Customized vic-dioximes and their metal complexes for enhanced chemical sensing of polar organic molecules

Abstract

Vic-dioximes and their nickel and palladium complexes were customized with fluorinated substituents including moieties capable of hydrogen bonding to improve selectivity in chemical sensing of polar analytes. Many analytes of interest in applications as diverse as food stuff or air quality analysis are of polar chemical nature. Such compounds, e.g., ketones, esters or alcohols contribute to the aroma of fruits and food products, but are also in industrial use as solvents in paints or in the production of plastic products. The gas sensing properties of the new compounds are demonstrated using the quartz crystal microbalance and selected volatile organic compounds as analytes. The results illustrate that fluorinated alkylamino and arylamino substituents efficiently enhance and direct the sorption preferences of vic-dioxime metal complexes toward polar analytes. High sensor responses to polar analytes including high vapor pressure analytes like acetone and methanol were observed, whereas the responses to aromatic hydrocarbons are low. Besides, the individual sensor responses were only little affected by water vapor. H bonding activities of the NH group are identified as the source for the observed selectivity patterns. The vic-dioximes are considered excellent sensing materials for practical use in chemical gas sensor arrays for sensing of polar compounds. (C) 2013 Elsevier B.V. All rights reserved.