ESKIMO-Pro-IRON - Excited State Kinetic Modelling and Properties Tuning of Iron Complexes

贵金属的短缺和不断上涨的价格使得用丰富且具有良好生物相容性的贱金属来替代这些元素成为一项重要的科学挑战。特别是在光化学应用中，阳光是一种可持续的能源来源，贱金属作为关键元素将极大地提高可持续性水平，因为不可再生资源的枯竭大大降低。根据目前的建议，我们希望通过在光化学中使用最丰富的过渡金属-铁来为这一全球目标做出贡献。在PP 2102的第一个资助期内，ESKIMO项目在采用5环和6环螯合物进行激发态调整的新型配体方面取得了重大进展，在铁（II）配合物中实现了高八面性和MLCT寿命延长。证明了一种新型的MC激发态反应，并探索了一种双显色的方法。实现了铁（III）配合物的重大突破，该配合物具有前所未有的双发射、创纪录的MLCT寿命和双分子反应性。这大量的新结果是通过全面的理论和光谱方法，如距离分离DFT功能调谐，超快瞬态吸收和发射以及同步加速器x射线光谱学来理解的。到目前为止，第一个筹资期出版了17份出版物。因此，本续提案旨在进一步探索和延伸不同的已取得成果。利用储层效应和具有特定供体/受体性质的新配体设计，将制备具有长寿命激发态3MLCT (3MC/5MC) / 2LMCT的新型低自旋铁（II）和铁（III）配合物。这些复合物的激发态景观，包括所有相关的激发态和光致动力学，将在从飞到微秒的所有时间尺度上通过光学和x射线光谱学的新方法和理论方法进行研究。所开发的配合物将在光化学应用和新型发光材料中得到开发。在这些总体目标中，该项目击中了优先计划主题焦点的核心，即基于丰富金属的分子发射器和敏化剂，以取代稀有和贵重金属中心，通过理解铁配合物中的电子激发态而获得的合理方法来开发。利用超快瞬态吸收光谱、超快x射线光谱和散射方法以及量子化学计算和动力学，将可以获得动态环境效应，从而全面了解所有相关过程。

The shortage and increasing prices of noble metals makes the substitution of such elements by abundant and preferably biocompatible base metals an important scientific challenge. Especially in photochemical applications, where sunlight is a sustainable source of energy, base metals as key element will tremendously increase the level of sustainability, as the non-renewable resource depletion is significantly lowered. With the present proposal, we want to contribute to this global aim by employing the most abundant transition metal – iron – in photochemistry. Within the first funding period of the PP 2102, the ESKIMO project achieved significant progress in novel ligands employing 5- and 6-ring chelates for excited state tuning, achieving high octahedricity and MLCT lifetime elongation in iron(II) complexes. A novel type of MC excited state reactivity was demonstrated and a bichromophoric approach was explored. A major breakthrough was achieved by realizing an iron(III) complex showing unprecedented dual emission, a record MLCT lifetime and bimolecular reactivity. This plethora of new results were understood by thorough theoretical and spectroscopic methods such as range-separated DFT functional tuning, ultrafast transient absorption and emission and synchrotron X-ray spectroscopy. Up to date, 17 publications resulted from the first funding period.Consequently, this continuation proposal aims at further exploration and extension of the different achieved results. Novel low-spin iron(II) and iron(III) complexes of tridentate ligands with long-lived excited 3MLCT (3MC/5MC) / 2LMCT states will be prepared by application of the reservoir effect and new ligand designs with tailor-made donor/acceptor properties. The excited state landscape of these complexes including all relevant excited states and photoinduced dynamics will be investigated on all timescales from femto- to microseconds by new approaches in optical and X-ray spectroscopy and theoretical methods. The developed complexes will be exploited in photochemical applications and novel luminescent materials.Within these overarching aims, the project hits the core of the priority program’s thematic focus as molecular emitters and sensitizers based on abundant metals to replace rare and precious metal centres are developed by rational approaches gained by understanding electronically excited states in iron complexes. With ultrafast transient absorption spectroscopy, ultrafast X-ray spectroscopy and scattering methods and quantum chemical calculations and dynamics, dynamic environmental effects will be accessible to gain a holistic view on all relevant processes.