Oxygen Sensors Based on Luminescence Quenching of Metal Complexes:  Osmium Complexes Suitable for Laser Diode Excitation

Oxygen quenching of a series of Os(II) complexes with α-diimine ligands has been studied in a predominantly poly(dimethylsiloxane) (PDMS) polymer and in Gp-163 (an acrylate modified PDMS). Unlike previous Ru(II) complexes used as oxygen sensors, the Os complexes can be excited by readily available, high-intensity, low-cost, red diode lasers at 635, 650, and 670 nm. Variations in the polymer properties have been made in order to delineate the structural features important for satisfactory use of supports for oxygen sensors. A key factor is matching the hydrophobicity of the sensor and support for optimal compatibility and minimizing the size of low oxygen diffusion domains.