Selective Schiff Base Formation of Group 9 Organometallic Complexes with Functionalized Spirobifluorene Ligands

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Organic Synthesis

Background:

• Organic amines are crucial in various products, necessitating effective detection methods.
• Organometallic complexes offer versatile platforms for chemical sensing and reactivity studies.

Purpose of the Study:

• To synthesize and characterize novel organometallic complexes featuring 9,9'-spirobifluorene-based ligands.
• To investigate the reactivity of these complexes, particularly in Schiff base formation with amines.
• To explore the selective reactivity of iridium and rhodium complexes towards different amine types.

Main Methods:

• Synthesis of group 9 organometallic complexes [MCp*X(2'-R-2-py-SBF)] and [IrCp*Cl(2', 7-diCHO-2-py-SBF)].
• Characterization using NMR spectroscopy, mass spectrometry, and IR spectroscopy.
• X-ray diffraction analysis for structural elucidation.
• Study of Schiff base formation via condensation reactions with various amines.

Main Results:

• Successful synthesis and characterization of novel iridium and rhodium complexes.
• Demonstration of Schiff base formation through condensation of amine with aldehyde groups on the complexes.
• Selective reactivity observed: iridium complexes react with aromatic amines, while rhodium complexes react with aliphatic amines at room temperature and aromatic amines upon heating.

Conclusions:

• The synthesized organometallic complexes serve as a platform for amine detection and reactivity studies.
• The metal center (Iridium vs. Rhodium) and the nature of the amine significantly influence the reaction pathway and conditions.
• These findings contribute to the development of selective chemical sensors for organic amines.