![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)
Reversible Ligand Pairing and Sorting Processes Leading to Heteroligated Palladium(II) Complexes with Hemilabile
Organometallics
|August 27, 2021
Summary
Halide-induced ligand rearrangement (HILR) drives reversible ligand pairing and sorting in Pd(II) complexes. This process allows for controlled formation of heteroligated "tweezer" complexes, offering new avenues in coordination chemistry.
Area of Science:
- Coordination Chemistry
- Organometallic Chemistry
- Supramolecular Chemistry
Background:
- Hemilabile ligands, such as P,S and P,O types, play a crucial role in stabilizing and functionalizing metal complexes.
- Understanding ligand behavior in palladium(II) complexes is essential for developing new catalytic systems and materials.
- Ligand pairing and sorting phenomena are critical for controlling the architecture and reactivity of coordination compounds.
Purpose of the Study:
- To investigate halide-induced ligand pairing and sorting processes in palladium(II) complexes featuring hemilabile P,S and P,O ligands.
- To explore the formation and characterization of heteroligated palladium(II) complexes.
- To demonstrate the reversible nature of these ligand manipulation processes and their potential for creating 'tweezer'-like structures.
Main Methods:
- Synthesis and characterization of palladium(II) complexes using P,S and P,O ligands.
- Employing techniques such as single-crystal X-ray diffraction and solid-state CPMAS 31P{1H} NMR spectroscopy for structural elucidation.
- Investigating reaction equilibria through controlled temperature changes and solvent precipitation.
Main Results:
- Observed halide-induced ligand pairing and sorting, leading to the formation of heteroligated Pd(II) complexes.
- Demonstrated that cooling or hexanes precipitation drives the equilibrium towards exclusive formation of semiopen heteroligated complex cis-[κ2-(7)-κ1-(8)ClPd]Cl (9a).
- Confirmed the reversible nature of the process, with dissolution of 9a in CH2Cl2 regenerating the initial mixture of complexes.
Conclusions:
- The study elucidates a novel halide-induced ligand rearrangement (HILR) mechanism governing ligand pairing and sorting in Pd(II) systems.
- Successfully synthesized and characterized reversible semiopen heteroligated complexes, showcasing control over 'tweezer'-like structures.
- These findings open possibilities for dynamic control over ligand arrangements and flexibility in coordination complexes.
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