Cyclometalation - Cyclometalation as an efficient route to tailor-made luminescent indicators for optical sensing

In analytical chemistry, luminescent sensors represent an invaluable and flexible tool to measure a variety of analytes under conditions unsuitable for other sensing schemes. Ideally, sensors can be optimized for any desired application, by proper choice of format, matrix and indicator chemistry. Indicator chemistry has yielded some exceptional dye classes with favourable photophysical properties, such as BODIPYs and porphyrins. Applications, however, often require very specific properties to achieve a satisfying performance. The toolbox of strategies to closely control these photophysical properties is yet limited so far. Cyclometalation is expected to serve as an efficient strategy to control the spectral properties, quantum yields and emissive lifetimes of luminescent indicator dyes. This enables adjustment of the properties of porphyrins and porphyrinoids to meet various requirements for development of bioanalytical labels and indicator dyes for oxygen, pH and ion sensing.