Synthesis, spectral properties, α-glucosidase inhibition, second-order and third-order NLO parameters and DFT calculations of Cr(III) and V(IV) complexes of 3-methylpicolinic acid

Abstract

The Cr(III) and V(IV) complexes of 3-methylpicolinic acid (3-mpaH) were synthesized. The XRD and LC-MS/MS were performed to determine experimental geometric structure of the synthesized complexes. Their experimental spectral analyses were carried out by FT–IR and UV–Vis spectra. Their α-glucosidase activities were also evaluated. The synthesized Cr(III) and V(IV) complexes exhibited α-glucosidase inhibitory activity with the IC50 values of >600 μM. Furthermore, the optimal molecular structure geometries, vibrational frequencies, electronic spectral properties, refractive index, band gap, second- and third-order nonlinear optical (NLO) parameters of these complexes were obtained by using DFT/HSEh1PBE/6–311G (d,p)/LanL2DZ level. NLO results demonstrate that the complex 1 is a promising candidate to materials with the high first- and second-order hyperpolarizability values obtained at 55.3 × 10−30 and 251.0 × 10−36 esu in ethanol solvent. The experimental refractive index and band gap parameters were comparatively presented. Lastly, NBO analysis was fulfilled to investigate inter- and intra-molecular bonding and the definition of coordination geometries around the central metal ions, as well as the electronic charge transfer interactions in the Cr(III) and V(IV) complexes.