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
Photocytotoxic trans-diam(m)ine platinum(IV) diazido complexes more potent than their cis isomers
Nicola J Farrer1, Julie A Woods, Vivienne P Munk
1Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.
Abstract:
The photocytotoxicity of a series of anticancer trans-dihydroxido [Pt(N(3))(2)(OH)(2)(NH(3))(X)] (X = alkyl or aryl amine) platinum(IV) diazido complexes has been examined, and the influence of cis-trans isomerism has been investigated. A series of photoactivatable Pt(IV)-azido complexes has been synthesized: The synthesis, characterization, and photocytotoxicity of six mixed-ligand ammine/amine Pt(IV) diazido complexes, cis,trans,cis-[Pt(N(3))(2)(OH)(2)(NH(3))(X)] where X = propylamine (4c), butylamine (5c), or pentylamine (6c) and aromatic complexes where X = pyridine (7c), 2-methylpyridine (8c), or 3-methylpyridine (9c) are reported. Six all-trans isomers have also been studied where X = methylamine (2t), ethylamine (3t), 2-methylpyridine (8t), 4-methylpyridine (10t), 3-methylpyridine (9t), and 2-bromo-3-methylpyridine (11t). All of the complexes exhibit intense azide-to-Pt(IV) LMCT bands (ca. 290 nm for trans and ca. 260 nm for cis). When irradiated with UVA light (365 nm), the Pt(IV) complexes undergo photoreduction to Pt(II) species, as monitored by UV-vis spectroscopy. The trans isomers of complexes containing aliphatic or aromatic amines were more photocytotoxic than their cis isomers. One of the cis complexes (9c) was nonphotocytotoxic despite undergoing photoreduction. Substitution of NH(3) ligands by MeNH(2) or EtNH(2) results in more potent photocytotoxicity for the all-trans complexes. The complexes were all nontoxic toward human keratinocytes (HaCaT) and A2780 human ovarian cancer cells in the dark, apart from the 3-methylpyridine (9t), 2-bromo-3-methylpyridine (11t), and 4-methylpyridine (10t) derivatives.
Related Concept Videos
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...
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
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 be...
Disubstituted Cyclohexanes: cis-trans Isomerism
In cyclohexane, the substituents can occupy different positions generating distinct isomers.

![[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)