Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Concept

Hammett equation

Related publications (18)

Synthesis of Four-Membered BN3 Heterocycles by the Borylation of Triazenes

Rosario Scopelliti, Kay Severin, Abdusalom Suleymanov

Borylated triazenes were synthesized by the dehydrocoupling of triazenes with 9-borabicyclo(3.3.1)nonane, by the condensation of triazenes with BEt3, or by the reaction of sodium triazenides with dialkyl- or diarylboron halides. The structures of the produ ...

2022

Oxidation of organic micropollutant surrogate functional groups with peracetic acid activated by aqueous Co(II), Cu(II), or Ag(I) and geopolymer-supported Co(II)

Urs von Gunten

Peracetic acid (PAA) in combination with transition metals has recently gained increasing attention for organic micropollutant abatement. In this study, aqueous Co(II), Cu(II), and Ag(I) were compared for their capacity to activate PAA. Co(II) outperformed ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Evaluation of Photocatalysts for Water Splitting through Combined Analysis of Surface Coverage and Energy-Level Alignment

Alfredo Pasquarello, Francesco Ambrosio, Zhendong Guo

To examine whether suitable conditions occur for the water splitting reaction at their interfaces with liquid water, we determine the pH-dependent surface coverage for a series of semiconductors, including GaAs, GaP, GaN, CdS, ZnO, SnO2, and rutile and ana ...

2020

Synthetic Studies toward Amanita Phalloides Toxins

Philipp Georg Werner Seeberger

Amatoxins are ribosomally synthesized and post-translationally modified bicyclic octapeptides biosynthesized by the deadly basidiomycete fungus Amanita phalloides. Amongst this group, alpha-amanitin is the most widely known toxin and is currently under inv ...

EPFL2020

Metal-Organic-Framework-Derived Co3S4 Hollow Nanoboxes for the Selective Reduction of Nitroarenes

Emad Oveisi, Wendy Lee Queen, Shuliang Yang, Daniel Teav Sun, Li Peng, Safak Bulut

MOF-derived Co3S4/CN hollow nanoboxes (CN=nitrogen-doped carbon) was used to catalyze the chemoselective reduction of nitroarenes to anilines under mild reaction conditions with H-2 as the reducing agent. The catalyst provides high conversion efficiencies ...

2018

Substituent effects on the relative rates and free energies of ortho-lithiation reactions: families of fluorobenzenes as the substrates

2-, 3- and 4-substituted fluorobenzenes and 5-substituted 1,3-difluorobenzenes were metalated with sec-butyllithium (LIS) and with lithium 2,2,6,6-tetramethylpiperidide (LiTMP) under irreversible conditions in order to determine the rates of reaction relat ...

Arkat Usa Inc2015

Reaction of bromine and chlorine with phenolic compounds and natural organic matter extracts - Electrophilic aromatic substitution and oxidation

Urs von Gunten, Eva Maria Rodriguez Franco

Phenolic compounds are known structural moieties of natural organic matter (NOM), and their reactivity is a key parameter for understanding the reactivity of NOM and the disinfection by-product formation during oxidative water treatment. In this study, spe ...

Elsevier2015

Structure-property relationships based on Hammett constants in cyclometalated iridium(III) complexes: their application to the design of a fluorine-free FIrPic-like emitter

Mohammad Khaja Nazeeruddin, Rosario Scopelliti, Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod, Julien Edouard Frey

While phosphorescent cyclometalated iridium(III) complexes have been widely studied, only correlations between oxidation potential EOX and Hammett constant sigma, and between the redox gap (Delta E-REDOX = E-OX-E-RED) and emission or absorption wavelength ...

2014

Reactivity of BrCl, Br2, BrOCl, Br2O and HOBr toward dimethenamid in solutions of bromide + aqueous free chlorine

Jeremy Samuel Arey, Peter Rudolf Tentscher

HOBr, formed via oxidation of bromide by free available chlorine (FAC), is frequently assumed to be the sole species responsible for generating brominated disinfection byproducts (DBPs). Our studies reveal that BrCl, Br-2, BrOCl, and Br2O can also serve as ...

Amer Chemical Soc2013

Highly cytotoxic trithiophenolatodiruthenium complexes of the type [(eta(6)-p-MeC6H4Pr (i) )(2)Ru-2(SC6H4-p-X)(3)](+): synthesis, molecular structure, electrochemistry, cytotoxicity, and glutathione oxidation potential

Paul Joseph Dyson, Olivier Pierre Zava, Mathurin Baquié

A series of cationic dinuclear p-cymene ruthenium trithiophenolato complexes of the type (eta(6)-p-MeC6H4Pr (i) )(2)Ru-2(SC6H4-p-X)(3) (1 X is H, 2 X is Me, 3 X is Ph, 4 X is Br, 5 X is OH, 6 X is NO2, 7 X is OMe, 8 X is CF3, 9 X is F, 10 X is Pr (i) ...

Springer2012

Influence of Halogen Atoms on a Homologous Series of Bis-Cyclometalated Iridium(III) Complexes

Michael Graetzel, Mohammad Khaja Nazeeruddin, Rosario Scopelliti, Ursula Röthlisberger, Ivano Tavernelli, Basile Curchod

A series of homologous bis-cyclometalated iridium(III) complexes Ir(2,4-di-X-phenyl-pyridine)2(picolinate) (X = H, F, Cl, Br) HIrPic, FIrPic, ClIrPic, and BrIrPic has been synthesized and characterized by NMR, X-ray crystallography, UV–vis absorption and e ...

2012

Rotational barriers of biphenyls having heavy heteroatoms as ortho-substituents: experimental and theoretical determination of steric effects

The free energies of activation for the aryl-aryl rotation of 17 biphenyl derivatives, bearing a heavy heteroatom (S, Se, Te, P, Si, Sn) as ortho substituent, have been measured by variable temperature NMR. These numbers, so called B values, represent a me ...

2012

Modulating the Steric, Electronic, and Catalytic Properties of Cp* Ruthenium Half-Sandwich Complexes with β-Diketiminato Ligands

Paul Joseph Dyson, Rosario Scopelliti, Kay Severin, Andrew Douglas Phillips, Katrin Anne Thommes

Five different types of β-diketiminate ligands, bearing electron-donating to strongly electron-withdrawing substituents, were synthesized and used in the synthesis of Cp* ruthenium complexes (Cp* = η5-C5Me5). One series consists of complexes with a covalen ...

American Chemical Society2011

Physico-chemical properties and photo-reactivity relationship for para-substituted phenols in photo-assisted Fenton system

César Pulgarin, Félicien Mazille

The reactivity of phenolic compounds can be drastically affected by the electronic nature of the substituting groups. In this work, the effect of physico-chemical properties on the reactivity via photo-assisted Fenton catalysis is reported for several para ...

2010

Photocatalytic degradation of p-halophenols in TiO2aqueous suspensions: halogen effect on removal rate aromatic intermediates and toxicity variations

César Pulgarin, Sandra Parra Cardona, Miléna Lapertot

he influence of the halogen upon the TiO2 photocatalytic degradation of p-halophenols in water has been investigated. Phenol was used as the reference compound. Compared with its value for phenol, the apparent first-order rate constant of removal, k, was s ...

2006

Metal-bearing and trifluoromethyl-substituted pyrimidines: generation and functionalization

Levente Ondi

5-Pyrimidyllithium species are fairly stable when the metal is flanked by two electron-withdrawing substituents such as trifluoromethyl and chlorine or bromine. Thus, the corresponding 5-carboxylic acids are produced in high yields from 4,5-dibromo-6-(trif ...

2006

Biomimetic catalysis with immobilized transition metal complexes

Alexander Schiller

The tetradentate chelate ligand tris[(1-vinylimidazol-2-yl)methyl]amine (10) was synthesized in five steps from commercially available starting materials. Upon reaction with MCl2 (M = Zn, Cu, Ni, Co) in the presence of NH4PF6, the complexes [M(10)Cl]PF6 (M ...

EPFL2006

The reactivity of 2-fluoro- and 2-chloropyridines toward sodium ethoxide: Factors governing the rates of nucleophilic (het)aromatic substitutions

Thierry Rausis

The relative displacement rates of the halide substituent from 2-fluoro- and 2-chloropyridines by EtONa in EtOH at +25 Deg were assessed by competition kinetics. The 2-fluoropyridine reacts 320 times faster than the chloro analog. A CF3 group increases the ...

2005