We describe a complete system for optical pH manipulation and imaging. The system consists of a photoactive Ruthenium complex capable of inducing a change of more than 5 pH units at the nanosecond time scale. A compatible imaging system acquires microscopic pH images at 1200 fps using a nonexpensive commercial digital camera and an LED illumination system. We use the system as a superb tool to investigate flow in Flow Injection Analysis (FIA) models.

We present a new method for controlled generation of HNO, based on the combination of a pH photoactuator induced by visible light with an HNO donor activated by pH increase. This method avoids the use of UV light, and in the future could be extended by using an IR photoactuator.

Ruthenium bis(bipyridine) complexes have proved to be useful as phototriggers for visible and IR-light photodelivery of molecules. They usually expel one ligand heterolytically upon absorption of blue or green light. However, their absorption capabilities at wavelengths longer than 500 nm are poor. Through coordination of fluorescent ligands to the Ru center, it is possible to establish an energy transfer pathway that allows these kinds of complexes to extend the range of photoactivation up to yellow wavelengths. We introduce a study of this effect in several complexes of the family using a modified Rhodamine as fluorescent ligand with different coordinated linkers. The observed trends show that a rational design of fluorophore-enhanced Ru-bpy phototriggers is possible and that photolysis efficiency can be increased by choosing the right combination of ligands.