TY  - JOUR
A1  - Full, Felix
A1  - Wölflick, Quentin
A1  - Radacki, Krzysztof
A1  - Braunschweig, Holger
A1  - Nowak‐Król, Agnieszka
T1  - Enhanced Optical Properties of Azaborole Helicenes by Lateral and Helical Extension
JF  - Chemistry – A European Journal
N2  - The synthesis and characterization of laterally extended azabora[5]‐, ‐[6]‐ and ‐[7]helicenes, assembled from N‐heteroaromatic and dibenzo[g,p]chrysene building blocks is described. Formally, the π‐conjugated systems of the pristine azaborole helicenes were enlarged with a phenanthrene unit leading to compounds with large Stokes shifts, significantly enhanced luminescence quantum yields (Φ) and dissymmetry factors (g\(_{lum}\)). The beneficial effect on optical properties was also observed for helical elongation. The combined contributions of lateral and helical extensions resulted in a compound showing green emission with Φ of 0.31 and |g\(_{lum}\)| of 2.2×10\(^{−3}\), highest within the series of π‐extended azaborahelicenes and superior to emission intensity and chiroptical response of its non‐extended congener. This study shows that helical and lateral extensions of π‐conjugated systems are viable strategies to improve features of azaborole helicenes. In addition, single crystal X‐ray analysis of configurationally stable [6]‐ and ‐[7]helicenes was used to provide insight into their packing arrangements.
KW  - azaborole
KW  - circularly polarized luminescence
KW  - fluorescence
KW  - helicene
KW  - π-extension
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293671
VL  - 28
IS  - 62
ER  - 
TY  - JOUR
A1  - Cataldi, Eleonora
A1  - Raschig, Martina
A1  - Gutmann, Marcus
A1  - Geppert, Patrick T.
A1  - Ruopp, Matthias
A1  - Schock, Marvin
A1  - Gerwe, Hubert
A1  - Bertermann, Rüdiger
A1  - Meinel, Lorenz
A1  - Finze, Maik
A1  - Nowak‐Król, Agnieszka
A1  - Decker, Michael
A1  - Lühmann, Tessa
T1  - Amber Light Control of Peptide Secondary Structure by a Perfluoroaromatic Azobenzene Photoswitch
JF  - ChemBioChem
N2  - The incorporation of photoswitches into the molecular structure of peptides and proteins enables their dynamic photocontrol in complex biological systems. Here, a perfluorinated azobenzene derivative triggered by amber light was site‐specifically conjugated to cysteines in a helical peptide by perfluoroarylation chemistry. In response to the photoisomerization (trans→cis) of the conjugated azobenzene with amber light, the secondary structure of the peptide was modulated from a disorganized into an amphiphilic helical structure.
KW  - amber light
KW  - decafluoroazobezene
KW  - peptide stapling
KW  - photocontrol
KW  - perfluoroarylation
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312480
VL  - 24
IS  - 5
ER  - 
TY  - JOUR
A1  - Wen, Xinbo
A1  - Nowak-Król, Agnieszka
A1  - Nagler, Oliver
A1  - Kraus, Felix
A1  - Zhu, Na
A1  - Zheng, Nan
A1  - Müller, Matthias
A1  - Schmidt, David
A1  - Xie, Zengqi
A1  - Würthner, Frank
T1  - Tetrahydroxy-perylene bisimide embedded in zinc oxide thin film as electron transporting layer for high performance non-fullerene organic solar cells
JF  - Angewandte Chemie International Edition
N2  - By introduction of four hydroxy (HO) groups into the two perylene bisimide (PBI) bay areas, new HO‐PBI ligands were obtained which upon deprotonation can complex ZnII ions and photosensitize semiconductive zinc oxide thin films. Such coordination is beneficial for dispersing PBI photosensitizer molecules evenly into metal oxide films to fabricate organic–inorganic hybrid interlayers for organic solar cells. Supported by the photoconductive effect of the ZnO:HO‐PBI hybrid interlayers, improved electron collection and transportation is achieved in fullerene and non‐fullerene polymer solar cell devices, leading to remarkable power conversion efficiencies of up to 15.95 % for a non‐fullerene based organic solar cell.
KW  - hydroxylation
KW  - metal complexenes
KW  - perylene bisimide
KW  - photoconductive interlayer
KW  - solar cells
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-204723
VL  - 58
IS  - 37
ER  - 
TY  - JOUR
A1  - Full, Julian
A1  - Panchal, Santosh P.
A1  - Götz, Julian
A1  - Krause, Ana‐Maria
A1  - Nowak‐Król, Agnieszka
T1  - Modulare Synthese helikal‐chiraler Organobor‐Verbindungen: Ausschnitte verlängerter Helices
JF  - Angewandte Chemie
N2  - Zwei Arten helikal-chiraler Verbindungen mit einem oder zwei Boratomen wurden nach einem modularen Ansatz synthetisiert. Die Bildung der helikalen Strukturen erfolgte durch Einführung von Bor in flexible Biaryl- bzw. Triaryl-Vorstufen, hergestellt aus kleinen achiralen Bausteinen. Die durchgehend ortho-fusionierten Azabora[7]helicene zeichnen sich dabei durch außergewöhnliche Konfigurationsstabilität, blaue oder grüne Fluoreszenz in Lösung mit Quantenausbeuten (Φ\(_{fl}\)) von 18–24 %, grüne oder gelbe Emission im Festkörper (Φ\(_{fl}\) bis zu 23 %) und starke chiroptische Resonanz mit großen Anisotropiefaktoren von bis zu 1.12×10\(^{-2}\) aus. Azabora[9]helicene, aufgebaut aus winkelförmig sowie linear angeordneten Ringen, sind blaue Emitter mit Φ\(_{fl}\) von bis zu 47 % in CH\(_{2}\)Cl\(_{2}\) und 25 % im Festkörper. DFT-Rechnungen zeigen, dass ihre P-M-Interkonversion über einen komplexeren Weg verläuft als im Fall von H1. Röntgenstrukturanalyse von Einkristallen zeigt deutliche Unterschiede in der Packungsanordnung von Methyl- und Phenylderivaten auf. Die Moleküle werden als Primärstrukturen verlängerter Helices vorgeschlagen.
KW  - Chiralität
KW  - Fluoreszenz
KW  - Helicen
KW  - Organobor
KW  - Zirkulardichroismus
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224385
VL  - 133
IS  - 8
SP  - 4396
EP  - 4403
ER  - 
TY  - JOUR
A1  - Full, Julian
A1  - Panchal, Santosh P.
A1  - Götz, Julian
A1  - Krause, Ana‐Maria
A1  - Nowak‐Król, Agnieszka
T1  - Modular Synthesis of Organoboron Helically Chiral Compounds: Cutouts from Extended Helices
JF  - Angewandte Chemie International Edition
N2  - Two types of helically chiral compounds bearing one and two boron atoms were synthesized by a modular approach. Formation of the helical scaffolds was executed by the introduction of boron to flexible biaryl and triaryl derived from small achiral building blocks. All‐ortho‐fused azabora[7]helicenes feature exceptional configurational stability, blue or green fluorescence with quantum yields (Φ\(_{fl}\)) of 18–24 % in solution, green or yellow solid‐state emission (Φ\(_{fl}\) up to 23 %), and strong chiroptical response with large dissymmetry factors of up to 1.12×10\(^{-2}\). Azabora[9]helicenes consisting of angularly and linearly fused rings are blue emitters exhibiting Φ\(_{fl}\) of up to 47 % in CH\(_{2}\)Cl\(_{2}\) and 25 % in the solid state. As revealed by the DFT calculations, their P–M interconversion pathway is more complex than that of H1. Single‐crystal X‐ray analysis shows clear differences in the packing arrangement of methyl and phenyl derivatives. These molecules are proposed as primary structures of extended helices.
KW  - chirality
KW  - circular dichroism
KW  - fluorescence
KW  - helicene
KW  - organoboron
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225775
VL  - 60
IS  - 8
SP  - 4350
EP  - 4357
ER  - 
TY  - JOUR
A1  - Wildervanck, Martijn J.
A1  - Hecht, Reinhard
A1  - Nowak-Król, Agnieszka
T1  - Synthesis and strong solvatochromism of push-pull thienylthiazole boron complexes
JF  - Molecules
N2  - The solvatochromic behavior of two donor-π bridge-acceptor (D-π-A) compounds based on the 2-(3-boryl-2-thienyl)thiazole π-linker and indandione acceptor moiety are investigated. DFT/TD-DFT calculations were performed in combination with steady-state absorption and emission measurements, along with electrochemical studies, to elucidate the effect of two different strongly electron-donating hydrazonyl units on the solvatochromic and fluorescence behavior of these compounds. The Lippert–Mataga equation was used to estimate the change in dipole moments (Δµ) between ground and excited states based on the measured spectroscopic properties in solvents of varying polarity with the data being supported by theoretical studies. The two asymmetrical D-π-A molecules feature strong solvatochromic shifts in fluorescence of up to ~4300 cm\(^{−1}\) and a concomitant change of the emission color from yellow to red. These changes were accompanied by an increase in Stokes shift to reach values as large as ~5700–5800 cm\(^{−1}\). Quantum yields of ca. 0.75 could be observed for the N,N-dimethylhydrazonyl derivative in nonpolar solvents, which gradually decreased along with increasing solvent polarity, as opposed to the consistently reduced values obtained for the N,N-diphenylhydrazonyl derivative of up to ca. 0.20 in nonpolar solvents. These two push–pull molecules are contrasted with a structurally similar acceptor-π bridge-acceptor (A-π-A) compound.
KW  - solvatochromism
KW  - donor–acceptor
KW  - fluorescence
KW  - hydrazone
KW  - Lippert–Mataga plot
KW  - push–pull thienylthiazole
KW  - tetracoordinated boron
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286186
SN  - 1420-3049
VL  - 27
IS  - 17
ER  -