Electrochemical Quantification of Intermolecular Hydrogen Bonding between Ferrocenemethanol and 3-Mercaptopropanoic Acid on Gold

Quantification of the amount of intermolecular hydrogen bonding between ferrocenemethanol and 3-mercaptopropanoic acid on gold was performed by cyclic voltammetry as well as by the finite element simulation, displaying a proof-of-concept that the slight changes of cyclic voltammetry features are used potentially for interpreting the weak molecular interactions. Ferrocenemethanol at a bulk concentration level of 0.5 mM adsorbs on the 3-mercaptopropanoic acid surface by hydrogen bonding, with the fractional surface coverage ranging from 0% to 14% of a monolayer in accordance with the surface coverage of 3-mercaptopropanoic acid which was explored by electrochemical quartz crystal microbalance. The intermolecular hydrogen bonding between ferrocenemethanol and the mercaptopropanoic acid was found to exhibit a Langmuir-type adsorption with the average value of K being 0.24 mM^-1. The intermolecular hydrogen bonding between FcCH₂OH and the artificial self-assembled monolayer (3-mercaptopropanoic acid) is evident, and the study on quantification of intermolecular hydrogen bonding with this artificial model is meaningful for understanding the molecular recognition events involved in the cell membrane.