Tungsten photosensitizers

The development of photosensitizers is of great interest due to their ability to carry out difficult inorg. and org. reactions in their excited states. We have developed a new class of homoleptic arylisocyanide tungsten photosensitizers, W(CNAr)_6, and studied their photoelectrochem. properties. A modular synthesis allows for the prodn. of a variety of oligoaryl isocyanide complexes of tungsten, all of which display intense metal-to-ligand charge transfer (MLCT) absorptions in the visible region. Their excited states, *W(CNAr)_6, are highly emissive with lifetimes ranging from 17 ns to 3.0 μs depending on the arylisocyanide ligand. *W(CNAr)_6, are extremely powerful reductants: [W(CNAr)_6]^+/*W(CNAr)_6 redn. potentials are more neg. than -2.6 V vs. Cp2Fe^+/Cp2Fe.