Positional isomerism of unsymmetrical semirigid ligands toward the construction of discrete and infinite coordination architectures of zinc(ii) and cadmium(ii) complexes
作者:Jing-Yun Wu、Pin-Ting Yuan、Cheng-Chu Hsiao
DOI:10.1039/c3ce42398k
日期:——
Three unsymmetrical semirigid ligands, HInMe-n-py (n = 2, 3, 4), showing positional isomerism have assembled with ZnCl2 and CdCl2 to yield supramolecular coordination assemblies. Compound [Zn(InMe-2-py)2]·1/2THF·1/2CH3OH·1/4H2O (1) has a two-dimensional rhombus gridlike (4,4) layer structure constructed from the dinuclear paddlewheel [Zn2(O2C)4N2] units with two pendant side-arms. Compound [Zn2Cl2(InMe-3-py)2(HInMe-3-py)2] (2) forms a discrete armed M2L2 macrocycle, which connects with others by intermolecular O–H⋯O and C–H⋯Cl hydrogen bonds to give rise to a decorated three-dimensional supramolecular pcu net. Compound [Zn(InMe-4-py)2]·1/2H2O (3) adopts a two-dimensional chiral wavy (4,4) square grid. Opposite-handedness chiral wavy grids are stacked in an ABAB type of sequence that has small voids accommodating lattice water molecules. Compound [CdCl(InMe-3-py)] (4) displays a two-dimensional achiral meso layer in which the opposite-handedness Cd–L helical chains are interconnected by the Cd–O bridging bonds and stitched by zigzag Cd–Cl chains. Compound [Cd(InMe-4-py)2(H2O)2] (5) features a two-dimensional rhombus gridlike (4,4)-net. Through the connections of net-to-net O–H⋯O hydrogen bonds, the grids are offset-stacked to be a hydrogen-bonded three-dimensional oblique pcu net. The structural diversity and complexity in these supramolecular coordination architectures are most likely attributed to the various coordination modes adopted by these N- and O-donor ligands of different substituent position and the coordination preference exhibited by the metal ions. Thermogravimetric (TG) analyses showed that all the frameworks of compounds 1–5 exhibit a thermal stability higher than 300 °C. In addition, the solid-state photoluminescent properties of compounds 1–5 were investigated.
三个具有位置异构性的不对称半刚性配体 HInMe-n-py (n = 2, 3, 4) 与 ZnCl2 和 CdCl2 组装形成超分子配位组装体。化合物[Zn(InMe-2-py)2]·1/2THF·1/2CH3OH·1/4H2O (1)具有由双核桨轮[Zn2(O2C)构成的二维菱形网格状(4,4)层结构)4N2] 带有两个悬垂侧臂的装置。化合物[Zn2Cl2(InMe-3-py)2(HInMe-3-py)2](2)形成离散的武装M2L2大环,通过分子间O–H⋯O和C–H⋯Cl氢键与其他大环连接,产生装饰的三维超分子pcu网。化合物[Zn(InMe-4-py)2]·1/2H2O(3)采用二维手性波状(4,4)方格。反手性手性波状网格以ABAB型序列堆叠,具有容纳晶格水分子的小空隙。化合物[CdCl(InMe-3-py)] (4)显示出二维非手性介观层,其中反手性Cd-L螺旋链通过Cd-O桥键互连并由锯齿形Cd-Cl链缝合。化合物 [Cd(InMe-4-py)2(H2O)2] (5) 具有二维菱形网格状 (4,4)-网。通过网与网的O-H⋯O氢键连接,网格偏置堆叠形成氢键三维倾斜pcu网。这些超分子配位结构的结构多样性和复杂性很可能归因于不同取代基位置的N-和O-供体配体采用的各种配位模式以及金属离子表现出的配位偏好。热重(TG)分析表明,化合物1-5的所有骨架均表现出高于300°C的热稳定性。此外,还研究了化合物 1-5 的固态光致发光特性。