Chalcogen-Transfer Rearrangement: Exploring Inter- versus Intramolecular P-P Bond Activation

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry

Background:

• Tert-butyl-substituted diphospha[2]ferrocenophane offers a stereochemically confined environment for exploring element additions.
• Understanding the reactivity of diphosphanes with chalcogens is crucial for developing new synthetic methodologies.

Purpose of the Study:

• To investigate the addition reactions of oxygen, sulfur, selenium, and tellurium to a specific diphosphane ligand.
• To elucidate the mechanism of rearrangement for diphosphane monochalcogenides to diphosphanylchalcoganes.
• To explore the redox properties of the resulting compounds.

Main Methods:

• Reactions involving elemental chalcogens and tert-butyl-substituted diphospha[2]ferrocenophane.
• Nuclear Magnetic Resonance (NMR) spectroscopy for kinetic studies.
• Density Functional Theory (DFT) calculations for mechanistic insights and electronic structure.
• Cyclic voltammetry to probe redox behavior.

Main Results:

• Tellurium addition yielded the diphosphanylchalcogane, while O, S, and Se formed diphosphane monochalcogenides.
• Heating induced a rearrangement of monochalcogenides to diphosphanylchalcoganes.
• Kinetic studies and DFT calculations suggested a disproportionation/synproportionation mechanism for sulfur and selenium derivatives.
• Cyclic voltammetry and DFT indicated ferrocene-centered oxidation for most compounds.

Conclusions:

• The study successfully characterized the addition of various chalcogens to a confined diphosphane ligand.
• A novel rearrangement pathway for diphosphane monochalcogenides was uncovered, with mechanistic details elucidated.
• The ferrocene moiety exhibits redox activity, suggesting potential applications in catalysis or materials science.