Synthesis and characterization of ferrocenyl camphor compounds

• Several camphor ferrocene complexes are structurally characterized.
• Elucidation by NMR of structural modifications induced by temperature variation.
• Assembling via intermolecular hydrogen bonding forming dimers.
• Non-trivial IR spectra due to solid state effects and conformational changes.

Several ferrocene camphor compounds of the general formula FcCONHR, where Fc = ferrocenyl and R is N(C10H13NSO2) (2), N(C10H14O) (3), N(C10H16) (4) or NLiCO(C10H14O) (6), were synthesized by the reaction of FcCONHNH2 (1) with the respective camphor derivatives. In the resulting compounds, the ferrocene and camphor units are connected via a hydrazone link formed through condensation of the terminal NH2 group in 1 and the carbonyl group of the camphor derivative. The characterization of the complexes is based mostly on analytical data and on NMR and IR spectra. Additional insight into the structural characteristics of complex (E)-FcCONHN(C10H14O) (3) was obtained from variable temperature and 2D NMR measurements while computational calculations were used to assign the bands in IR spectra of FcCONHN(C10H13NSO2) isomers. X-ray diffraction analysis has shown that the molecules of (E)-FcCONHN(C10H13NSO2) associate into symmetric dimers in the solid state via N–H⋯O hydrogen bonds between the hydrazone moieties.

Several ferrocenyl camphor complexes are reported. Two of them (FcCONHN(C10H13NSO2) and FcCONHN(C10H14O) display isomeric forms (E and Z) with considerably different NMR and IR characteristics. (E)-FcCONHN(C10H14O) has a dynamic behavior in solution.Figure optionsDownload as PowerPoint slide