title: Generation of powerful tungsten reductants by visible light excitation.
abstract: 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(n)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(n)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.
authors.affiliation: Beckman Institute, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Wesley
authors.initials: W
authors.lastname: Sattler
authors.forename: Maraia E
authors.initials: ME
authors.lastname: Ener
authors.forename: James D
authors.initials: JD
authors.lastname: Blakemore
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Rachford
authors.forename: Paul J
authors.initials: PJ
authors.lastname: LaBeaume
authors.forename: James W
authors.initials: JW
authors.lastname: Thackeray
authors.forename: James F
authors.initials: JF
authors.lastname: Cameron
authors.forename: Jay R
authors.initials: JR
authors.lastname: Winkler
authors.forename: Harry B
authors.initials: HB
authors.lastname: Gray