Complexes of N-(2-thiazolyl)-1H-benzotriazole-1-carbothioamide with Pd(II), Pt(II), and Zn(II): Spectral, DFT, cytotoxicity and anti-angiogenic effect on MCF-7 cell line

[ZnL₂]·4EtOH (1), [PdL(EtOH)₂]·Cl (2) and [PtL(EtOH)Cl] (3) (HL = N-(2-thiazolyl)-1H-benzotriazole-1-carbothioamide complexes have been synthesized, and characterized by elemental analysis, IR, ¹H NMR, UV-Vis, and TGA. In complex 1, the thiazole N and C-S^-donor sites of two deprotonated ligand molecules are coordinated to Zn(II) forming a tetrahedral structure, while in case of 2 and 3, the benzotriazole N and C-S^-are participated in the coordination spheres of square planar complexes. Optimized structures, natural bond orbital analysis, molecular electrostatic potential maps, and frontier molecular orbitals have been obtained by DFT/B3LYP/LANL2DZ method. Time-dependent DFT calculations have been performed to assign the electronic spectra. The complexes in comparison to HL have been screened for their antimicrobial and cytotoxicity activities. Complex 2 (3.08 μg/mL) is more potent than HL and the other complexes that may be attributed to its ionic nature and presence of two easily replaceable ethanol molecules. The capacity of complexes to slow down the proliferation of the MCF7 cell line has been achieved by down regulation of the vascular endothelial growth factors using RT-PCR technique.