Cyanide-Bridged Mn(III)-Fe(III) Bimetallic Complexes Based on the Pentacyano(1-methylimidazole)ferrate(III) Building Block: Structure and Magnetic Characterizations

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• 作者：Wei-Wei Ni ; Zhong-Hai Ni ; Ai-Li Cui ; Xin Liang ; Hui-Zhong Kou
• 刊名：Inorganic Chemistry
• 出版年：2007
• 出版时间：January 8, 2007
• 年：2007
• 卷：46
• 期：1
• 页码：22 - 33
• 全文大小：320K
• 年卷期：v.46,no.1(January 8, 2007)
• ISSN：1520-510X

文摘

Seven cyanide-bridged bimetallic complexes have been synthesized by the reaction of [Fe(1-CH₃im)(CN)₅]^2- withMn(III) Schiff base complexes. Their crystal structure and magnetic properties have been characterized. Fivecomplexes, [Mn₂(5-Brsalen)₂Fe(CN)₅(1-CH₃im)]·H₂O (1), [Mn₂(5-Clsalen)₂(H₂O)₂Fe(CN)₅(1-CH₃im)]·H₂O (2), [Mn₂(5-Clsaltn)₂(H₂O)₂Fe(CN)₅(1-CH₃im)] (3), [Mn₂(5-Clsaltmen)₂(H₂O)₂Fe(CN)₅(1-CH₃im)]·H₂O (4), and [Mn₂(5-Brsaltmen)₂(H₂O)₂Fe(CN)₅(1-CH₃im)]·CH₃OH (5), are neutral and trinuclear with two [Mn(SB)]⁺ (SB^2- = Schiff base ligands)and one [Fe(1-CH₃im)(CN)₅]^2-. Complex {[Et₄N][Mn(acacen)Fe(CN)₅(1-CH₃im)]}_n·6nH₂O (6) is one-dimensionalwith alternate [Mn(acacen)]⁺ and [Fe(CN)₅(1-CH₃im)]^2- units. The two-dimensional complex {[Mn₄(saltmen)₄Fe(CN)₅(1-CH₃im)]}_n[ClO₄]_2n·9nH₂O (7) consists of Mn₄Fe units which are further connected by the phenoxo oxygenatoms. Magnetic studies show the presence of ferromagnetic Mn(III)-Fe(III) coupling in the trinuclear compoundswith the magnetic coupling constant (J) ranging from 4.5 to 6.0 cm^-1, based on the Hamiltonian = -2J_Fe(_Mn(1)+ _Mn(2)). Antiferromagnetic interaction has been observed in complex 6, whereas ferromagnetic coupling occurs incomplex 7. Complexes 6 and 7 exhibit long-range magnetic ordering with a T_N value of 4.0 K for 6 and T_c of 4.8K for 7. Complex 6 shows metamagnetic behavior at 2 K, and complex 7 possesses a hysteresis loop with acoercive field of 500 Oe, typical of a soft ferromagnet.