A cyclometalated diruthenium complex 2 bridged by 1,2,4,5-tetra(pyrid-2-yl)benzene with six carboxylic acid groups at two ends was synthesized. Monolayer and multilayer films FTO/TiO₂/(2)_n(Zr) (n=1,2) and FTO/SnO₂:Sb/(2)_n(Zr) (n=1–4) have been prepared via interfacial layer-by-layer coordination assembly of 2 with zirconium(IV) ions. All films show two consecutive redox couples in the potential range between 0 and +1.0 V vs. Ag/AgCl. These films exhibit reversible near-infrared electrochromism upon switching of redox potential. The response time of the films on SnO₂:Sb is around a few seconds, while that on TiO₂ is around a few tens of seconds. The film deposition cycles were found to have a great impact on the electrochromic performance. Among six films examined, the two-layered film on SnO₂:Sb displays the best balanced performance with a contrast ratio of 56% at 1,150 nm and good cyclic stability (9% loss of contrast ratio after 1,000 continuous double-potential-switching cycles), which is superior to that of the previously reported electropolymerized films of a related diruthenium complex with the same bridging ligand. In addition, the X-ray photoelectron spectroscopy, scanning electron microscopy, and electron transfer mechanism of these films have been investigated.

中文翻译：

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通过在金属氧化物基底上逐层沉积制备的环金属化钌络合物多层膜的近红外电致变色

合成了由在两个末端具有六个羧酸基团的1,2,4,5-四（吡啶-2-基）苯桥接的环金属化钌络合物2。通过界面制备了单层和多层薄膜FTO / TiO ₂ /（2）_n（Zr）（n = 1,2）和FTO / SnO ₂：Sb /（2）_n（Zr）（n = 1–4）2与锆（IV）离子的逐层配位组装。所有薄膜均显示出两个连续的氧化还原对，相对于Ag / AgCl的电势范围为0至+1.0V。这些膜在氧化还原电势转换时表现出可逆的近红外电致变色。薄膜在SnO ₂上的响应时间：Sb大约需要几秒钟，而TiO ₂大约需要几十秒钟。发现膜沉积循环对电致变色性能具有很大的影响。在所检查的六张薄膜中，SnO ₂：Sb上的两层薄膜表现出最佳的平衡性能，在1,150 nm处的对比度为56％，并且具有良好的循环稳定性（在进行1000次连续双电势转换循环后，对比度损失了9％） ），其优于先前报道的具有相同桥联配体的相关二钌配合物的电聚合膜。另外，还研究了这些膜的X射线光电子能谱，扫描电子显微镜和电子转移机理。