Synthesis, characterization, biological and dielectric studies of a proton transfer compound of pyridine-2,6-dicarboxylic acid with 1H-benzimidazole-2-amine and its vanadium and iron complexes

A proton transfer salt, (HBIA +)(HPDA -) Greek ano teleiaH(2)O ( L ), and its vanadium (HBIA)[VO2(PDA)] ( C1 ) and iron com-plexes, (HBIA)[Fe(PDA)2] Greek ano teleia2H(2)O ( C2 ) [H(2)PDA = pyridine-2,6-dicarboxylic acid; BIA = H-1-benzimidazole-2-amine] have been synthesized and characterized by elemental analysis, FT-IR, UV-Visible, (1) H and (13) C NMR and single crystal X-ray diffraction (SC-XRD) studies. According to SC-XRD, compound L and C2 crystalizes in Monoclinic ( P 2 (1 /c) ) and C1 in Triclinic ( P-1) crystal system and exist as multi-component proton transfer systems stabilized by COO -NH+ ion pair interactions. Thermal, biological and mate-rial aspects of compounds were explored by TG-DTA study, antimicrobial, antidiabetic and dielectric study. Antibacterial activity was evaluated against the microorganisms, Escherichia coli (ATCC 25,922 ), Staphylococcus aureus (ATCC 25,923 ), Pseudomonas aeroginosa (ATCC 2783 ), Streptococcus mutans (MTCC 890 ) and Klebsiella pneumonia (ATCC 13,883 ) . Antifungal activity was evaluated against Aspergillus niger (ATCC16404) and Candida albicans (ATCC 10,231). Band gap energy values with UV-Visible spectra reveal the semiconducting nature of compounds. The vanadium complex shows significant antidiabetic activ-ity (IC(50)value = 315 mu g/mL) compared with the standard reference. Presence of easily polarizable water molecule is responsible for the high dielectric constant value ( epsilon = 41.96 at 1 Hz) and ac conductivity (sigma(ac)) for the iron complex C2.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

A proton transfer salt and its vanadium and iron complexes were synthesized and characterized. Their thermal, biological and material aspects were explored. The vanadium complex showed significant antidiabetic activity, and the iron complex exhibited high dielectric constant and ac conductivity.