两个基于Mn^(Ⅲ)席夫碱氰基桥联化合物的合成、结构和磁性

Synthesis,Structure and Magnetic Properties of Two Cyano-Bridged Complexes Based on Mn^(Ⅲ)-Schiff Bases

本文利用MnⅢ席夫碱配合物作为前驱体,与含有氰根桥联配体的构筑基块K3[CoⅢ(CN)6]或Na[N(CN)2]反应合成了2个新的化合物[MnⅢ6(Salen)6(H2O)6.CoⅢ(CN)6][CoⅢ(CN)6].6H2O(1)和[MnⅢ(5-Br)Salen.N(CN)2].H2O(2),其中Salen为二-邻苯甲醛乙二胺。利用红外光谱、元素分析和X-射线单晶衍射分析对其结构进行了表征并测试了其磁学性质。结构分析表明化合物1由1个七核阳离子簇[Mn6Co]3+和一个平衡阴离子[Co(CN)6]3-组成的离子对化合物。而化合物2则为由MnⅢ组成的一维中性链结构,[N(CN)2]-利用叠氮桥联方式和金属离子配位。磁性研究表明,化合物1中[Co(CN)6]3-几乎不传递磁耦合作用,所以是一个顺磁体,但MnⅢ自身的零场分裂导致低χMT在低温时随温度下降而减小,而2则表现出弱的链内反铁磁性耦合作用。对比化合物1和2的磁性得知共轭体系[N(CN)2]-比同样是五原子配体[Co(CN)6]3-传递较强磁耦合作用。

Based on Mn^Ⅲ-Schiff bases and the building blocks of K3[Co^Ⅲ（CN）6] and Na[N（CN）2], two new cyano-bridged assemblies, [Mn^Ⅲ6（Salen）6（H2O）6·Co^Ⅲ（CN）6][Co^Ⅲ（CN）6]·6H2O （1） and [Mn^Ⅲ（5-Br）Salen·N（CN）2]·H2O （2） [salen=N,N′-ethylenebis （salicylideneiminato） dianion] have been synthesized and characterized structurally through IR, elemental analyses and single crystal X-ray structure analysis. The magnetic measurement of complex 1 and 2 were also carried out. The structure analysis reveals that 1 is a ion-pair complex, which is composed of a heptanuclear cation [Mn6Co]^3＋ and a counteranions [Co（CN）6]^3-. In contrast to 1, complex 2 is a 1D neutral chain constructed by Mn^Ⅲ, which is found that [N（CN）2]^- bridges between metal ions by a same mode as end-to-end N3-. Magnetic investigation indicates the overall paramagnetic nature of complex 1 with the strong zero field splitting （ZFS） effect of Mn^Ⅲ. However, complex 2 exhibits the weak intrachain antiferromagnetic coupling mediated by [N（CN）2]^-, which implies that the conjugated [N（CN）2]^- mediates the stronger magnetic coupling interaction between Mn^Ⅲ ions than [Co（CN）6]^3- although they both are the five-atom bridging ligands. CCDC： 847146, 1; 847147, 2.