Hybrid polyacrylamide chiral stationary phases for HPLC prepared by surface‐initiated photopolymerization

Abstract

Two hybrid polyacrylamide chiral stationary phases (CSPs) for HPLC have been synthesized by a new surface-initiated photo-induced radical polymerization approach of enantiopure N,N'-diacryloyl derivatives of (1R,2R)-diaminocyclohexane (CSP1) and (1R,2R)-diphenylethylenediamine (CSP2). This system is based on the activation of mesoporous silica microparticles by chemically bonded trichloroacetyl groups and dimanganese decacarbonyl as catalyst. UV irradiation was performed using a lab-made quartz photochemical reactor, ad hoc designed for the photo-induced polymerization process on the surface of microparticles. The two phases were evaluated and compared as chromatographic supports for the enantioselective HPLC of model chiral compounds. Their physico-chemical properties and chromatographic performances were also evaluated in comparison with those exhibited by the homologue CSPs obtained by the grafting-from thermal-induced process (CSP3 and CSP4). The new photopolymerization approach yielded higher grafting density than the thermal-induced one, especially in the case of the less reactive monomer (the diacryloyl derivative of (1R,2R)-diphenylethylenediamine), good chromatographic efficiency and a broad application field under normal phase and polar organic mode conditions.

Synthesis and characterization of new optically active poly(acrylamide/methacrylurea-co-vinyl acetate) copolymers with dansyl units

“…In fact, the presence of the peak due to the carbonyl carbon atom can be identified at 163.93 ppm, whereas the peaks for the aromatic carbons are visible at 143.50, 128. 16 Figure 1(c) has illustrated 1 H, 1 H-COSY (Correlation Spectroscopy) spectrum corresponding to R-MEBzU, where two-dimensional data suggested the formation of the urea monomer by correlating the protons. Additionally, the 13 C-NMR spectrum in CDCl 3 of the above commented optically active acrylic monomer (Figure 1(d)) displayed well-resolved signals, which could be attributed to the different carbon atoms that sustain the anticipated structure as it follows: the peak of the carbon from the ester function was identified at 167.36 ppm, the one of the carbonyl carbon atom from urea groups appeared at 157.94 ppm, while the peaks for the aromatic carbons were visible at 143.02, 128.53, 127.14, and 126.30 ppm, respectively.…”

“…[9] The method frequently used to obtain chiral polymers consists of the polymerization of optically active monomers [5,10,11] or by means of a polycondensation reaction, [2] free radical polymerization, [9] and dispersion polymerization. [12] Based on their chiral structure, the optically active poly(meth)acrylamides have found potential applications in biomedicine, [13,14] pharmacy, [15] high-performance liquid chromatography, [16] catalytic activity in asymmetric transformations, as well as high chiral recognition ability, [10,[17][18][19] and for the elimination of different environmentally toxic metal ion/counterion couples. [20] The most important reason to utilize these compounds are primarily a good biocompatibility with DNA in vitro, and secondly low cost, relatively easy copolymerization, and versatility in applications.…”

Homochiral organic molecular cage RCC3‐R‐modified silica as a new multimodal and multifunctional stationary phase for high‐performance liquid chromatography

“…The good chiral resolution performance may be attributed to the hydrogen bonding formed by the polyhydroxy groups and the spatial coordination of the macrocyclic molecular cage. Some chiral stationary phases based on 1,2-diaminocyclohexane have been prepared and used for the resolution of various racemic compounds with very short analysis times and high column efficiency [32][33][34]. Although the C18-embedded RCC3-R stationary phase with enhanced hydrophobic properties was prepared for RP-HPLC applications, the separation efficiency of the hydrophilic compounds was relatively low, the types of the compounds were few, and there were some limitations with less separation modes and functions during the separation of complex compounds [35].…”

Optimization of the surface modification process of cross‐linked polythiol‐coated chiral stationary phases synthesized by a two‐step thiol‐ene click reaction

“…Enantioselective LC using chiral stationary phases (CSPs) has become a workhorse for chiral separations in drug discovery and quality control of enantiomeric drugs as well as many other applications . In general, two distinctly different concepts for the preparation of CSPs have been pursued: brush type CSPs, in which the chiral selectors are covalently linked to the surface (usually silica) by a spacer and polymeric type CSPs with polymeric selectors . Each of the two concepts, brush‐ and polymer‐type CSPs, has its advantages and disadvantages.…”

“…other applications [1,2]. In general, two distinctly different concepts for the preparation of CSPs have been pursued: brush type CSPs, in which the chiral selectors are covalently linked to the surface (usually silica) by a spacer [3][4][5] and polymeric type CSPs with polymeric selectors [6][7][8][9][10][11][12]. Each of the two concepts, brush-and polymer-type CSPs, has its advantages and disadvantages.…”