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Photochemical Electrocyclic Reactions: Stereochemistry

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Updated: Jan 7, 2026

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

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Published on: April 10, 2015

Leveraging Intramolecular π-Stacking in Ru(II)-Pyridine Complexes to Induce Photoinduced Ligand Dissociation.

Alexia Marques Silva¹, Austin P Lanquist¹, Curtis E Moore¹

¹Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.

Journal of the American Chemical Society

|December 28, 2025

Summary

Intramolecular π-stacking in ruthenium(II) complexes enhances pyridine ligand release upon irradiation. This discovery offers a novel strategy for improving the targeted delivery of pyridine-containing drugs in photochemotherapy.

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Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Published on: November 29, 2018

Area of Science:

Coordination Chemistry
Photochemistry
Materials Science

Background:

Ruthenium(II) polypyridyl complexes are widely studied for their photophysical properties.
Developing photosensitive systems for drug delivery requires precise control over ligand exchange dynamics.

Purpose of the Study:

To synthesize and characterize novel ruthenium(II) complexes with varying phenanthroline ligands.
To investigate the impact of intramolecular π-stacking on excited-state properties and ligand exchange.

Main Methods:

Synthesis and characterization of three ruthenium(II) complexes: [Ru(tpy)(phen)(py)]2+, [Ru(tpy)(phenyl-phen)(py)]2+, and [Ru(tpy)(pyrenyl-phen)(py)]2+.
1D and 2D 1H NMR spectroscopy and X-ray crystallography for structural elucidation.
Density Functional Theory (DFT) calculations to understand electronic structure and excited states.

Main Results:

Complexes with phenyl-phen and pyrenyl-phen ligands exhibit intramolecular π-stacking.
DFT calculations reveal lower energy dissociative metal-centered (MC) excited states in these complexes.
Ruthenium(II) complexes with π-stacking show significantly enhanced pyridine ligand exchange quantum yields (>100-fold increase).

Conclusions:

Intramolecular π-stacking in ruthenium(II) complexes facilitates access to dissociative excited states.
This facilitates photoinduced ligand exchange, a key step for drug delivery applications.
This study presents a new approach to enhance ligand release in photosensitive ruthenium complexes for photochemotherapy.