MOE Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
Inorg Chem. 2010 Nov 1;49(21):10166-73. doi: 10.1021/ic1014384.
By using the tripodal ligand ntb (tris(benzimidazole-2-ylmethyl)amine) and lanthanide nitrate, three isomorphous series of coordination frameworks of the general formula [Ln(ntb)(NO(3))(3)]·solvents (series 1: monoclinic C2/c, Ln = Gd(3+) and Yb(3+); series 2: hexagonal P3(1)/c, Ln = Nd(3+), Eu(3+), Gd(3+), and Er(3+); series 3, cubic Pa3̅, Ln = Gd(3+) and Er(3+); solvent = H(2)O or CH(3)OH) have been assembled and characterized with IR, elemental analyses, and single crystal and powder X-ray diffraction methods. In all isomorphous complexes, analogous [Ln(ntb)(NO(3))(3)] coordination monomers of the same structure act as the building blocks to be assembled via hydrogen bonds into three-dimensional (3D) frameworks. So the complexes of the same lanthanide ion (for example, the Gd(3+) ion) from three isomorphous series form polymorphs, for example, monoclinic polymorph 1-Gd, hexagonal polymorph 2-Gd, and cubic polymorph 3-Gd. The single-crystal analyses revealed that the polymorphism was related to different fashions of hydrogen bonding interactions, which was caused by different crystallization conditions, leading to the formation of different 3D hydrogen-bonded frameworks showing distinct porous and topological structures. The monoclinic and hexagonal crystals contain 1D channels, while the cubic crystal is nonporous. The thermogravimetric analyses indicated that all polymorphic crystals have high thermal stability against the removal of guest molecules, and the robust porosity of the hexagonal crystals has been verified by temperature-dependent single-crystal-to-single-crystal measurements upon guest removal/uptake. The solvents adsorption study disclosed that the porous frameworks show high selectivity of benzene against toluene and xylene, while the gas adsorption measurements indicated a moderate H(2), CO(2), and MeOH storage capacity in contrast to low N(2) uptake. The solid-state photoluminescence of the Eu(3+) and Nd(3+) complexes in the near-infrared and visible region has also been investigated, offering examples with optical properties tunable by means of isomorphous replacement.
使用三脚架配体 ntb（三（苯并咪唑-2-基甲基）胺）和镧系硝酸盐，合成了通式为[Ln(ntb)(NO3)(3)]·溶剂（系列 1：单斜 C2/c，Ln=Gd(3+)和 Yb(3+)；系列 2：六方 P3(1)/c，Ln=Nd(3+)、Eu(3+)、Gd(3+)和 Er(3+)；系列 3，立方 Pa3̅，Ln=Gd(3+)和 Er(3+)；溶剂=H2O 或 CH3OH）的三个同构系列的配位框架。通过红外光谱、元素分析以及单晶和粉末 X 射线衍射方法对它们进行了表征。在所有同构配合物中，结构相同的类似[Ln(ntb)(NO3)(3)]配位单体作为构建块，通过氢键组装成三维（3D）框架。因此，来自三个同构系列的相同镧系离子（例如 Gd(3+)离子）的配合物形成多晶型物，例如单斜多晶型物 1-Gd、六方多晶型物 2-Gd 和立方多晶型物 3-Gd。单晶分析表明，多晶型性与不同的氢键相互作用方式有关，这是由不同的结晶条件引起的，导致形成不同的 3D 氢键连接框架，呈现出不同的多孔和拓扑结构。单斜和六方晶体含有 1D 通道，而立方晶体是非多孔的。热重分析表明，所有多晶型晶体都具有很高的热稳定性，能够去除客体分子，并且通过去除/吸收客体后的温度依赖单晶到单晶测量验证了六方晶体的坚固多孔性。溶剂吸附研究表明，多孔框架对苯具有很高的选择性，而对甲苯和二甲苯则没有，而气体吸附测量表明，与氮气的低吸附量相比，H2、CO2 和甲醇的储存能力适中。Eu(3+)和 Nd(3+)配合物在近红外和可见光区域的固态光致发光也进行了研究，提供了通过同构取代可调谐光学性质的实例。
