Generation of Powerful Tungsten Reductants by Visible Light Excitation

The homoleptic arylisocyanide tungsten complexes, W(CNXy)_6 and W(CNIph)_6 (Xy = 2,6-dimethylphenyl, Iph = 2,6-diisopropylphenyl), display intense metal to ligand charge transfer (MLCT) absorptions in the visible region (400–550 nm). MLCT emission (λ_max ≈ 580 nm) in tetrahydrofuran (THF) solution at rt is observed for W(CNXy)6 and W(CNIph)_6 with lifetimes of 17 and 73 ns, respectively. Diffusion-controlled energy transfer from electronically excited W(CNIph)_6 (*W) to the lowest energy triplet excited state of anthracene (anth) is the dominant quenching pathway in THF solution. Introduction of tetrabutylammonium hexafluorophosphate, [Bun4N][PF_6], to the THF solution promotes formation of electron transfer (ET) quenching products, [W(CNIph)6]+ and [anth]^•–. ET from *W to benzophenone and cobalticenium also is observed in [Bun4N][PF6]/THF solutions. The estimated reduction potential for the [W(CNIph)6]^(+)/*W couple is −2.8 V vs Cp_(2)Fe^(+/0), establishing W(CNIph)_6 as one of the most powerful photoreductants that has been generated with visible light

Driving Force Dependence of Electron Transfer from Electronically Excited [Ir(COD)(μ-Me_2pz)]_2 to Photo-Acid Generators

We report the rates of electron transfer (ET) reactions of electronically excited [Ir(COD)(μ-Me_2pz)]_2 with onium salt photoacid generators (PAGs). The reduction potentials of the PAGs span a large electrochemical window that allows determination of the driving force dependence of the ET reactions. Rate constants of ET from electronically excited [Ir(COD)(μ-Me_2pz)]_2 to onium PAGs are determined by the reaction driving force until the diffusion limit in acetonitrile is reached

Generation of Powerful Tungsten Reductants by Visible Light Excitation

The homoleptic arylisocyanide tungsten complexes, W­(CNXy)₆ and W­(CNIph)₆ (Xy = 2,6-dimethylphenyl, Iph = 2,6-diisopropylphenyl), display intense metal to ligand charge transfer (MLCT) absorptions in the visible region (400–550 nm). MLCT emission (λ_max ≈ 580 nm) in tetrahydrofuran (THF) solution at rt is observed for W­(CNXy)₆ and W­(CNIph)₆ with lifetimes of 17 and 73 ns, respectively. Diffusion-controlled energy transfer from electronically excited W­(CNIph)₆ (*W) to the lowest energy triplet excited state of anthracene (anth) is the dominant quenching pathway in THF solution. Introduction of tetrabutylammonium hexafluorophosphate, [Bu^<i>n</i>₄N]­[PF₆], to the THF solution promotes formation of electron transfer (ET) quenching products, [W­(CNIph)₆]⁺ and [anth]^•–. ET from *W to benzophenone and cobalticenium also is observed in [Bu^<i>n</i>₄N]­[PF₆]/THF solutions. The estimated reduction potential for the [W­(CNIph)₆]⁺/*W couple is −2.8 V vs Cp₂Fe^+/0, establishing W­(CNIph)₆ as one of the most powerful photoreductants that has been generated with visible light

Generation of Powerful Tungsten Reductants by Visible Light Excitation

The homoleptic arylisocyanide tungsten complexes, W­(CNXy)₆ and W­(CNIph)₆ (Xy = 2,6-dimethylphenyl, Iph = 2,6-diisopropylphenyl), display intense metal to ligand charge transfer (MLCT) absorptions in the visible region (400–550 nm). MLCT emission (λ_max ≈ 580 nm) in tetrahydrofuran (THF) solution at rt is observed for W­(CNXy)₆ and W­(CNIph)₆ with lifetimes of 17 and 73 ns, respectively. Diffusion-controlled energy transfer from electronically excited W­(CNIph)₆ (*W) to the lowest energy triplet excited state of anthracene (anth) is the dominant quenching pathway in THF solution. Introduction of tetrabutylammonium hexafluorophosphate, [Bu^<i>n</i>₄N]­[PF₆], to the THF solution promotes formation of electron transfer (ET) quenching products, [W­(CNIph)₆]⁺ and [anth]^•–. ET from *W to benzophenone and cobalticenium also is observed in [Bu^<i>n</i>₄N]­[PF₆]/THF solutions. The estimated reduction potential for the [W­(CNIph)₆]⁺/*W couple is −2.8 V vs Cp₂Fe^+/0, establishing W­(CNIph)₆ as one of the most powerful photoreductants that has been generated with visible light