Article
Chemistry, Organic
Ester Sans-Panades, Juan J. Vaquero, Manuel A. Fernandez-Rodriguez, Patricia Garcia-Garcia
Summary: The reaction of BCl3 with suitably substituted o-alkynylani-lines promotes a cascade reaction to obtain BN-polycyclic compounds through the formation of two new cycles and three new bonds in a single operational step. This reaction is highly efficient and can be conducted at room temperature, providing a mild and straightforward strategy for the preparation of BN-aromatic compounds, which can further be transformed into various BN-PAHs with different polycyclic cores and substituents.
Article
Chemistry, Multidisciplinary
Max Wienhold, John J. Molloy, Constantin G. Daniliuc, Ryan Gilmour
Summary: Modular beta-borylacrylates have been shown to play a crucial role in generating diverse coumarins, with the BPin unit enabling the cascade annulation of 2-halo-phenol derivatives. Mild isomerisation allows for the synthesis of structurally varied coumarins, and the method has potential applications in bioassay development and drug repurposing.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Stephan Hagspiel, Felipe Fantuzzi, Rian D. Dewhurst, Annalena Gaertner, Felix Lindl, Anna Lamprecht, Holger Braunschweig
Summary: Lewis base adducts and cyclodimers of the parent boraphosphaketene were prepared for the first time, with one adduct undergoing decarbonylation and phosphinidene insertion to form very rare 1,2-phosphaborinines, B/P isosteres of benzene. The strong donor properties of these 1,2-phosphaborinines were confirmed through synthesis of their pi complexes with Group 6 metals.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Peng-Fei Zhang, Jing-Cai Zeng, Fang-Dong Zhuang, Ke-Xiang Zhao, Ze-Hao Sun, Ze-Fan Yao, Yang Lu, Xiao-Ye Wang, Jie-Yu Wang, Jian Pei
Summary: Introducing BN units into polycyclic aromatic hydrocarbons expands the chemical space of conjugated materials with novel properties. The study shows that the orientation of BN has significant effects on the structure, (anti)aromaticity, crystal packing, and photophysical properties. These findings provide guidance for the synthesis of BN-PAHs with specific stacking structures.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Wanhui Li, Cheng-Zhuo Du, Xing-Yu Chen, Lin Fu, Rong-Rong Gao, Ze-Fan Yao, Jie-Yu Wang, Wenping Hu, Jian Pei, Xiao-Ye Wang
Summary: We have successfully developed high-mobility organic semiconductors based on BN-PAHs through the periphery engineering strategy. One particular BN-PAH, DPBNA, showed remarkable performance in organic field-effect transistors with a hole mobility of 1.3 cm(2) V-1 s(-1), surpassing TPBNA and all previously reported BN-PAHs. Remarkably, this is the first BN-PAH with a mobility exceeding 1 cm(2) V(-1) s(-1), making it a benchmark for practical applications comparable to amorphous silicon. Additionally, high-performance phototransistors based on DPBNA were demonstrated, indicating the high potential of BN-PAHs for optoelectronic applications when the periphery engineering strategy is implemented.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Grace L. Trammel, Prashansa B. Kannangara, Dmytro Vasko, Oleksandr Datsenko, Pavel Mykhailiuk, M. Kevin Brown
Summary: Two catalytic systems have been developed for the arylboration of endocyclic enecarbamates, resulting in the synthesis of versatile borylated saturated N-heterocycles with good regio- and diastereoselectivities. The Cu/Pd dual catalytic reaction enables the synthesis of borylated, alpha-arylated azetidines, while the Ni-catalysed arylboration reaction efficiently functionalizes 5-, 6-, and 7-membered enecarbamates. The use of additives in the Cu/Pd system allows for a broader scope of reactions, and the products can be further manipulated to access biologically active compounds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Xin-Shen Liang, Rui-Dong Li, Wei Sun, Zhong Liu, Xiao-Chen Wang
Summary: Borane-mediated hydride abstraction has been shown to be a powerful tool for the C(sp(3))-H functionalization of amines, but its activity with ethers is still unknown. In this study, we discovered this activity in 2H-chromenes and established a catalytic C(sp(3))-H functionalization reaction using silyl ketene acetals as nucleophiles.
Article
Chemistry, Multidisciplinary
Henric Steffenfauseweh, Yury V. Vishnevskiy, Beate Neumann, Hans-Georg Stammler, Diego M. Andrada, Rajendra S. Ghadwal
Summary: In this study, the synthesis, characterization, and reactivity of the first cyclic C2As2-diradicaloid compound were reported. The compound exhibits a planar C2As2 ring, is diamagnetic, and shows well resolved NMR signals.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Organic
Xu Xiaoyang, Liu Meiyan, Li Chenglong, Liu Xuguang
Summary: By replacing carbon carbon (CC) units with an isoelectronic and isostructural boron nitrogen (BN) units, the electronic structure and intermolecular interactions of polycyclic aromatic hydrocarbons (PAHs) can be fine-tuned, resulting in new BN-heteroaromatics with unique optoelectronic properties and bioactivity. The recent advance of 1,2-BN heteroaromatics in China from the chemistry perspective is summarized, including their synthetic development and applications in various research fields, with the development prospects of BN-heteroaromatics pointed out.
CHINESE JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Ming Zhang, Qingyang Zhou, Heng Luo, Zi-Lu Tang, Xiufang Xu, Xiao-Chen Wang
Summary: Here, we present a method for C3-selective cyanation of pyridines by a tandem process using an in situ generated dihydropyridine and a cyano electrophile. This method is suitable for late-stage functionalization of pyridine drugs. The success of this method relies on the low reduction potential of the electrophile and effective transfer of the nitrile group. Detailed investigation of the reaction mechanism revealed that a combination of electronic and steric factors determines the regioselectivity of reactions involving C2-substituted pyridines.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Quentin Dherbassy, Srimanta Manna, Chunling Shi, Watcharapon Prasitwatcharakorn, Giacomo E. M. Crisenza, Gregory J. P. Perry, David J. Procter
Summary: In this study, an enantioselective copper-catalyzed borylative cyclization was reported for the assembly of privileged pyrroloquinazolinone motifs. The reaction demonstrated high enantio- and diastereocontrol, yielding products with quaternary stereocenters. The utility of the products was further demonstrated through additional manipulations.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Cheng Chen, Ming-Wei Wang, Xing-Yu Zhao, Shuang Yang, Xing-Yu Chen, Xiao-Ye Wang
Summary: This study reports the synthesis of highly stable boron-embedded heptacene (DBH) and air-sensitive nonacene (DBN). The structures of these compounds were confirmed and found to have a linear backbone with an antiaromatic C4B2 core. Photophysical characterizations showed that both compounds exhibit efficient anti-Kasha emissions. The air-stable DBH showed an ultrahigh photoluminescence quantum yield and can be chemically reduced to its radical anion and dianion states.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Junki Kashida, Yoshiaki Shoji, Yasuhiro Ikabata, Hideo Taka, Hayato Sakai, Taku Hasobe, Hiromi Nakai, Takanori Fukushima
Summary: By replacing carbon-carbon bonds with polar boron-nitrogen bonds, a highly stable B4N4-heteropentalene derivative 1 with excellent photophysical properties was synthesized. In a glassy matrix, 1 exhibited a high-energy triplet state and was successfully used to fabricate a phosphorescent organic light-emitting diode.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Ming Zhang, Xiao-Chen Wang
Summary: This method presents a mild and efficient approach for synthesizing enantioenriched tetrahydroquinoline-fused cyclobutenes through a cascade reaction, catalyzed by chiral spiro-bicyclic bisboranes. The bisboranes function by catalyzing hydride transfer and activating the alkynone substrate for an enantioselective cycloaddition reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Josh Abbenseth, Oliver P. E. Townrow, Jose M. Goicoechea
Summary: A geometrically constrained phosphine bearing a tridentate NNS pincer ligand has been successfully used to reversibly activate ammonia through N-H bond scission upon mild heating in solution, as demonstrated through experimental and theoretical studies. The geometric constraint also leads to the formation of cooperative addition products, and the thermodynamics of these transformations are substrate-dependent.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Kevin Bold, Matthias Stolte, Kazutaka Shoyama, Marco Holzapfel, Alexander Schmiedel, Christoph Lambert, Frank Wuerthner
Summary: Two macrocyclic architectures comprising oligothiophene strands that connect the imide positions of a perylene biscimide (PBI) dye have been synthesized via a platinum-mediated cross-coupling strategy. The crystal structure of the double bridged PBI reveals all syn-arranged thiophene units enclosed a planar PBI chromophore via a 12-membered macrocycle. The target structures exhibit ultrafast Forster Resonance Energy Transfer and photoinduced electron transfer, resulting in extremely low fluorescence quantum yields even in the lowest polarity cyclohexane solvent.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Polymer Science
Joshua Selby, Marco Holzapfel, Krzysztof Radacki, Asim Kumar Swain, Holger Braunschweig, Christoph Lambert
Summary: This study investigates the influence of chirality on the structure and properties of cisoid indolenine squaraine polymers with different side chains. The absorption spectroscopy and circular dichroism results show that the behavior of the polymers is strongly dependent on the solvent and the type of side chains. The temperature-dependent absorption spectroscopy reveals the thermodynamic parameters of helix folding and suggests that increasing the steric demand of the side chains leads to an increase in entropy and enthalpy. Fluorescence spectroscopy confirms the structural characteristics of the polymers.
Article
Chemistry, Multidisciplinary
Rebecca Renner, Matthias Stolte, Julia Heitmueller, Tobias Brixner, Christoph Lambert, Frank Wuerthner
Summary: The study focused on the functional properties of different PBI anions and dianions with varying bay-substituents, revealing significant changes in their absorption spectra, indicating their potential for optoelectronic device applications.
MATERIALS HORIZONS
(2022)
Article
Chemistry, Multidisciplinary
Goutam Kumar Kole, Marta Koscak, Anissa Amar, Dragomira Majhen, Ksenija Bozinovic, Zlatko Brkljaca, Matthias Ferger, Evripidis Michail, Sabine Lorenzen, Alexandra Friedrich, Ivo Krummenacher, Michael Moos, Holger Braunschweig, Abdou Boucekkine, Christoph Lambert, Jean-Francois Halet, Ivo Piantanida, Klaus Mueller-Buschbaum, Todd B. Marder
Summary: A series of bis-(4'-pyridylethynyl)arenes were synthesized and investigated for their photophysical and electrochemical properties, as well as their interactions with DNA/RNA. These compounds showed potential as therapeutic and diagnostic agents due to their interactions with DNA/RNA.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Matthias Ferger, Chantal Roger, Eva Koester, Florian Rauch, Sabine Lorenzen, Ivo Krummenacher, Alexandra Friedrich, Marta Koscak, Davor Nestic, Holger Braunschweig, Christoph Lambert, Ivo Piantanida, Todd B. Marder
Summary: This study synthesized three novel tetracationic bis-triarylboranes with 3,4-ethylenedioxythiophene (EDOT) linkers, resulting in red-shifted absorption and emission. One of the EDOT derivatives emitted in the near-infrared (NIR) region. Comparative analysis showed that only the EDOT-linked trixylylborane tetracation was stable in aqueous solution, suggesting the insufficient hydrolytic stability of directly attaching thiophene or 3-methylthiophene to the boron atom. Furthermore, the EDOT-linked trixylylborane tetracation and its bis-thiophene analogue exhibited efficient photo-induced singlet oxygen production with significant biological implications.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Thomas Wiesner, Zhu Wu, Jie Han, Lei Ji, Alexandra Friedrich, Ivo Krummenacher, Michael Moos, Christoph Lambert, Holger Braunschweig, Benjamin Rudin, Hilmar Reiss, Olena Tverskoy, Frank Rominger, Andreas Dreuw, Todd B. Marder, Jan Freudenberg, Uwe H. F. Bunz
Summary: Tetraiodotetraazapentacene I(4)TAP, a new derivative in the series of halogenated silylated tetraazapentacenes, has been successfully synthesized and characterized by crystallography. Its air-stable monoanion and relatively air-stable dianion were obtained through reduction reactions and also confirmed by crystallography. Additionally, the structural and spectroscopic properties of I(4)TAP were compared to non-halogenated TAP and Br(4)TAP. It was found that I(4)TAP exhibits high electron mobility in thin-film transistors.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Biochemistry & Molecular Biology
Ksenija Bozinovic, Davor Nestic, Evripidis Michail, Matthias Ferger, Marta Koscak, Christoph Lambert, Dragomira Majhen, Todd B. Marder, Ivo Piantanida
Summary: We reported a new type of compound that shows remarkable sensing ability in DNA/RNA and also exhibits biological activity in photodynamic therapy, making them potential therapeutic probes. These compounds can effectively enter living cells with negligible inhibition on cell proliferation. Regarding viruses, some of these compounds have high affinity to adenovirus type 5 and can weaken its ability to infect human cells. Upon visible light irradiation, these compounds generate reactive oxygen species, resulting in a significant increase in cytotoxicity and antiviral activity.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY
(2022)
Article
Chemistry, Physical
Julian Luettig, Peter A. Rose, Pavel Maly, Arthur Turkin, Michael Buehler, Christoph Lambert, Jacob J. Krich, Tobias Brixner
Summary: Time-resolved spectroscopy is widely used to study various phenomena in chemistry, biology, and physics. This study focuses on pump-probe experiments and coherent two-dimensional (2D) spectroscopy, which have been successful in visualizing energy transfer and electronic couplings. The researchers demonstrate that the appearance of a two-quantum (2Q) signal indicates the contamination of a one-quantum (1Q) signal by non-negligible fifth-order interactions. By performing partial integrations, the study shows that clean rQ signals can be obtained in 2D spectra, free from higher-order artifacts.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Organic
Emely Freytag, Lasse Kreimendahl, Marco Holzapfel, Jens Petersen, Heiko Lackinger, Matthias Stolte, Frank Wuerthner, Roland Mitric, Christoph Lambert
Summary: Five chiral squaraine dimers were synthesized by fusing chiral indolenine semisquaraines with three different benzobisthiazole bridges. The resulting dimers exhibited strong splitting of the lowest energy absorption bands due to exciton coupling. The electric circular dichroism spectra of the dimers showed intense Cotton effects whose sign depended on the used squaraine chromophores. TD-DFT calculations revealed that the electric-magnetic coupling was the dominant contribution to the rotational strength.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Correction
Chemistry, Multidisciplinary
Avijit Maiti, Fangyuan Zhang, Ivo Krummenacher, Moulika Bhattacharyya, Sakshi Mehta, Michael Moos, Christoph Lambert, Bernd Engels, Abhishake Mondal, Holger Braunschweig, Prince Ravat, Anukul Jana
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Lea Ress, Pavel Maly, Jann B. Landgraf, Dominik Lindorfer, Michael Hofer, Joshua Selby, Christoph Lambert, Thomas Renger, Tobias Brixner
Summary: This article presents the experimental and theoretical foundations for femtosecond time-resolved circular dichroism (TRCD) spectroscopy of excitonic systems. A new experimental setup, with a polarization grating as the key element, is introduced to generate circularly polarized pulses for TRCD experiments. By applying a specific chopping scheme, left and right circular polarizations can be switched, and transient absorption (TA) and TRCD spectra can be detected simultaneously. Experiments on a squaraine polymer are performed to investigate excitonic dynamics, and a general theory for TRCD experiments of excitonically coupled systems is developed and applied to describe the experimental data.
Article
Chemistry, Multidisciplinary
Fridolin Saal, Asim Swain, Alexander Schmiedel, Marco Holzapfel, Christoph Lambert, Prince Ravat
Summary: We describe a helically chiral push-pull molecule named 9,10-dimethoxy-[7]helicene diimide, which exhibits fluorescence and circularly polarised luminescence over nearly the entire visible spectrum dependent on solvent polarity, along with high dissymmetry factors.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Emely Freytag, Marco Holzapfel, Asim Swain, Gerhard Bringmann, Matthias Stolte, Frank Wuerthner, Christoph Lambert
Summary: Yamamoto homocoupling of two chiral oxindoles led to the formation of an axially chiral oxindole dimer. This dimer served as the starting material for the syntheses of axially chiral squaraine and merocyanine chromophore dimers. The chiroptical properties of these dimers, including high ECD signals and circularly polarised emission, were analyzed using computational calculations, which showed that exciton coupling is the dominant contributor to the rotational strength.
Article
Chemistry, Physical
Paul Mentzel, Marco Holzapfel, Alexander Schmiedel, Ivo Krummenacher, Holger Braunschweig, Artur Wodynski, Martin Kaupp, Frank Wuerthner, Christoph Lambert
Summary: While spin-orbit coupling is not crucial for the photophysics of unsubstituted perylene diimides (PDI), it plays a dramatic role when two phenylselenyl or phenyltelluryl substituents are attached to the PDI bay positions. The introduction of these substituents leads to a decrease in fluorescence quantum yield and an increase in intersystem crossing (ISC) rate. Time-dependent density functional calculations suggest that increased spin-orbit coupling is due to the internal heavy-atom effect, resulting in fast ISC. Moreover, the selenium PDI derivative shows significant sensitization of singlet oxygen via the PDI triplet state.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Lei Ji, Stefan Riese, Alexander Schmiedel, Marco Holzapfel, Maximillian Fest, Joern Nitsch, Basile F. E. Curchod, Alexandra Friedrich, Lin Wu, Hamad H. Al Mamari, Sebastian Hammer, Jens Pflaum, Mark A. Fox, David J. Tozer, Maik Finze, Christoph Lambert, Todd B. Marder
Summary: Reversible conversion between excited states is crucial in various photophysical phenomena. By conducting experiments and calculations, we discovered that the energy gaps and barriers among the locally-excited and charge-transfer states in 1-(pyren-2'-yl)-o-carborane are negligible, making all three states accessible at room temperature. Furthermore, the internal-conversion and reverse internal-conversion processes occur much faster than radiative decay, resulting in the same lifetimes and thermodynamic equilibrium of the two states.
