Effect of Hartree-Fock exact exchange on intramolecular magnetic coupling constants of organic diradicals

Daeheum Cho, Kyoung Chul Ko, Yasuhiro Ikabata, Kazufumi Wakayama, Takeshi Yoshikawa, Hiromi Nakai, Jin Yong Lee

Research output: Contribution to journalArticle

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Abstract

The intramolecular magnetic coupling constant (J) of diradical systems linked with five- or six-membered aromatic rings was calculated to obtain the scaling factor (experimental J/calculated J ratio) for various density functional theory (DFT) functionals. Scaling factors of group A (PBE, TPSSh, B3LYP, B97-1, X3LYP, PBE0, and BH&HLYP) and B (M06-L, M06, M06-2X, and M06-HF) were shown to decrease as the amount of Hartree-Fock exact exchange (HFx) increases, in other words, overestimation of calculated J becomes more severe as the HFx increases. We further investigated the effect of HFx fraction of DFT functional on J value, spin contamination, and spin density distributions by comparing the B3LYP analogues containing different amount of HFx. It was revealed that spin contamination and spin densities at each atom increases as the HFx increases. Above all, newly developed BLYP-5 functional, which has 5% of HFx, was found to have the scaling factor of 1.029, indicating that calculated J values are very close to that of experimental values without scaling. BLYP-5 has potential to be utilized for accurate evaluation of intramolecular magnetic coupling constant (J) of diradicals linked by five- or six-membered aromatic ring couplers.

Original languageEnglish
Article number024318
JournalJournal of Chemical Physics
Volume142
Issue number2
DOIs
Publication statusPublished - 2015 Jan 14

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Magnetic couplings
Density functional theory
Contamination
scaling
contamination
density functional theory
Atoms
rings
functionals
couplers
density distribution
analogs
evaluation
atoms

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Effect of Hartree-Fock exact exchange on intramolecular magnetic coupling constants of organic diradicals. / Cho, Daeheum; Ko, Kyoung Chul; Ikabata, Yasuhiro; Wakayama, Kazufumi; Yoshikawa, Takeshi; Nakai, Hiromi; Lee, Jin Yong.

In: Journal of Chemical Physics, Vol. 142, No. 2, 024318, 14.01.2015.

Research output: Contribution to journalArticle

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