Article
Chemistry, Multidisciplinary
Sabine Frisch, Christian Neiss, Sebastian Lindenthal, Nicolas F. Zorn, Frank Rominger, Andreas Goerling, Jana Zaumseil, Milan Kivala
Summary: A novel synthesis strategy has been developed to synthesize stable and highly absorbent TPNA compounds. The experimental findings were confirmed by theoretical studies, suggesting that TPNA is a promising platform for the development of near-IR fluorophores.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Tanner C. Jankins, Raul Martin-Montero, Phillippa Cooper, Ruben Martin, Keary M. Engle
Summary: This tungsten-catalyzed hydroboration of unactivated alkenes at distal C(sp(3))-H bonds with the aid of native directing groups is characterized by simplicity, exquisite regio- and chemoselectivity, and wide substrate scope, providing a complementary site-selectivity pattern to other metal-catalyzed borylation reactions and chain-walking protocols.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Multidisciplinary Sciences
B. Roesch, T. X. Gentner, J. Langer, C. Faerber, J. Eyselein, L. Zhao, C. Ding, G. Frenking, S. Harder
Summary: The attempted preparation of low-valent Ca-I complexes in the form of LCa-CaL under dinitrogen atmosphere led to the isolation of LCa(N-2)CaL, which acts as a synthon for the target LCa-CaL.The N-2(2-) anion in this complex reacted as a potent two-electron donor and could be protonated to diazene. The role of Ca d orbitals in N-2 activation is also discussed.
Article
Chemistry, Multidisciplinary
Estefania del Horno, Jesus Jover, Miguel Mena, Adrian Perez-Redondo, Carlos Yelamos
Summary: Low-valent titanium species were prepared by reacting [TiCp*X-3] with LiEH4 or BH3(thf), and their structures were elucidated using experimental and theoretical methods. The compounds can be described as either titanium(II) or titanium(III) species, with specific molecular structures and interactions between the Ti-Ti bond and the Al atoms.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Organic
Xingwei Cai, Yang Shen, Wei Li, Wentao Zhan, Fanjun Zhang, Chen Xu, Heng Song
Summary: In this study, an efficient tungsten-catalyzed homogeneous system was developed for the selective synthesis of various azoaromatics, azoxyaromatics, and 2-substituted indolone N-oxides from anilines. This was achieved by regulating the reaction solvent with peroxide as a terminal oxidant under additive-free conditions. These findings not only provide an experimental framework for exploring tungsten catalysis in organic synthesis but also offer an efficient and convenient tactic for the selective oxidation of anilines.
Article
Chemistry, Physical
Shivani, Akriti Mishra, Paramjit Kaur, Kamaljit Singh
Summary: Comparing the first hyperpolarizability (#HRS) and intrinsic first hyperpolarizability (#int) values of fluorene-based chromophores with different lengths and/or z-conjugation pathways, it is found that extending z-conjugation beyond a certain limit does not necessarily improve the nonlinear optical (NLO) response. Factors such as the red shift of the intramolecular charge transfer (ICT) bands, optical band gap, and dipole moment of the chromophores all play a combined role in determining the NLO response. Additionally, the spatial distance between the donor and acceptor units also affects the #HRS.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Yohei Kojima, So Sugiura, Keiji Suzuki, Yilihamu Yisilamu, Katsuhiko Ono
Summary: In this study, bis(dioxaborin) compounds with extended pi-conjugated systems were synthesized and found to exhibit red-shifted absorption maxima, high electron affinity, and reduced on-site Coulomb repulsion in the two-electron reduction. An OFET fabricated using one of these compounds with a layer-by-layer crystal structure demonstrated n-type semiconductor behavior.
CHEMISTRY-AN ASIAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Prakash Chandra Joshi, Vivek Kumar Singh, Pratima Shukla, Hemant Kumar, Jyoti Shukla, Pritam Mahawar, Dharmendra Singh, Selvarajan Nagendran
Summary: The possibility of stabilizing compounds containing low-valent main group elements using aza-dipyrromethene (a-DPM) ligands is shown through the isolation of germylenes. These germylenes, including a-DPM(p-tol)GeCl (2), a-DPM(Naph)GeCl (6), and a-DPM(Naph)GeN(TMS)(2) (7) (tol=tolyl, Naph=naphthyl), exhibit a highly red-shifted absorption maximum at around 640 nm, a value not previously observed for germylenes.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Polymer Science
Yohei Adachi, Keisuke Kondo, Xiaodong Yin, Frieder Jakle, Joji Ohshita
Summary: Incorporating non-conventional elements into pi-conjugated systems allows for control of electronic structures. In this study, electron-deficient tricoordinate boron units were combined with electron-rich dithienogermole units to create a hybrid conjugated macrocycle with m-phenylene linkers. The fluorescence spectra of the element-hybrid macrocycle exhibited solvatochromism, and the addition of fluoride intensified the fluorescence. This mechanism was confirmed through fluorescence spectroscopy and TDDFT calculations.
Article
Chemistry, Multidisciplinary
Michaela Dobeneck, Ramandeep Kaur, Benedikt Platzer, Dirk M. Guldi, Andreas Hirsch
Summary: A modified synthetic pathway and purification method were used to successfully synthesize perylene-perylene dimers and perylene-naphthalene heterodimers, with the regioisomers separated. It was observed that tuning the configuration and length of aromatic systems can impact the opto-electronic properties of the chromophores.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Analytical
Jaeyoon Kim, Kyunglim Pyo, Dongil Lee, Won-Yong Lee
Summary: This study characterized the ECL behavior of atomically precise Au-22(SG)(18) NCs in aqueous solution and found that their ECL intensity was significantly higher than that of commonly used Au@BSA NCs, showing sensitivity to the concentrations of Au-22(SG)(18) NCs and TPA.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Philipp Dabringhaus, Silja Zedlitz, Luisa Giarrana, David Scheschkewitz, Ingo Krossing
Summary: Schnockel's [(AlCp*)(4)] and Jutzi's [SiCp*][B(C6F5)(4)] are important in modern main-group chemistry with various applications in synthesis and catalysis. However, the reactivity between AlCp* and [SiCp*](+) has not been explored. In this study, their reaction was investigated and complex salts [Cp*Si(AlCp*)(3)][WCA] were obtained. The tetrahedral [SiAl3](+) core not only represents a rare example of a low-valent silicon-doped aluminium-cluster, but also provides a convenient preparative entry towards low-valent Si-Al clusters.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Pedada Srinivasa Rao, Samantha Brixi, Dada B. Shaikh, Mohammad Al Kobaisi, Benoit H. Lessard, Sidhanath V. Bhosale, Sheshanath V. Bhosale
Summary: The research designed and synthesized asymmetrical and symmetrical push-pull chromophores based on TPA donors and NDI acceptors, investigated the influence of TCNE and TCNQ linkers on the properties of these molecules, and studied their charge transfer characteristics in organic thin-film transistors.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Skye Fortier, Alejandra Gomez-Torres
Summary: Titanium is a versatile metal with important applications in practical synthesis, typically limited to stoichiometric reactions or Lewis acid catalysis. Interest has grown in using titanium and other early-metals for redox catalysis, but limitations exist due to their thermodynamic preference for high oxidation states. However, low-valent titanium complexes and their synthons are known, and recent developments have focused on reversible oxidative-addition/reductive-elimination reactions using these systems.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Chance M. Boudreaux, Dinesh Nugegoda, Wenzhi Yao, Nghia Le, Nathan C. Frey, Qing Li, Fengrui Qu, Matthias Zeller, Charles Edwin Webster, Jared H. Delcamp, Elizabeth T. Papish
Summary: Low-valent cobalt complexes with phosphine substitution have been synthesized and shown to be highly active catalysts for photocatalytic CO2 reduction.
Article
Chemistry, Multidisciplinary
Niklas Noll, Tobias Gross, Kazutaka Shoyama, Florian Beuerle, Frank Wuerthner
Summary: We report a series of bipyridine-containing di- to tetranuclear Ru(bda) macrocycles 2C-4C that promote O-O bond formation for photocatalytic water oxidation. Under neutral conditions, all complexes 2C-4C adopt a folded conformation and follow the water nucleophilic attack (WNA) pathway with high turnover frequencies up to 15.5 s(-1) per Ru unit. Crystal structure analysis reveals increased intramolecular pi-pi stacking and preorganization of proximal bases for larger macrocycles. H/D kinetic isotope effect studies and electrochemical data confirm the key role of proximal bipyridines as proton acceptors in lowering the activation barrier for the crucial nucleophilic attack of H2O in the WNA mechanism.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Subhadip Jana, Benedict J. Elvers, Sebastian Patsch, Pallavi Sarkar, Ivo Krummenacher, Mithilesh Kumar Nayak, Avijit Maiti, Nicolas Chrysochos, Swapan K. Pati, Carola Schulzke, Holger Braunschweig, Cem B. Yildiz, Anukul Jana
Summary: We developed a new method for synthesizing different quinodimethane derivatives by oxidizing bis-N-heterocyclic olefins linked by pi-conjugated aromatic spacers. Stable diimidazolium para- and ortho-quinodimethane derivatives were obtained with para- and ortho-phenylene bridges, as well as with tetrafluoro-p-phenylene and p-anthracene spacers. The influence of imidazolium substituents on the air and moisture stability of the quinodimethane derivatives was emphasized. Different electron transfer processes were observed depending on the pi-conjugated aromatic spacer used, with two one-electron or one two-electron redox transitions between bis-N-heterocyclic olefins and diimidazolium-quinodimethanes. The formation of pi-conjugated radical-cations, which are transient redox intermediates, was confirmed by EPR investigation.
Article
Chemistry, Multidisciplinary
Iida Partanen, Omar Al-Saedy, Toni Eskelinen, Antti J. Karttunen, Jarkko J. Saarinen, Ondrej Mrozek, Andreas Steffen, Andrey Belyaev, Pi-Tai Chou, Igor O. Koshevoy
Summary: Crystalline diphosphonium iodides with different aromatic spacers exhibit photoemissive properties under ambient conditions. The emission colors and intensities are determined by the structure and substitution geometry of the chromophore motif, as well as the anion-p interactions. Time-resolved and variable-temperature luminescence studies confirm the phosphorescent nature of these compounds, with observed lifetimes ranging from 0.46 to 92.23 μs at 297 K. The fast radiative rate constants for salts 1-3 suggest the involvement of spin-orbit coupling and charge transfer in the triplet excited state. This metal-free phosphorescence mechanism is comparable to that of transition metal complexes and organic luminophores utilizing thermally activated delayed fluorescence.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Andre M. T. Muthig, Justin Wieland, Carsten Lenczyk, Stefan Koop, Jacopo Tessarolo, Guido H. Clever, Benjamin Hupp, Andreas Steffen
Summary: A series of chiral mechanochromic copper(I) cAAC complexes were studied to investigate the structure-property relationships for efficient triplet exciton emitters with circularly polarized luminescence. Depending on the environment, either thermally activated delayed fluorescence or phosphorescence was observed. However, chiral moieties in carbene or carbazolate ligands did not provide detectable luminescence dissymmetries. One exception was [Cu(phenoxazinyl)(cAAC)] which exhibited orange to deep red thermally activated delayed fluorescence with high radiative rate and detectable luminescence dissymmetry.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Iida Partanen, Andrey Belyaev, Bo-Kang Su, Zong-Ying Liu, Jarkko J. Saarinen, Ishfaq Ibni Hashim, Andreas Steffen, Pi-Tai Chou, Carlos Romero-Nieto, Igor O. Koshevoy
Summary: Phosphonium-based compounds are gaining attention as promising photofunctional materials. This study presents a series of donor-acceptor ionic dyes constructed by tailoring phosphonium and extended π-NR2 fragments to an anthracene framework. The introduction of a P-heterocyclic acceptor substantially narrows the optical bandgap and improves the efficiency of fluorescence. The phospha-spiro moiety allows for near-infrared emission with high fluorescence efficiency.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Lara Kleine-Kleffmann, Vladimir Stepanenko, Kazutaka Shoyama, Marius Wehner, Frank Wuerthner
Summary: Molecular chaperones are proteins that help in the folding and assembly of other structures. In this study, a chaperone-like two-component system was used to control supramolecular polymerization. A new kinetic trapping method was developed to retard self-assembly, which could be regulated with a cofactor. The system was characterized using various techniques and demonstrated the possibility for effective control over supramolecular polymerization processes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Bernhard Mahlmeister, Tim Schembri, Vladimir Stepanenko, Kazutaka Shoyama, Matthias Stolte, Frank Wuerthner
Summary: Chiralpolycyclic aromatic hydrocarbons have potential as next-generation photonic materials, and their molecular and supramolecular architectures can be carefully designed to enhance their chiroptical response. In this study, a quaterrylene bisimide derivative with a conformationally stable twisted pi-backbone was developed, and its chiral arrangement was achieved by self-assembly in low polarity solvents. The resulting solid-state aggregate exhibited strong J-type excitonic coupling in the near infrared region, confirmed by atomic force microscopy and single-crystal X-ray analysis.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Xiaoqi Tian, Kazutaka Shoyama, Bernhard Mahlmeister, Felix Brust, Matthias Stolte, Frank Wuerthner
Summary: Two heliceno-bis(naphthalimides) compounds with electron-accepting naphthalimide moieties attached at both ends of helicene core were synthesized by an effective two-step strategy. Their enantiomers were successfully resolved using chiral stationary-phase high-performance liquid chromatography (HPLC). The helical structure and absolute configuration of the compounds were confirmed through single-crystal X-ray diffraction analysis and experimental and calculated circular dichroism (CD) spectra. Both compounds exhibited high molar extinction coefficients and fluorescence quantum yields, and compound 2 demonstrated potential for applications in chiral optoelectronics due to its red circularly polarized luminescence emission and high brightness.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Annalena Gaertner, Uhut S. Karaca, Maximilian Rang, Myron Heinz, Philipp D. Engel, Ivo Krummenacher, Merle Arrowsmith, Alexander Hermann, Alexander Matler, Anna Rempel, Robert Witte, Holger Braunschweig, Max C. Holthausen, Marc-Andre Legare
Summary: We present a comprehensive study on the fixation and reductive coupling of dinitrogen with low-valent boron compounds, combining computational and experimental approaches. The results demonstrate that the selectivity of nitrogen fixation or coupling can be controlled by steric bulk or reaction conditions, enabling the synthesis of nitrogen chains as needed. Furthermore, we elucidate the electronic structure and magnetic properties of intermediates and products of the reaction using high-level computational methods.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Myron Heinz, Merle Arrowsmith, Julia I. Schweizer, Ivo Krummenacher, Max C. Holthausen, Holger Braunschweig
Summary: In this study, the dimerization process of borylenes to diborenes was observed for the first time. Experimental and computational analysis revealed that the process is complex and autocatalytic.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Jorge Labella, Kazutaka Shoyama, David Guzman, Tim Schembri, Matthias Stolte, Tomas Torres, Frank Wuerthner
Summary: Imide-fused porphyrinoid compounds with naphthalimide were synthesized as NIR-absorbing n-type organic semiconductors. Two different synthetic routes were used, including an annulation reaction between a boronic ester and dibromo-NMI, and a cyclotrimerization of NMI-fused phthalonitrile. The N-alkyl substituted derivative was utilized as a nonfullerene acceptor in organic solar cells, achieving a highest power conversion efficiency of 7.0%.
ACS MATERIALS LETTERS
(2023)
Article
Education, Scientific Disciplines
David Johannes Hauck, Andreas Steffen, Insa Melle
Summary: A large number of chemistry students drop out due to high requirements for content knowledge, particularly in quantum chemical models like MO theory. This study developed an intervention on MO theory using the Computer-Supported Collaborative Learning framework. Results showed that students improved significantly in both single-choice and open-ended questions by working with learning videos, while concept mapping did not lead to significant content knowledge changes. There were also no significant differences between treatment groups or between teacher students and other chemistry freshmen.
CHEMISTRY TEACHER INTERNATIONAL
(2023)
Article
Chemistry, Physical
Julia Heitmueller, Rebecca Froehlich, Rebecca Renner, Frank Wuerthner, Tobias Brixner
Summary: In this study, ultrafast transient absorption spectroelectrochemistry and coherent two-dimensional electronic spectroelectrochemistry were performed on three different neutral perylene bisimide derivatives and their singly and doubly reduced species. The charged species showed significantly shorter lifetimes compared to the neutral ones. Additionally, Fermi resonance was observed in the flat dianion of parent perylene bisimide, indicating the potential for enhanced charge separation and triplet formation.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Correction
Chemistry, Multidisciplinary
Lara Kleine-Kleffmann, Vladimir Stepanenko, Kazutaka Shoyama, Marius Wehner, Frank Wurthner
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Jonas Spengler, Chongwei Zhu, Kazutaka Shoyama, Frank Wuerthner
Summary: In this study, a series of non-alternant aromatic dicarboximides were synthesized by manipulating the perylene bisimide framework through the introduction of heptagonal rings. Characterization and theoretical studies provided insights into the optoelectronic properties and aromaticity of these newly synthesized compounds.
