Article
Biochemical Research Methods
Fady Nahra, Nikolaos Tzouras, Alba Collado, Steven P. Nolan
Summary: N-heterocyclic carbene gold(I) chloride and hydroxide complexes are commonly used as synthetic reagents and efficient catalysts. This study describes a straightforward and practical method for synthesizing mononuclear gold complexes with high yields, as well as the synthesis of a mononuclear gold(I) hydroxide complex and an improved synthesis method for a dinuclear gold(I) hydroxide complex. This methodology offers advantages such as the use of sustainable reaction solvents and commercially available starting materials.
Review
Chemistry, Inorganic & Nuclear
Yidan Wang, Bo Zhang, Shuai Guo
Summary: The combination of NHC and pincer framework in transition metal complexes has been widely studied and applied in various fields, including catalysis and optical material chemistry. This minireview focuses on the synthesis, reactivity study and applications of metal pincer NHCs.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Thomas P. Nicholls, Zhongfan Jia, Justin M. Chalker
Summary: An electrochemical synthesis method has been developed for the production of gold(I)-N-heterocyclic carbene (Au-NHC) complexes. This method allows for the production of complexes without any by-products, which can be directly used as catalysts without purification.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Felix Ziegler, Johanna R. Bruckner, Michal Nowakowski, Matthias Bauer, Patrick Probst, Boshra Atwi, Michael R. Buchmeiser
Summary: The immobilization of tungsten-based catalysts inside ordered mesoporous silica results in enhanced macrocyclization and Z-selectivity, allowing high substrate concentrations. Smaller mesopores exhibit a stronger confinement effect. The two supported catalysts show different selectivities, which can be rationalized by their structures.
Article
Chemistry, Multidisciplinary
Mathis J. Benedikter, Janis V. Musso, Wolfgang Frey, Roman Schowner, Michael R. Buchmeiser
Summary: Despite their excellent selectivities and activities, Mo- and W-based catalysts for olefin metathesis have not been widely used due to their air sensitivity. The synthesized cationic-at-metal molybdenum and tungsten imido alkylidene NHC nitrile complexes are stable in air and can catalyze olefin metathesis reactions without prior activation. The presence of a nitrile ligand is crucial for their stability, while variations in imido and anionic ligands affect reactivities and stability.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Ichraf Slimani, Serap Sahin-Bolukbasi, Mustafa Ulu, Enes Evren, Nevin Gurbuz, Ilknur Ozdemir, Naceur Hamdi, Ismail Ozdemir
Summary: A series of rhodium(i) complexes with N-heterocyclic carbene ligands showed high in vitro cytotoxic activity against human cancer cells, with complex 2b exhibiting the most selective cytotoxic activity. These complexes demonstrated greater cytotoxicity against cancer cells compared to established anticancer agents cisplatin and 5-fluorouracil.
NEW JOURNAL OF CHEMISTRY
(2021)
Review
Chemistry, Inorganic & Nuclear
Halliru Ibrahim, Muhammad D. Bala, Holger B. Friedrich
Summary: This review elaborates on the chronological development of imino-NHC ligands and their complexes with late first-row transition metals utilized in homogeneous catalysis. Imino-NHC ligands have gained popularity due to their general stability, better resistance to degradation, and suitable coordinative and electronic properties for various catalytic transformations.
COORDINATION CHEMISTRY REVIEWS
(2022)
Article
Chemistry, Organic
Zhen Li, Pengju Ji, Jin-Pei Cheng
Summary: A Brønsted basicity scale was established for nine representative N-heterocyclic olefins (NHOs) using an UV-visible spectroscopic method. The unsaturated NHOs were found to have stronger basicities compared to their N-heterocyclic carbene (NHC) analogues, while the basicities of the saturated NHOs were weaker. The nucleophilicity of the NHOs was also stronger than commonly used Lewis bases but weaker than their NHC analogues.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Keita Tanaka, Martin-Louis Y. Riu, Brian Valladares, Christopher C. Cummins
Summary: In this study, a new class of Azophosphines and N-heterocyclic iminophosphoranes (NHIPs) were successfully synthesized. The NHIPs exhibited tunability of steric demands and good basicity. The facile and scalable synthesis of NHIPs suggests their potential applications in synthetic chemistry.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Keita Tanaka, Martin-Louis Y. Riu, Brian Valladares, Christopher C. Cummins
Summary: This study presents the preparation and cycloaddition reactions of Azophosphines. The results show that these compounds have good adaptability to phosphorus atom substituents and can generate structures similar to cyclic (alkyl)(amino)carbenes. The NHIPs exhibit strong sigma-donor strengths and basicity, and display unique reactivity in certain reactions. The tunability of steric demands and scalability of these compounds suggest that they may have a wide range of applications in synthetic chemistry.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Hang Shen, Michael B. Larsen, Allison G. Roessler, Paul M. Zimmerman, Andrew J. Boydston
Summary: A new flex-activated mechanophore has been discovered, which releases an N-heterocyclic carbene (NHC) under mechanical load. This design demonstrates a promising first step towards flex-activated designs with downstream reactivities, allowing for iterative activation increases in the material through non-destructive compression cycles. The potential modularity of the mechanophore design is highlighted by the demonstration of two different NHC structures.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Review
Polymer Science
Isha Jain, Payal Malik
Summary: Metal-N-heterocyclic carbene complexes (M-NHCs) have shown great potential as a catalytic system for the synthesis of various biodegradable polymers via ring opening polymerization. This review provides an overview of the field's major achievements and developments from 2004 to 2020, with a focus on the structure-activity relationship of M-NHC complexes.
EUROPEAN POLYMER JOURNAL
(2021)
Review
Chemistry, Multidisciplinary
Muneshwar Nandeshwar, Suman Mandal, Subramaniam Kuppuswamy, Ganesan Prabusankar
Summary: Sustainable noble metal-N-heterocyclic carbenes (NHC's) have gained significant attention in both the chemical industry and academic community due to environmental concerns and resource scarcity. The choice of catalyst supports plays a crucial role in heterogeneous catalysis, with graphene oxide (GO)/reduced graphene oxide (rGO) support showing great potential due to their larger surface area, inertness towards chemical transformations, and easy surface functionalization. Marrying metal-N-heterocyclic carbenes with GO/rGO support offers novel heterogeneous complexes with improved catalytic efficiency without sacrificing product selectivity, presenting opportunities for the chemical and pharmaceutical industry. However, limited examples of this approach are reported in the literature, highlighting the need for comprehensive reviews on metal-NHC synthesis on GO/rGO support and synthetic strategies for grafting M-NHC onto GO/rGO surface, as well as understanding the catalytic efficiency and mechanisms of non-covalent grafting methodology to design engineered catalysts for unexplored catalytic applications.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Physical
Bao-Gui Cai, Qian Li, Claire Empel, Lei Li, Rene M. Koenigs, Jun Xuan
Summary: In this study, we reported the visible light and N-heterocyclic carbene (NHC) jointly promoted multicomponent carbene transfer reactions. Two kinds of important hydroxamic acid esters were obtained in good yields under optimized reaction conditions depending on the reaction media used. The utility and practicality of this method were demonstrated through mild reaction conditions, excellent functional group tolerance, useful synthetic transformations, and successful modification of natural products and drug molecules.
Article
Chemistry, Physical
Janis Musso, Roman Schowner, Laura Falivene, Wolfgang Frey, Luigi Cavallo, Michael R. Buchmeiser
Summary: A series of cationic tungsten oxo alkylidene N-heterocyclic carbene (NHC) complexes were synthesized and characterized by single crystal X-ray diffraction. The correlation between the C-13 NMR chemical shifts of alkylidene C atoms and the DFT calculated chemical shifts was studied, revealing a good correlation and strong correlation with the rate of ring-closing metathesis. Analysis of catalyst geometries and magnetic shielding tensors allowed for assigning different structures to different levels of shielded alkylidene C atoms and corresponding reaction rates.