Electronic structure of Ni(II) porphyrins and phthalocyanine studied by soft X-ray absorption spectroscopy
(2007) In Chemical Physics 332(2-3). p.318-324- Abstract
- Investigations of chemical bonding and electronic structure features for polycrystalline Ni(II) phthalocyanine (NiPc), Ni(II) tetrabenzoporphyrin (NiTBP), Ni(II) 2,3,7,8,12,13,17,18-octaethylporphyrin (NiOEP), Ni(II) 5,10,15,20-tetraisobutylporphyrin (NiTiBuP), Ni(II) 5,15-diphenylporphyrin (NidPP) and Ni(II) 5,15-diisobutylporphyrin (NidiBuP) have been performed by means of high-resolution soft X-ray absorption spectroscopy. It has been found that the low-lying unoccupied electron states in nickel porphyrins are mainly generated by the NiN4 quasi-molecule: the lowest empty state is the weakly antibonding molecular orbital (MO) of sigma b(1g), symmetry with nearly pure Ni 3d(x2-y2) character, while the next empty state is the e(g) MO,... (More)
- Investigations of chemical bonding and electronic structure features for polycrystalline Ni(II) phthalocyanine (NiPc), Ni(II) tetrabenzoporphyrin (NiTBP), Ni(II) 2,3,7,8,12,13,17,18-octaethylporphyrin (NiOEP), Ni(II) 5,10,15,20-tetraisobutylporphyrin (NiTiBuP), Ni(II) 5,15-diphenylporphyrin (NidPP) and Ni(II) 5,15-diisobutylporphyrin (NidiBuP) have been performed by means of high-resolution soft X-ray absorption spectroscopy. It has been found that the low-lying unoccupied electron states in nickel porphyrins are mainly generated by the NiN4 quasi-molecule: the lowest empty state is the weakly antibonding molecular orbital (MO) of sigma b(1g), symmetry with nearly pure Ni 3d(x2-y2) character, while the next empty state is the e(g) MO, which has a hybridized Ni 3d pi-N 2p pi character and reflects pi chemical bonding (pi-back-donation) between nickel and neighbouring nitrogen atoms of the pyrrole rings. The differences observed in the Ni 2p spectra of nickel porphyrins and phthalocyanines indicate a limited usefulness of the NiN4 quasi-molecule and a need for its extension to the whole porphyrin (phthalocyanine) macrocycle. As a result, the differences in the Ni 2p spectra of the complexes and in their electronic structure are associated with a torsion of the opposite pyrrole ring planes (NiOEP, NiTiBuP) and the presence of N atoms in meso positions (NiPc). These conclusions are further confirmed by a comparative analysis of the Ni 2p and N Is absorption spectra for NiPc and NiOEP. (c) 2007 Elsevier B.V. All rights reserved. (Less)
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- author
- Krasnikov, S. A. ; Preobrajenski, Alexei LU ; Sergeeva, N. N. ; Brzhezinskaya, M. M. ; Nesterov, M. A. ; Cafolla, A. A. ; Senge, M. O. and Vinogradov, A. S.
- organization
- publishing date
- 2007
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- x-ray absorption, electronic structure, phthalocyanine, porphyrin, spectroscopy, NEXAFS
- in
- Chemical Physics
- volume
- 332
- issue
- 2-3
- pages
- 318 - 324
- publisher
- Elsevier
- external identifiers
-
- wos:000244549500021
- scopus:33846839181
- ISSN
- 0301-0104
- DOI
- 10.1016/j.chemphys.2006.12.015
- language
- English
- LU publication?
- yes
- id
- b96471d3-1712-41ba-8a31-690e17a4fe50 (old id 672846)
- date added to LUP
- 2016-04-01 16:18:20
- date last changed
- 2022-04-15 03:37:28
@article{b96471d3-1712-41ba-8a31-690e17a4fe50,
abstract = {{Investigations of chemical bonding and electronic structure features for polycrystalline Ni(II) phthalocyanine (NiPc), Ni(II) tetrabenzoporphyrin (NiTBP), Ni(II) 2,3,7,8,12,13,17,18-octaethylporphyrin (NiOEP), Ni(II) 5,10,15,20-tetraisobutylporphyrin (NiTiBuP), Ni(II) 5,15-diphenylporphyrin (NidPP) and Ni(II) 5,15-diisobutylporphyrin (NidiBuP) have been performed by means of high-resolution soft X-ray absorption spectroscopy. It has been found that the low-lying unoccupied electron states in nickel porphyrins are mainly generated by the NiN4 quasi-molecule: the lowest empty state is the weakly antibonding molecular orbital (MO) of sigma b(1g), symmetry with nearly pure Ni 3d(x2-y2) character, while the next empty state is the e(g) MO, which has a hybridized Ni 3d pi-N 2p pi character and reflects pi chemical bonding (pi-back-donation) between nickel and neighbouring nitrogen atoms of the pyrrole rings. The differences observed in the Ni 2p spectra of nickel porphyrins and phthalocyanines indicate a limited usefulness of the NiN4 quasi-molecule and a need for its extension to the whole porphyrin (phthalocyanine) macrocycle. As a result, the differences in the Ni 2p spectra of the complexes and in their electronic structure are associated with a torsion of the opposite pyrrole ring planes (NiOEP, NiTiBuP) and the presence of N atoms in meso positions (NiPc). These conclusions are further confirmed by a comparative analysis of the Ni 2p and N Is absorption spectra for NiPc and NiOEP. (c) 2007 Elsevier B.V. All rights reserved.}},
author = {{Krasnikov, S. A. and Preobrajenski, Alexei and Sergeeva, N. N. and Brzhezinskaya, M. M. and Nesterov, M. A. and Cafolla, A. A. and Senge, M. O. and Vinogradov, A. S.}},
issn = {{0301-0104}},
keywords = {{x-ray absorption; electronic structure; phthalocyanine; porphyrin; spectroscopy; NEXAFS}},
language = {{eng}},
number = {{2-3}},
pages = {{318--324}},
publisher = {{Elsevier}},
series = {{Chemical Physics}},
title = {{Electronic structure of Ni(II) porphyrins and phthalocyanine studied by soft X-ray absorption spectroscopy}},
url = {{http://dx.doi.org/10.1016/j.chemphys.2006.12.015}},
doi = {{10.1016/j.chemphys.2006.12.015}},
volume = {{332}},
year = {{2007}},
}