Noncovalent imprinted microspheres: Preparation, evaluation and selectivity of DBU template

Abstract

1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) imprinted polymer was prepared as microspheres by precipitation polymerization method to obtain molecular recognition systems based on the noncovalent interactions between DBU template, methacrylic acid (MAA), and ethylene .glycol dimethacrylate (EDMA) in acetonitrile. 1 H NMR analysis of DBU/ MAA mixture has been performed and hydrogen bonding interactions have been established. Microspheres have been characterized by FTIR studies with evidence of DBU linkage in polymer particles and by Scanning Electron Microscopy (SEM) to study their morphological properties. How pH values affect the binding capacity of imprinted polymer during the binding stage has been also discussed and results suggest that imprinted poly-(MAA-EDMA) behavior is related to the influence of DBU basicity during rebinding processes and the optimum pH value for binding has been found around neu-tral range. Binding ability of the imprinted polymer towards different concentration of DBU buffered solutions has been evaluated and compared with binding ability of the nonimprinted polymer. A more sensitive response to the template in the imprinted system suggests that a reasonable number of specific binding sites is formed. Finally, differential selectivity towards other less strong than DBU nitrogen bases, such as pyridine, imidazole, and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) has been also discussed. Our results indicate that both specific sites and basic properties are involved in the rebinding process.

Experimental and Computational Studies on Non-Covalent Imprinted Microspheres as Recognition System for Nicotinamide Molecules

“…Syntheses of nia imprinted microspheres were carried out following the method described in our previous paper [ 52 ] with slight variations. The conditions used for the synthesis are summarized in Table 1 : in every experiment, 0.43 mmol of nia and 1.55 mmol of MAA were dissolved in the solvent in a 100 mL three necked round bottom flask and the solution was kept into a ultrasonic bath for 10 min; then, EGDMA and 0.15 mmol of AIBN were added to the solution.…”

“…In a previous work we prepared polymeric microspheres by using a non-covalent imprinting technique and precipitation polymerization of methacrylic acid (MAA) in the presence of 1,8-diaza-bicyclo[5.4.0]undec-7-ene (DBU) as the template [ 52 ]. Now, in continuation of our interest in MIP research, we report herein a study of a molecular imprinted system based on non-covalent interactions between nia template molecules and MAA functional monomers.…”

Emerging Tools for Recognition and/or Removal of Dyes from Polluted Sites: Molecularly Imprinted Membranes

“…Anyway, some analytical techniques can help to perform chemical and morphological characterizations. They include solid-state magnetic nuclear resonance (NMR) [68], elemental microanalysis (EDX) and Fourier-transform infrared spectroscopy (FT-IR) [69] which can be applied for the determination of the chemical composition of a polymer. As example, Annamma and co-workers [68] confirmed the incorporation of the crosslinking agent EGDMA and of the functional monomer 4-vynilpyridine in the polymer backbone of a prepared MIP by 13 C NMR spectra.…”

“…More often, the presence of the functional monomer in the synthesized polymers is confirmed by FT-IR studies, which allow to compare the spectrum of a single functional monomer with that one of the polymer. In this case, it is possible to follow the shifting or the disappearance of some signals into the polymer with respect to the monomer as results of the polymerization process [62,69,70].…”

A New Ion-Imprinted Chitosan-Based Membrane with an Azo-Derivative Ligand for the Efficient Removal of Pd(II)

“…Starting from the experience of our research group in the field of molecularly imprinted polymers [ 23 , 24 , 25 , 26 , 27 , 28 ], the imprinting technology was used here to develop a new membrane for palladium uptake based on crosslinked CS containing an azo-derivative ligand: a Pd(II)-imprinted, azobenzene-modified chitosan membrane (Pd-IAzoCsM).…”