Structural diversity in hybrid vanadium(iv) oxyfluorides based on a common building block

Abstract

There are only limited reports on vanadium(IV) oxyfluorides (VOFs) with extended crystal structures. Here we expand and enrich the list of existing VOFs with a series of 14 new materials “VOF-n (n = 1–14)” prepared using ionothermal and solvothermal synthesis methods. All of these materials arise from the condensation of a dimeric structural motif. These VOFs can be classified into three groups depending on their key structural features; layer structures: VOF-1 “[HN₂C₇H₆][V₂O₂F₅]”, VOF-2 “[HN₂C₄H₄][V₂O₂F₅]”, VOF-3 “[HN₂C₃H₄][V₂O₂F₅]” and VOF-4 “V₂(N₂C₄H₄)O₂F₄”, ladder like structures: VOF-5 “[NH₄(HN₂C₃H₄)][V₂O₂F₆]”, VOF-6 “[K(HN₂C₃H₄)][V₂O₂F₆]”, VOF-7 “[HNH₂CH₂CH₃][VOF₃]”, VOF-8 “[HN₂C₇H₆][VOF₃]”, VOF-9 “[H₂N₂C₄H₆][V₂O₂F₆]”, VOF-10 “β-RbVOF₃”, VOF-11“α-KVOF₃”, VOF-12 “β-KVOF₃”, VOF-13 “[H₂(NH₂)₂(CH₂)₂][V₂O₂F₆]”, and a chain structure: VOF-14 “[H₂N₂C₆H₁₂][V₂O₂F₇]”. The crystal structures of VOF-n are presented, and their synthetic and structural relationships are discussed.