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

贵金属的短缺和价格的上涨使得用丰富且优选生物相容的贱金属替代这些元素成为重要的科学挑战。特别是在光化学应用中，阳光是一种可持续的能源，贱金属作为关键元素将大大提高可持续性水平，因为不可再生资源的消耗大大降低。通过本提案，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-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，实现了铁（II）络合物的高八面体性和MLCT寿命延长。一种新型的MC激发态的反应性被证明和双色的方法进行了探索。通过实现铁（III）络合物实现了重大突破，该络合物显示出前所未有的双发射、创纪录的MLCT寿命和双分子反应性。这过多的新结果被理解的透彻的理论和光谱方法，如范围分离DFT功能调谐，超快瞬态吸收和发射和同步X射线光谱。到目前为止，第一个供资期产生了17个出版物，因此，本延续建议旨在进一步探索和推广已取得的不同成果。新的低自旋铁（II）和铁（III）配合物的三齿配体与长寿命的激发3 MLCT（3 MC/5 MC）/ 2LMCT状态将通过应用水库效应和新的配体设计与定制的供体/受体的性能。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所有的时间尺度从毫微微到微秒的光学和X射线光谱学和理论方法的新方法进行研究。在这些总体目标范围内，该项目触及优先计划主题的核心，即通过理解铁络合物中的电子激发态获得的合理方法，开发基于丰富金属的分子发射体和敏化剂，以取代稀有和贵金属中心。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，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.