Fluorescent Oligomeric Nanoparticle from Diaminopyridine Compound Via Enzyme-Catalyzed Oxidation

An oligomeric nanoparticle was obtained through an enzyme-catalyzed oxidation reaction using Horse Radish Peroxidase (HRP) with the 2,3-diaminopyridine (DAP) compound as the starting material. The structural characterizations of the synthesized oligomeric nanoparticles [[oligo(DAP)]_Enz] were performed with ¹H-NMR and FT-IR. The surface features were determined by scanning electron microscopy. The optical properties were determined by UV-Vis and fluorescence spectra. It was found that the obtained oligomeric nanoparticles had a different fluorescent character with 15.90% quantum yield from the monomer and emitted green color at 485 nm when excited with light at a wavelength of 420 nm. The electrochemical band gap of the oligomeric nanoparticles, whose electrochemical character was investigated by cyclic voltammetry, was calculated as 2.09 eV. The thermal stability of the oligomeric material was determined from the mass loss against increasing temperature. The monomer exhibited greater thermal stability in comparison to the polymer, both in terms of the temperature at which the maximum mass loss occurred and the residual amount after heating concluded.