UnissResearch

Logo Universitàegli studi di Sassari
titoli, abstracts, parole chiave >>>
Oxovanadium(IV) complexes with pyrazinecarboxylic acids: the coordinating properties of ligands with the (Naromatic, COO-) donor set

Garribba, Eugenio and Micera, Giovanni and Lodyga-Chruscinska, Elzbieta and Sanna, Daniele (2006) Oxovanadium(IV) complexes with pyrazinecarboxylic acids: the coordinating properties of ligands with the (Naromatic, COO-) donor set. European Journal of Inorganic Chemistry, Vol. 13 , p. 2690-2700. eISSN 1099-0682. Article.

Full text not available from this repository.

DOI: 10.1002/ejic.200600230

Abstract

Complex formation between the VIVO ion and four pyrazine derivatives, 2-pyrazinecarboxylic acid (pzc), 5-methyl-2-pyrazinecarboxylic acid (5-Mepzc), 2,3-pyrazinedicarboxylic acid (3-COOHpzc) and 5-hydroxy-2-pyrazinecarboxylic acid (5-OHpzc), was studied in aqueous solution and in the solid state through the combined application of potentiometric and spectroscopic (EPR and FT-IR) techniques. The results indicate that in acidic and neutral aqueous solution all theligands form mono(chelated), bis(chelated) and dinuclear species of composition VOL, VOL2 and (VO)2L2H-2. Hexacoordinated VOL2 complexes are characterised by a cis/trans isomerism, where cis and trans are the species with a water molecule bound in the cis or trans position with respect to the V=O group. The trans arrangement is favoured over the cis arrangement. Three solid derivatives, [VO(5-Mepzc)2] (1), cis-[VO(pzc)2(H2O)] (2) and cis-[VO(3-COOHpzc)2(H2O)] (3), were isolated and characterised. Based on the experimental results and on the data in the literature, the stability of cis and trans isomers in aqueous solution and in the solid state has been discussed, showing that with ligands of comparable basicity and size of the chelate ring the hydrophilicity favours the cis species and determines the relative amount of the two isomers. The analysis of the magnetic properties of the hydroxo-bridged VIVO dimers suggests that for the (VO)2L2H-2 species the anti-coplanar arrangement is realised.

Item Type:Article
ID Code:1455
Status:Published
Refereed:Yes
Uncontrolled Keywords:Vanadium, N,O ligands, isomers, magnetic properties, EPR spectroscopy
Subjects:Area 03 - Scienze chimiche > CHIM/03 Chimica generale e inorganica
Divisions:001 Università di Sassari > 01 Dipartimenti > Chimica
002 Altri enti e centri di ricerca del Nord Sardegna > CNR-Consiglio Nazionale delle Ricerche > Istituto di chimica biomolecolare, Sassari
Publisher:Wiley
eISSN:1099-0682
Deposited On:18 Aug 2009 10:05

I documenti depositati in UnissResearch sono protetti dalle leggi che regolano il diritto d'autore

Repository Staff Only: item control page