An ideal one-dimensional antiferromagnetic spin system observed in hydrogen-bonded naphth[2,3-d]imidazol-2-yl nitronyl nitroxide crystal: The role of the hydrogen bond

Hideaki Nagashima, Hidenari Inoue, Naoki Yoshioka

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A novel stable organic radical, 2-(naphth[2,3-d]imidazol-2-yl)-4,4,5,5- tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl-3-oxide (4), has been designed, synthesized, and structurally characterized to examine the effects of ring extension on 2-(benzimidazol-2-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H- imidazolyl-1-oxyl-3-oxide (2). 4 forms four-centered intramolecular and intermolecular hydrogen bonds, and the hydrogen bonds are repeated along the c-axis to form a one-dimensional chain structure. This hydrogen-bonding motif contrasts that of 2, which forms three-centered intramolecular and intermolecular hydrogen bonds. The magnetic susceptibility measurement of 4 reveals that an antiferromagnetic interaction is dominant between spins, and the magnetic behavior is reproduced by the Bonner-Fisher model with J = -14 cm -1. Because each hydrogen-bonded chain is well isolated, a magnetic interaction pathway was thought to exist along the chain direction. Two interaction pathways have been assumed: (i) through-space interaction between the 0 atoms of the nitroxide and (ii) through die NH...ON intermolecular hydrogen bond. We have concluded that pathway (i) is predominant, by considering the identical magnetic data between the NH nondeuterated and deuterated samples. The hydrogen bond mainly has a role in crystal scaffolding.

Original languageEnglish
Pages (from-to)6144-6151
Number of pages8
JournalJournal of Physical Chemistry B
Issue number20
Publication statusPublished - 2004 May 20


ASJC Scopus subject areas

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

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