Antimicrobial and antioxidant activity evaluation of Co(II), Ni(II), Cu(II) and Zn(II) complexes with 15-thia-3,4,9,10-tetraazabicyclo[10.2.1]pentadeca-1(14),2,10,12-tetraene-5,8-dione

•Template macrocyclic synthesis.•Characterization: TGA, PXRD.•Molecular modelling.•Bioactivity: antimicrobial and antioxidant.

A new mixed thia-aza macrocyclic complexes with Schiff base viz. 15-thia-3,4,9,10-tetraazabicyclo[10.2.1]pentadeca-1(14),2,10,12-tetraene-5,8-dione containing transition metals, M = Co(II), Ni(II), Cu(II) and Zn(II) and X = Cl−, NO3−, OAc−, has been synthesized, resulting in the final constitution of 1:1:1 M ratio, by the condensation of succinyldihydrazide and thiophenedicarboxaldehyde. The metal complexes have been investigated with the help of various physico-chemical techniques viz. elemental analyses, magnetic susceptibility, thermal, conductivity measurements, spectral (IR, UV, ESR, NMR and mass) and X-ray diffraction techniques. The low value of molar conductivity indicates the non-electrolytic nature of the complexes and a distorted octahedral geometry has been proposed on the basis of various physico-chemical studies. X-ray diffraction indicates the presence of monoclinic crystal system. The complexes have been investigated for in vitro antibacterial, antifungal and antioxidant activity. All the complexes show moderate to significant activity.

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