Synthesis, crystal structure and magnetic properties of novel Mn12 single-molecule magnets with thiophenecarboxylate, [Mn12O12(O2CC4H3 S)16(H2O)4], and its tetraphenylphosphonium salt

Takayoshi Kuroda-Sowa, Tadahiro Nogami, Hisashi Konaka, Masahiko Maekawa, Megumu Munakata, Hitoshi Miyasaka, Masahiro Yamashita

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31 Citations (Scopus)

Abstract

The preparation and physical characterization are reported for novel Mn12 single-molecule magnets having thiophenecarboxylate bridges, [Mn12O12(O2CC4H3 S)16(H2O)4] (1), and its PPh4 salt (2). The reaction of the excess amount of 2-thiophenecarboxylic acid (tpcH) and [Mn12O12(OAc)16(H2O)4] in CH2Cl2 gave black crystals of 1, which could be reduced by PPh4I to give 2. From the crystal structure analysis of 2, it is revealed that there are two five-coordinated Mn ions, one of which is assigned to a MnII ion being in the vicinity of the tetraphenylphosphonium cation. Both complexes exhibit out-of-phase a.c. magnetic susceptibility (XM") signals in the 5.0-6.5 K range at 997 Hz a.c. frequency, which indicate that they are single-molecule magnets. From Arrhenius plots of the frequency dependence of the temperature of the XM" peaks, the effective energy barriers Ueff were estimated to be 69 and 57 K for high-temperature phases of 1 and 2, respectively, and 40 K for the low-temperature phase of 1. The reduced magnetization measurement and its analysis indicate that 2 has S = 19/2 ground state with g = 1.99 and D = -0.61 K.

Original languageEnglish
Pages (from-to)1795-1801
Number of pages7
JournalPolyhedron
Volume22
Issue number14-17
DOIs
Publication statusPublished - 2003 Jul 15
Externally publishedYes

Keywords

  • 2-Thiophenecarboxylic acid
  • Mn complexes
  • PPh salt
  • Single crystal X-ray analysis
  • Single-molecule magnet
  • a.c. and d.c. magnetic susceptibility

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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