Vanadium Polyoxoanions within Coordination Polymers Based on a Macrocyclic Nickel Complex: Structural Diversities and Single‐Crystal to Single‐Crystal Transformation

Abstract

Five three‐dimensional (3D) coordination polymers, {(NiL)[(NiL)(V16O42)]}n·2nH2O (1), [(NiL)3(VO3)6]n·5nH2O (2), [(NiL)3(V6O18)]n·7nH2O (3), [(NiL)3(V8O23)]n (4), and [(NiL)4(V10O29)]n (5), have been obtained by the reaction of the macrocyclic nickel complex [NiL](ClO4)2 (L = 1,4,8,11‐tetraazacyclotetradecane) with NH4VO3 under different conditions. Single‐crystal X‐ray diffraction analyses revealed that the [VO3]– anion assumes diverse species and structures in these five coordination polymers, including the [V16O42]n4n– sheet, [V6O18]6– ring, [VO3]nn– chain, [VO3]nn– sheet, and [V10O29]n8n– chain. The [V16O42]n4n– sheets, [V6O18]6– rings, [VO3]nn– chains, [VO3]nn– sheets, and [V10O29]n8n– chains are linked together through [NiL]2+ bridges to form the 3D frameworks of 1–5. The single‐crystal to single‐crystal transformation between 2 and desolvated 2 was successfully realized. Electrochemical measurements indicate that 2 and 4 are potential catalysts for water splitting.