Research Area C: Spectroscopy and Optical Properties
Ab Initio Computation of Optical Properties of Transition-Metal and Lanthanoid Compounds
The primary aims of the subproject are the computation of vertical and adiabatic excitation energies of metal complexes, their structure determination in ground and electronically excited states, and the prediction and interpretation of absorption and emission spectra with the methods of time-dependent density functional theory (TDDFT). Wave function based methods shall be employed for calibration. The (TD)DFT methods shall be supplemented with additional constraints and new functionals. Two-component explicitly correlated wave function based linear response methods shall be developed.
Structure, Electronic States and Reactions of Isolated Clusters and Complexes Containing Transition Metals
In order to describe catalytical processes and magnetic behaviours more detailed, a precise knowledge of structure and reactivity on a molecular level is extremely important. For this purpose isolated neutral and anionic clusters or complexes containing two or three metal atoms are analyzed as model systems in molecular beam experiments by a variety of partly new IR spectroscopic or combined IR/UV spectroscopic techniques. Structure, spin states and partly reactivity are discussed with respect to functional cooperativity in dependence of number, arrangement and type of metal centres and ligands.
Multinuclear Gold Complexes
The aim of the project is the synthesis of dinuclear Au(I) complexes having aurophilic interactions. Optical and catalytic properties of the new compounds will be investigated. Two gold(I) ion will be coordinated to a rigid Ph2P-X-PPh2 core, in which X is either an amine of a chiral group. Based on these frameworks complexes with different Au-Au distances will be synthesized. In comparison to related gold complexes without aurophilic interactions the luminescence properties in the solid state and in the gas phase will be investigated. Moreover dyes will be attached to the ligand to generate an antenna effect. Further modification of the ligand framework should lead to heterobimetallic complexes with and without direct metal-to-metal bonds. The incorporation of the metal ions into the gold complexes will influence the Au-Au interactions and concomitant the luminescence properties. In cooperation with other research groups a comprehensive study of the all photo physical properties of the new compounds will be performed.
Ultrafast Molecular Dynamics in Metal Complexes
In this collaborative project methods of femtosecond time-resolved laser spectroscopy (transient absorption in the UV/Vis and midIR, transient photofragmentation with mass spectrometry analysis) is employed for both condensed (Diller) and gas phase (Riehn) investigation of the dynamics of photophysical and photochemical elementary and transport processes in solvated transition metal-ligand-systems.
C5: Aeschlimann/Ruben (till 2018)
Spectroscopy and Electron Dynamics of Polynuclear Lanthanide Complexes (Multi-Lanthanoid)
The project C5 Aeschlimann/Ruben is based on the interdisciplinary cooperation of two scientific approaches: (i) tailored synthesis of multinuclear complexes including Lanthanide metal ions, and (ii) the space- and time-resolved spectroscopic investigation of these complexes, partially deposited on different substrates. Occupied as well as unoccupied states of the multinuclear complexes are supposed to be investigated; in particular, the relaxation dynamic of optical excited states in function of the nature of the substrate.
Polynuclear Metal Phthalocyanine and Metal Porphyrin Complex Ions: Gas-phase Structures and Reactivities
The goal of the sub project is the investigation of the structures and reactivities of mononuclear and polynuclear metal-aromatics-complexes in gas phase. The focus will be multiply negatively charged metal porphyrine and metal phthalocyanine complexes. Their structural characterisation will be done via ion mobility mass spectrometry in combination with photoelectron and photo dissociation spectroscopy. Furthermore we plan temperature dependent kinetics measurements in a Penning trap regarding the redox reactivity aiming towards a better understanding of the metal-aromatic-metal interaction, i.e. to find answers to the question as to which extent an aromatic molecule between two metal centers influences their cooperativity.
Methodologies for gas-phase studies as supplied in this project are virtually ideally suited to study these phenomena and will be applied to 3MET complexes – in most cases for the first time.
Luminescence Properties of Isolated Lanthanide and Transition Metal Complexes
The subproject seeks to study the luminescence properties of isolated lanthanoid- and transition metal ion complexes. The goal is to obtain a deeper understanding of associated energy transfer mechanisms and inter-metal-ion coupling processes. Towards this aim we will also probe the influence of the environment (solvent molecules and crystal fields) on optical properties. Gas phase experiments will be supported by analogous measurements in condensed phase and by quantum chemical calculations. One focus will be on complexes containing trivalent rare earth ions. Among the latter we will search for molecular models of NIR-Quantum-Cutters.
Electronic dynamics of luminescent 3MET systems
This 3MET project studies 3MET complexes for their interaction with surfaces of various reactivity. It utilizes Mo2 complexes, multidecker lanthanide phthalocyanines, multi-metallic porphyrin complexes, and endohedral fullerenes. It exerts external control of the intramolecular cooperativity of 3MET complexes on surfaces by temperature or light in order to manipulate the electronic properties of substrate surfaces ranging from noble metals towards topological insulators and 2D graphene-like honey comb structures. Both approaches will significantly contribute to an in-depth understanding of intramolecular cooperativity effects for 3MET molecules on surfaces.