Design and construction of the imidazole-2-thione-based copper(I) complexes by varying the co-anion and synthesis conditions and verifying their antimicrobial activity

Highlights: • Four Cu(I) polymers were synthesized by branched tube and solvothermal methods. • These polymers were designed by changing the synthesis method and co-anion. • The dimension of the polymers are sensitive to the crystallization techniques. • By using cyanide as a co-ligand the structure directed toward a 2D polymer. • The 1D polymers are bactericidal while the 2D polymer has bacteriostatic behaviour. A series of copper-based polymers of [Cu(bbit)I]_n (1), {[Cu(bbit)₂](HSO₄).(S₈)_0.5}_n (2), [Cu₄(CN)₄ (bbit)₂]_n (3) and [Cu(bbit)Cl]_n (4) have been designed and synthesized from reaction of CuX (X=I, Cl and CN) with 1,1-(1,4-butanediyl) bis (1,3-dihydro-3-methyl-1H-imidazole- 2-thione) (bbit) ligand. These compounds were characterized by IR, CHNS, PL, TGA, PXRD and their crystal structures were determined by X-ray crystallography. The final structure of synthesized polymers was affected by applied co-ligand and reaction conditions. Treating copper(I) iodide with equimolar ratio of bbit ligand afforded 1D wavelike polymer 1 with a distorted trigonal planar geometry by branched tube method. Polymer 2 has synthesized by the same starting material for 1 through unexpected process by solvothermal method with a distorted S₄ tetrahedral environment. With addition of CN⁻ to the reaction mixture of 1, 2D wavelike polymer of 3 with distorted trigonal CNS and tetrahedral CNS₂ coordination environments was formed. Polymer 4 is analogue of 1 and was prepared by the same method as for 1 using copper chloride instead of copper iodide. The action of the title polymers on several pathogens were verified via antibacterial, MIC and MBC tests. The obtained results displayed that the polymers 1, 2 and 4 have bactericidal behavior, while the polymer 3 is a bacteriostatic agent.