Related Experiment Video
Updated: Jun 17, 2026
Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents
Published on: May 28, 2014
Systematic Investigation of Coordination Chemistry in Iridium(III) and Ruthenium(II) Complexes Derived from
Lihua Guo1, Zhihao Yang1, Heqian Dong1
1Key Laboratory of Life-Organic Analysis of Shandong Province, Key Laboratory of Green Natural Products and Pharmaceutical Intermediates in Colleges and Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, P. R. China.
Abstract:
A systematic investigation of the coordination chemistry of iridium(III) and ruthenium(II) complexes synthesized from pyridyl-amine ligands was performed, focusing on how ligand steric hindrance and metal centers affect oxidation behavior, coordination modes, and biological activities. The study revealed that steric hindrance at the ligand's bridge carbon strongly influenced both oxidation behavior and coordination modes. Smaller substituents (e.g., H and Me) facilitated oxidation to form pyridyl-imine species under adventitious oxygen, whereas bulky substituents (e.g., i-Bu and mesityl) suppressed oxidation, yielding stable pyridyl-amine or 16-electron pyridyl-amido complexes. Moreover, iridium(III) complexes were more prone to oxidation than the corresponding ruthenium(II) complexes under similar conditions. The aqueous stability of the newly synthesized complexes was confirmed. Cytotoxicity assays demonstrated that most of the complexes exhibited notable anticancer potency against A549, HeLa and cisplatin-resistant A549/DDP cancer cells. Mechanistic studies suggested a redox-driven pathway involving the catalytic oxidation of NADH to NAD+, the elevation of ROS levels and depolarization of the mitochondrial membrane. Notably, pyridyl-amine complexes induced apoptosis, while 16-electron pyridyl-amido complexes did not, though both caused S phase cell cycle arrest. Additionally these complexes can inhibit A549 cell migration, suggesting their potential to reduce cancer metastasis.
More Related Videos
Related Concept Videos
02:54Coordination Compounds and Nomenclature
02:51Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
02:57Coordination Number and Geometry
02:34Structural 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 be...
02:52Stereoisomerism
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...
03:02Colors 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 eye.