Interaction of thin films of hydroxo-oxobis(8-quinolyloxo) vanadium (V) with ammonia vapour

Hydroxo-oxobis(8-quinolyloxo) vanadium (V) organometallic complex has been prepared as thin films from dichloromethane solution by spin coating and the kinetics of its interaction with ammonia vapour is investigated using Surface plasmon resonance (SPR) technique. Thin film parameters are deduced from SPR measurements as well as spectroscopic ellipsometry and UV-vis spectral absorption measurements. Initial exposure to ammonia vapour has resulted in a permanent change to the baseline of the measured kinetic response, which is explained by the formation of the ammonium salt of the complex. Further exposures to ammonia vapour after 24 h and beyond, are shown to be highly reversible, which can be ascribed to formation of hydrogen bonding of second ammonia molecule with the highly negatively charged ammonium salt of the vanadium complex. Exposures to other organic vapours such as ethanol, chloroform and benzene are also studied in order to examine the selectivity of this material to ammonia vapour. (C) 2008 Elsevier B.V. All rights reserved.