A new multicomponent salt of imidazole and tetrabromoterepthalic acid: Structural, optical, thermal, electrical transport properties and antibacterial activity along with Hirshfeld surface analysis

•The crystal structure of multicomponent salt has been determined both from SCXRD and PXRD technique.•Supramolecular interactions and short contacts through Hirshfeld surface analysis.•The optical band gap has been found by Density Functional Theory.•The salt is more active than imidazole against Gram-negative bacteria.

Herein, we report the structural, optical, thermal and electrical transport properties of a new multicomponent salt (TBTA2−)·2(IM+)·(water) [TBTA–IM] of tetrabromoterepthalic acid (TBTA) with imidazole (IM). The crystal structure of TBTA–IM is determined by both the single crystal and powder X-ray diffraction techniques. The structural analysis has revealed that the supramolecular charge assisted O−⋯HN+ hydrogen bonding and Br⋯π interactions play the most vital role in formation of this multicomponent supramolecular assembly. The Hirshfeld surface analysis has been carried out to investigate supramolecular interactions and associated 2D fingerprint plots reveal the relative contribution of these interactions in the crystal structure quantitatively. According to theoretical analysis the HOMO–LUMO energy gap of the salt is 2.92 eV. The salt has been characterized by IR, UV–vis and photoluminescence spectroscopic studies. It shows direct optical transition with band gaps of 4.1 eV, which indicates that the salt is insulating in nature. The photoluminescence spectrum of the salt is significantly different from that of TBTA. Further, a comparative study on the antibacterial activity of the salt with respect to imidazole, Gatifloxacin and Ciprofloxacin has been performed. Moreover, the current–voltage (I–V) characteristic of ITO/TBTA–IM/Al sandwich structure exhibits good rectifying property and the electron tunneling process governs the electrical transport mechanism of the device.

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