The Redox-Active Chromium Phthalocyanine System: Isolation of Five Oxidation States from Pc⁴⁻Cr^I to Pc²⁻Cr^III

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• 作者：Dr. Wen Zhou ; John R. Thompson ; Prof. Clifford C. Leznoff and Prof. Daniel B. Leznoff
• 刊名：Chemistry - A European Journal
• 出版年：2017
• 出版时间：February 16, 2017
• 年：2017
• 卷：23
• 期：10
• 页码：2323-2331
• 全文大小：3614K
• ISSN：1521-3765

文摘

The preparation and structural characterization of a series of chromium phthalocyanine complexes with multiple metal and ring oxidation states were achieved using PcCr^II (1) (Pc=phthalocyanine) or PcCr^II(THF)₂ (1⋅THF₂) as starting materials. The reaction of soluble 1⋅THF₂ with Br₂ or I₂ gave the PcCr^III halide 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 AgSbF₆ to 1 resulted in oxidation to THF-solvated octahedral [PcCr^III(THF)₂]SbF₆ (6). The reduction of 1 with three sequential equivalents of KEt₃BH resulted in the isolation of [K(DME)₄][Pc³⁻Cr^II] (7), [K(DME)₄]₂[Pc⁴⁻Cr^II] (8) and [K₆(DME)₄][Pc⁴⁻Cr^I]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]₂ units with intercalated K⁺ cations and supported by Cr−Cr interactions of 2.988(2) Å. Addition of four equivalents of KC₈ resulted 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.