Aktueller Hinweis

Die Veranstaltungen werden seit dem WS 2022/23 wieder in Präsenz durchgeführt. Hybride oder Online-Veranstaltungen sind aber auch möglich.

Foto Weynand.jpeg
© U. Weynand

Forschungsthemen

Biochemie und Naturstoffe
Katalyse und nachhaltige Chemie
Neue Methoden in der Synthese
Organo-Elektrochemie
Organometallverbindungen in der Synthese
Organische Materialien
Polymerchemie
Supramolekulare Chemie und Sensoren

OC-News
Research Training Group "Template-designed Organic Electronics“ (TIDE): Up to 14 funded PhD positions (f/m/x)

The Research Training Group “Template-Designed Organic Electronics – TIDE“, funded by the DFG (Deutsche Forschungsgemeinschaft) invites for applications.

 

Nanoscale π-conjugated ladders

It is challenging to increase the rigidity of a macromolecule while maintaining solubility. Established strategies rely on templating by dendrons, or by encapsulation in macrocycles, and exploit supramolecular arrangements with limited robustness. Covalently bonded structures have entailed intramolecular coupling of units to resemble the structure of an alternating tread ladder with rungs composed of a covalent bond. We introduce a versatile concept of rigidification in which two rigid-rod polymer chains are repeatedly covalently associated along their contour by stiff molecular connectors. This approach yields almost perfect ladder structures with two well-defined π-conjugated rails and discretely spaced nanoscale rungs, easily visualized by scanning tunnelling microscopy. The enhancement of molecular rigidity is confirmed by the fluorescence depolarization dynamics and complemented by molecular-dynamics simulations. The covalent templating of the rods leads to self-rigidification that gives rise to intramolecular electronic coupling, enhancing excitonic coherence. The molecules are characterized by unprecedented excitonic mobility, giving rise to excitonic interactions on length scales exceeding 100 nm. Such interactions lead to deterministic single-photon emission from these giant rigid macromolecules, with potential implications for energy conversion in optoelectronic devices.

Subcomponent self-assembly of circular helical Dy6(L)6 and bipyramid Dy12(L)8 architectures

Subcomponent self-assembly gave access to Dy12(L)8 and Dy6(L)6 architectures via second-order template effects. The Dy6(L)6 assembly behaves as a single-molecule magnet exhibiting a high anisotropy barrier and butterfly-shaped magnetic hysteresis.

Structural Disorder as the Origin of Optical Properties and Spectral Dynamics in Squaraine Nano-Aggregates

In contrast to regular J- and H-aggregates, thin film squaraine aggregates usually have broad absorption spectra containing both J-and H-like features, which are favorable for organic photovoltaics. Despite being successfully applied in organic photovoltaics for years, a clear interpretation of these optical properties by relating them to specific excited states and an underlying aggregate structure has not been made. In this work, by static and transient absorption spectroscopy on aggregated n-butyl anilino squaraines, we provide evidence that both the red- and blue-shifted peaks can be explained by assuming an ensemble of aggregates with intermolecular dipole–dipole resonance interactions and structural disorder deriving from the four different nearest neighbor alignments - in sharp contrast to previous association of the peaks with intermolecular charge-transfer interactions. In our model, the next-nearest neighbor dipole-dipole interactions may be negative or positive, which leads to the occurrence of J- and H-like features in the absorption spectrum. Upon femtosecond pulse excitation of the aggregated sample, a transient absorption spectrum deviating from the absorbance spectrum emerges. The deviation finds its origin in the excitation of two-exciton states by the probe pulse. The lifetime of the exciton is confirmed by the band integral dynamics, featuring a single-exponential decay with a lifetime of 205 ps. Our results disclose the aggregated structure and the origin of red- and blue-shifted peaks and explain the absence of photoluminescence in squaraine thin films. Our findings underline the important role of structural disorder of molecular aggregates for photovoltaic applications.

 

Veranstaltungen
Dr. Francisco Juliá-Hernández, University of Murcia
Kekulé-Institut
10:00 - 12:00
"Illuminating Earth-abundant Metals: New Opportunities in Organic Synthesis" Visible-light photoredox catalysis has driven the evolution towards more ...
GDCh-Preisverleihung
Chemische Institute - ...
17:00 - 19:00
Stefan Flesch, Universität Bonn Ultrafast dynamics of photochemical nitrile imine formation Claudia Gräve, Universität Bonn 2DIR Spectroscopy of ...
GDCh-Kolloquium Prof. Dr. Oliver Reiser
Chemische Institute - ...
17:00 - 18:00
Copper makes the difference: Developing Sustainable Photoredox Catalyzed Transformations Synthetic organic chemistry undertakes significant efforts to ...
GDCh-Kolloquium Prof. Dr. Tsuyoshi Kato
Chemische Institute ...
17:00 - 18:00
Low-valent silicon complexes and their analogues: surprising and peculiar behaviors For over ten years, we have been developing the chemistry of low-value ...

Arbeitsgruppen

                                                                                              

Jun. Prof. Dr. Bunescu
© A. Bunescu

Jun. Prof. Ala Bunescu

Transition Metal Catalysis
Organic Synthesis

Dickschat
© J. Dickschat

Prof. Dr. Jeroen Dickschat

Naturstoffchemie
Biosynthese, Synthese, Strukturaufklärung

Engeser
© M. Engeser

PD Dr. Marianne Engeser

Massenspektrometrie
Mechanismenaufklärung

AndreasGansäuerNeu
© Sophia Gansäuer

Prof. Dr. Andreas Gansäuer

Katalyse
Radikalchemie
Stereoselektive Synthese

höger
© S. Höger

Prof. Dr. Sigurd Höger

Organische Chemie
komplexer
Systeme

Lützen
© A. Lützen

Prof. Dr. Arne Lützen

Supramolekulare Chemie
Organische Synthese
NMR-Spektroskopie

menche
© D. Menche

Prof. Dr. Dirk Menche                        

Naturstoffe:
Charakterisierung, Totalsynthese,
Synthesemethoden

Jester.png
© Jester

Dr. Stefan-Sven Jester

Nachwuchsgruppe
Supramolekulare Parkettierung von Oberflächen,
Rastersondenmethoden

von Krbek
© L. von Krbek

Dr. Larissa von Krbek

Nachwuchsgruppe
Treibstoffgetriebene supramolekulare Systeme:
Synthese, Entwicklung und Untersuchung

Fachbibliothek Chemie

Die Fachbibliothek Chemie ist eine gemeinsame Bibliothek der Fachgruppe Chemie, die sich im Gebäude des Kekulé-Institut für Organische Chemie und Biochemie (EG) befindet. Sie besteht aus einer Sammlung von Monographien (Büchern), Zeitschriften und Serien und wird als Präsenzbibliothek geführt. Ein öffentliches Kopiergerät steht in der Bibliothek zur Verfügung.

Chemie im Nebenfach

Lehrveranstaltungen für Studierende der Humanmedizin, Zahnmedizin und Ernährungs- und Lebensmittelwissenschaften

Chemie für Mediziner und Zahnmediziner

Seminar, Vorlesung und Praktikum

Chemie für Ernährungs- und Lebensmittelwissenschaftler

Seminar, Vorlesung und Praktikum

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