1,1′-Ferrocenedicarboxylic acid/tetrahydrofuran induced precipitation of calcium carbonate with a multi-level structure in water

Abstract

A system of organic solvents and ligands had been successfully applied to regulate the coordination of metal ions in organic chemistry. Inspired by previous work, we conducted a study on the effect of 1,1′-ferrocenedicarboxylic acid (FA)/tetrahydrofuran (THF, aprotic solvent) on the precipitation of calcium carbonate (CaCO₃). The influence of FA concentrations was systematically investigated to achieve controllable and reliable CaCO₃ particles. As a control, the effect of H₂O–THF solutions on CaCO₃ precipitation was explored and compared with that of H₂O-1,4-dioxane solutions. It was demonstrated that the presence of FA/THF in water solutions not only affected the dimensions and morphology of the precipitates but also determined the CaCO₃ polymorphism. The proportion of THF in the solvent affects the polymorphism distribution of CaCO₃. The presence of THF led to the formation of rod-like CaCO₃, and the higher the proportion of THF in the solvent, the smaller the size of CaCO₃ particles found. This was a common feature of ether solvents, and identical results could be obtained with 1,4-dioxane under the same experimental conditions. FA was the driving force for the formation of calcite, which could stack CaCO₃ layers on the surface of CaCO₃ particles induced by THF. The product exhibited a multi-level structure. The results shed light on the mechanism of FA and ether solutions during precipitation of CaCO₃ and opened a novel synthetic avenue of regulating CaCO₃ precipitation with a multi-level structure.