Synthesis, Analysis, and Antimicrobial Screening of a New Thiophene-Based Schiff Base Complexes

Abstract

Copper (II) and zinc(II) complexes from (2E)-N-phenyl-2-[1-(thiophen-2-yl)ethylidene]hydrazine-1-carbothioamide (AT-PTSC) Schiff base were synthesized and characterized. A variety of analytical techniques were used to confirm their structure and properties. Elemental analysis supported a 2:1 ligand-to-metal ratio, while molar conductivity showed they were electrolytes. The complexes exhibited excellent thermal stability, with decomposition temperatures above 220°C. Magnetic measurements identified the copper complex as paramagnetic (2.2 BM) and the zinc complex as diamagnetic (0.0 BM). IR spectroscopy confirmed the ligand’s coordination to the metal through the azomethine nitrogen, as indicated by a shift in the v(C=N) peak from 1648 cm⁻¹ to a lower frequency. In antimicrobial testing, both the ligand and the complexes showed moderate activity against various microbes. Notably, the metal complexes were significantly more effective than the free ligand, a result attributed to the chelation effect. This research highlights the potential of these new complexes as promising antimicrobial agents.