Vanadium Part I. Quinaldinic Acid Complexes

Quinaldinic acid (QH) produces with vanadyl salt (1) a cream-coloured compound, characterised as [VOQ₂]H₂O and (2) an olive-green complex [VO(H₂0)Q₂]. Both change on heating to cream-coloured [VOQ₂] and finally decompose to V₂O₅. A whole series of bluish green complexes of the type [VO (X)Q₂)] (where X = pyridine, aniline, etc.) has been prepared by the action of aromatic amine or heterocyclic base on either [VOQ₂] H₂O or on [VO(H₂0)Q₂] These, too, change on heating to [VOQ₂]. All these product are paramagnetic ( \(\mu=\)1.6 to 1.9 B.M.) and are extremely stable towards air.

Quinquevalent vanadium reacts with this ligand to give pale cream-coloured, diamagnetic [VO(OH)Q₂]- 2H₂O. Compounds of the type [VO₂Q (X)] (where X= pyridine or \(\propto\) -picoline) have been prepared by the action of heterocyclic bases on [V0(OH)Q₂)2H₂O