An aggregation-induced emission active vitamin B6 cofactor derivative: application in pH sensing and detection of latent fingerprints

Photochem Photobiol Sci. 2020 Oct 14;19(10):1402-1409. doi: 10.1039/d0pp00262c.

Abstract

Aggregation-induced emission (AIE) properties of an easy-to-prepare and structurally planar Schiff base derivative of the vitamin B6 cofactor pyridoxal (L) were investigated in DMSO-H2O mixed solvents. Compound L showed weak fluorescence (λem = 425 nm) in pure DMSO, but increasing the fraction of water in DMSO resulted in a significant fluorescence enhancement at 575 nm due to the restriction of intramolecular rotation (RIR) of L upon aggregation. SEM analyses revealed the formation of hairy micelle-like or needle-shaped self-assemblies/aggregates of L. The DFT calculations were performed to examine the tendency of L to form self-aggregates, and the results indicate the formation of several intramolecular non-covalent interactions that energetically favored the self-aggregation of L. The pH sensing study revealed that the red-emission of aggregates of L between pH 5.9 and 9.0 turned into green emission at the basic pH with the estimated pKa values of 9.39 and 10.22. Further, the aggregates of L were applied for the visualization of latent fingerprints (LFPs) over a non-porous glass slide.

MeSH terms

  • Density Functional Theory
  • Dimethyl Sulfoxide / chemistry
  • Hydrogen-Ion Concentration
  • Molecular Structure
  • Particle Size
  • Pyridoxal / chemistry*
  • Schiff Bases / chemistry
  • Surface Properties
  • Vitamin B 6 / chemistry*
  • Water / chemistry

Substances

  • Schiff Bases
  • Water
  • Pyridoxal
  • Vitamin B 6
  • Dimethyl Sulfoxide