Macrocyclic bis-diphosphenes demonstrating bimetallic exo- and endo-cyclic binding modes

Area of Science:

• Inorganic Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Macrocyclic azobenzenes are well-studied organic compounds.
• Heavier analogues of main group elements are of significant interest.
• Novel phosphorus-containing macrocycles present unique chemical properties.

Purpose of the Study:

• To synthesize macrocyclic bis-diphosphenes for the first time.
• To explore their coordination chemistry with transition metals.
• To investigate their structural and electronic properties.

Main Methods:

• Nickel-mediated homocoupling of NHC-stabilised bis-phosphinidene units.
• Metal complexation using copper(I) chloride.
• Variable temperature Nuclear Magnetic Resonance (NMR) spectroscopy.
• Computational bonding analyses.

Main Results:

• Successful synthesis of macrocyclic bis-diphosphenes.
• Demonstration of both exo-cyclic and endo-cyclic metal binding modes.
• Formation of a tetra-metallic complex with simultaneous exo- and endo-cyclic binding.
• Observation of fluctional behavior in solution.

Conclusions:

• This study reports the first synthesis of macrocyclic bis-diphosphenes.
• These compounds exhibit diverse metal coordination capabilities.
• The findings provide initial insights into the chemistry of this new class of compounds.