Five-Coordinate Zinc(II) Complex: Synthesis, Characterization, Molecular Structure, and Antibacterial Activities of Bis-[(E)-2-hydroxy-N′-{1-(4-methoxyphenyl)ethylidene}benzohydrazido]dimethylsulfoxidezinc(II) Complex

Abstract

The titled Zn(II) complex was synthesized by reacting the compound (E)-2-hydroxy-N -{1-(4-methoxyphenyl)ethylidene}benzohydrazide with zinc(II) acetate dihydrate in alkaline DMSO and ethanol solution under reflux condition for 28 hours. The resulting solid was filtered and recrystallized from the mixture of ethanol and DMSO. The hydrazone Schiff base and its Zn(II) complex were characterized using 1 H, 13 C NMR, FTIR, UV-Vis spectroscopy, and single crystal X-ray diffraction analysis. Meanwhile, their antibacterial activities were examined using disc diffusion method. The spectral studies showed that the hydrazone Schiff base underwent keto-enol tautomerization, forming a bidentate ligand (N,O) towards Zn(II) ion. Surprisingly, on top of the two hydrazone Schiff base molecules which coordinated to the Zn metal center, an additional DMSO molecule was found attached to the Zn metal center in the crystal data, resulting in a 5-coordinate distorted trigonal bipyramidal Zn(II) complex. Both hydrazone Schiff base and its Zn(II) complexes were found to exhibit low antibacterial activity even when the concentrations were increased to 800 ppm.

Spectroscopic characterization for new model from Schiff base and its complexes

“…The consequences of calculations show that the LUMO of metal ions desire to react with the HOMO of four‐donor atoms of two oxygen and nitrogen(CO and CN) for free ligand (H 2 L). [ 16–37 ]…”

Synthesis, Characterization and DNA-Binding Affinity of a New Zinc(II) Bis(5-methoxy-indol-3-yl)propane-1,3-dione Complex

“…Although many zinc(II) coordination compounds are stable in a tetrahedral geometry, some five-coordinated complexes have been reported in recent years [ 60 , 61 , 62 ]. One notable example is provided by DMSO coordination [ 63 ]. As 1 is optimally soluble in this organic solvent, we investigated the proneness of DMSO to act as extra ligand in the coordination sphere of 1 .…”

Synthesis and crystal structure of a mixed-ligand zinc(II) complex derived from ethyl (2,6-dimethylphenylcarbamoyl) formate and 1,10-phenanthroline

“…The Zn ion is penta-coordinated by two nitrogen atoms from one phen ligand, two oxygen atoms from a bidentate oxamate moiety and one chloride ion (Figure 4b). Selected bond lengths and angles are listed in [29]. The ligand bite angles of the 5-membered chelate rings are almost equal as shown by coordinating bond angles of N-Zn-N = 79.20(5)° and O-Zn-O = 79.63(4)°.…”