Related Experiment Video
Updated: Aug 18, 2025

Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
Published on: October 5, 2019
Synthesis, Spectroscopic Characterization, Biocidal evaluation Molecular Docking & DFT Investigation of 16-18
Subhash1, Ashu Chaudhary1, Jyoti2
1Department of Chemistry, Kurukshetra University, Kurukshetra, 136119 Haryana India.
Abstract:
Macrocyclic ligands (MacL1-MacL3) and Co(II) complexes were synthesized via template condensation of o-phenylenediamine with various aromatic dicarboxylic acids. The elemental analysis, FT-IR, mass spectrometry, 1H NMR, 13C NMR, UV-vis, SEM analysis, powder X-ray diffraction, thermogravimetric (TG) analysis, electrochemical studies, and DFT analysis were used to characterize these synthesized ligands and their cobalt (II) complexes. TGA analysis to determine the stability and decomposition kinetic parameters. In element analysis, the percentage of different elements present and also the stoichiometry of compounds were confirmed. The proposed framework for tetraaza macrocyclic cobalt (II) complexes was supported by spectral analysis, which also revealed distorted octahedral geometry surrounding the central metal atom. The molecular structure of cobalt (II) complexes was also optimized theoretically, and their electronic or thermodynamic parameters were obtained from density functional theory (DFT). The synthesized ligands and their cobalt (II) complexes were tested against bacteria: Escherichia coli, Bacillus subtitles. Candida albicans were tested for antifungal properties. It was found that ligands and complexes show good antimicrobial results. Finally, using the Auto Dock VinaPyRx programme, molecular docking studies were used to evaluate the biological significance of the synthesized ligands to identify the probable and efficient binding mechanisms between the various ligands and the active site of the receptor protein.
Graphical Abstract:
Antimicrobial, DFT, and Docking representation of Cobalt (II) macrocyclic complexes.
Supplementary Information:
The online version contains supplementary material available at 10.1007/s12039-022-02109-2.
Related Concept Videos
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Valence Bond Theory
Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...

