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Published on: April 10, 2015
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Pd(II) complexes of meso-tetraaryl triphyrin(2.1.1)s: synthesis and studies
Gayathri Sekar1, Akrti Sharma1, Mangalampalli Ravikanth1
1Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. ravikanth@chem.iitb.ac.in.
Dalton Transactions (Cambridge, England : 2003)
|April 28, 2026
Summary
New palladium(II) complexes with meso-tetraaryl triphyrin(2.1.1) ligands were synthesized and characterized. These complexes exhibit unique saddle-shaped conformations and altered electronic properties compared to their free-base counterparts.
Area of Science:
- Coordination Chemistry
- Supramolecular Chemistry
- Materials Science
Background:
- Triphyrins are macrocyclic ligands with tunable electronic and photophysical properties.
- Palladium complexes are widely used in catalysis and materials science.
- Understanding metal-ligand interactions is crucial for designing functional molecules.
Purpose of the Study:
- To synthesize and characterize novel Palladium(II) complexes of meso-tetraaryl triphyrin(2.1.1).
- To investigate the structural, spectral, and redox properties of these new complexes.
- To compare the properties of the palladium complexes with their corresponding free-base triphyrins.
Main Methods:
- Synthesis of Pd(II) triphyrin(2.1.1) complexes via reaction with PdCl2.
- Purification using basic alumina column chromatography.
- Structural elucidation using X-ray crystallography.
- Spectroscopic analysis (1H NMR, UV-Vis absorption).
- Electrochemical studies (redox potentials).
- Computational studies (DFT/TD-DFT).
Main Results:
- Successful synthesis and purification of three Pd(II) triphyrin(2.1.1) complexes.
- X-ray structure revealed a rigid cis square-planar geometry with a saddle-shaped conformation.
- Spectral studies showed upfield/downfield shifts in 1H NMR and red-shifted absorption bands.
- Redox studies indicated easier reductions and more difficult oxidations for the complexes.
- DFT/TD-DFT calculations supported the experimental findings, including a reduced HOMO-LUMO energy gap.
Conclusions:
- Pd(II) complexation significantly alters the structural and electronic properties of meso-tetraaryl triphyrin(2.1.1) ligands.
- The observed saddle-shaped conformation influences the electronic structure and redox behavior.
- These findings provide insights into the design of novel metal-triphyrin complexes for potential applications in catalysis and electronics.
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