1D and 2D assembly structures by imidazole⋯chloride hydrogen bonds of iron(ii) complexes [FeII(HLn-Pr)3] Cl·Y (HLn-Pr = 2-methylimidazol-4-yl-methylideneamino-n- propyl; Y = AsF6, BF4) and their spin states

Takeshi Fujinami, Koshiro Nishi, Naohide Matsumoto, Seiichiro Iijima, Malcolm A. Halcrow, Yukinari Sunatsuki, Masaaki Kojima

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Two FeII complexes fac-[FeII(HLn-Pr) 3]Cl·Y (Y = AsF6 (1) and BF4 (2)) were synthesized, where HLn-Pr is 2-methylimidazole-4-yl-methylideneamino- n-propyl. Each complex-cation has the same octahedral N6 geometry coordinated by three bidentate ligands and assumes facial-isomerism, fac-[FeII(HLn-Pr)3]2+ with Δ- and Λ-enantiomorphs. Three imidazole groups per Δ- or Λ-fac-[FeII(HLn-Pr)3]2+ are hydrogen-bonded to three Cl- ions or, from the viewpoint of the Cl- ion, one Cl- ion is hydrogen-bonded to three neighbouring fac-[FeII(HLn-Pr)3]2+ cations. The 3:3 NH⋯Cl- hydrogen bonds between Δ- or Λ-fac-[FeII(HLn-Pr)3]2+ and Cl- generate two kinds of assembly structures. The directions of the 3:3 NH⋯Cl- hydrogen bonds and hence the resulting assembly structures are determined by the size of the anion Y, though Y is not involved into the network structure and just accommodated in the cavity. Compound 1 has a 1D ladder structure giving a larger cavity, in which the Δ- and Λ-fac-[FeII(HLn-Pr)3]2+ enantiomorphs are bridged by two NH⋯Cl- hydrogen bonds. Compound 2 has a 2D network structure with a net unit of a cyclic trimer of {fac-[FeII(HLn-Pr)3]2+⋯ Cl-}3 giving a smaller cavity, in which Δ- or Λ-fac-[FeII(HLn-Pr)3]2+ species with the same chirality are linked by NH⋯Cl- hydrogen bonds to give a homochiral 2D network structure. Magnetic susceptibility and Mössbauer spectral measurements demonstrated that compound 1 showed an abrupt one-step spin crossover with 4.0 K thermal hysteresis of T c↓ = 125.5 K and Tc↑ = 129.5 K and compound 2 showed no spin transition and stayed in the high-spin state over the 5-300 K temperature range.

Original languageEnglish
Pages (from-to)12301-12309
Number of pages9
JournalDalton Transactions
Volume40
Issue number45
DOIs
Publication statusPublished - Dec 7 2011

ASJC Scopus subject areas

  • Inorganic Chemistry

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