Bespoke Photoreductants: Tungsten Arylisocyanides

Modular syntheses of oligoarylisocyanide ligands that are derivatives of 2,6-diisopropylphenyl isocyanide (CNdipp) have been developed; tungsten complexes incorporating these oligoarylisocyanide ligands exhibit intense metal-to-ligand charge-transfer visible absorptions that are red-shifted and more intense than those of the parent W(CNdipp)(6) complex. Additionally, these W(CNAr)(6) complexes have enhanced excited-state properties, including longer lifetimes and very high quantum yields. The decay kinetics of electronically excited W(CNAr)(6) complexes (*W(CNAr)(6)) show solvent dependences; faster decay is observed in higher dielectric solvents. *W(CNAr)(6) lifetimes are temperature dependent, suggestive of a strong coupling nonradiative decay mechanism that promotes repopulation of the ground state. Notably, *W(CNAr)(6) complexes are exceptionally strong reductants: [W(CNAr)6](+)/*W(CNAr)(6) potentials are more negative than -2.7 V vs [Cp2Fe](+)/Cp2Fe.