基于环金属钌配合物的电极表界面电子转移

The electron transfer studies in solution state have been largely disconnected with those occurring at the interface between electrodes and thin films. Previous works have established that bridged cyclometalated diruthenium complexes or amine-ruthenium conjugated complexes with a Ru-C bond show appealing electron transfer and optoelectronic properties in solution states. The present project is devoted to the interfacial electron studies of thin films of such ruthenium complexes at electrode surfaces. A series of molecular wires based on cyclometalated ruthenium complexes with excellent geometries and conducting ability will be designed and synthesized. These complexes are used to prepare monolayer and multilayer thin films with well-defined morphology, orderness, and thickness. By systematic modulation of the molecular structures of these coordination molecular wires, interfacial long-range electron transfer with high conductivity will be realized. In addition, thin films with different compositions will be prepared by in situ electropolymerization. Depending on the composition and energy level, these films are used to regulate the direction and efficiency of interfacial electron transfer. Further studies will focus on the potential applications of these films on single molecular conductance and organic resistive memories. With these studies, the difference of the electron transfer mechanism of the same materials under different measurement conditions, e.g., electrochemical environment, single molecular conductance measurement condition, and solid devices, is expected to be rationalized.

一直以来，溶液状态的电子转移研究与电极表界面电子转移的探索未能形成有效衔接。前期工作表明，含有碳-钌金属键的桥联环金属双钌配合物和胺-钌共轭配合物在溶液状态中具有优秀的电子转移和光电性质。本项目拟开展此类配合物在电极表界面的电子转移研究。设计、合成一系列具有优秀构型和导电能力的环金属钌配合物导线分子，制备形貌、规整度、厚度精确可控的配合物自组装单层膜和多层膜，通过分子结构的系统优化，实现配合物导线分子诱导的表界面长程电子转移和高导电性能。通过电化学原位聚合，制备具有不同薄膜结构的金属钌配合物电聚合薄膜，研究薄膜结构和能级排列对表界面电子转移方向和效率的影响。进一步探索基于环金属钌功能配合物材料的新型分子电子学器件，实现分子层次多态导电和有机电存储，并阐明相同分子材料在电化学环境、单分子导电以及固态薄膜器件几种不同测试条件下导电机制的差异。

电子转移过程在自然界中广泛存在。基于光功能配合物的纳米薄膜的可控制备与界面电子转移研究对理解自然界的电子转移和人工模拟光合作用有重要意义。本项目基于金属钌、铂配合物，开展具有锚定基团的配合物的合成，配位组装薄膜的可控制备以及相应有机电子学方面的应用等方面工作。设计、合成了一系列响应型电化学活性金属钌配合物，通过Ru-C金属键实现低氧化还原电位和强金属-金属电子相互作用。通过吡啶多位点锚定基团和金属钯-吡啶的配位组装，实现金属配合物在ITO, Au表面的单层和多层薄膜的可控制备；通过羧基官能团与氧化物纳米晶体的共价作用以及Zr-O共价作用，实现环金属钌单核、双核以及三核配合物在氧化物纳米晶体表面的单层和多层薄膜的制备，进一步利用高效的界面电子转移过程，实现1150、1310、1550 nm等不同波长的较高性能的近红外电致变色。制备吡啶官能团化的金属铂大环配合物，利用主-客体相互作用调控大环分子的单分子导电行为；合成了一系列光功能金属钌、铂配合物，对其聚集发光和聚集增加圆偏振发光开展了研究。本项目研究成果在Nat. Commun., J. Am. Chem. Soc., Angew. Chem.等期刊上发表论文28篇, 申请或授权专利5项，应邀在Coord. Chem. Rev., ACS Sustainable Chem. Eng.和Chin. J. Chem.等期刊撰写综述。