By using squarates as coordination building units, six new complexes formulated as [Mg(C₄O₄)(H₂O)₂]_n (1), [Pr₂(C₄O₄)₂(OA)(H₂O)₄]_n (2), [Eu₂(C₄O₄)₃(H₂O)₈]_n (3) [Cd₂(C₄O₄)₂(bpdo)(H₂O)₄]_n (4), [Cd(C₄HO₄)₂(H₂O)₄]·(MV)₂·(C₄O₄)₂ (5), and [Cd(C₄HO₄)₂(H₂O)₄]·(EV)·(C₄HO₄)₂ (6), where (C₄O₄)²⁻ = squarate, OA = oxalic acid, MV = methyl viologen, EV = ethyl viologen, and bpdo = 4,4′-dipyrdiyl-N,N′-dioxide, have been synthesized under hydro/solvothermal conditions. They present structural dimensions from 3-D networks (1, 2), 2-D layers (3, 4) to 0-D clusters (5, 6) based on the versatile bridged modes of squarates and the introduction of second ligands. In particular, 5 and 6 are the first examples incorporating squarates (electronic-rich species) with viologens (electronic-poor species) in one lattice. Consequently, they exhibit not only photocurrent responses but also reversible thermochromism, which will be beneficial for the design of multi-functional materials.

中文翻译：

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基于方酸的复合物的结构多样性：紫精增强的光电流响应和热致变色行为

通过使用方阵作为协调构建单元，六个新的配合物被公式化为[Mg（C ₄ O ₄）（H ₂ O）₂ ] _n（1），[Pr ₂（C ₄ O ₄）₂（OA）（H ₂ O） ）₄ ] _n（2），[Eu ₂（C ₄ O ₄）₃（H ₂ O）₈ ] _n（3）[Cd ₂（C ₄ O ₄）₂（bpdo）（H ₂ O）₄ ] _n（4），[Cd（C ₄ HO ₄）₂（H ₂ O）₄ ]·（MV）₂ ·（C ₄ O ₄）₂（5）和[ Cd（C ₄ HO ₄）₂（H ₂ O）₄ ]·（EV）·（C ₄ HO ₄）₂（6），其中（C ₄ O ₄）²⁻方酸二=，OA =草酸，MV =甲基紫精，EV =乙基紫精，和bpdo = 4,4'- dipyrdiyl- Ñ，Ñ '二氧化物，已被加氢/溶剂热条件下合成。从3- d网络（它们本结构尺寸1，2），2-d层（3，4），以0-d簇（5，6基于1,2方酸衍生物多功能桥接模式和引入第二配体）。特别是5和6第一个例子是将方格（电子丰富的物种）与紫精（电子贫乏的物种）合并在一个晶格中。因此，它们不仅表现出光电流响应，而且表现出可逆的热致变色现象，这对于多功能材料的设计将是有益的。