Search results for "54"

Incentives in Corporate Governance: The Role of Self-Regulation

2004

Corporate governance stems from the interplay of legal norms, security regulation, self-regulation and best practices. Recent scandals and frauds have forced governments to update laws on corporate governance: the legislation process has been very fast in some countries, others have lagged. Law and regulation intervene and become effective only ex-post, when damages have been done and malpractice is self-evident. On the contrary, self-regulation is a quicker and more flexible response to changing market conditions and of great impact on the relationship between firms and their environment. A self-regulatory organization (SRO) such as the stock exchange could administer the screening device,…

Electrosynthesis of 3,3′,5,5’-tetramethyl-2,2′-biphenol in flow

2020

Abstract3,3′,5,5’-Tetramethyl-2,2′-biphenol is well known as an outstanding building block for ligands in transition-metal catalysis and is therefore of particular industrial interest. The electro-organic method is a powerful, sustainable, and efficient alternative to conventional synthetic approaches to obtain symmetric and non-symmetric biphenols. Here, we report the successive scale-up of the dehydrogenative anodic homocoupling of 2,4-dimethylphenol (4) from laboratory scale to the technically relevant scale in highly modular narrow gap flow electrolysis cells. The electrosynthesis was optimized in a manner that allows it to be easily adopted to different scales such as laboratory, semit…

HANSEN, Folker (2015): La economía del cáñamo en la España suroriental. El cultivo, manipulación y transformación del cáñamo en su significado para l…

2018

Spatial structure and nest demography reveal the influence of competition, parasitism and habitat quality on slavemaking ants and their hosts

2010

Abstract Background Natural communities are structured by intra-guild competition, predation or parasitism and the abiotic environment. We studied the relative importance of these factors in two host-social parasite ecosystems in three ant communities in Europe (Bavaria) and North America (New York, West Virginia). We tested how these factors affect colony demography, life-history and the spatial pattern of colonies, using a large sample size of more than 1000 colonies. The strength of competition was measured by the distance to the nearest competitor. Distance to the closest social parasite colony was used as a measure of parasitism risk. Nest sites (i.e., sticks or acorns) are limited in …

Ammonium formate-Pd/C as a new reducing system for 1,2,4-oxadiazoles. Synthesis of guanidine derivatives and reductive rearrangement to quinazolin-4-…

2021

1,2,4-Oxadiazole is a heterocycle with wide reactivity and many useful applications. The reactive O-N bond is usually reduced using molecular hydrogen to obtain amidine derivatives. NH4CO2H-Pd/C is here demonstrated as a new system for the O-N reduction, allowing us to obtain differently substituted acylamidine, acylguanidine and diacylguanidine derivatives. The proposed system is also effective for the achievement of a reductive rearrangement of 5-(2′-aminophenyl)-1,2,4-oxadiazoles into 1-alkylquinazolin-4(1H)-ones. The alkaloid glycosine was also obtained with this method. The obtained compounds were preliminarily tested for their biological activity in terms of their cytotoxicity, induce…

An ab initio and DFT study of the fragmentation and isomerisation of MeP(O)(OMe)+

2004

The fragmentation behaviour of the ion MeP(O)OMe+ has been investigated using quantum mechanical calculations at the B3LYP and MP2 levels to support experiments made with an Ion Trap Mass Spectrometer. Two mechanisms for the loss of CH2O are found, one involving a 1,3-H migration to phosphorus and the other a 1,2-methyl migration to give P(OMe)2+ followed by a 1,3-H migration. In each case an ion-dipole complex is formed that rapidly dissociates to yield CH2O. The relative importance of each route has been previously determined experimentally via isotopic labelling experiments, and the theoretical results are found to be consistent with these experimental results. The mechanisms suggested i…

La censura nella Francia settecentesca e la figura del colporteur tra realtà e finzione

2015

La censura assume un’importanza fondamentale nella Francia settecentesca se si considera il vistoso aumento dei censori che passa da quarantuno all’inizio del secolo a settantotto alla vigilia della Rivoluzione. Cercando di raggirare i divieti imposti dalla censura, i colporteur ossia i venditori francesi ambulanti di libri eludano la sorveglianza nascondendo sotto il loro mantello sia scritti libertini che libelli politici, vale a dire i libri più amati e contestati dell’epoca, per poi venderli ai clienti piùabbienti. Censorship is of fundamental importance in eighteenth-century France, a fact corroborated by the increase in the number of censors throughout the century: from forty-one in t…

La correspondencia entre el P. Guzmán, Barbieru y Pedrell: revelaciones inéditas

2014

Understanding light-driven H 2 evolution through the electronic tuning of aminopyridine cobalt complexes

2017

A new family of cobalt complexes with the general formula [CoII(OTf)2(Y,XPyMetacn)] (1R,Y,XPyMetacn ¼ 1-[(4-X-3,5-Y-2-pyridyl)methyl]-4,7-dimethyl-1,4,7-triazacyclononane, (X ¼ CN (1CN), CO2Et (1CO2Et), Cl (1Cl), H(1H), NMe2 (1NMe2)) where (Y ¼ H, and X ¼ OMe when Y ¼ Me (1DMM)) is reported. We found that the electronic tuning of the Y,XPyMetacn ligand not only has an impact on the electronic and structural properties of the metal center, but also allows for a systematic water-reduction-catalytic control. In particular, the increase of the electron-withdrawing character of the pyridine moiety promotes a 20-fold enhancement of the catalytic outcome. By UV-Vis spectroscopy, luminescence quenc…

Fonctionnalisation et métallisation des diamantoïdes

2015

The thesis deals with development of synthetic methods for preparation of novel carbon-metal organohybrid based on diamondoid and palladium. The vapor pressure of various diamondoids was measured from a new measurement protocol at solid-vapor thermodynamic equilibrium state. Their volatile tendency opened a possibility to do deposition from gas phase and at various pressure (ambient, primary vacuum, and high vacuum) of diamondoids on silicon or mica substrates. SEM observations have shown that depending on the type of functional groups on the diamondoid, different crystal shapes can be produced (rods, needles, triangles, truncated octahedral form).OMCVD of palladium on functionalized diaman…