title: The Redox-Active Chromium Phthalocyanine System: Isolation of Five Oxidation States from Pc4-CrIto Pc2-CrIII.
abstract: The preparation and structural characterization of a series of chromium phthalocyanine complexes with multiple metal and ring oxidation states were achieved using PcCrII(1) (Pc=phthalocyanine) or PcCrII(THF)2(1⋅THF2) as starting materials. The reaction of soluble 1⋅THF2with Br2or I2gave the PcCrIIIhalide complexes PcCrX(THF) (X=I/I3, Br; 3, 4, respectively). Treatment of 1 with 0.5 equivalent of PhIO or air generated the dinuclear [PcCr(THF)]2(μ-O) (5), whereas the addition of one equivalent of AgSbF6to 1 resulted in oxidation to THF-solvated octahedral [PcCrIII(THF)2]SbF6(6). The reduction of 1 with three sequential equivalents of KEt3BH resulted in the isolation of [K(DME)4][Pc3-CrII] (7), [K(DME)4]2[Pc4-CrII] (8) and [K6(DME)4][Pc4-CrI]2(9), respectively. The reduced products are deep purple in colour, with visible absorption maxima between 500-580 nm. The ring-reduced complexes 7 and 8 are monomeric, whereas 9 is a 1D chain of dinuclear [PcCr]2units with intercalated K+cations and supported by Cr-Cr interactions of 2.988(2) Å. Addition of four equivalents of KC8resulted in the demetallated product PcK2(DME)4(10), which has a 1D chain structure. The isolation and structural characterization of new PcCr complexes spanning five oxidation states, including rare examples of crystalline reduced Pc-ring species emphasizes the broad redox activity and stability of phthalocyanine-based complexes.
authors.affiliation: Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
authors.forename: Wen
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
authors.forename: John R
authors.identifier: http://orcid.org/0000-0001-9272-3529
authors.initials: JR
authors.lastname: Thompson
authors.affiliation: Department of Chemistry, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada.
authors.forename: Clifford C
authors.initials: CC
authors.lastname: Leznoff
authors.affiliation: Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
authors.forename: Daniel B
authors.identifier: http://orcid.org/0000-0002-3426-2848
authors.initials: DB
authors.lastname: Leznoff
keywords: chromium; oxidation states; phthalocyanine; redox chemistry