Magnetic properties of [Ni(dmit)2]- anions induced by flexible hydrogen-bonded supramolecular cations [(p-xylylenediammonium)0.5(Crown ethers)]+

Tomoyuki Akutagawa, Asako Hashimoto, Sadafumi Nishihara, Tatsuo Hasegawa, Takayoshi Nakamura

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)

Abstract

Flexible supramolecular cation structures, [(XyDA)0.5(crown ethers)]+ complexes, were introduced as countercations to [Ni(dmit)2]- anions, which bear an S = 1/2 spin, to form novel magnetic crystals (XyDA = p-xylylenediammonium, dmit2- = 2-thioxo-1,3-dithiole-4,5-dithiolate, and crown ethers = [12]crown-4, [15]crown-5, or [18]crown-6). Sandwich-type [(XyDA)0.5(crown ethers)]+ structures were formed through hydrogen-bonding interactions in the crystals between the ammonium moieties of XyDA and the oxygen atoms of the crown ethers. [12]Crown-4 yielded three types of [(XyDA)0.5([12]crown-4)]+[Ni(dmit)2] polymorphs, whereas two types of [(XyDA)0.5([15]crown-5)]+[Ni(dmit)2] polymorphs were obtained using [15]crown-5. Three types of [(XyDA)0.5(crown ethers)]+ structures were identified for these polymorphs. Since the flexible -CH2-NH3+ moieties connected to benzene plane have rotational freedom, the [(XyDA)0.5-(crown ethers)]+ structures varied according to the conformations of the XyDA cation in the crystals. The larger ring size of [18]crown-6 than that of [12]crown-4 and [15]crown-5 reduced the flexibility of the XyDA cation, and provided only one type of crystal. The [Ni(dmit)2]- anion existed as dimer structures, which are in the singlet ground state. The arrangement of the [Ni(dmit)2]- anion in the crystals were depended on the structure of [(XyDA)0.5(crown ethers)]+. Correlation of the absolute values of magnetic exchange energy J to the square of the intradimer transfer integral t2 were confirmed.

Original languageEnglish
Pages (from-to)66-74
Number of pages9
JournalJournal of Physical Chemistry B
Volume107
Issue number1
DOIs
Publication statusPublished - 2003 Jan 9
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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