Research output: Contribution to journal › Article › peer-review
Photoelectron spectra and electronic structure of boron diacetate formazanates. / Tikhonov, Sergey A.; Sidorin, Andrey E.; Samoilov, Ilya S.; Borisenko, Aleksandr V.; Vovna, Vitaliy I.
In: Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy, Vol. 238, 118441, 05.09.2020.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Photoelectron spectra and electronic structure of boron diacetate formazanates
AU - Tikhonov, Sergey A.
AU - Sidorin, Andrey E.
AU - Samoilov, Ilya S.
AU - Borisenko, Aleksandr V.
AU - Vovna, Vitaliy I.
N1 - Publisher Copyright: © 2020 Elsevier B.V.
PY - 2020/9/5
Y1 - 2020/9/5
N2 - The electronic structure and cationic states of two 1,5-diphenylformazanes and two boron diacetate (B(OAc)2) formazanates were modeled using the outer valence Green's function (OVGF) and density functional theory (DFT) methods. Comparison of data of the OVGF and ultraviolet photoelectron spectroscopy (UPS) methods made it possible to determine an effect of functional groups and complexing agents on energies of cationic states. Addition of NO2-group at the γ-position of the chelate cycle causes stabilization of levels the five upper occupied molecular orbitals (MO) and destabilization of the bonding orbital π3Ph + π3 level. The levels of MOs π3Ph–π3 and n– are stabilized due to influence of the complexing agent B(OAc)2, with a difference in the shift of 0.67 eV. The ionization energies (In) changes for the π-orbitals of benzene rings are within the error of the OVGF method. Under methylation of phenyl groups, the differences between the calculated In, corresponding to the π-orbitals of aromatic substituents, are in good agreement with the experimental In shifts at transition from benzene to toluene. According to the OVGF method, in all the studied complexes the lowest unoccupied molecular orbital (LUMO) is localized mainly on the chelate cycle and has a strong acceptor character, which should contribute the low-lying charge-transfer electronic excitations. Moreover, an application of the DFT analog of the Koopmans' theorem with the BHHLYP and B2PLYP functionals made it possible to determine qualitatively a sequence of cationic states and energy intervals between them in the spectral range up to 10 eV. The DFT/wB97x/cc-pVTZ method data on the energy gap between the highest occupied molecular orbital (HOMO) and LUMO levels correlate with the OVGF/cc-pVTZ calculation results.
AB - The electronic structure and cationic states of two 1,5-diphenylformazanes and two boron diacetate (B(OAc)2) formazanates were modeled using the outer valence Green's function (OVGF) and density functional theory (DFT) methods. Comparison of data of the OVGF and ultraviolet photoelectron spectroscopy (UPS) methods made it possible to determine an effect of functional groups and complexing agents on energies of cationic states. Addition of NO2-group at the γ-position of the chelate cycle causes stabilization of levels the five upper occupied molecular orbitals (MO) and destabilization of the bonding orbital π3Ph + π3 level. The levels of MOs π3Ph–π3 and n– are stabilized due to influence of the complexing agent B(OAc)2, with a difference in the shift of 0.67 eV. The ionization energies (In) changes for the π-orbitals of benzene rings are within the error of the OVGF method. Under methylation of phenyl groups, the differences between the calculated In, corresponding to the π-orbitals of aromatic substituents, are in good agreement with the experimental In shifts at transition from benzene to toluene. According to the OVGF method, in all the studied complexes the lowest unoccupied molecular orbital (LUMO) is localized mainly on the chelate cycle and has a strong acceptor character, which should contribute the low-lying charge-transfer electronic excitations. Moreover, an application of the DFT analog of the Koopmans' theorem with the BHHLYP and B2PLYP functionals made it possible to determine qualitatively a sequence of cationic states and energy intervals between them in the spectral range up to 10 eV. The DFT/wB97x/cc-pVTZ method data on the energy gap between the highest occupied molecular orbital (HOMO) and LUMO levels correlate with the OVGF/cc-pVTZ calculation results.
KW - Electronic structure
KW - Photoelectron spectroscopy
KW - UPS
KW - Density functional theory
KW - Outer-valence Green's function (OVGF) method
KW - Boron formazanate
KW - Formazanate ligands
KW - Electronic structure
KW - photoelectron spectroscopy
KW - UPS
KW - Density Functional Theory
KW - Outer-valence Green's function (OVGF) method
KW - Boron formazanate
KW - Formazanate ligands
KW - Density functional theory
KW - Photoelectron spectroscopy
KW - IONIZATION ENERGIES
KW - Outer-valenceGreen's function (OVGF) method
KW - AB-INITIO
KW - COMPLEXES
KW - GREENS-FUNCTION
KW - OPTICAL-PROPERTIES
KW - BINDING ENERGIES
KW - EXCITED-STATES
KW - DYSON ORBITALS
KW - BASIS-SETS
KW - PROPAGATOR THEORY
UR - http://www.scopus.com/inward/record.url?scp=85084265964&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.saa.2020.118441
DO - https://doi.org/10.1016/j.saa.2020.118441
M3 - Article
VL - 238
JO - SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
JF - SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
SN - 1386-1425
M1 - 118441
ER -
ID: 62722487