A New Trinuclear Oxovanadium(V) Complex with DMPP Ligands − Synthesis and Structural Characterization in the Solid State and in Aqueous Solution

✍ Scribed by Fernando Avecilla; Carlos F. G. C. Geraldes; M. Margarida C. A. Castro

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 416 KB
• Volume: 2001
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/1099-0682(200112)2001:12<3135::aid-ejic3135>3.0.co;2-k

✦ Synopsis

A new trinuclear oxovanadium(V) complex with the anionic dmpp ligand (Hdmpp = 3-hydroxy-1,2-dimethyl-4-pyridinone), [V 3 O 6 (dmpp) 3 (H 2 O)](H 2 O) 2 , was isolated from the reaction of Hdmpp, KOH and sodium metavanadate at pH 4.5. The solid state structure of the [V 3 O 6 (H 2 O)(dmpp) 3 ](H 2 O) 2 complex, investigated by X-ray diffraction methods, was found to contain a cyclic trinuclear metal cluster. This complex crystallises in the monoclinic system: P2 1 /n, a = 9.5324( 7) A ˚, b = 16.4107(11) A ˚and c = 18.0638(12) A ˚, β = 91.1010(10)°, V = 2825.3(3) A ˚3, Z = 4 and R 1 (wR 2 ) = 0.0704 (0.2025). Two of the vanadium atoms (V1 and V3) are sixcoordinated, with distorted octahedral geometries, and the other one (V2) is five-coordinated with a distorted square pyramidal geometry. The cyclic V 3 O 4 framework has one oxygen atom bridging two vanadium atoms in two V-O-V groups, V1-O4-V2 and V2-O5-V3, and two oxygens bridging the V1-V3 atoms, V1-O6-V3 and V1-O12-V3. IR data confirm the crystallographic results, showing the characteristic V=O band in the 973-935 cm -1 frequency range. This compound has three bands corresponding to V=O stretching, indicative of different chemical environments around the vanadium atoms in the solid state. The ES mass spectrum in aqueous solution displays an intense peak cor-

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