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A Novel Expansion Mode of Polyoxovanadate Clusters: Synthesis, Crystal Structure and Properties of {[Cu(H 2 O)(C 5 H 14 N 2 ) 2 ] 2 [V 16 O 38 (Cl)]}·4(C 5 H 16 N 2 )
Author(s) -
Wutkowski Adam,
Näther Christian,
Speldrich Manfred,
Kögerler Paul,
Bensch Wolfgang
Publication year - 2009
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200900083
Subject(s) - crystallography , chemistry , antiferromagnetism , vanadium , tetragonal crystal system , crystal structure , valence (chemistry) , transition metal , ion , square pyramidal molecular geometry , cluster (spacecraft) , square pyramid , space group , metal , stereochemistry , x ray crystallography , inorganic chemistry , catalysis , physics , biochemistry , organic chemistry , optics , computer science , diffraction , programming language , condensed matter physics
The new polyoxovanadate (POV) compound {[Cu(H 2 O)(C 5 H 14 N 2 ) 2 ] 2 [V 16 O 38 (Cl)]} · 4(C 5 H 16 N 2 ) was synthesized under solvothermal conditions and crystallizes in the tetragonal space group I4 1 /amd with a = 13.8679(6), c = 45.558(2) Å, V = 8761.7(7) Å 3 . The central structural motif is a {V 16 O 38 (Cl)} cluster constructed by condensation of 16 square‐pyramidal VO 5 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 [V 15 IV V V O 38 (Cl)] 12– , i.e., only one vanadium atom is not reduced. To the best of our knowledge this is the first reported {V 16 O 38 (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(H 2 O)(C 5 H 14 N 2 ) 2 ] 2+ complexes and the [V 15 IV V V O 38 (Cl)] 12– anion. The Cu 2+ ion binds to a μ 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 antiferromagnetic exchange interactions between the V 4+ d 1 centers, whereas the Cu 2+ d 9 cations are magnetically decoupled from the cluster anion. Upon heating, the title compound decomposes in a complex fashion.