Probing the radialene-character in triplesalophen ligands by spectroscopic and structural analysis

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Materials Science

Background:

• The triplesalen ligand system facilitated single-molecule magnet synthesis via supramolecular recognition.
• Optimization for magnetic anisotropy necessitated a new ligand system, leading to the triplesalophen framework.

Purpose of the Study:

• To describe the convergent synthesis of the novel triplesalophen ligand system.
• To elucidate the molecular and electronic structures of the synthesized triplesalophen ligands.
• To establish spectral and structural signatures for the heteroradialene motif.

Main Methods:

• Convergent synthesis of triplesalophen ligands.
• Single-crystal X-ray diffraction for structural analysis.
• NMR, FTIR, and UV-vis spectroscopies for electronic structure determination.

Main Results:

• Successful convergent synthesis of the triplesalophen ligand system (H(6)baron(R)).
• Established the N-protonated tautomer with keto-enamine resonance (heteroradialene motif).
• Identified unique spectral and structural signatures for the heteroradialene motif.

Conclusions:

• The convergent synthesis of triplesalophen ligands is effective.
• The N-protonated heteroradialene tautomer is prevalent in the central compartment.
• Established signatures will aid in understanding transition metal complexes with this ligand system.