Synthesis, Structure, Magnetism and Electrochemical Properties of Linear Pentanuclear Complex: Ni5(μ-dmpzda)4(NCS)2

吡啶修饰的线性五核金属化合物[Ni5(μ-dmpzda)4(NCS)2][ dmpzda-H2=N,N’-Di(4-methyl pyrydin-2-yl)pyrazine-2,6-diamine]被合成并表征,其电化学和磁性被报告。 化合物含有接近180º的 Ni-Ni-Ni角,末端含有两个轴配体的Ni5 线性链。这个五核线性金属链被四个顺式的dmpzda2-配体螺旋包裹。化合物中存在两种类型的Ni-Ni键长：末端连接有轴配体的Ni-Ni键长被配体影响,其键长为2.3821 Å;内部的Ni-Ni距离比较短,为2.2959 Å。两末端的Ni(II)离子由于连接轴配体构成四方锥形(NiN4NCS)并存在较长的Ni-N 键长（2.103 Å),这个键长符合高自旋Ni(II)构型。内部的三个Ni-N 距离为1.886-1.906 Å,这样构成正方形平面(NiN4)并呈低自旋的顺磁构型。化合物显示了同[Ni5(μ-tpda)4(NCS)2]类似的磁性,即在化合物中两末端Ni(II)仍存在反铁磁性的作用。     

A Defective Linear Pentachromium Complex for the Enhanced Catalysis of the Cycloaddition of CO_2 with Propylene Oxide

Based on the ligand(2,7-bis(α-pyrimidylamino)-1,8-naphthyridine(H2 bpmany)), a linear pentachromium complex [Cr_5(μ_5-bpmany)_4Cl_2]PF_6(1, μ5-bpmany = 2,7-bis(a-pyrimidylamino)-1,8-naphthyridine) was synthesized. The crystal structure of compound 1 has been characterized by X-ray crystallography. Interestingly, one metal atom in the center is missing in this linear chain, leading to the defective pentachromium metal string structure which is similar with the reported complex [Cr_5(μ_5-dpznda)_4Cl_2](2, dpznda = N~2,N~7-di(pyrazin-2-yl)-1,8-naphthyridine-2,7-diamine). The central Cr(Ⅲ) ion of 1 is eight-coordinated and is also rare in the chromium complex. The reaction of carbon dioxide with propylene oxide that generates propylene carbonate(PC) when catalyzed by [Cr_5(μ_5-bpmany)_4Cl_2]PF_6 was investigated. Different reaction conditions including temperature and pressure were studied to optimize the reaction conditions.     

多吡啶胺线性金属串配合物

近几年来多吡啶胺线性金属串配合物的研究取得了长足的进步,目前合成的最长金属串为9核。本文对多吡啶胺线性金属串配合物的左右手性、对称和不对称结构、金属串的化学氧化和轴向扩展等进行了介绍。