Novel ferrocene imide derivatives: synthesis, conformational analysis and X-ray structure

Area of Science:

• Organometallic Chemistry
• Supramolecular Chemistry
• Organic Synthesis

Background:

• Ferrocene derivatives are versatile compounds with applications in various fields.
• Understanding the structural and conformational properties of ferrocene imides is crucial for their design and application.
• Previous studies have explored ferrocene imides, but a comprehensive analysis of their solid-state and solution behavior is needed.

Purpose of the Study:

• To synthesize and structurally characterize novel mononuclear, dinuclear, and trinuclear ferrocene imide derivatives.
• To investigate the presence of intramolecular hydrogen bonds in these compounds using IR spectroscopy.
• To elucidate the crystal packing and intermolecular interactions in solid-state structures.
• To perform a detailed conformational analysis using DFT calculations and compare with experimental data.

Main Methods:

• Synthesis of ferrocene imide derivatives via reactions of ferrocenecarboxamide with acyl chlorides.
• Infrared (IR) spectroscopy for detecting intramolecular hydrogen bonds.
• X-ray crystallography for determining crystal structures and packing arrangements.
• Density Functional Theory (DFT) calculations for conformational analysis.

Main Results:

• Successful synthesis of ferrocene imide derivatives: Fc-CO-NH-CO-Me (4), Fc-CO-NH-CO-Fc (7), and Fc-CO-NH-CO-Fn-CO-NH-CO-Fc (8).
• IR spectroscopy indicated the absence of intramolecular hydrogen bonds in solutions.
• Crystal structure of N-acetylferrocenecarboxamide (4) showed N-H⋯O hydrogen bonds forming dimers; N-methylferrocenecarboxamide (5) formed infinite chains via intermolecular N-H⋯O bonds.
• DFT study suggested a cis-trans configuration for ferrocene imide derivative 7 in solution.

Conclusions:

• The study successfully synthesized and characterized a series of ferrocene imide derivatives.
• Solid-state structures exhibit distinct hydrogen bonding motifs, influencing molecular assembly.
• Solution conformation of bis-ferrocenyl imide 7 is predominantly cis-trans.
• The findings provide insights into structure-property relationships in ferrocene imides, aiding future molecular design.