Synthesis, spectroscopic studies and biological aspects of bis(cyclopentadienyl)titanium(IV) complexes with 4-amino-5-(nicotinic/picolinic/isonicotinic/indole-3-propyl/indole-3-ethyl)-3- mercapto-1,2,4-triazole

Department of Chemistry, D.D.U Gorakhpur University, Gorakhpur-273 009, Uttar Pradesh, India E-mail: sengupta@hotmail.co.uk Manuscript received online 12 October 2020, revised and accepted 27 November 2020 Titanium(IV) complexes of type [(ɳ5-C5H5)2TiCl(L)] have been synthesized by the reactions of bis(cyclopentadienyl)- titanium(IV)dichloride with ligand (LH) derived from condensation of (nicotinic/picolinic/isonicotinic/indole-3-propyl/indole-3- ethyl)carboxylic acid and thiocarbohydrazide in dry tetrahydrofuran in the presence of triethylamine. All these complexes are soluble in PhNO2, DMF and DMSO. The complexes are characterized by elemental analyses, electrical conductance, mag­netic susceptibility, UV-Vis, IR, 1H NMR, 13C NMR, XRD and SEM spectral techniques. Low molar conductance values indi­cate that they are non-electrolytes. The spectral data indicate five-coordinate geometry for the complexes. XRD pattern indi­cate that the complexes have monoclinic crystal system and particle sizes were found at ca. 57.71 nm (nano-size). In vitro antifungal activity of synthesized compounds was evaluated against fungi Aspergillus niger, Aspergillus flavus, Colletotrichum falcatum and in vitro antibacterial activity was determined by screening the compounds against Gram-negative (P. aeruginosa, S. typhi) and Gram-positive (S. aureus and B. subtilis) bacterial strains using minimum inhibition concentration method (MIC) by serial dilution technique. The titanium(IV) complexes have higher antimicrobial effect than the parent Schiff bases