin films on solid supports -for enantiomeric separation. Optically active polysaccharides (chitosan and amylose) with aromatic substituents were pre-functionalized with pendent norbornene groups and subsequently employed as macrocross-linkers in the CAP ROMP process, building cross-linked films from initiator-functionalized mesoporous silica particles. The immobilized cross-linked films on mesoporous silica particles can act as CSPs. Therefore, the chiral recognition abilities of the CSPs were explored by liquid chromatography (LC). It was found that CSPs with higher amount of polysaccharide cross-linked films -made from multiple CAP reactionshave better chiral separation capabilities. This work demonstrates the versatility of the CAP approach to fabricate CSPs to tailor specific separation needs.

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…In several cases a surface bound ruthenium carbene complex was generated through reaction of a metathesis catalyst with a surface bound alkene, and the resulting carbene was then used to initiate a polymerization. Examples of second monomers employed in this way include: (1) 5-(perfluorooctyl)norbornene [400]; (2) norbornenecarboxylate ester bound to a polythiophene [401]; and (3) chitosan or amylose-bound norbornenecarboxylate esters [402]. Additional examples of ROMP were presented in the sections on Z-selective metathesis.…”

Chiral Stationary Phases for Liquid Chromatography Based on Chitin- and Chitosan-Derived Marine Polysaccharides

“…These techniques employed a catalyst immobilized on silica particles to produce stable CSPs suitable to be used in a wide range of mobile phases. The obtained CSP proved to be effective in separating the enantiomers of Trögers base and trans-stilbene oxide [63].…”

“…To our knowledge, the most recent study with chitosan tris-phenylcarbamates was published by Guntari et al, in 2014 [63]. In this study, they developed and evaluated a new way of immobilization of chitosan tris-3,5-dimethylphenylcarbamate (23) using continuous assembly of polymers techniques.…”

Photocontrolled Cargo Release from Dual Cross-Linked Polymer Particles

“…The CAP approach utilizes controlled polymerization protocols to polymerize macrocross-linkers–(bio)­macromolecules with pendant polymerizable moieties–from initiator functionalized substrates . The CAP approach is a versatile method for the fabrication of various functional nanocoatings, including superhydrophobic and switchable thin films, chiral stationary phases, low-biofouling coatings and compartmentalized micelle-based films . When CAP mediated by ring-opening metathesis polymerization (CAP ROMP ) is applied to particle templates, only 7 mol % of pendant polymerizable groups are required to form stable replica particles in one-step after template dissolution .…”