Butadiene-Based Multidentate Ligand Formation via Stannylene Assisted C-C Coupling

Area of Science:

• Organometallic Chemistry
• Ligand Design
• Tin Chemistry

Background:

• Redox-active ligands are crucial for tuning metal center reactivity.
• Bis(α-iminopyridine) ligands offer unique coordination environments.
• Tin(II) compounds are versatile precursors for novel organotin species.

Purpose of the Study:

• To synthesize and characterize novel bisstannylene compounds derived from redox-active bis(α-iminopyridine) ligands.
• To investigate the C-C coupling reactions of these bisstannylene compounds.
• To explore the formation of new multifunctionalized ligands through demetalation.

Main Methods:

• Reaction of bis(α-iminopyridine) ligands with Sn[N(SiMe3)2]2.
• In situ NMR spectroscopy for intermediate detection.
• Single crystal X-ray diffraction (SCXRD) for structural characterization.
• NMR, mass spectrometry, and absorbance spectroscopy for compound analysis.
• Density Functional Theory (DFT) calculations.

Main Results:

• Synthesis of bisstannylene compounds 1 and 2 via intermolecular and intramolecular C-C coupling, respectively.
• Characterization of ene-amide stabilized bisstannylene intermediates (I1, I2) and a monostannylene.
• Formation of oxidized compounds 3 and 4, and bisstannylene 5.
• Generation of new multifunctionalized ligands L3 and L4 via demetalation.

Conclusions:

• Redox-active bis(α-iminopyridine) ligands facilitate the formation of unique bisstannylene compounds.
• C-C coupling reactions lead to the incorporation of butadiene units into the ligand backbone.
• The study demonstrates a pathway to novel organotin compounds and valuable multifunctionalized ligands.