A Novel Expansion Mode of Polyoxovanadate Clusters: Synthesis, Crystal Structure and Properties of {[Cu(H2O)(C5H14N2)(2)](2)[V16O38(Cl)]}center dot 4(C5H16N2)

作者：Wutkowski Adam; Naether Christian; Speldrich Manfred; Koegerler Paul; Bensch Wolfgang^*

来源：Zeitschrift fur Anorganische und Allgemeine Chemie, 2009, 635(8): 1094-1099.

DOI：10.1002/zaac.200900083

• Solvothermal synthesis
• Polyoxovanadates
• Inorganic-organic hybrid material
• Magnetic properties
• IR spectroscopy

The new polyoxovanadate (POV) compound {[Cu(H2O)(C5H14N2)(2)](2)[V16O38(Cl)]}center dot 4(C5H16N2) was synthesized under solvothermal conditions and crystallizes in the tetragonal space group I4(1)/amd with a = 13.8679(6), c = 45.558(2) angstrom, V = 8761.7(7) angstrom(3). The central structural motif is a {V16O38(Cl)} cluster constructed by condensation of 16 square-pyramidal VO5 polyhedra. The cluster hosts a central Cl- anion. According to valence bond sum calculations, chemical analysis and magnetic properties the cluster anion may be formulated as [(V15VO38)-V-IV-O-V(Cl)](12-), i.e., only one vanadium atom is not reduced. To the best of our knowledge this is the first reported {V16O38(X)} cluster in this V-IV:V-V ratio. The presence of the two different vanadium oxidation states is clearly seen in the IR spectrum. An unusual and hitherto never observed structural feature is the binding mode between the [Cu(H2O)(C5H14N2)(2)](2+) complexes and the [(V15VO38)-V-IV-O-V(Cl)](12-) anion. The Cu2+ ion binds to a mu(2)-O atom of the cluster anion whereas in all other transition metal complex-augmented POVs bonding between the transition metal cation and the anion occurs through terminal oxygen atoms of the POV. The magnetic properties are dominated by strong anti ferromagnetic exchange interactions between the V4+ d(1) centers, whereas the Cu2+ d(9) cations are magnetically decoupled from the cluster anion. Upon heating, the title compound decomposes in a complex fashion.

• 出版日期2009