A New Family of Spin Crossover Complexes with a Tripod Ligand Containing Three Imidazoles: Synthesis, Characterization, and Magnetic Properties of [FeIIH3LMe](NO3

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• 作者：Yuichi Ikuta ; Makoto Ooidemizu ; Yuichi Yamahata ; Masahiro Yamada ; Shutaro Osa ; Naohide Matsumoto ; Seiichiro Iijima ; Yukinari Sunatsuki ; Masaaki Kojima ; Franç ; oise Dahan ; and Jean-Pierre Tuchague
• 刊名：Inorganic Chemistry
• 出版年：2003
• 出版时间：November 3, 2003
• 年：2003
• 卷：42
• 期：22
• 页码：7001 - 7017
• 全文大小：816K
• 年卷期：v.42,no.22(November 3, 2003)
• ISSN：1520-510X

文摘

A new family of spin crossover complexes, [Fe^IIH₃L^Me](NO₃)₂·1.5H₂O (1), [Fe^IIIL^Me]·3.5H₂O (2), [Fe^IIH₃L^Me][Fe^IIL^Me]NO₃ (3), and [Fe^IIH₃L^Me][Fe^IIIL^Me](NO₃)₂ (4), has been synthesized and characterized, where H₃L^Me denotes ahexadentate 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 tunedby the degree of deprotonation of the imidazole groups and by the 2-methyl imidazole substituent. Magneticsusceptibility and Mössbauer studies revealed that 1 is an HS-Fe^II complex, 2 exhibits a spin equilibrium betweenHS and LS-Fe^III, 3 exhibits a two-step spin transition, where the component [Fe^IIL^Me]^- with the deprotonated ligandparticipates in the spin transition process in the higher temperature range and the component [Fe^IIH₃L^Me]²⁺ with theneutral ligand participates in the spin transition process in the lower temperature range, and 4 exhibits spin transitionof both the Fe^II and Fe^III sites. The crystal structure of 3 consists of homochiral extended 2D puckered sheets, inwhich the capped tripodlike components [Fe^IIH₃L^Me]²⁺ and [Fe^IIL^Me]^- are alternately arrayed in an up-and-downmode and are linked by the imidazole-imidazolate hydrogen bonds. Furthermore, the adjacent 2D homochiralsheets are stacked in the crystal lattice yielding a conglomerate as confirmed by the enantiomeric circular dichorismspectra. Compounds 3 and 4 showed the LIESST (light induced excited spin state trapping) and reverse-LIESSTeffects upon irradiation with green and red light, respectively.