Three hybrid networks based on octamolybdate: Ionothermal synthesis, structure and photocatalytic properties

Abstract

Three hybrid networks based on octamolybdate building units, Cu^I₈BBTZ₆[(α-Mo₈O₂₆)(β-Mo₈O₂₆)] (1), (Cu^IBBTZ)₄[Mo₇Cu^IIO₂₄(H₂O)₂]·6H₂O (2), and Cu^IICu^I₂BBTZ₅[β-Mo₈O₂₆] (3) (BBTZ = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene), have been synthesized under ionothermal conditions and structurally characterized by single-crystal X-ray diffraction. 1 exhibits a rare 3D three-fold self-penetration network (SPN) structure, in which the interpenetrating polymer networks (IPN) formed by α-Mo₈O₂₆ units, Cu^I ions and BBTZ ligands are united by β-Mo₈O₂₆ units. 2 shows a classic 10³-utp net built by transition-metal monosubstitution octamolybdate β-Mo₇CuO₂₆, Cu^I and BBTZ ligands. 3 displays an interesting interpenetrating network (IPN) structure formed by 2D poly-rings layers and 3D NaCl topology framework. IR, TG, and electrochemical studies were also conducted to further authenticate the identities of these compounds. Photocatalytic investigation indicates that compounds 1–3 are active for photocatalytic H₂ evolution under UV irradiation.