Solvent effects of cobalt(II) phthalocyanine in sulfuric acid: a continuous wave and pulse EPR study

Finazzo, Cinzia; Doorslaer, Sabine Van; Schweiger, Arthur

doi:10.1142/s1088424603000124

Cited by 5 publications

(3 citation statements)

References 44 publications

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“…Besides 19 F NMR, X-ray diffraction, and magnetic measurements, we use a combination of continuous-wave electron paramagnetic resonance (CW EPR), electron spin echo envelope (ESEEM), and pulsed electron nuclear double resonance (ENDOR) techniques to characterize F 64 PcCu in the solid phase and in an ethanol solution. Although X-band (9.5 GHz) CW EPR methods have been used extensively to investigate metal phthalocyanines, − the application of high-field EPR , or ESEEM and ENDOR techniques − to these systems is still quite limited. Some of us showed in earlier work the strength of the latter EPR methods to detect the subtle effects of the matrix and peripheral substituents on the electronic structure of PcM's (M = Cu, Co) .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, X-ray Structure, Magnetic Resonance, and DFT Analysis of a Soluble Copper(II) Phthalocyanine Lacking C−H Bonds

et al. 2010

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The synthesis, crystal structure, and electronic properties of perfluoro-isopropyl-substituted perfluorophthalocyanine bearing a copper atom in the central cavity (F(64)PcCu) are reported. While most halogenated phthalocyanines do not exhibit long-term order sufficient to form large single crystals, this is not the case for F(64)PcCu. Its crystal structure was determined by X-ray analysis and linked to the electronic properties determined by electron paramagnetic resonance (EPR). The findings are corroborated by density functional theory (DFT) computations, which agree well with the experiment. X-band continuous-wave EPR spectra of undiluted F(64)PcCu powder, indicate the existence of isolated metal centers. The electron-withdrawing effect of the perfluoroalkyl (R(f)) groups significantly enhances the complexes solubility in organic solvents like alcohols, including via their axial coordination. This coordination is confirmed by X-band (1)H HYSCORE experiments and is also seen in the solid state via the X-ray structure. Detailed X-band CW-EPR, X-band Davies and Mims ENDOR, and W-band electron spin-echo-detected EPR studies of F(64)PcCu in ethanol allow the determination of the principal g values and the hyperfine couplings of the metal, nitrogen, and fluorine nuclei. Comparison of the g and metal hyperfine values of F(64)PcCu and other PcCu complexes in different matrices reveals a dominant effect of the matrix on these EPR parameters, while variations in the ring substituents have only a secondary effect. The relatively strong axial coordination occurs despite the diminished covalency of the C-N bonds and potentially weakening Jahn-Teller effects. Surprisingly, natural abundance (13)C HYSCORE signals could be observed for a frozen ethanol solution of F(64)PcCu. The (13)C nuclei contributing to the HYSCORE spectra could be identified as the pyrrole carbons by means of DFT. Finally, (19)F ENDOR and easily observable paramagnetic NMR were found to relate well to the DFT computations, revealing negligible isotropic hyperfine (Fermi contact) contributions. The single-site isolation in solution and solid state and the relatively strong coordination of axial ligands, both attributed to the introduction of R(f) groups, are features important for materials and catalyst design.

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Section: Introductionmentioning

confidence: 99%

Synthesis, X-ray Structure, Magnetic Resonance, and DFT Analysis of a Soluble Copper(II) Phthalocyanine Lacking C−H Bonds

et al. 2010

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“…20,22 It has been reported that the utilized solvent influences the electronic properties of the central ion for phthalocyanines, such as energies and compositions of the molecular orbitals as well as g-and A-tensors. 23,24 In these extended studies, no coherence times were published.…”

mentioning

confidence: 99%

Tuning of molecular qubits: very long coherence and spin–lattice relaxation times

2016

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“…Metallophthalocyanines (PcM) are a class of tetradentate macrocyclic ligands with extremely strong absorptions in the UV‐vis regions, high thermal and chemical stability, as well as a resistance to UV‐degradation [1–6] . This has driven their primary industrial use as pigments and dyes, commonly blue or green in colour [7,8] .…”

Section: Introductionmentioning

confidence: 99%

Preferential Formation of Side‐Pocket‐Substituted Zinc Phthalocyanines Emitting Beyond 800 nm

et al. 2021

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A series of zinc (1,4,8,11,15,18,22,25‐octabutoxy)phthalocyanine (2) complexes that spontaneously form 5‐coordinate complexes with anionic axial ligands neutralized with side‐pocket cations, of the form Cation‐PcZnX (X=Cl, OAc; Cation=H+ or Li+), was synthesized and structurally characterized. The side‐pocket protonation of the axial‐chloride species pushed the emission maximum from 760 nm (for axial ligand‐free 2) to 826 nm, well into the NIR region. A 1D‐coordinated chain bridged by lithium and chloride atoms was isolated and structurally characterized, representing the first side‐pocket metalated PcM species. This preferential formation of axially substituted [PcZnX]− “ate” complexes and their sequestration of both protons and lithium cations, opens a new series of materials with unique structural and electronic properties. Furthermore, their ability to both absorb and emit in the NIR region makes them desirable for numerous applications.

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Solvent effects of cobalt(II) phthalocyanine in sulfuric acid: a continuous wave and pulse EPR study

Cited by 5 publications

References 44 publications

Synthesis, X-ray Structure, Magnetic Resonance, and DFT Analysis of a Soluble Copper(II) Phthalocyanine Lacking C−H Bonds

Synthesis, X-ray Structure, Magnetic Resonance, and DFT Analysis of a Soluble Copper(II) Phthalocyanine Lacking C−H Bonds

Tuning of molecular qubits: very long coherence and spin–lattice relaxation times

Preferential Formation of Side‐Pocket‐Substituted Zinc Phthalocyanines Emitting Beyond 800 nm

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