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Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents
Published on: May 28, 2014
Acetate-bridged platinum(III) complexes derived from cisplatin.
Justin J Wilson1, Stephen J Lippard
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Inorganic Chemistry
|September 6, 2012
Summary
Oxidation of platinum(II) complexes forms platinum(III) species with a metal-metal bond, confirmed by crystallography and NMR. DFT calculations explain spectral changes in these novel dinuclear and tetranuclear platinum compounds.
Area of Science:
- Coordination Chemistry
- Inorganic Chemistry
- Materials Science
Background:
- Acetate-bridged platinum(II) complexes serve as precursors for higher oxidation states.
- Understanding metal-metal bonding in platinum complexes is crucial for catalysis and materials science.
Purpose of the Study:
- To synthesize and characterize novel platinum(III) dinuclear and tetranuclear complexes.
- To investigate the structural and electronic consequences of oxidizing platinum(II) to platinum(III).
- To explore the formation of metal-metal bonds in dinuclear platinum systems.
Main Methods:
- Synthesis of platinum complexes using iodobenzene dichloride, bromine, and bis(trifluoroacetoxy)iodobenzene as oxidizing agents.
- Structural characterization by X-ray crystallography.
- Solution characterization using multinuclear NMR spectroscopy ((1)H, (13)C, (14)N, (195)Pt).
- Computational analysis using Density Functional Theory (DFT).
Main Results:
- Oxidation of cis-[Pt(II)(NH(3))(2)(μ-OAc)(2)Pt(II)(NH(3))(2)](NO(3))(2) yielded halide-capped platinum(III) dinuclear complexes with short Pt-Pt separations (≈2.6 Å), indicating a metal-metal bond.
- X-ray crystallography confirmed the structures, revealing elongated axial Pt-X distances due to the trans influence of the Pt-Pt bond.
- NMR spectroscopy showed downfield shifts and decreased line widths for (14)N and (195)Pt resonances in platinum(III) complexes, explained by DFT calculations.
- A novel tetranuclear platinum(III) complex was synthesized and structurally characterized.
Conclusions:
- The study successfully synthesized and characterized novel dinuclear and tetranuclear platinum complexes in higher oxidation states.
- The formation of a Pt-Pt metal-metal bond in dinuclear platinum(III) complexes was confirmed structurally and spectroscopically.
- DFT calculations provided insights into the electronic structure and spectroscopic properties of the platinum complexes.
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