Two Series of Cu-II-Substituted Sandwich-Type Polyoxotungstates Constructed from Trivacant Germanotungstate Fragments

摘要

abstract_textpUnder hydrothermal conditions, two families of new Cu-II-substituted sandwich-type germanotungstates (GTs): Cu-6-GTs (enH(2))(2)Cu(en)(2)(2)Cu-6(en)(2)(H2O)(2)(B-alpha-GeW9O34)(2) 4H(2)O (1), H-4Cu(deta)(H2O)(2)Cu-6(en)(2)(H2O)(2)(B-GeW9O34)(2)8H(2)O (2), Cu(en)(H2O)(2)(2)Cu(en)(2)(2)Cu-6(en)(2)(H2O)(2)(B-alpha-GeW9O34)(2) 8H(2)O (3) (en=ethylenediamine, deta=diethylenetriamine) and Cu-4-GTs H-4Cu(H2O)(4)(2)Cu(H2O)(5)(2)Cu-4(H2O)(2)(B-alpha-GeW9O34)(2)8H(2)O (4), H-10Cu(H2O)(3)(Cl)(2)Cu-4(B-alpha-GeW9O34)(2)8H(2)O (5), H-8Na(H2O)(4)(2)Cu(H2O)(3)(Cl)(2)Cu-4(B-alpha-GeW9O34)(2)8H(2)O (6) have been made and characterized. Single-crystal structural analyses indicate that 1-3 contain a belt-like hexa-Cu-II substituted sandwich-type Cu-6(en)(2)(H2O)(2)(B-alpha-GeW9O34)(2)(8+) unit. Notably, 1-3 are rare organic-inorganic hybrid polyoxometalates with Cu-6(en)(2)(H2O)(2)(B-alpha-GeW9O34)(2)(8-) subunits, displaying the assembly from 1-D chain to 3-D framework by the Cu(en)(2)(2+) or Cu(deta)(2)(H2O)(2+) linkers. 4-6 contain rhomb-like tetra-Cu-II substituted sandwich-type Cu-4(H2O)(n)(B-alpha-GeW9O34)(2)(12-) (n=2, 0) units linked by Cu(H2O)(4)(2+) or Cu-2(H2O)(6)Cl-2 (+) clusters to from 1-D chain. Magnetic measurements performed on 3 indicate the occurrence of ferromagnetic interactions within the copper ions. Furthermore, the electrochemical and electro-catalysis properties of 3 have been studied in 0.02 M H2SO4 + 0.5 M Na2SO4 solution, and show good electro-catalytic activity to the reduction of nitrite./p/abstract_text