Synthesis, crystal structure, density functional theory calculations, and antimicrobial activity of silver(I) complex derived from 2‐aminobenzothiazole ligand

Reaction of silver nitrate with 2‐aminobenzothiazole (abbreviated as Habt) in methanol at 45°C gave mononuclear complex of formula [Ag (Habt)2]NO3•CH3OH. The structure of the complex was characterized by infrared (IR) spectra, single crystal X‐ray diffraction, and elemental analysis. X‐ray diffraction analysis indicated that the title complex was crystallized in the triclinic crystal system with space group P–1, in which silver(I) ion was coordinated to two 2‐aminobenzothiazole ligands through the benzothiazol nitrogen atom. Theoretical study of the complex was carried out by density functional theory (DFT) B3LYP method. The antimicrobial effects of the ligand and its silver(I) complex were evaluated by bio‐microcalorimetry on the growth of Schizosaccharomyces pombe (S. pombe). Some quantitative metabolic parameters, such as growth rate constant (k), maximum heat power (Pmax), inhibition ratio (I), and half inhibition concentration (IC50), were derived from the metabolic power–time curves of S. pombe growth. The half inhibition concentration (IC50) of the ligand was calculated to be 2.58 × 10−3 mol L−1. The complex could strongly influence the lag phase of S. pombe. A silver(I) 2‐aminobenzothiazole complex was prepared and characterized by single crystal X‐ray diffraction. Highest Occupied Molecular Orbital–Lowest Unoccupied Molecular Orbital (HOMO–LUMO) energy gap of the complex is 5.57 eV, which is little larger than that of the ligand (5.43 eV). The inhibitory concentration of the complex is much lower than that of the ligand, and the complex can strongly influence the lag phase of bacteria.