Singlet oxygen is an emissive ligand

Unprecedented experimental evidence shows that gaseous singlet oxygen ( 1 O 2 ) acts as an emissive ligand following collisional photosensitization. This evidence was obtained by monitoring 1 O 2 phosphorescence intensity at 1275-1280 nm and the excited state lifetime of singlet oxygen generated by known tetraphenylporphyrin photosensitizers, while varying the atmospheric environment. Experimental evidence of the existence of a ZnTPP-O 2 complex following photosensitization at the solid-gas interface is presented, confirming prior hypotheses.