title: The use of FTIR and NMR spectroscopies to study prepolymerisation interactions in nitrogen heterocycles.
abstract: A detailed investigation into the functional groups responsible for the formation of a noncovalent complex between 2-aminopyridine (template) and methacrylic acid (functional monomer) has been carried out using FTIR spectroscopy and confirmed by (1)H NMR spectroscopic data. The approach adopted to confirm the mechanism of interaction was the analysis of the template plus the structurally similar 2-methylaminopyridine and 2-dimethylaminopyridine. A 1:1 stoichiometry of complexation was determined by Job plot analysis following titration, with FTIR results complementing those of the (1)H NMR study. The strength of interaction between 2-aminopyridine and the functional monomer measured through band shifts by FTIR spectroscopy was compared with such interactions for the isomers 3- and 4-aminopyridine. This comparison identified a clear correlation between template pK(a), degree of interaction and subsequent nonspecific binding in the nonimprinted polymer. Using FTIR spectroscopy it was also possible to observe the effect of temperature on the prepolymerisation solution. IR spectra showed that lower temperatures led to more stabilized interactions of the hydrogen-bonded complex. The potential advantages of FTIR spectroscopy compared with (1)H NMR spectroscopy in studying prepolymerisation solutions have been identified.
authors.affiliation: Department of Chemical and Life Sciences, Waterford Institute of Technology, Cork Road, Waterford, Ireland. qosmani@wit.ie
authors.forename: Qendresa
authors.initials: Q
authors.lastname: Osmani
authors.forename: Helen
authors.initials: H
authors.lastname: Hughes
authors.forename: Kevin
authors.initials: K
authors.lastname: Flavin
authors.forename: Jimmy
authors.initials: J
authors.lastname: Hedin-Dahlstrom
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Allender
authors.forename: June
authors.initials: J
authors.lastname: Frisby
authors.forename: Peter
authors.initials: P
authors.lastname: McLoughlin
mesh_terms: D000631:Aminopyridines / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000032:analysis* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008689:Methacrylates / Q000737:chemistry; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
chemical_list: D000631:Aminopyridines; D006571:Heterocyclic Compounds; D008689:Methacrylates; D009584:Nitrogen; C032439:alpha-aminopyridine