Masciocchi Norberto, Castelli Fulvio, Forster Paul M, Tafoya Maya M, Cheetham Anthony K
Dipartimento di Scienze Chimiche, Fisiche e Matematiche, Università dell'Insubria, via Valleggio 11, 22100 Como, Italy.
Inorg Chem. 2003 Sep 22;42(19):6147-52. doi: 10.1021/ic034619o.
Nickel(II) bisimidazolate is polymorphic. Depending on the synthetic strategy adopted, two crystalline phases (alpha- and beta-Ni(im)(2)) or an amorphous material of the same composition can be prepared. The thermodynamically stable alpha-Ni(im)(2) phase, which can be prepared in water at elevated temperatures, contains a two-dimensional polymer (of nearly square meshes) with square-planar NiN(4) chromophores and exo-bidentate imidazolate ligands bridging nickel atoms that are ca. 5.73 A apart. The beta-Ni(im)(2) phase can be kinetically stabilized at lower temperatures, but the structural complexity and the lack of single crystals prevented its full structural characterization, even in the presence of an indexed powder diffraction pattern. The spectroscopic features of these crystalline phases are compared with those of the amorphous material.
咪唑镍（II）具有多晶型性。根据所采用的合成策略，可以制备出两种晶相（α-和β-Ni(im)₂）或相同组成的无定形材料。热力学稳定的α-Ni(im)₂相可在高温下于水中制备，它包含一种二维聚合物（近方形网格），其中有平面正方形的NiN₄发色团以及桥接相距约5.73 Å镍原子的外双齿咪唑配体。β-Ni(im)₂相可在较低温度下动力学稳定，但结构复杂性和缺乏单晶阻碍了其完整结构表征，即使存在索引粉末衍射图谱。将这些晶相的光谱特征与无定形材料的光谱特征进行了比较。
