Rodríguez-Jiménez Santiago, Bennington Michael S, Akbarinejad Alireza, Tay Elliot J, Chan Eddie Wai Chi, Wan Ziyao, Abudayyeh Abdullah M, Baek Paul, Feltham Humphrey L C, Barker David, Gordon Keith C, Travas-Sejdic Jadranka, Brooker Sally
Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.
The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand.
ACS Appl Mater Interfaces. 2021 Jan 13;13(1):1301-1313. doi: 10.1021/acsami.0c16317. Epub 2020 Dec 22.
The successful covalent attachment, via copper(I)-catalyzed azide alkyne cycloaddition (CuAAC), of alkyne-functionalized nickel(II) and copper(II) macrocyclic complexes onto azide (N)-functionalized poly(3,4-ethylenedioxythiophene) () films on ITO-coated glass electrodes is reported. To investigate the surface attachment of the selected metal complexes, which are analogues of the cobalt-based complex previously reported to be a molecular catalyst for hydrogen evolution, first, three different PEDOT films were formed by electropolymerization of pure or pure , and last, were formed by co-polymerizing a 1:4 mixture of N-EDOT:EDOT monomers. The successful surface immobilization of the complexes on the latter two azide-functionalized films, by CuAAC, was confirmed by X-ray photoelectron spectroscopy (XPS) and electrochemistry as well as by UV-vis-NIR and resonance Raman spectroelectrochemistry. The ratio between the N groups, and hence, the number of surface-attached metal complexes after CuAAC functionalization, in pristine versus is expected to be 3:1 and seen to be 2.86:1 with a calculated surface coverage of 3.28 ± 1.04 and 1.15 ± 0.09 nmol/cm, respectively. The conversion, to the metal complex attached films, was lower for the films (Ni 74%, Cu 76%) than for the copolymer films (Ni 83%, Cu 91%) due to the former being more sterically congested. The Raman and UV-vis-NIR results were simulated using density functional theory (DFT) and time-dependent DFT (TD-DFT), respectively, and showed good agreement with the experimental data. Importantly, the spectroelectrochemical behavior of both anchored metal complexes is analogous to that of the free metal complexes in solution. This proves that PEDOT films are promising conducting scaffolds for the covalent immobilization of metal complexes, as the existing electrochromic features of the complexes are preserved on immobilization, which is important for applications in electrocatalytic proton and carbon dioxide reduction, optoelectronics, and sensing.
报道了通过铜（I）催化的叠氮化物-炔烃环加成反应（CuAAC），将炔烃功能化的镍（II）和铜（II）大环配合物成功共价连接到涂覆有ITO的玻璃电极上的叠氮化物（N）功能化聚（3,4-乙撑二氧噻吩）（）薄膜上。为了研究所选金属配合物的表面附着情况，这些配合物是先前报道的用于析氢的钴基配合物的类似物，首先，通过纯或纯的电聚合形成三种不同的PEDOT薄膜，最后，通过共聚N-EDOT：EDOT单体的1:4混合物形成。通过X射线光电子能谱（XPS）、电化学以及紫外可见近红外光谱和共振拉曼光谱电化学证实了通过CuAAC将配合物成功表面固定在后两种叠氮化物功能化薄膜上。原始中N基团之间的比例，以及因此在CuAAC功能化后表面附着金属配合物的数量，与中的比例预计为3:1，实际观察到为2.86:1，计算得到的表面覆盖率分别为3.28±1.04和1.15±0.09 nmol/cm²。由于薄膜空间位阻更大，其转化为金属配合物附着薄膜的转化率（镍74%，铜76%）低于共聚物薄膜（镍83%，铜91%）。分别使用密度泛函理论（DFT）和含时密度泛函理论（TD-DFT）对拉曼光谱和紫外可见近红外光谱结果进行了模拟，结果与实验数据吻合良好。重要的是，两种锚定金属配合物的光谱电化学行为与溶液中游离金属配合物的行为相似。这证明PEDOT薄膜是用于金属配合物共价固定的有前途的导电支架，因为配合物现有的电致变色特性在固定后得以保留，这对于电催化质子和二氧化碳还原、光电子学及传感应用很重要。
