Ligand Exchange Reaction between Ferrocene and Multiwalled Carbon Nanotubes: A Contemporary Approach

Ligand exchange reaction (LER) between carbon nanoparticles and ferrocene (Cp₂Fe) was conducted several times, but there was no convincing evidence of half-sandwich CpFe⁺ coordination to multiwalled carbon nanotubes (MWCNT). In this study, MWCNT is modified by LER with ferrocene using AlCl₃/Al as a catalytic system. The modified MWCNT (Fc-MWCNT) are investigated for better understanding of the processes taking place on the surface of MWCNT using different spectroscopic and electrochemical methods. The formation of the Fe-C covalent bond between CpFe⁺ and MWCNT is confirmed by changes in the Raman spectrum of Fc-MWCNT compared to pristine MWCNT. The densest structure of Fc-MWCNT is investigated by transmission electronic microscopy. According to density-functional theory calculations of the model interaction between Fe and coronene, the Fe-C bond length is 2.1687-2.1855 Å. X-ray photoelectron spectroscopy also confirms the coordination of the Fe atom to MWCNT by analysis of oxidation states of Fe 2p and deconvolution of C 1s. Utilization of cyclic voltammetry corroborated MWCNT modification via LER. These data are important for both theoretical and practical applications due to increased interest in LER-modified compounds in different areas including thermoelectric devices, sensors, and its potential application in the field of molecular machine construction.