Synthesis, antimicrobial evaluation, and measurement of physical and thermo-acoustical parameters of novel 1,3,4-thiadiazole and benzo[d]imidazole scaffolds by ultrasonic studies

We prepared 15 novel series of 1,3,4-thiadiazole containing benzo[d]imidazole compounds for the development of potential antimicrobial agents (6a–o). IR, ¹H NMR, ¹³C NMR, and mass spectrometry were used to identify the bioactive structures of these compounds. Using the Broth Dilution method, the synthesized compounds were examined for antimicrobial activity against a variety of bacterial and fungal strains. Compounds 6j showed potency against bacterial strain P. aeruginosa, E. coli, and antifungal activity against A. clavatus at MIC values of 12.5 µg/mL, 50 µg/mL, and 100 µg/mL respectively. 6c, and 6e indicated antibacterial activity against P. aeruginosa at MIC values 62.5, and 50 µg/mL and antifungal activity against C. albicans MIC 250, 100, µg/mL respectively. Density (ρ), ultrasonic velocity (U), and viscosity (η) have been measured in a binary liquid mixture containing 1,3,4-thiadiazole and benzo[d]imidazole over the entire molality range at temperatures T = (303.15,308.15,313.15 and 318.15) K and different solvent DMSO and DMF. The experimentally obtained data have been used to determine the thermo-acoustical parameters adiabatic compressibility (κ_s), intermolecular free length (L_f), acoustical impedance (Z), and internal pressure (π). It is observed that in DMSO solutions, solute–solute interactions exist whereas solvent–solute interactions are predominant in DMF systems.