Quasi-one-dimensional molecular magnets based on derivatives of (fluorobenzyl)pyridinium with the [M(mnt)2] monoanion (M = Ni, Pd or Pt; Mnt2- = maleonitriledithiolate): Syntheses, crystal structures and magnetic properties

X. M. Ren, S. Nishihara, T. Akutagawa, S. Noro, T. Nakamura, W. Fujita, K. Awaga, Z. P. Ni, J. L. Xie, Q. J. Meng, R. K. Kremer

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

The syntheses, structural characterizations and magnetic behaviors of three new complexes, 1-(3′,4′,5′-trifluorobenzyl)pyridinium [M(mnt)2]- [M = Ni (1), Pd (2) or Pt (3)], are reported. These complexes are isomorphous and their prominent structural character is that the [M(mnt)2]- anions form columnar stacks, in which the dimerization was observed. Complexes 2 and 3 are diamagnetic, while 1 possesses an energy gap of 2474 K. For crystal 4, 1-(4′-fluorobenzyl)pyridinium [Ni(mnt)2] (its structure and magnetic susceptibility were briefly reported earlier), the magnetic behavior can be divided into two regimes, namely, weakly ferromagnetic coupling above 93 K and strongly antiferromagnetic coupling below 93 K. A transition occurs at 93 K which switches the magnetic exchange nature from ferromagnetic to antiferromagnetic. A sharp thermal abnormality with λ-shape, associated with the transition, appears from its heat capacity measurement to indicate that the transition is first order. The temperature dependences of the superlattice diffractions revealed the existence of the pretransitional phenomena up to at least 140 K. The unusual magnetic behavior of 4, such as the origin of the ferromagnetic interaction in the high temperature phase and what causes the spin transition, are discussed further.

Original languageEnglish
Pages (from-to)1988-1994
Number of pages7
JournalDalton Transactions
Issue number16
DOIs
Publication statusPublished - 2006 Jun 5
Externally publishedYes

ASJC Scopus subject areas

  • Inorganic Chemistry

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