Publications de Zhaowen Dong | EPFL Graph Search

Synthesis and Reactivity of an Anionic Diazoolefin

Rosario Scopelliti, Kay Severin, Farzaneh Fadaei Tirani, Bastiaan Kooij, Zhaowen Dong

Bent (hetero)allenes such as carbodicarbenes and carbodiphosphoranes can act as neutral C-donor ligands, and diverse applications in coordination chemistry have been reported. N-Heterocyclic diazoolefins are heterocumulenes, which can function in a similar ...

Wiley-VCH Verlag GmbH2023

Head‐to‐Tail Dimerization of N‐Heterocyclic Diazoolefins

Rosario Scopelliti, Kay Severin, Farzaneh Fadaei Tirani, Andrzej Sienkiewicz, Tak Hin Wong, Zhaowen Dong, Paul Varava, Anastasia Gitlina, Wolfram Feuerstein

The head-to-tail dimerization of N-heterocyclic diazoolefins is described. The products of these formal (3+3) cycloaddition reactions are strongly reducing quinoidal tetrazines. Oxidation of the tetrazines occurs in a stepwise fashion, and we were able to ...

Wiley-VCH Verlag GmbH2023

A Mesoionic Diselenolene Anion and the Corresponding Radical Dianion

Rosario Scopelliti, Kay Severin, Farzaneh Fadaei Tirani, Andrzej Sienkiewicz, Cesare Berton, Abdusalom Suleymanov, Zhaowen Dong

Dichalcogenolenes are archetypal redox non-innocent ligands with numerous applications. Herein, we describe a diselenolene ligand with fundamentally different electronic properties. By selenation of a C2-protected imidazolium salt, we have prepared a mesoi ...

2022

Vanadium complexes with N-heterocyclic vinylidene ligands

Rosario Scopelliti, Kay Severin, Farzaneh Fadaei Tirani, Laura Piveteau, Bastiaan Kooij, Zhaowen Dong, Paul Varava

The preparation and the structural characterization of vanadium complexes with terminal and bridging N-heterocyclic vinylidene ligands is reported. The synthesis of the complexes was enabled by utilization of diazoolefins as ligand precursors. Structural d ...

Royal Society of Chemistry2022

Multimodal host–guest complexation for efficient and stable perovskite photovoltaics

Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Ursula Röthlisberger, Felix Thomas Eickemeyer, Jovana Milic, Marko Mladenovic, Ulf Anders Hagfeldt, Hong Zhang, Dan Ren

Formamidinium lead iodide perovskites are promising light-harvesting materials, yet stabilizing them under operating conditions without compromising optimal optoelectronic properties remains challenging. We report a multimodal host–guest complexation strat ...

Nature Research2021

Construction of Functional Superhydrophobic Biochars as Hydrogen Transfer Catalysts for Dehydrogenation of N-Heterocycles

Zhaowen Dong, Feng Zhou

To endow metal-free materials with the high catalytic activity that is typically featured by a metal-based catalyst is yet a constant pursuit in the field of catalytic chemistry. In this work, novel functional biochars (DCNs) were prepared from wheat straw ...

AMER CHEMICAL SOC2021

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

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

Triazene-Activated Donor–Acceptor Cyclopropanes: Ring-Opening and (3 + 2) Annulation Reactions

Rosario Scopelliti, Kay Severin, Jérôme Waser, Farzaneh Fadaei Tirani, Abdusalom Suleymanov, Zhaowen Dong, Bastian Antoine Rodolphe Claude Muriel, Eliott Hugo Joran Le Du

Donor–acceptor cyclopropanes substituted with 3,3-dialkyltriazenyl groups are described herein. The strong electron-donating character of the triazene renders the cyclopropanes highly reactive, allowing for catalyst-free ring-opening reactions with methano ...

2020