A New Family of Spin Crossover Complexes with a Tripod Ligand Containing Three Imidazoles (see abstract)

Yuichi Ikuta, Makoto Ooidemizu, Yuichi Yamahata, Masahiro Yamada, Shutaro Osa, Naohide Matsumoto, Seiichiro Iijima, Yukinari Sunatsuki, Masaaki Kojima, Françoise Dahan, Jean Pierre Tuchagues

Research output: Contribution to journalArticle

119 Citations (Scopus)

Abstract

A new family of spin crossover complexes, [FeIIH 3LMe](NO3)2·1.5H 2O (1), [FeIIILMe]·3.5H2O (2), [FeIIH3LMe][FeIIL Me]NO3 (3), and [FeIIH3L Me][FeIIILMe]NO3)2 (4), has been synthesized and characterized, where H3LMe denotes a hexadentate N6 tripod ligand containing three imidazole groups, tris[2-(((2-methylimidazol-4-yl)methylidene)amino)ethyl]amine). It was found that the spin and oxidation states of the iron complexes with this tripod ligand are tuned by the degree of deprotonation of the imidazole groups and by the 2-methyl imidazole substituent. Magnetic susceptibility and Mössbauer studies revealed that 1 is an HS-FeII complex, 2 exhibits a spin equilibrium between HS and LS-FeIII, 3 exhibits a two-step spin transition, where the component [FeIILMe]- with the deprotonated ligand participates in the spin transition process in the higher temperature range and the component [FeIIH3L Me]2+ with the neutral ligand participates in the spin transition process in the lower temperature range, and 4 exhibits spin transition of both the FeII and FeIII sites. The crystal structure of 3 consists of homochiral extended 2D puckered sheets, in which the capped tripodlike components [FeIIH3LMe] 2+ and [FeIILMe]- are alternately arrayed in an up-and-down mode and are linked by the imidazole-imidazolate hydrogen bonds. Furthermore, the adjacent 2D homochiral sheets are stacked in the crystal lattice yielding a conglomerate as confirmed by the enantiomeric circular dichorism spectra. Compounds 3 and 4 showed the LIESST (light induced excited spin state trapping) and reverse-LIESST effects upon irradiation with green and red light, respectively.

Original languageEnglish
Pages (from-to)7001-7017
Number of pages17
JournalInorganic Chemistry
Volume42
Issue number22
DOIs
Publication statusPublished - Nov 3 2003

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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