Publications related to Persistent carbene

Investigations about the Chemistry of Tetraarylethene- and Iridium-Based Luminophores

The work described in this thesis focuses on two classes of luminophores: tetraarylethene-based polymers and Ir(III) complexes with orthometalated ligands. Tetraarylethene-based polymers show aggregation-induced emission (AIE) and they are of interest for ...

EPFL2024

The acid-mediated isomerization of iridium(iii) complexes with cyclometalated NHC ligands: kinetic vs. thermodynamic control

Kay Severin, Farzaneh Fadaei Tirani, Anastasia Gitlina

The isomerization of iridium(III) complexes with metalated N-heterocyclic carbene (NHC) ligands was studied. The fac isomers of complexes with 1-phenyl-3-methylbenzimidazolin-2-ylidene or 1-phenyl-3-benzylbenzimidazolin-2-ylidene ligands are transformed cl ...

2023

Photocatalyzed [2σ + 2σ] and [2σ + 2π] Cycloadditions for the Synthesis of Bicyclo[3.1.1]heptanes and 5- or 6-Membered Carbocycles

Jérôme Waser, Matthew Wodrich, André Bossonnet

We report the use of photocatalysis for the homolytic ring-opening of carbonyl cyclopropanes. In contrast to previous studies, our approach does not require a metal cocatalyst or a strong reductant. The carbonyl cyclopropanes can be employed for both [2σ + ...

2023

Chiral Cyclic Alkyl Amino Carbene (CAAC) Transition-Metal Complexes: Synthesis, Structural Analysis, and Evaluation in Asymmetric Catalysis

Adrien Jules Louis Madron Du Vigné

Despite recent advances in the field of cyclic alkyl amino carbenes (CAACs) including a few complementary synthetic strategies affording CAACs with various substitution patterns, the application potential of chiral CAACs to efficiently catalyze asymmetric ...

2022

Multiple Surface Site Three-Dimensional Structure Determination of a Supported Molecular Catalyst

Pierrick Berruyer, Moreno Lelli, David Benjamin Roger Antoine Gajan, Zhuoran Wang

The structural characterization of supported molecular catalysts is challenging due to the low density of active sites and the presence of several organic/organometallic surface groups resulting from the often complex surface chemistry associated with supp ...

AMER CHEMICAL SOC2022

Isolation, Characterisation and Reactivity of N-Heterocyclic Diazoolefins

Paul Varava

Examples for applications of nitrous oxide in organic synthesis remain rare up until today. First mayor contributions of our group were published in 2012, when nitrous oxide was successfully captured by N-heterocyclic carbenes. Subsequent studies investiga ...

EPFL2022

Synthetic chemistry with nitrous oxide and triazenes

Iris Roswitha Landman

Nitrous oxide (N2O) has gained much interest because of its physiological effects ("laughing gas") and its negative environmental impact ("greenhouse gas", "ozone-depleting substance"): It has a lifetime of more than 100 years in the atmosphere. Its persis ...

EPFL2022

Development of metal-organic frameworks based on N-heterocyclic ligands

Ilia Kochetygov

Metal-organic frameworks (MOFs) have firmly established in the field of porous materials since their early discovery in the 1990s. With a plethora of applications, these materials offer endless possibilities owing to their tunable, modular nature. The vast ...

EPFL2022

Asymmetric Cyclopropanation and Epoxidation via a Catalytically Formed Chiral Auxiliary

Jérôme Waser, Mikus Purins

For the enantioselective diversification of a single starting material, a different chiral catalyst is usually required for each transformation. Herein, we extend the concept of catalytically formed chiral auxiliary from hydrogenation to the asymmetric cyc ...

Wiley-VCH Verlag GmbH2022

In depth analysis of heterogeneous catalysts for the chemoenzymatic dynamic kinetic resolution of beta-amino esters

Kumar Varoon Agrawal, Cédric Karel J Van Goethem

The chemoenzymatic dynamic kinetic resolution of beta-amino esters is established after detailed evaluation of metal-based heterogeneous catalysts for racemization and enzyme catalysts for kinetic resolution. Several heterogeneous palladium catalysts prove ...

ROYAL SOC CHEMISTRY2022

Optimizing the Thermodynamics and Kinetics of the Triplet-Pair Dissociation in Donor–Acceptor Copolymers for Intramolecular Singlet Fission

Anne-Clémence Corminboeuf, Maria Fumanal Quintana

Singlet fission (SF) is a two-step process in which a singlet splits into two triplets throughout the so-called correlated triplet-pair (1TT) state. Intramolecular SF (iSF) materials, in particular, have attracted growing interest as they can be easily imp ...

2022

Stabilizing Unusual Oxidation States of Lanthanides in Molecular Complexes: Synthesis, Properties, and Reactivity

Aurélien René Willauer

The chemistry of divalent lanthanides has generated increasing interest in the past years due to their redox properties and unique reaction pathways. Notably, molecular complexes of low-valent lanthanides have been shown to be suitable one-electron reducta ...

EPFL2022

Co(III) carboxamide complexes as electrocatalysts for water splitting

Kurt Schenk, Farzaneh Fadaei Tirani

Water splitting is a promising approach for storing intermittent renewable energies, such as sunlight in the clean chemical bonds as a hydrogen fuel. Two water-soluble octahedral cobalt (III) complexes, [Co(bpb)(OAc)(H2O)], 1, (bpb(2-) = N,N' -bis[(2-pyrid ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Tuning the π‐Accepting Properties of Mesoionic Carbenes: A Combined Computational and Experimental Study

Rosario Scopelliti, Kay Severin, Farzaneh Fadaei Tirani, Andrzej Sienkiewicz, Anne-Clémence Corminboeuf, Zhaowen Dong, Jacob Terence Blaskovits

Mesoionic imidazolylidenes are recognized as excellent electron-donating ligands in organometallic and main group chemistry. However, these carbene ligands typically show poor π-accepting properties. We have performed a computational analysis of 71 mesoion ...

2021

Three-membered cyclic digermylenes stabilised by an N-heterocyclic carbene dagger

Zhaowen Dong

Treatment of potassium salts of silole dianions with donor stabilised germanium dichlorides gave the anticipated silagermafulvenylidenes R2Si = Ge(Do) (R2Si = 1-silacyclopentadiendiyl, Do = N-heterocyclic carbene (NHC)) only as transient intermediates in a ...

2021

Isolation and characterization of diazoolefins

Rosario Scopelliti, Kay Severin, Farzaneh Fadaei Tirani, Zhaowen Dong, Paul Varava

Diazoolefins tend to be highly reactive compounds that rapidly lose dinitrogen. So far, most experimental evidence for diazoolefins is indirect, via trapping experiments. Here we show that diazoolefins are observed to form in reactions of N-heterocyclic ol ...

2021

New Vinylation and Alkynylation Strategies with Hypervalent Iodine Reagents and Diazo Compounds

Guillaume Dominique Pisella

The development of a sequential copper-catalyzed oxy-alkynylation/intramolecular [4+2] cycloaddition of allenes and arenes was investigated at first. This one-pot protocol allowed the construction of complex polycylic architectures with high efficiency fro ...

EPFL2021

Propelling the hydrogen economy: from chemical storage and delivery to utilization in biomass conversion

Lu Chen

Since H2 is a non-polluting, inexhaustible, efficient, and sustainable energy carrier, it has been forecast to become one of the major carriers of energy in the future and is also essential in the production of feedstock chemicals derived from renewable ca ...

EPFL2021

Supported ruthenium nanoparticles for supercritical water gasification - synthesis, activity and stability

Christopher Marc Hunston

Supercritical water gasification (SCWG) is a promising and versatile technology for the conversion of a variety of wet biomass streams into renewable natural gas. In this work, the focus was set on methane production with the help of an active and stable m ...

EPFL2021

Influence of N-heterocyclic carbenes (NHCs) on the hydrolysis of a diphosphene

Shubhajit Das

We report the influence of N-heterocyclic carbenes (NHCs) on the hydrolysis of a diphosphene TerP?PTer (1; Ter = 2,6-Mes(2)C(6)H(3); Mes = 2,4,6-Me3C6H2), a phosphorus-analogue of an alkene. The diphosphene 1 itself is completely inert towards water. Howev ...

ROYAL SOC CHEMISTRY2020