Ruthenium Acetate Cluster Amphiphiles and Their Langmuir–Blodgett Films for Electrochromic Switching Devices

Abstract

We synthesized a long-chain phenylazopyridine ligand and used it to obtain three new amphiphilic trinuclear ruthenium acetate clusters. The amphiphilicity and anisometric form of the long-chain ligand allowed the complexes to selfassemble at the liquid-air interface and enabled their deposition by the Langmuir-Blodgett technique. We obtained the linear complex [Ru 3 O(C 2 H 3 O 2 ) 6 (py) 2 L] + [L = 4-(4-dodecyl-

Understanding the Electrochemistry of Ruthenium Complex Thin Films to Guide the Design of Improved Energy Storage Electrodes

“…The model was used to rationalize the observed electrochemical behavior of amphiphilic tri-ruthenium cluster thin films constructed in a controlled way through the LB method using a pressure of 23 mN m –1 . According to the previous experience of our group, , at this pressure, the obtained films exhibit wide redox peaks and considerable material loading, maintaining the integrity of the film. The film exhibited an organized structure with molecules oriented in a preferred direction.…”

“…Besides, the charge transfer between ruthenium clusters of different layers is expected to be relatively fast according to a previous work using a ruthenium complex with the same ligand. 13 The characteristics mentioned above should favor wide redox peaks and a behavior close to the ideal (without charge diffusion limitations) when the number of layers is not so high. In the next section, the electrochemical behavior of AzoRu LB films with different numbers of layers are further analyzed with CV and the aid of the model proposed here.…”

“…A 4-(4-dodecyl-oxy-phenylazo)pyridine ligand (L) was synthesized, and then, Ru 3 O-(C 2 H 3 O 2 ) 6 (Py) 2 L (AzoRu) was synthesized according to a previous work. 13 Briefly, in a round-bottom flask, the μ-oxocentered tri-ruthenium acetate cluster precursor with the composition Ru 3 O(C 2 H 3 O 2 ) 6 (Py) 2 MeOH, previously prepared as in ref 47, was dissolved in dichloromethane (4.2 mg•mL −1 , 4.1 μmol•mL −1 ). Next, the ligand L was dissolved in dichloromethane (3.0 mg•mL −1 , 8.2 μmol•mL −1 ) and was added such that the moles of the ligand were 4 times that of the cluster precursor.…”

“…16 We note that the electrochemical response of multilayer films fabricated with the LB method was influenced by the molecule geometry and molecular packing. 12,13 Likewise, it was demonstrated that designing the interactions and components within the multilayer structures with ruthenium complexes could lead to highly organized structures with tuned properties, 17−20 such as fast electronic transport within the film. 17,18 The tailored films are especially suitable for electrochemical energy conversion and storage devices since their functioning relies on processes occurring at the electrode−electrolyte interface (e.g., electron transfer across the interface).…”

“…Organized films of molecular materials based on metal complexes have been the focus of our studies. We use the layer-by-layer method to obtain polyruthenated porphyrin films organized in stacked structures − and the LB technology to obtain films of amphiphilic − and non-amphiphilic ruthenium complexes and heterostructured films combining highly ordered structures and electroactive ruthenium complexes . We note that the electrochemical response of multilayer films fabricated with the LB method was influenced by the molecule geometry and molecular packing. , Likewise, it was demonstrated that designing the interactions and components within the multilayer structures with ruthenium complexes could lead to highly organized structures with tuned properties, − such as fast electronic transport within the film. , The tailored films are especially suitable for electrochemical energy conversion and storage devices since their functioning relies on processes occurring at the electrode–electrolyte interface (e.g., electron transfer across the interface). − …”