Johnson Hannah M, Hurlock Matthew J, Lare Monipak F, Forseth Lauren V, Mosset Dylan M, Li Jiahong, Zhang Qiang
Department of Chemistry, Washington State University, Pullman, WA, United States.
Nanoscale Sciences Department, Sandia National Laboratories, Albuquerque, NM, United States.
Front Chem. 2024 Apr 25;12:1396123. doi: 10.3389/fchem.2024.1396123. eCollection 2024.
Tetraphenylethene-based ligands with lowered symmetry are promising building blocks for the construction of novel luminescent metal-organic frameworks (MOFs). However, few examples have been reported, and predicting the ligand conformation and the dimensionality of the resulting MOF remains challenging. In order to uncover how synthetic conditions and accessible ligand conformations may affect the resulting MOF structure, four new MOF structures were synthesized under solvothermal conditions using the meta-coordinated tetraphenylethene-based ligand -ETTC and paddlewheel SBUs composed of Co(II), Cu(II), and Zn(II). WSU-10 (WSU = Washington State University) is formed with either Zn or Cu comprising stacked psuedo-2D layers. The dimensionality of WSU-10 can be intentionally increased through the addition of pyrazine as a pillar ligand into the synthesis, forming the 3D structure WSU-11. The third structure, WSU-20, is formed by the combination of Zn or Co with -ETTC and is intrinsically 3D without the use of a pillar ligand; interestingly, this is the result of a distortion in the paddlewheel SBU. Finally, Cu was also found to form a new structure (WSU-12), which displays an -ETTC conformation unique from that found in the other isolated MOFs. Structural features are compared across the series and a mechanistic relationship between WSU-10 and -20 is proposed, providing insight into the factors that can encourage the generation of frameworks with increased dimensionality.
对称性降低的基于四苯乙烯的配体是构建新型发光金属有机框架（MOF）的有前景的构建单元。然而，报道的例子很少，预测配体构象和所得MOF的维度仍然具有挑战性。为了揭示合成条件和可及的配体构象如何影响所得MOF结构，在溶剂热条件下使用间位配位的基于四苯乙烯的配体-ETTC和由Co（II）、Cu（II）和Zn（II）组成的桨轮型次级构筑单元（SBU）合成了四种新的MOF结构。WSU-10（WSU = 华盛顿州立大学）由Zn或Cu形成，包含堆叠的准二维层。通过在合成中加入吡嗪作为支柱配体，可以有意增加WSU-10的维度，形成三维结构WSU-11。第三种结构WSU-20由Zn或Co与-ETTC组合形成，在不使用支柱配体的情况下本质上是三维的；有趣的是，这是桨轮型SBU中扭曲的结果。最后，还发现Cu形成了一种新结构（WSU-12），其显示出与其他分离的MOF中发现的-ETTC构象不同的构象。对该系列的结构特征进行了比较，并提出了WSU-10和-20之间的机理关系，从而深入了解可以促进生成维度增加的框架的因素。
