Article
Chemistry, Physical
Renat Kadyrov
Summary: An efficient and simple catalytic system has been developed for the hydrogenation of carboxylic esters using commercially available Ru-salts and imidazolium salts. This combination enables the reduction of esters to alcohols at moderate temperature and pressure, offering a practical method for alcohol synthesis.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Louis Monsigny, Anna Kajetanowicz, Karol Grela
Summary: This review discusses a distinct class of ruthenium olefin metathesis catalysts with unsymmetrical N-heterocyclic carbene (uNHC) ligands, highlighting their advantages such as thermodynamic stability, chemical latency, selectivity, and compatibility with green solvents in specialized metathesis transformations. Despite being niche, uNHC complexes have the potential to be implemented in various industrial processes like valorization of Fischer-Tropsch olefin fractions, ethenolysis of renewable products, and modern pharmaceutical production.
Article
Chemistry, Inorganic & Nuclear
Sanjit Das, Dinesh Nugegoda, Wenzhi Yao, Fengrui Qu, Matthew T. Figgins, Robert W. Lamb, Charles Edwin Webster, Jared H. Delcamp, Elizabeth T. Papish
Summary: A new method for synthesizing complexes of the type [(CNC)Ru-II(NN)L](n+) has been introduced and a series of six new complexes have been characterized. The study shows that catalysts with benzimidazole derived CNC pincers exhibit better activity in photocatalysis, and a diimine ligand is required for self-sensitized photocatalysis.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Nida Shahid, Rahul Kumar Singh, Navdeep Srivastava, Amrendra K. K. Singh
Summary: A series of Ru(III)-NHC complexes have been prepared through a base-free route. These air and moisture-stable complexes, which represent rare examples of paramagnetic Ru(III)-NHC complexes, were shown to be excellent metal precursors for the synthesis of new Ru(II)-NHC complexes. This work allows easy access to new Ru-NHC complexes for the study of new properties and novel applications.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Anne-Frederique M. Pecharman, Erika M. Roberts, Fedor M. Miloserdov, Victor Varela-Izquierdo, Mary F. Mahon, Michael K. Whittlesey
Summary: The addition of excess ZnMe2 to a mixture of [Ru(PPh3)(3)HCl] and IMes resulted in the formation of a bis-cyclometallated complex [Ru(IMes)(PPh3)(2)] 2 and a mono-cyclometallated Ru-Zn heterobimetallic complex [Ru(IMes)'(PPh3)(2)(ZnMe)] 3. Further reactions of these complexes with H-2, PhSiH3, pinacolborane, and CO were investigated. Compounds 1, 4, 5, and 6 were synthesized and structurally characterized.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Javier Ruiz, Maria A. Mateo
Summary: An isocyanide-functionalized imidazole was synthesized from 4-(1H-imidazol-1-yl)aniline using the Ugi method, and subsequently converted into the corresponding imidazolium salt. Coordination of the isocyanide residue allowed the synthesis of several transition metal complexes containing a peripheral imidazolium cation, which serve as suitable starting materials for the formation of mixed ligand isocyanide-NHC heterometallic complexes.
DALTON TRANSACTIONS
(2022)
Review
Chemistry, Multidisciplinary
Rajendra S. Ghadwal
Summary: This review article aims to highlight recent advances in accessing stable iMICs, quantifying their properties, and exploring their applications in synthesis and catalysis. The synthetic viability and use of vicinal C4,C5-anionic dicarbenes (ADCs) based on a 1,3-imidazole framework are also presented. iMICs and ADCs have the potential to push the limit of classical NHCs by enabling access to conceptually new main-group heterocycles, radicals, molecular catalysts, ligand sets, and more.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Qingyang Wang, Richard A. Manzano, Hendrik Tinnermann, Simon Sung, Baptiste Leforestier, Tobias Kraemer, Rowan D. Young
Summary: The use of PCcarbeneP pincer ligands allows for metal-ligand cooperative reactivity and support for a variety of iron oxidation states, making it potentially useful in catalytic applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Lia Sotorrios, Fedor M. Miloserdov, Anne-Frederique Pecharman, John P. Lowe, Stuart A. Macgregor, Mary F. Mahon, Michael K. Whittlesey
Summary: The syntheses, reactivity, and electronic structure analyses of [Ru(PPh3)(2)(ZnMe)(4)H-2] and [Ru(PPh3)(2)(ZnPh)(4)H-2] are reported. [Ru(PPh3)(2)(ZnMe)(4)H-2] exhibits an 8-coordinate Ru center with axial phosphines and a symmetrical (2 : 2) arrangement of ZnMe ligands in the equatorial plane. The ZnMe ligands in [Ru(PPh3)(2)(ZnMe)(4)H-2] undergo facile, sequential exchange with ZnPh2 to give [Ru(PPh3)(2)(ZnPh)(4)H-2], which shows a 3 : 1 arrangement of ZnPh ligands. Mechanisms for ZnMe/ZnPh exchange and isomerization are proposed using DFT calculations, and the relationships of these {Ru(ZnR)(4)H-2} species to isoelectronic Group 8 transition metal polyhydrides and related Schlenk equilibria in the Negishi reaction are discussed.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Biochemistry & Molecular Biology
Araceli Martinez, Daniel Zarate-Saldana, Joel Vargas, Arlette A. Santiago
Summary: The synthesis and properties of copolyesters with different molar ratios of HDL and NB were investigated, with Ru1 catalyst showing higher activity and stability. The copolymer HDN-NB exhibited good thermal stability and increased stress values as the NB content increased.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Inorganic & Nuclear
Victoria Mechrouk, Aline Maisse-Francois, Stephane Bellemin-Laponnaz, Thierry Achard
Summary: A catalytic system for the direct beta-alkylation of secondary alcohol with primary alcohol has been studied, using cationic Ru(II)(eta(6)-p-cymene) complexes with thioether-functionalized N-heterocyclic carbene ligands as catalysts. The results show that modifications in the ligand moiety have a strong effect on both selectivity and reactivity. Imidazole-based complex 1c exhibited the best catalytic activity and highest selectivity for the beta-alcohol, with 98:2 selectivity. Moderate yields of beta-alkylated secondary alcohols have been obtained with complete conversion and high selectivity.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Review
Chemistry, Multidisciplinary
Justus Diekamp, Thomas Seidensticker
Summary: The recycling of homogeneous catalysts in a homogeneous matrix is a challenging task for many reactions aiming for industrial applications. Although various synthetic approaches for recyclable homogeneous catalysts exist, a concise overview of catalyst modifications is lacking in the literature. This review aims to fill this gap by summarizing the existing synthesis pathways for polar, non-polar, fluorous, and molecular-weight-enlarged catalysts and examining their modular and late-stage approaches. Additionally, the potential for a generally applicable tag library to facilitate catalyst modifications for specific recycling strategies is explored.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Tianjiao Hu, Lukas Lueckemeier, Constantin Daniliuc, Frank Glorius
Summary: The direct enantioselective hydrogenation of 2-quinolones using Ru(II)-NHC catalyst has been achieved, providing alkyl-, aryl- and halogen-substituted optically active dihydro-2-quinolones in high yields with moderate to excellent enantioselectivities. This reaction presents an efficient and atom-economic pathway to construct simple chiral 3,4-dihydro-2-quinolones.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Niklas F. Both, Anke Spannenberg, Haijun Jiao, Kathrin Junge, Matthias Beller
Summary: The use of bis(NHC) manganese(I) complexes 3 as catalysts for the hydrogenation of esters was investigated. Various aromatic and aliphatic esters were successfully hydrogenated at mild temperatures and low catalyst loadings using complexes 3 with KHBEt3 as additive, highlighting the efficiency of the novel catalytic system. Additionally, the versatility of the developed catalytic system was demonstrated by the hydrogenation of other substrate classes like ketones, nitriles, N-heteroarenes, and alkenes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Louis Monsigny, Jakub Piatkowski, Damian Trzybinski, Krzysztof Wozniak, Tomasz Nienaltowski, Anna Kajetanowicz, Karol Grela
Summary: Two new ruthenium complexes, Sil-II and Sil-II', were synthesized and characterized as catalysts for olefin metathesis reactions. Sil-II' showed better stability and productivity compared to Sil-II, and kinetic experiments revealed differences in initiation mechanisms between the two catalysts.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Inorganic & Nuclear
Ivan Maisuls, Felix Boisten, Marian Hebenbrock, Julian Alfke, Lina Schurmann, Beate Jasper-Peter, Alexander Hepp, Melanie Esselen, Jens Mueller, Cristian A. Strassert
Summary: This study successfully synthesized a family of Pt(II) complexes with luminophoric units, and investigated their photophysical properties in relation to the structure and substitution pattern of the ligands. By comparing the photoluminescence under different conditions, the correlation between the properties and substitution pattern was analyzed. In addition, density functional theory calculations were performed to gain a deeper understanding of the electronic states responsible for the optical properties. The cytotoxicity evaluation showed that the cationic complexes exhibited strong antitumor activity, while the neutral species had potential for bioimaging applications.
INORGANIC CHEMISTRY
(2022)
Article
Biochemistry & Molecular Biology
Thomas M. Kirse, Joschua Lueke, Ivan Maisuls, Alexander Hepp, Cristian A. Strassert
Summary: In this work, coordination compounds featuring caffeine-based carbene co-ligands and tridentate dianionic pincer luminophores were studied. The influence of different substituents on the photophysical properties was assessed. The results showed that the four luminophores performed similarly and cyclometallation improved the synthetic efficiency but was not essential for achieving high photoluminescence quantum yields. In summary, coordination chemical concepts based on natural products can lead to stable phosphorescent species with interesting excited-state properties.
PHOTOCHEMISTRY AND PHOTOBIOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Ye Lu, Patrick D. Dutschke, Jenny Kinas, Alexander Hepp, Guo-Xin Jin, F. Ekkehardt Hahn
Summary: Here, we report the synthesis and characterization of a series of organometallic Borromean rings (BRs) and [2]catenanes prepared from benzobiscarbene ligands. The formation and stability of these interlocked species are strongly influenced by solvophobic effects. The stability of BRs can be enhanced by using precursors with longer alkyl substituents, while the proportion of [2]catenanes in solution can be increased by lengthening the N-alkyl substitutes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Tobias Theiss, Stefan Buss, Ivan Maisuls, Rafael Lopez-Arteaga, Dana Bruenink, Jutta Koesters, Alexander Hepp, Nikos L. Doltsinis, Emily A. Weiss, Cristian A. Strassert
Summary: The synthesis, structure, and photophysical properties of two isoleptic bis-cyclometalated Pt(II) and Pd(II) complexes, [PtL] and [PdL], were reported. NMR spectroscopy and X-ray diffraction analysis confirmed the isostructural nature and intermolecular interactions of the complexes. Both complexes exhibited ligand-controlled aggregation, with the photophysical properties tunable through molecular design. The introduction of fluorine atoms and methoxy groups led to metal-metal interactions, resulting in luminescence from metal-perturbed ligand-centered or metal-metal-to-ligand charge-transfer triplet states.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Inorganic & Nuclear
Sebastian Termuehlen, Patrick D. Dutschke, Alexander Hepp, F. Ekkehardt Hahn
Summary: The 2-Chloro-3,3-dimethyl-N-ethylindoleninium tetrafluoroborate was reacted with three different carbon-ylmetalates to obtain neutral carbonyl complexes with a benzannu-lated cyclic (alkyl)(amino)carbene ligand. The chromium complex was then used to transfer the CAAC ligand to gold, resulting in a new gold complex. The quantitative information regarding the sigma-donor properties of the CAAC ligand was determined from the 13C NMR spectrum of this gold complex.
Article
Chemistry, Multidisciplinary
Stefan Buss, Maria Victoria Cappellari, Alexander Hepp, Jutta Koesters, Cristian A. Strassert
Summary: This research focuses on the synthesis and characterization of Pt(II) complexes that contain different tri- and tetradentate luminophores serving as C^N*N- and C^N*N^C chelators. The study explores different substitution patterns to enhance their processability and examines how structural variations affect their excited state properties. The photophysical properties of these complexes are analyzed using steady-state and time-resolved photoluminescence spectroscopy, including absorption and emission spectra, photoluminescence efficiencies, and excited state lifetimes at different temperatures. The findings demonstrate that the decoration of the bridging unit on tridentate luminophores has minimal impact on excited state properties, while double cyclometallation related to tetradentate chelators prolongs excited state lifetime and enhances photoluminescence quantum yield.
CHEMISTRY-SWITZERLAND
(2023)
Article
Chemistry, Multidisciplinary
Clemens Taube, Jannis Fidelius, Kai Schwedtmann, Christopher Ziegler, Florian Kreuter, Leigh Loots, Leonard J. Barbour, Ralf Tonner-Zech, Robert Wolf, Jan J. Weigand
Summary: In this study, diphosphene complexes capable of reversible photoisomerizations through haptotropic rearrangements were investigated. Upon irradiation with blue or UV light, the complexes undergo isomerization and change in color. The reversible nature of the isomerization can be controlled by changing the environmental conditions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Christian M. Hoidn, Karolina Trabitsch, Kai Schwedtmann, Clemens Taube, Jan J. Weigand, Robert Wolf
Summary: In this study, a new complex was synthesized by reacting diphosphorus derivatives with a cyclotetraphosphido cobalt complex at low temperature. The synthesized complex was characterized using NMR spectroscopy and single-crystal X-ray diffraction. A mechanism of formation was proposed based on the 31P NMR monitoring studies.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Editorial Material
Chemistry, Multidisciplinary
Rory Waterman, Jan J. Weigand, Robert Wolf
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Miguel A. Chacon-Teran, Vanessa R. R. Landaeta, Robert Wolf, Rafael E. E. Rodriguez-Lugo
Summary: A Rh(I) complex with a P,N ligand has been synthesized and characterized. It has been found that this complex can catalyze the 1,2-regioselective hydroboration of pyridines and quinolines with high yield and low catalyst loading.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Benedikt N. Baumann, Helge Lange, Felix Seeberger, Philipp Bueschelberger, Robert Wolf, Marko Hapke
Summary: In this study, highly reduced anthracene and naphthalene cobaltates and ferrates were found to catalyze the cyclization of diynes and triynes, resulting in the expected cycloaddition products as well as unexpected annulation products. Additionally, the solvent was found to significantly affect the substrate conversion rate.
MOLECULAR CATALYSIS
(2023)
Article
Chemistry, Inorganic & Nuclear
Sebastian Termuehlen, Patrick D. Dutschke, Alexander Hepp, F. Ekkehardt Hahn
Summary: In this study, it was found that 2-Chloro-3,3-dimethyl-N-ethylindoleninium tetrafluoroborate underwent oxidative addition with three carbon-ylmetalates, resulting in the formation of neutral carbonyl complexes with a benzannulated cyclic (alkyl)(amino)carbene (CAAC) ligand. The chromium complex was further utilized for the transmetalation of the CAAC ligand to gold(I), and the electronic properties of the CAAC ligand in the resulting gold complex were quantitatively characterized.
Article
Biochemistry & Molecular Biology
Stefan Buss, Leon Geerkens, Maria Victoria Cappellari, Alexander Hepp, Jutta Koesters, Cristian A. Strassert
Summary: This study investigates the impact of auxiliary ligands on the photophysical properties of Pt(II) complexes and demonstrates that the properties of the auxiliary ligands have some influence on the photoluminescence characteristics, but cannot significantly improve the photoluminescence quantum yield at room temperature.
Article
Biochemistry & Molecular Biology
Matias E. Gutierrez Suburu, Meik Blanke, Alexander Hepp, Oliver Maus, Dominik Schwab, Nikos L. Doltsinis, Wolfgang G. Zeier, Michael Giese, Jens Voskuhl, Cristian A. Strassert
Summary: A series of Pt(II) complexes with different regioisomers were synthesized and characterized. The position of the regioisomer affects the emission color and deactivation rate constants. Some of the complexes also exhibit thermochromic properties due to the metal-metal interactions and alkyl groups.
Article
Chemistry, Multidisciplinary
Christian Roedl, Gabriele Hierlmeier, Robert Wolf
Summary: The synthesis and characterization of a compound containing two cobalt atoms and three diphosphacyclobutadiene ligands are described. This compound is the first triple-decker sandwich complex exclusively containing cyclobutadiene ligands.
CHEMICAL COMMUNICATIONS
(2022)
