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Ion pair charge-transfer complexes between anionic and cationic metal-dithiolenes [M(II) = Pd, Pt]
Francesco Bigoli1, Paola Deplano, Maria Laura Mercuri
1Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Università di Parma, Parco Area delle Scienze 17A, I-43100 Parma, Italy.
Inorganic Chemistry
|October 2, 2002
Summary
New redox-active cationic dithiolene complexes were synthesized and reacted with anionic dithiolenes to form ion pair charge-transfer salts. These salts exhibit unique one-dimensional stacking and charge-transfer interactions, leading to visible-near-infrared absorptions and electrical conductivity.
Area of Science:
- Coordination Chemistry
- Materials Science
- Solid-State Physics
Background:
- Dithiolene complexes are known for their redox activity and potential in charge-transfer materials.
- The synthesis of novel cationic dithiolene complexes can lead to new material properties.
Purpose of the Study:
- To synthesize and characterize new redox-active cationic dithiolene complexes.
- To investigate the formation and properties of ion pair charge-transfer salts derived from these complexes.
- To explore the solid-state electronic and optical properties of the resulting salts.
Main Methods:
- Synthesis and characterization of [M(R(2)pipdt)(2)](BF(4))(2) salts (M = Pd(II), Pt(II)).
- Reaction of cationic dithiolenes with anionic [M(mnt)(2)](2-) dithiolenes to form charge-transfer salts.
- X-ray crystallography to determine the solid-state structure of the salts.
- UV-Visible-Near-Infrared spectroscopy to study optical properties.
- Marcus-Hush model application for electron transfer analysis.
- Vibrational spectroscopy to confirm charge-transfer interactions.
Main Results:
- Successful synthesis and characterization of new cationic dithiolene complexes.
- Formation of ion pair charge-transfer salts with [M(mnt)(2)](2-) anions.
- Isomorphous crystal structures for Pd and Pt complexes, featuring one-dimensional anion-cation stacks.
- Observed strong visible-near-infrared absorptions attributed to charge-transfer transitions.
- Demonstrated relationship between optical and thermal electron transfer.
- Observed solid-state electrical conductivity consistent with charge-transfer behavior.
Conclusions:
- The synthesized cationic dithiolene complexes effectively form ion pair charge-transfer salts.
- The one-dimensional stacking in the solid state is crucial for the observed electronic and optical properties.
- These materials hold potential for applications in optoelectronics due to their charge-transfer characteristics.