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Updated: Jun 18, 2025

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Substituent effects on spin-crossover Fe(II)N4O2 pyrenylhydrazone complexes
Xuan Wang1, Nan Zhang1, Hui-Zhong Kou1
1Engineering Research Center of Advanced Rare Earth Materials (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China. kouhz@mail.tsinghua.edu.cn.
Abstract:
Multifunctional magnetic materials have broad application prospects in molecular switches and information storage. In this study, four mononuclear Fe(II) complexes are synthesized using a series of pyrenylhydrazone ligands HL1-4. Two deprotonated ligands are coordinated to the iron(II) ions in an enolic form, leading to neutral complexes FeII(L)2·xsol with a FeIIN4O2 octahedral coordination environment. Magnetic measurements suggest that complex Fe(L1)2·2ACE (1·2ACE, ACE = acetone) is mainly low spin below 300 K and complex Fe(L3)2·ACE (3·ACE) is high spin, whereas complexes Fe(L2)2 (2) and Fe(L4)2·6H2O (4·6H2O) exhibit gradual spin crossover behavior. The spin states of complexes 1-4 are confirmed by single-crystal X-ray diffraction analysis. The substituent effect on the magnetic properties of the complexes is significant in this system. Temperature-dependent fluorescence emission spectra show the coexistence but no coupling effect of spin crossover and fluorescence for complexes 2 and 4·6H2O.
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