Solvent Control Over Mechanistic Pathways of Ferrocene Intercalation in the Layered Host VOPO ₄ ·2H ₂ O

Understanding how solvents influence the mechanism of intercalation is essential for advancing layered materials for energy storage devices, catalysis, and molecular electronics. In this study, we explore intercalation into the layered vanadium phosphate host using ferrocene as the reducing agent and guest, revealing three distinct solvent-dependent mechanistic pathways that depend on the solvent-host interaction, ferrocene concentration, and product lattice energy. Different aliphatic organonitrile solvents, while they do not react directly with VOPO4·2H2O, can nevertheless affect the ratio between stage 1 and stage 2 products, and a kinetics analysis suggests the two products follow different mechanistic pathways. In contrast to the aliphatic nitriles, primary alcohol molecules can be directly inserted into VOPO4·2H2O layers. With in situ measurements, preintercalation of the alcohol, followed by cointercalation of alcohol and the guest, is observed experimentally for the first time. A stage 1 phase is formed in 1-propanol, and a stage 2 phase is formed in ethanol, indicating that the propanol-host interaction is moderate, allowing ferrocene to fully occupy the host layers, whereas the ethanol-host interaction is too strong to be completely expelled by the guest. These differences underscore the influence of solvent-host interactions during intercalation, enhancing the understanding of solvent-assisted intercalation and its applications in hybrid materials.