Synthesis of Bis(imidazole) Metal Complexes and Their Use in Rapid NO Detection and Quantification Devices

To explore the release of nitrogen oxide gases from reaction solutions, we developed a series of colorimetric sensors based on the cis-nitrogen-donating ligand bis­(1-methylimidazol-2-yl)­phenylmethoxymethane (BIPhMe). The complexes M­(BIPhMe)­X2, where M is Fe2+ or Co2+ and X is Cl–, Br–, or I–, were prepared and structurally and spectroscopically characterized. The reactivity of these complexes toward NO­(g) and NO2(g) in solution was explored. These complexes were then incorporated into test strips and syringes to provide devices that can qualitatively, and in the case of the syringes quantitatively, detect NO­(g) and NO2(g) in a reaction headspace without additional equipment.