Synthesis, X-ray Structures, and Optical and Magnetic Properties of Cu(II) Octafluoro-octakisperfluoro(isopropyl)phthalocyanine: The Effects of Electron Addition and Fluorine Accretion

[Image: see text] The stepwise reduction of copper(II) 1,4,8,11,15,18,22,25-octafluoro-2,3,9,10,16,17,23,24-octakisperfluoro(isopropyl) phthalocyanine (Cu(II)F(64)Pc) in o-dichlorobenzene (C(6)H(4)Cl(2)) by potassium graphite in the presence of cryptand(K(+)), abbreviated L(+), results in the formation of (L(+))[Cu(II)(F(64)Pc(•3–))](−)·2C(6)H(4)Cl(2) (1), (L(+))(2)[Cu(II)(F(64)Pc(4–))](2–)·C(6)H(4)Cl(2) (2), and (L(+))(2)[Cu(II)(F(64)Pc(4–))](2–) (3) complexes. Single-crystal X-ray structures revealed their composition and a monotonic increase with increased phthalocyanine (Pc) negative charges of the magnitude of alternative shortening and elongation of the prior equivalent N(meso)–C bonds. The complexes are separated by bulky i-C(3)F(7) substituents, large cryptand counterions, and solvent molecules. Weak, new bands are generated in the visible and near-infrared (NIR) domains upon reductions. The one-electron reduced complex, [Cu(II)(F(64)Pc(•3–))](−), is a diradical, exhibiting broad electron paramagnetic resonance (EPR) signals, with intermediate parameters between those typical to Cu(II) and F(64)Pc(•3–). The two-electron reduced complexes, [Cu(II)(F(64)Pc(4–))](2–), contain a diamagnetic F(64)Pc(4–) macrocycle and a single spin, S = 1/2, on Cu(II). The bulky perfluoroisopropyl groups are suppressing intermolecular π–π interactions between Pcs in the [Cu(II)(F(64)Pc(n–))]((n−2)–) (n = 3, 4) anions, 1–3, similar to the case of the nonreduced complex. However, π–π interactions between 1 and o-dichlorobenzene are observed. The d(9) and Pc electrons in 1 are antiferromagnetically coupled, J = −0.56 cm(–1), as revealed by superconducting quantum interference device (SQUID) magnetometry, but the coupling is at least 1 order of magnitude smaller compared with the coupling observed for Cu(II)(F(8)Pc(•3–)) and Cu(II)(F(16)Pc(•3–)), a testimony to the F accretion effect of rendering the Pc macrocycle progressively more electron-deficient. The data for Cu(II)(F(64)Pc) provide structural, spectroscopic, and magnetochemical insights, which establish a trend of the effects of fluorine and charge variations of fluorinated Pcs within the macrocycle series Cu(II)(F(x)Pc), x = 8, 16, 64. Diamagnetic Pcs might be useful for photodynamic therapy (PDT) and related biomedical applications, while the solvent-processable biradicalic nature of the monoanion salts may constitute the basis for designing robust, air-stable electronic, and magnetically condensed materials.