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

贵金属的短缺和价格上涨使得用丰富的、最好是生物相容的贱金属取代这些元素是一项重大的科学挑战。特别是在光化学应用中，阳光是一种可持续的能源，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消耗显著降低。通过目前的提议，我们希望通过使用光化学中含量最丰富的过渡金属-铁-来为这一全球目标做出贡献。在PP 2102的第一个资助期内，爱斯基摩项目在使用5环和6环螯合物进行激发态调节的新型配体方面取得了重大进展，在铁(II)络合物中实现了高八面体和MLCT寿命延长。证明了一种新型的MC激发态反应性，并探索了一种双色方法。通过实现前所未有的双发射、创纪录的MLCT寿命和双分子反应活性的铁(III)络合物，实现了重大突破。这一过多的新结果被深入的理论和光谱方法所理解，如距离分离的DFT函数调谐、超快瞬时吸收和发射以及同步辐射X射线光谱。到目前为止，第一个资助期产生了17种出版物，因此，这项延续建议的目的是进一步探索和推广不同的成果。利用储备库效应和具有特殊给体/受体性质的新型配体设计，可以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。利用光学和X射线光谱的新方法和理论方法，将在从飞秒到微秒的所有时间尺度上研究这些络合物的激发态景观，包括所有相关的激发态和光诱导动力学。开发的配合物将被用于光化学应用和新型发光材料。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，因为通过了解铁配合物中的电子激发态，通过合理的方法开发基于丰富金属的分子发射体和敏化剂来取代稀有金属和贵金属中心。有了超快瞬变吸收光谱、超快X射线光谱和散射方法以及量子化学计算和动力学，动态环境效应将可以获得对所有相关过程的整体看法。

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.