Fourier Transform Infrared Spectroscopic Studies of Charge-Transfer Intercalation Compounds

Fourier transform infrared spectroscopy has been used to characterize the charge-transfer nature of cobaltocene, Co(C₅H₅)₂, intercalated into the layered host lattices Cd₂P₂S₆ and SnS₂- In the Cd₂P₂S₆ case, the infrared spectrum is consistent with the presence of both neutral cobaltocene and cationic cobaltocenium, Co(C₅H₅)₂⁺¹. Spectra taken after a reaction time of several hours as well as several weeks both lead to the same conclusion. Spatially resolved infrared spectra suggest that the intercalation reaction is a charge-transfer reaction followed by diffusion of neutral cobaltocene into the Cd₂P₂S6 host. In the SnS₂case, the infrared spectrum is consistent with the presence of only the cationic form of the cobaltocene with no evidence that neutral cobaltocene remains within the host. Electron spin resonance spectroscopy was used to further substantiate these conclusions.