One electron oxidation of triferrocenylmethanol: Synthesis, metal atom dynamics, electron delocalization, and the crystal structure of [Fc ₃COH]⁺ PF₆^-

The title compound 2 was prepared and its crystal structure was determined at 100 K. The neat solid was examined by temperature dependent ⁵⁷Fe Mössbauer effect (ME) spectroscopy over the interval 92 < T < 318 K, and evidences two diamagnetic Fe(ii) sites and one paramagnetic Fe(iii) site. The latter shows spin-lattice relaxation, but there is no evidence of electron delocalization among the three iron sites in the above temperature interval. The mean-square-amplitude-of-vibration of the diamagnetic iron site has been determined from the recoil-free fraction ME resonance, and compared to the neutral Fc₃COH homologue (1). The ME dynamical data are in good agreement with the U_i,j value at 100 K extracted from the crystallographic results. The ME parameters at 5 K have also been determined with the sample compound embedded in a paraffin wax matrix as well as pelletized with BN.