Article
Chemistry, Inorganic & Nuclear
Greta G. Zambo, Johannes Mayr, Michael J. Sauer, Tim P. Schlachta, Robert M. Reich, Fritz E. Kuehn
Summary: The synthesis and characterization of a novel macrocyclic and abnormally coordinating, mesoionic N-heterocyclic carbene iron complex are reported. The complex exhibits strong sigma-donor ability of the carbene moieties, indicating efficient catalytic activity in oxidation reactions. Initial tests on the epoxidation of cis-cyclooctene validate the assumption.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Xian B. Carroll, Dylan Errulat, Muralee Murugesu, David M. Jenkins
Summary: An isostructural set of macrocyclic tetra-N-heterocyclic carbene (NHC) complexes were synthesized and characterized in this study. The complexes showed highly distorted geometries and exhibited magnetic and electrochemical properties. Additionally, a macrocycle variant of the complex was synthesized for comparison.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Shih-Chieh Aaron Lin, Bo-Kai Su, Yi-Hung Liu, Shie-Ming Peng, Shiuh-Tzung Liu
Summary: The interconversion of three palladium complexes and their catalytic activity in carbonylative Suzuki-Miyaura cross-coupling reaction were studied. Among them, complex 2 showed excellent catalytic activity under specific conditions.
Article
Chemistry, Inorganic & Nuclear
Thien H. Nguyen, Xiaojuan Yu, Greggory T. Kent, Jochen Autschbach, Trevor W. Hayton
Summary: Reaction of [U(NR2)3] (R = SiMe3) with 1 equiv of bis(diisopropylamino)cyclopropenylidene (BAC) in Et2O leads to the formation of [(NR2)3U(BAC)] (1), which can be obtained in moderate yields. Thermal decomposition of 1 in C6D6 at 85 degrees C results in the formation of ring-opened U(IV) product, [(NR2)2U{N(R)-(SiMe2CH=C(NiPr2)C(NiPr2)=CH)}] (2), with low yields. The proposed mechanism suggests that 2 is formed via dissociation of BAC from 1, followed by conversion of [U(NR2)3] to [U{N(R)(SiMe2CH2)}(NR2)2] at elevated temperatures. BAC then inserts into the U-C bond of [U{N(R)(SiMe2CH2)}(NR2)2] to generate a cyclopropenyl intermediate, which undergoes ring opening and C-H activation to afford the final product, 2. It is hypothesized that the ring-opening process generates an unobserved carbene intermediate. The clean formation of 2 from a 1:1 mixture of independently prepared [U{N(R)(SiMe2CH2)}(NR2)2] and BAC provides strong support for the proposed mechanism. The formulations of both 1 and 2 were confirmed by X-ray crystallography. Theoretical calculations suggest that the hypothesized uranium carbene intermediate features strong U-C bonding.
Article
Chemistry, Multidisciplinary
Zhi-Xiang Zhao, Lin-Hai Hu, Shao-Cong Yu, Qing-Xiang Liu
Summary: An open tetra-benzimidazolium salt and a cyclic tetra-imidazolium salt based on tetramethylbenzene were synthesized and characterized. The recognition performance of these compounds for two guests was investigated using various spectroscopic methods. In particular, the cyclic tetra-imidazolium salt showed remarkable color change upon recognition of F-, which could be observed with the naked eye, providing great convenience in practical applications.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Bamlaku Semagne Aweke, Cheng-Han Yu, Jiun-Shian Shen, Sheng Wang, Glenn P. A. Yap, Wen-Ching Chen, Tiow-Gan Ong
Summary: In this study, a carbone-transfer agent Ag-I complex of a bis(carbone) pincer ligand was synthesized, which eliminated the requirement for isolating the free ligand. The complex was efficiently used to transfer the ligand to other transition metals. This approach has potential for isolating metal complexes of carbone ligands, which has been challenging due to the reactivity and sensitivity of free carbones.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Tim P. Schlachta, Jonas F. Schlagintweit, Markus R. Anneser, Eva-Maria H. J. Esslinger, Maximilian Muhr, Stefan Haslinger, Fritz E. Kuehn
Summary: In this study, axial MeCN ligands of highly active iron(II) and iron(III) tetra N-heterocyclic carbene (NHC) olefin epoxidation (pre-)catalysts are substituted with t-BuCN and PhCN, resulting in more stable axial ligands against C-H oxidation with similar electrochemical properties. These new complexes pave the way towards more robust catalysts by enhancing the stability against oxidation of the axial ligand, which competes with substrate oxidation.
INORGANICA CHIMICA ACTA
(2021)
Article
Chemistry, Physical
Florian Dyckhoff, Jonas F. Schlagintweit, Marco A. Bernd, Christian H. G. Jakob, Tim P. Schlachta, Benjamin J. Hofmann, Robert M. Reich, Fritz E. Kuhn
Summary: The pivotal degradation pathway of the most active non-heme iron epoxidation catalyst to date is the weak Fe-NHC bond, where direct oxidation of a carbene leads to catalyst deactivation.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Zhe Wang, Rikuo Akisaka, Sohshi Yabumoto, Tatsuo Nakagawa, Sayaka Hatano, Manabu Abe
Summary: By implementing the new concept of stretch effect, a kinetically stabilised singlet diradicaloid was successfully obtained in this study, allowing for experimental examination of its nature. Experimental results showed that the kinetically stabilised diradicaloid exhibited a low carbon-carbon coupling reaction rate, and a significant dynamic solvent effect was observed for the first time in viscous solvents.
Article
Chemistry, Multidisciplinary
Diego Sorbelli, Leonardo Belpassi, Paola Belanzoni
Summary: This work systematically studied the electronic structure and reactivity of Au-Al complexes with different aluminyl scaffolds, comparing them to carbene analogues. The results reveal that aluminyls and carbenes exhibit different behavior when bound to gold, with aluminyls forming an electron-sharing and weakly polarized Au-Al bond. The poor modulability of their electronic structure and bond nature is reflected in the similar reaction mechanisms of gold-aluminyl complexes towards CO2.
Article
Chemistry, Inorganic & Nuclear
Ben Liu, Zhiyin Chen, Yu Li, Xiang-Fu Du, Wenjing Zhang, Wei Zhang, Yuxiao Lai, Yi Li
Summary: Mitochondria-targeted iridium complexes have shown promise as potential anticancer agents. These complexes localize in the mitochondria through a reactive nucleophilic reaction with mitochondrial proteins and exhibit high anticancer activity, inducing mitochondrial depolarization, increasing intracellular reactive oxygen species levels, inhibiting colony formation, and angiogenesis. Mechanistically, one specific complex, Ir2, activates caspase-3, regulates the expression of Bax and Ki67, and triggers apoptosis.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Richard Y. Kong, Mark R. Crimmin
Summary: Eight new first-row transition metal aluminylene complexes were synthesized and characterized, with DFT and ab initio calculations providing insight into the metal-metal bond. The aluminylene ligand was found to be both a strong sigma-donor and competent pi-acceptor, with properties varying based on the transition metal center. Dispersion was shown to play a key role in stabilizing these complexes, with potential implications for the design of next-generation catalysts based on aluminium metalloligands.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Multidisciplinary
Zhi-Xiang Zhao, Yuan-Yuan Wu, Dong-Xue Zhao, Qing-Xiang Liu
Summary: A macrocyclic tetra-imidazolium salt (2) based on quinoxaline was synthesized and characterized. The recognition ability of 2 towards nitro compounds was investigated using fluorescence spectroscopy, 1H NMR titrations, MS, IR spectroscopy, and UV/vis spectroscopy. The results demonstrated that 2 could effectively differentiate p-dinitrobenzene from other nitro compounds through fluorescence spectroscopy.
Article
Chemistry, Physical
Alexander D. Boeth, Michael J. Sauer, Walter Baratta, Fritz E. Kuehn
Summary: The bis-abnormal N-heterocyclic carbene (aNHC) ruthenium complexes showed high catalytic activity in transfer hydrogenation and Oppenauer-type oxidation reactions. The order of reactivity was found to be influenced by steric effects.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Inorganic & Nuclear
Satoshi Takebayashi, Robert R. Fayzullin
Summary: This study successfully isolated [Co(L)(CO)(3)] using new ligands, and revealed its activation of H-2 through a bimolecular mechanism rather than the previously proposed termolecular mechanism. This finding will contribute to the design of cobalt carbonyl complexes for H-2 activation under mild conditions and the development of a more energy efficient oxo process based on economic cobalt catalysts.
Article
Chemistry, Multidisciplinary
Joseph F. DeJesus, Lindy M. Sherman, Darius J. Yohannan, Jeffrey C. Becca, Shelby L. Strausser, Leonhard F. P. Karger, Lasse Jensen, David M. Jenkins, Jon P. Camden
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Multidisciplinary
Joseph F. DeJesus, David M. Jenkins
CHEMISTRY-A EUROPEAN JOURNAL
(2020)
Article
Chemistry, Multidisciplinary
Karthikeyan Gnanasekaran, Kristina M. Vailonis, David M. Jenkins, Nathan C. Gianneschi
Article
Chemistry, Multidisciplinary
Lindy M. Sherman, Shelby L. Strausser, Rowan K. Borsari, David M. Jenkins, Jon P. Camden
Summary: N-heterocyclic carbenes (NHCs) have emerged as versatile ligands for noble metal surface modifications due to their ability to form compact, self-assembled monolayers. Different types of NHC moieties, such as saturated NHCs, can be more effective in homogeneous catalysis and offer advantages such as increased stability and access to chiral groups on NHC surfaces. This study explores the preparation and stability of NHC-coated gold surfaces using imidazolium and imidazolinium NHC ligands, with imidazolinium showing enhanced stability compared to traditional imidazolium under harsh acidic conditions.
Article
Chemistry, Inorganic & Nuclear
Shelby L. Strausser, David M. Jenkins
Summary: N-Heterocyclic carbenes (NHCs) are important auxiliary ligands in organometallic chemistry, with the most common variants based on five-membered rings. Research on six-membered-ring NHC variants has mainly focused on nonconjugated versions, with limited reports on conjugated six-membered ring NHCs.
Article
Chemistry, Analytical
Nathaniel L. Dominique, Shelby L. Strausser, Jacob E. Olson, William C. Boggess, David M. Jenkins, Jon P. Camden
Summary: This study investigates the stability and potential biological applications of N-heterocyclic carbene (NHC) self-assembled monolayers (SAMs) on gold surfaces, while utilizing laser desorption ionization mass spectrometry (LDI-MS) to explore the surface chemistry of NHC. By studying NHC-functionalized gold nanoparticles using LDI-MS, insights into the packing of NHC monolayers on gold surfaces and the stability of NHC ligands post-ligation were gained. The ability of LDI-MS to probe postsynthetic modifications of anchored NHCs, such as the reduction of nitro-NHC-AuNPs to amine-NHC-AuNPs, highlights its importance for current and future applications of NHC surfaces.
ANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Xian B. Carroll, Dylan Errulat, Muralee Murugesu, David M. Jenkins
Summary: An isostructural set of macrocyclic tetra-N-heterocyclic carbene (NHC) complexes were synthesized and characterized in this study. The complexes showed highly distorted geometries and exhibited magnetic and electrochemical properties. Additionally, a macrocycle variant of the complex was synthesized for comparison.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Lindy M. Sherman, Matthew D. Finley, Rowan K. Borsari, Naviya Schuster-Little, Shelby L. Strausser, Rebecca J. Whelan, David M. Jenkins, Jon P. Camden
Summary: The study investigated the long-term stability of NHC-functionalized gold nanoparticles in various biological media, and found that imidazole-based NHCs remained stable over the 21-day examination period in all tested environments, indicating their potential as an alternative to thiols in biomedical applications.
Article
Chemistry, Inorganic & Nuclear
Kevin M. Blatchford, Carson J. Mize, Sharani Roy, David M. Jenkins
Summary: A neutral D-2-symmetric macrocyclic tetra-N-heterocyclic carbene ligand was synthesized and ligated to iron(ii) via transmetalation. The resulting iron complex catalyzed the stereospecific aziridination between aryl azides and aliphatic alkenes, albeit with low enantioselectivity.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Multidisciplinary
Joseph F. DeJesus, Ryan W. F. Kerr, Deborah A. Penchoff, Xian B. Carroll, Charles C. Peterson, Polly L. Arnold, David M. Jenkins
Summary: Highly symmetrical thorium and uranium octakis-carbene 'sandwich' complexes have been prepared by sandwiching the An(IV) cations between two anionic macrocyclic tetra-NHC ligands of different sizes. X-ray crystallography confirmed that the geometry of the metal center can be determined by the size of the macrocyclic ring, leading to different shapes, while DFT calculations revealed that the NHC ligands predominantly exhibit sigma-donation to the metal without pi-backbonding.
Article
Nanoscience & Nanotechnology
Umesh M. Shrestha, Kristina M. Vailonis, David M. Jenkins, Mark D. Dadmun
ACS APPLIED NANO MATERIALS
(2020)
Meeting Abstract
Chemistry, Multidisciplinary
Deborah Penchoff, Charlie Peterson, John Auxier, George Schweitzer, David Jenkins, Robert Harrison, Howard Hall
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY
(2019)
Meeting Abstract
Chemistry, Multidisciplinary
Kristina Vailonis, Karthikeyan Gnanasekaran, Xian Powers, David Jenkins, Nathan Gianneschi
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY
(2019)
Meeting Abstract
Chemistry, Multidisciplinary
Joseph DeJesus, Sara Isbill, Nathaniel Dominique, Robert Ozburn, Sharani Roy, David Jenkins
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY
(2019)
Meeting Abstract
Chemistry, Multidisciplinary
Markus Anneser, Gaya Elpitiya, Xian Powers, Elizabeth Johnson, Jacob Townsend, Konstantinos Vogiatzis, Theodore Betley, David Jenkins
ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY
(2019)
