Achieving NIR circularly polarized luminescence (CPL) by triad change of d10 systems

手性光活性化合物在近红外（λem > 700 nm）三重激发态显示出圆偏振发光（CPL），有可能极大地影响可能改变游戏规则的技术的发展，如量子计算和密码学，自旋电子学和生物传感器。设计适合于基于电致发光的这种应用的分子系统的挑战是多方面的，具有与同时高发光效率和左和右偏振发射的高不对称性的互斥先决条件相关的特别有趣的智力困境。根据能隙定律，分子低能发射体通常显著地遭受非辐射衰变，并且因此高辐射速率常数k（r）（即高电跃迁偶极矩）是强制性的以胜过k（nr）。然而，具有高不对称因子g（lum）的CPL需要大的磁跃迁偶极矩，这对k（r）是有害的。因此，需要在这两种性质之间找到非常精细的平衡，以有效地收获NIR中的三重态用于手性光学应用。虽然第11族的d10金属络合物通常表现出LLCT/MLCT激发态，但第12族化合物主要由LLCT/LMCT电子结构控制，并且已经发现，实现具有高k（r）的NIR发射存在严重限制。相比之下，具有强供体配体的第10族络合物受益于高氧化电位，允许具有高自旋-轨道耦合的非常低能量的MLCT状态。因此，在这个合作项目中，我们的目标是联合收割机结合我们在合成化学，光谱学和理论化学领域的专业知识，构建线性和三角形配位几何结构的手性高效（Ni 0/Pd 0/Pt 0）发光体，其中三重态发射的不对称性通过配体环境进行微调。合适的候选化合物将在概念验证应用中进行测试，例如NIR-CPL-OLED或非经典单光子源。

Chiral photoactive compounds that exhibit circularly polarized luminescence (CPL) in the near-IR (λem > 700 nm) from triplet excited states have the potential to greatly influence the development of possibly game-changing technologies, such as quantum computing and cryptography, spintronics, and biosensors. The challenges to design molecular systems suitable for such applications based on electroluminescence are manifold, with a particularly intriguing intellectual dilemma related to the mutually exclusive prerequisites for simultaneously high luminescence efficiency and high dissymmetry of left and right polarized emission. Molecular low-energy emitters typically suffer significantly from non-radiative decay according to the energy gap law, and thus high radiative rate constants k(r) (i.e. high electric transition dipole moments) are mandatory to outcompete k(nr). However, CPL with a high dissymmetry factor g(lum) requires a large magnetic transition dipole moment, that is detrimental to k(r). Thus, a very fine balance needs to be found between these two properties to efficiently harvest triplet states in the NIR for chiroptical applications. While d10 metal complexes of group 11 typically exhibit LLCT/MLCT excited states, group 12 compounds are dominated by LLCT/LMCT electronic structures and it has been found that there are severe limitations to achieve NIR emission with high k(r). In contrast, group 10 complexes bearing strongly donating ligands benefit from high oxidation potentials, allowing for very low energy MLCT states with high spin-orbit coupling. Thus, within this collaborative project, we aim to combine our expertise in the fields of synthetic chemistry, spectroscopy and theoretical chemistry to construct chiral highly efficient (Ni0/Pd0/Pt0) luminophores in linear and trigonal coordination geometries, of which the dissymmetry of the triplet state emission is fine-tuned by the ligand environment. Suitable candidate compounds will be tested in proof-of-concept applications such as NIR-CPL-OLEDs or non-classical single-photon sources.