Heterodinuclear Cu(I)/Mo(VI) chemistry with bifunctional dibenzobarrelene ligands

Area of Science:

• Coordination Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Bifunctional dibenzobarrelene ligands with diphosphine and diol functionalities are known mononucleating ligands.
• These ligands can act as tetradentate or potentially heterodinucleating agents, coordinating both early and late transition metals.
• The heterodinucleating reactivity of these ligands remains largely unexplored.

Purpose of the Study:

• To investigate the coordination chemistry of diphosphine/diol (L1H2) and diphosphine/diester (L2) ligands with copper(I) and molybdenum(VI).
• To explore the potential of these ligands in forming heterometallic complexes.
• To characterize the resulting complexes using spectroscopic and structural methods.

Main Methods:

• Synthesis of stable copper(I) complexes with L1H2 and L2 ligands, coordinating as bidentate diphosphines.
• Spectroscopic characterization including 31P {1H} NMR and 63Cu NMR.
• Investigation of reactions with Mo(VI) precursors, leading to the isolation and structural determination of a trinuclear complex via X-ray crystallography.

Main Results:

• Both ligands formed stable Cu(I) complexes where they acted as bidentate diphosphines.
• 31P {1H} NMR showed an AB system due to diastereotopic phosphine groups, with large 2J(P-P) coupling constants (120-150 Hz).
• A trinuclear complex, [MoO2(μ2-O)2{Cu(DMSO)(L1H2)}2], was successfully synthesized and structurally characterized, revealing Mo(VI)-Cu(I) linkage via oxo bridges.

Conclusions:

• Diphosphine/diol ligands can stabilize Cu(I) centers and participate in the formation of complex heterometallic structures.
• The study provides initial insights into the Cu(I)/Mo(VI) chemistry of these bifunctional ligands.
• Further research is warranted to fully explore the heterodinucleating potential of these ligand systems.