Reductive coordination replication of V2O5 sacrificial macrostructures into vanadium-based porous coordination polymers

Abstract

Vanadium-based porous coordination polymers (or metal–organic frameworks) possess both porous and electronic properties, which make these new materials appealing for applications in molecular separation, sensing and heterogeneous catalysis. Their integration into systems that fully exploit their intrinsic properties requires versatile methods allowing assembly of the PCP crystals into well-defined films, patterns, fibers or the formation of heterostructures. In this contribution, polycrystalline macrostructures and heterostructures made of [V(OH)ndc]_n (ndc = 1,4-naphthalenedicarboxylate) PCP crystals were synthesized through a dissolution–recrystallization process, so-called coordination replication, where a pre-shaped V₂O₅ sacrificial phase was replaced by well-intergrown PCP crystals in the presence of H₂ndc as an organic linker and under a reductive environment. In this process, V₂O₅ acts both as the metal source and as the template that provides the shape to the resulting mesoscopic polycrystalline architecture. Ascorbic acid, acting as the reducing agent, both promotes the dissolution of the sacrificial V₂O₅ phase and provides the V^III species required for the construction of the [V(OH)ndc]_n framework. Two-dimensional patterns were successfully synthesized by applying this procedure.