Crystal fields of porphyrins and phthalocyanines from polarization-dependent 2p-to-3d multiplets

Johnson, Phillip S.; Garcı́a-Lastra, J. M.; Kennedy, Colton K.; Jersett, N.; Boukahil, Idris; Himpsel, F. J.; Cook, Peter L.

doi:10.1063/1.4868552

Cited by 17 publications

(23 citation statements)

References 54 publications

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“…This effect has a major influence on the multiplet structure, and also on the 3d level realignment. Ligand and crystal field theory are used to describe the magnetic and spectroscopic properties of transition metal complexes as shown by the many studies dedicated to L

_{2, 3}

edge X‐ray absorption spectroscopy (XAS) and X‐ray magnetic circular dichroism (XMCD) results of different transition metal Pcs . The interpretation of the experimental metal 2p XP spectra of transition metals, therefore, clearly requires complex theoretical considerations including atomic multiplets, ligand fields as well as charge transfer ().…”

Section: Resultsmentioning

confidence: 99%

Characterization of gas phase iron phthalocyanine with X‐ray photoelectron and absorption spectroscopies

Bidermane

Lüder

Totani

et al. 2015

Physica Status Solidi (b)

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Despite the numerous studies dedicated to phthalocyanine molecules adsorbed on surfaces, in monolayer or thin film, very few works have been focused on the characterization of vapors of these molecules. In this article we present the C 1s, N 1s and Fe 2p photoemission results as well as N K-edge X-ray absorption data of iron phthalocyanine (FePc) in gas phase. Presented comparison of X-ray photoelectron spectroscopy and X-ray absorption spectroscopy spectra of FePc films show a great similarity with the gas phase results, con- firming the molecular character of thick films. The Fe 2p photoemission spectrum of the gas phase FePc, shown for the first time, can be considered as a fingerprint of the Fe(II) ionic state of the central metal of the iron phthalocyanine. The performed multiplet calculations for describing the Fe 2p XP spectrum indicate 3 Eg (a1g 2 eg 3 b2g 1 ) state as the most probable ground state for thick film of iron phthalocyanine

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_{2, 3}

Section: Resultsmentioning

confidence: 99%

Characterization of gas phase iron phthalocyanine with X‐ray photoelectron and absorption spectroscopies

Bidermane

Lüder

Totani

et al. 2015

Physica Status Solidi (b)

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“…Evidence for the ground electronic state of MnPc has previously been gleaned by interpreting spectroscopic data using ligand field theory and/or group theory. A wide range of experiments [11,12,37,38,9,39,30,40,41,42] have been carried out using different sample preparations (argon matrix, [42] thin film, [41,40,38,37,12] crystalline [39,43]) and/or spectroscopies (optical absorption, [42,40,41] magnetic circular dichroism, [42,39] photoelectron emission, [12,37,38,41] electron energy loss [40,38]), leading to conflicting assignments for the ground state of MnPc.…”

Section: Ground State Assignments 341 Mnpcmentioning

confidence: 99%

“…[8] Over the past 5-10 years, transition-metal phthalocyanines have become the focus of intense and resurgent interest, due to their potential applications in molecular electronics; as key components of light-emitting diodes and organic photovoltaic materials. Despite this, fundamental questions remain about the electronic structure of transition-metal phthalocyanines, with conflicting evidence in the literature supporting different assignments for excited states beyond the first [9,10], and even disagreement on the nature of the manganese [11,12,13] and iron [14,15,16,11,17,18,19,20] phthalocyanine ground states.…”

Section: Introductionmentioning

confidence: 99%

CASSCF-based explicit ligand field models clarify the ground state electronic structures of transition metal phthalocyanines (MPc; M = Mn, Fe, Co, Ni, Cu, Zn)

2016

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Multireference electronic structure methods are used to assign ground state electronic configurations for a series of metallophthalocyanines. Ligand orbital occupancies remain constant across the period and are consistent with a formal 2– charge on the ligand. The d electron configurations of some metallophthalocyanines are straightforward and can be unambiguously assigned, (dxy)2(dxz,dyz)2,2( [Formula: see text])2([Formula: see text])n, with n = 2, 1, 0, respectively, for ZnPc, CuPc, and NiPc. Controversies over ground state electronic structure assignments for other metallophthalocyanines arise due to multiple complicating factors: accidental near-degeneracies, environmental effects, and different ligand field models used in interpreting experimental spectra. We demonstrate that explicit ligand field models provide more reliable and consistent interpretations of experimental data than implicit, parameterized alternatives. On this basis, we assign gas-phase electronic ground states for MnPc, (dxy)2(dxz,dyz)1,1([Formula: see text])1 and CoPc, (dxy)2(dxz,dyz)2,2([Formula: see text])1, and show that the ground state of FePc cannot be resolved to a single state, with two near-degenerate states that are likely spin-orbit coupled: (dxy)2(dxz,dyz)1,1( [Formula: see text])2 and (dxy)2(dxz,dyz)2,1([Formula: see text])1. Remaining differences between computational predictions and experimental observations are small and may be ascribed primarily to environmental effects but are also partly due to incomplete modelling of electron correlation.

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“…The soft X-ray absorption spectroscopy (XAS) at Co L 2,3 -edge is a powerful technique for determining the Co ions ground state and the first excited state, thus was usually employed in previous studies. [18][19][20][21] Numerous investigations have been performed, but controversial conclusions were deduced due to the different simulation parameters used. The atomic multiplet of a 3d 7 21 It is well known that the orbital hybridization can significantly affect the ground state.…”

Section: Introductionmentioning

confidence: 99%

The significant role of covalency in determining the ground state of cobalt phthalocyanines molecule

Zhou

Zhang

et al. 2016

AIP Advances

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To shed some light on the metal 3d ground state configuration of cobalt phthalocyanines system, so far in debate, we present an investigation by X-ray absorption spectroscopy (XAS) at Co L2,3 edge and theoretical calculation. The density functional theory calculations reveal highly anisotropic covalent bond between central cobalt ion and nitrogen ligands, with the dominant σ donor accompanied by weak π-back acceptor interaction. Our combined experimental and theoretical study on the Co-L2,3 XAS spectra demonstrate a robust ground state of 2A1g symmetry that is built from 73% 3d7 character and 27% 3d8L¯ (L¯ denotes a ligand hole) components, as the first excited-state with 2Eg symmetry lies about 158 meV higher in energy. The effect of anisotropic and isotropic covalency on the ground state was also calculated and the results indicate that the ground state with 2A1g symmetry is robust in a large range of anisotropic covalent strength while a transition of ground state from 2A1g to 2Eg configuration when isotropic covalent strength increases to a certain extent. Here, we address a significant anisotropic covalent effect of short Co(II)-N bond on the ground state and suggest that it should be taken into account in determining the ground state of analogous cobalt complexes.

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Crystal fields of porphyrins and phthalocyanines from polarization-dependent 2p-to-3d multiplets

Cited by 17 publications

References 54 publications

Characterization of gas phase iron phthalocyanine with X‐ray photoelectron and absorption spectroscopies

Characterization of gas phase iron phthalocyanine with X‐ray photoelectron and absorption spectroscopies

CASSCF-based explicit ligand field models clarify the ground state electronic structures of transition metal phthalocyanines (MPc; M = Mn, Fe, Co, Ni, Cu, Zn)

The significant role of covalency in determining the ground state of cobalt phthalocyanines molecule

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