A5009181509- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Catalytic Cross-Coupling Reactions
- Catalytic C–H Functionalization Methods
- Radical Photochemical Reactions
- Molecular Junctions and Nanostructures
- Semiconductor materials and devices
- Sulfur-Based Synthesis Techniques
- Asymmetric Hydrogenation and Catalysis
- Synthesis and Catalytic Reactions
- Synthetic Organic Chemistry Methods
- CO2 Reduction Techniques and Catalysts
- Carbon dioxide utilization in catalysis
- Organic Electronics and Photovoltaics
- Oxidative Organic Chemistry Reactions
- Photochromic and Fluorescence Chemistry
- Advanced Photocatalysis Techniques
- Cyclopropane Reaction Mechanisms
- Porphyrin and Phthalocyanine Chemistry
- Nanomaterials for catalytic reactions
- Covalent Organic Framework Applications
- Organic Light-Emitting Diodes Research
- MXene and MAX Phase Materials
- Surface and Thin Film Phenomena
University of Münster
2019-2024
Indian Institute of Technology Kanpur
2018
Abstract Herein, we report the redox‐neutral, intermolecular, and highly branch‐selective amidation of allylic C−H bonds enabled by Cp*Ir III catalysis. A variety readily available carboxylic acids were converted into corresponding dioxazolones efficiently coupled with terminal internal olefins in high yields selectivities. Mechanistic investigations support formation a nucleophilic Ir –allyl intermediate rather than direct insertion an Ir–nitrenoid species bond.
Heterogeneous palladium catalysts modified by N-heterocyclic carbenes (NHCs) are shown to be highly effective toward the direct synthesis of hydrogen peroxide (H
A novel photoresponsive and fully conjugated N-heterocyclic carbene (NHC) has been synthesized that combines the excellent photophysical properties of arylazopyrazoles (AAPs) with an NHC acts as a robust surface anchor (AAP-BIMe). The formation self-assembled monolayers (SAMs) on gold was proven by ToF-SIMS XPS, organic film displayed very high stability at elevated temperatures. This also reflected in desorption energy, which determined temperature-programmed SIMS measurements....
Herein, we describe the formation of quaternary carbon centers with excellent diastereoselectivity via a strain-release protocol. An organometallic species is generated by Cp*Rh(III)-catalyzed C–H activation, which then coupled strained bicyclobutanes (BCBs) and prochiral electrophile in three-component reaction. This work illustrates rare example BCBs transition metal catalysis demonstrates their broad potential to access novel reaction pathways. The method developed exhibits ample...
Tuning the properties of oxide surfaces through adsorption designed ligands is highly desirable for several applications, such as catalysis. N-Heterocyclic carbenes (NHCs) have been successfully employed modification metallic surfaces. On other hand, their potential modifiers ubiquitous still needs to be developed. Here we show that a model NHC binds covalently copper surface under UHV conditions. In particular, report first example covalent bond between NHCs and oxygen atoms from layer....
Abstract N‐Heterocyclic carbenes (NHCs) have superior properties as building blocks of self‐assembled monolayers (SAMs). Understanding the influence substrate in molecular arrangement is a fundamental step before employing these ligands technological applications. Herein, we study model NHC on Cu(100) and Cu(111). While mostly disordered phases appear Cu(100), Cu(111) well‐defined structures are formed, evolving from magic‐number islands to ribbons with coverage. This work presents first...
Abstract The C−C bond formation reaction represents a fundamental and important transformation in synthetic chemistry, exploring new types of reactions is recognized as appealing, yet challenging. Herein, we disclose the first example rhodium‐catalyzed dealkenylative arylation alkenes with arylboronic compounds, thereby providing an unconventional access to bi(hetero)aryls excellent chemoselectivity. In this method, C(aryl)−C(alkenyl) C(alkenyl)−C(alkenyl) bonds various 1,3‐dienes can be...
Self-assembly of cyclohexyl cyclic (alkyl)(amino)carbenes (cyCAAC) can be realized and reversibly switched from a close-packed trimer phase to chainlike dimer phase, enabled by the ring-flip wingtip. Multiple methods including scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS) density functional theory (DFT) calculations identified distinct isomer (axial or equatorial chair conformer) in each consequently support conclusion regarding determination molecular surface...
The strongly electron-donating N-heterocyclic imines (NHIs) have been employed as excellent surface anchors for the thermodynamic stabilization of electron-deficient species due to their enhanced nucleophilicity. However, binding mode and interfacial property these new ligands are still unclear, representing a bottleneck advanced applications in functionalization catalysis. Here, NHIs with different side groups rationally designed, synthesized, analyzed on various metal surfaces (Cu, Ag)....
Abstract Wir berichten über die redoxneutrale, intermolekulare und verzweigt‐selektive Amidierung von allylischen C‐H‐Bindungen durch Cp*Ir III ‐Katalyse. Eine Vielzahl leicht verfügbarer Carbonsäuren wurde in entsprechenden Dioxazolone umgewandelt effizient mit terminalen internen Olefinen hohen Ausbeuten Selektivitäten gekuppelt. Mechanistische Untersuchungen stützen Bildung eines nukleophilen Ir ‐Allyl‐Intermediats nicht direkte Insertion einer Ir‐Nitrenoidspezies allylische C‐H‐Bindung.
Using light as an external stimulus to alter the reactivity of Lewis bases is intriguing tool for controlling chemical reactions. Reversible photoreactions associated with pronounced changes are particularly valuable in this regard. We herein report first photoswitchable nitrogen superbases based on guanidines equipped a photochromic dithienylethene unit. The resulting N-heterocyclic imines (NHIs) undergo reversible, near quantitative electrocyclic isomerization upon successive exposure UV...
A fluorinated N-heterocyclic carbene is chemically bonded to Au and employed as a surface modifier improve contact between electrodes semiconductors in organic field-effect transistors, showing significant improvement device performance.
A simple synthetic route to access racemic 3,3-disubstituted propylamines in excellent yields (up 95%) via Lewis acid catalyzed SN2-type ring opening of activated azetidines with electron-rich arenes and heteroarenes under mild conditions has been accomplished. The methodology is efficiently used for the synthesis an antimuscarinic drug, tolterodine, four steps 47% overall yield.
A coordination-induced trigger for catalytic activity is proposed on an N-heterocyclic carbene (NHC)-decorated ceria catalyst incorporating Cr and Rh (ICy-r-Cr0.19Rh0.06CeOz). ICy-r-Cr0.19Rh0.06CeOz was prepared by grafting 1,3-dicyclohexylimidazol-2-ylidene (ICy) onto H2-reduced Cr0.19Rh0.06CeOz (r-Cr0.19Rh0.06CeOz) surfaces, which went to exhibit substantial the 1,4-arylation of cyclohexenone with phenylboronic acid, whereas r-Cr0.19Rh0.06CeOz without ICy inactive. FT-IR, K-edge XAFS, XPS,...
The synthesis and properties of photoswitchable electron-rich phosphines containing N-heterocyclic imines equipped with a photochromic dithienylethene unit are reported. Heteronuclear NMR spectroscopy UV/vis studies reveal that the imine substituents undergo reversible electrocyclic ring-closing ring-opening reactions upon exposure to UV visible light, respectively. photoisomerization alters electron-donating ability by up ΔTEP = 8 cm-1.
We demonstrate the formation of highly ordered cyCAAC monolayers on silicon showing strong work function reductions. The grade ordering thereby strongly depends surface defect density revealing an initial adsorption defects.
Abstract Hydroarylation is an effective strategy to rapidly increase the complexity of organic structures by transforming flat alkene moieties into three‐dimensional frameworks. Many strategies have already been developed achieve hydroarylation styrenes, however most these reports examine unpolar, β‐mono‐ or β‐unsubstituted while exploring mainly electron‐rich benzene nucleophiles. Herein, we report a mild and general catalytic system for selective hydroheteroarylation multiply substituted...
The adsorption of N-heterocyclic olefins (NHOs) on silicon is investigated in a combined scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory study. We find that both the studied NHOs bind covalently, with ylidic character, to adatoms substrate exhibit good thermal stability. geometry strongly depends N-substituents: for large N-substituents, an upright favored, while flat-lying found NHO smaller wingtips. These different geometries influence quality...
Surface modification through the formation of a self-assembled monolayer (SAM) can effectively engineer physicochemical properties surface/material. However, precise design multifunctional SAMs at molecular level is still major challenge. Here, we jointly use N-heterocyclic carbenes (NHCs) and thiols to form hetero-SAM systems that demonstrate excellent chemical stability, electrical conductivity, and, in silico, catalytic activity. This synergistic effect facilitated by high surface...
Abstract Ein neuartiges photoempfindliches und vollständig konjugiertes N‐heterocyclisches Carben (NHC) wurde synthetisiert, um die hervorragenden photophysikalischen Eigenschaften von Arylazopyrazolen (AAPs) mit einem NHC als robustem Oberflächenanker (AAP‐BIMe) zu kombinieren. Die Bildung selbstorganisierten Monoschichten (SAMs) auf Gold durch ToF‐SIMS XPS nachgewiesen, der organische Film zeigte eine sehr hohe Stabilität bei erhöhten Temperaturen. Diese sich auch in einer hohen...