Donor-type nickel–dithiolene complexes fused with bulky cycloalkane substituents and their application in molecular conductors

Kazuya Kubo, Mamoru Sadahiro, Sonomi Arata, Norihisa Hoshino, Tomofumi Kadoya, Tomoyuki Akutagawa, Reizo Kato, Jun Ichi Yamada

Research output: Contribution to journalArticlepeer-review

Abstract

The effects of substituents on the arrangement of metal–dithiolene complexes based on π-conjugated systems, which are extensively used to synthesize various functional materials, have not been studied adequately. New donor-type nickel–dithiolene complexes fused with bulky cycloalkane substituents [Ni(Cn-dddt)2] (C5-dddt = 4a,5,6,6a-pentahydro-1,4-benzodithiin-2,3-dithiolate; C6-dddt = 4a,5,6,7,8,8a-hexahydro-1,4-benzodithiin-2,3-dithiolate; C7-dddt = 4a,5,6,7,8,9,9a-heptahydro-1,4-benzodithiin-2,3-dithiolate; and C8-dddt = 4a,5,6,7,8,9,10,10a-octahydro-1,4-benzodithiin-2,3-dithiolate) were synthesized in this study. All the complexes were crystallized in cis-[Ni(cis-Cn-dddt)2] conformations with cis-oriented (R,S) conformations around the cycloalkylene groups in the neutral state. Unique molecular arrangements with a three-dimensional network, a one-dimensional column, and a helical molecular arrangement were formed in the crystals owing to the flexible cycloalkane moieties. New 2:1 cation radical crystals of [Ni(C5-dddt)2]2 (X) (X = ClO4 or PF6), obtained by electrochemical crystallization, exhibited semiconducting behaviors (ρrt = 0.8 Ω cm, Ea = 0.09 eV for the ClO4 crystal; 4.0 Ω cm, 0.13 eV for the PF6 crystal) under ambient pressure due to spin-singlet states between the dimers of the donor, which were in accordance with the conducting behaviors under hydrostatic pressure (ρrt = 0.2 Ω cm, Ea = 0.07 eV for the ClO4 crystal; 1.0 Ω cm, 0.12 eV for the PF6 crystal at 2.0 GPa).

Original languageEnglish
Article number1154
JournalCrystals
Volume11
Issue number10
DOIs
Publication statusPublished - 2021 Oct

Keywords

  • Cycloalkane substituent
  • Molecular conductor
  • Nickel–dithiolene complex

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

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