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A New Mixed‐Valent High Nuclearity Polyoxovanadate Cluster Based on the {V 18 O 42 } Archetype
Author(s) -
Wutkowski Adam,
Niefind Felix,
Näther Christian,
Bensch Wolfgang
Publication year - 2011
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.201100329
Subject(s) - orthorhombic crystal system , crystallography , protonation , chemistry , molecule , thermal decomposition , ion , amine gas treating , crystal structure , cluster (spacecraft) , stereochemistry , organic chemistry , computer science , programming language
The compound (enH 2 ) 6 [HV 16 IV V 2 V O 42 (Cl)] · Cl 2 · 2H 2 O (en = 1,2‐diaminoethane) ( 1 ), was synthesized under solvothermal conditions employing the amine as reducing agent. Compound 1 crystallizes in the orthorhombic space group Pbcn with a = 13.3343(7), b = 22.3697(3), c = 19.8012(11) Å, V = 5906.4(5) Å 3 , Z = 4. The central structural motif is a polyoxovanadate anion [HV 18 O 42 (Cl)] 10– being composed of 18 VO 5 square pyramids. The cluster shell contains a (VO 5 ) 8 ring in the vertical plane and two (VO 5 ) 5 pentagons above and below the ring which are twisted by 45° against each other.Bond valence sum analysis indicates a mixture of V IV /V V atoms with a ratio of 16:2, which is further supported by redox titration. An arrangement of these clusters within the (001) plane leads to the formation of channels hosting the protonated amine molecules, the Cl – anions and water molecules which are joined by an extended hydrogen bonding network. TG‐MS investigation shows a thermal decomposition reaction in at least three steps. The optical band gap was determined as 2.5 eV.