1,723,812 research outputs found
Alkyne Hydroamination Promoted by NHC-Gold(I) Complexes: Activity and Mechanistic Insight
No full textThe pharmaceutical and chemical industries heavily rely on the production of N-containing
compounds, as these molecules serve as scaffolds for the synthesis of both fine chemicals and
polymers of interest. The hydroamination reaction can be hailed as a paradigm of a
contemporary, sustainable, catalytically promoted chemical process, since it can form C-N
bonds by adding amines to multiple carbon bonds with a 100% atom economy.1 By reducing
the high energy barriers connected to alkyne activation, use of metal complexes can facilitate
this process; lately, gold(I) N-heterocyclic (NHC) complexes were demonstrated to be
promising in this regard.2 Herein, we present a library of gold(I)-NHC complexes which were
identified as promising catalysts for regioselective Markovnikov addition of aromatic and
aliphatic alkynes to anilines, with high yields.3 Accurate catalyst’ design, experimental reaction
scope and computational mechanistic insight will be presented, by means of which the nonmonotonic
impact of substrate substituents on the reaction course was elucidated.
References
(1) Müller, T. E.; Hultzsch, K. C.; Yus, M.; Foubelo, F.; Tada, M. Chem. Rev. 2008, 108, 3795–3892.
(2) Mariconda, A.; Sirignano, M.; Troiano, R.; Russo, S.; Longo, P. Catalysts 2022, 12(8), 836.
(3) Sirignano, M.; D’Amato, A.; Costabile, C.; Mariconda, A.; Crispini, A.; Scarpelli, F.; Longo, P. Front. Chem.
2023, 11, 1260726
La polizza malattia: riflessioni medico-legali sulla garanzia “Grandi Interventi Chirurgici”. (in collaborazione con A. Sirignano). Medicina Legale Quaderni Camerti, XXIII, 3, 2001.
No full text
Distruggi questo diario di Keri Smith: il valore formativo di una narrazione autobiografica (d)istruttiva
No full text“Distruggi questo diario di Keri Smith: il valore formativo di una narrazione autobiografica (d)istruttiva”, in Sirignano F. M., Maddalena S. (a cura di), Come schegge di cometa. Il formatore autobiografico: spunti e coordinate pedagogiche per l’insegnamento narrativo, Collana Scienze Pedagogiche, Suor Orsola Benincasa, Napoli 2021, ISBN 9791280426031
A sectional soot formation kinetics scheme with a new model for coagulation efficiency
Full text linkA sectional scheme for soot formation is combined with a novel model for coagulation efficiency based on the thermal rebound concept and involves the minimisation of the Lennard-Jones potential energy between two colliding particles. Here, a novel generalisation of the interaction potential well depth is formulated for particles of any size or material composition that contains a free parameter which is related to the soot particle void fraction. A simplification that expresses the coagulation rate in an Arrhenius-like form is proposed so that the entire gas-phase and soot kinetics can be easily coupled and integrated using existing chemical kinetics solvers. The model is included in the sectional scheme, which accounts for nucleation, surface growth/oxidation, coagulation and fragmentation, and is validated against experimental data for a series of ethylene burner stabilised stagnation (BSS) premixed flames and a methane laminar coflow diffusion flame. The soot kinetics is discretised into lumped species according to soot particle size (or number of carbon atoms) and the soot evolution follows a 23-step abstract reaction scheme that is a reduced form of an existing multisectional soot kinetics scheme (Sirignano et al., Energy & Fuels 27, 2013). Overall, the model predictions produce a satisfactory agreement with the experimental data but there is considerable sensitivity to . In particular, has a strong effect on the soot particle size distribution (PSD) in the BSS flames. or 1.25 lead to an overprediction of large particle concentrations but result in the correct transition to a bimodal PSD as the stagnation plate separation distance increases, whereas is found to produce accurate predictions for nascent soot but suppresses the transition to a bimodal PSD. In the methane coflow diffusion flame increasing reduces the soot volume fraction but the predictions are also found to be very sensitive to the chosen numerical threshold for the lower soot size detection limit and results are presented for 2 nm and 7 nm thresholds for comparison against both laser-based and probe-based experimental data
Requisiti e limiti del certificato medico in ambito assicurativo privato
No full textviene discussa la caratterizzazione tecnica della rettificazione della certificazione rilasciata dal medico per un uso in ambito assicurativo privat
Co.Me.Te. - Concetti, metodi e tecnologie per un approccio innovativo alla cittadinanza e al benessere responsabile nella società della conoscenza
No full textIl progetto di ricerca intende trovare soluzioni, innovative ed efficaci, alle sfide che l'odierno sistema socio-culturale lancia all'uomo nelle varie età della vita e nello svolgimento delle sue differenti funzioni, tali da venire utilmente raccolte all'interno della categoria della complessità; individuando, altresì, nella formazione e nell'educazione ai suoi diversi livelli, le strategie e gli asset fondamentali di risposta.
In un mondo evidentemente complesso, il compito dell'educazione, nella sua globalità, non è di banalizzare o negare siffatta complessità, quanto, piuttosto, quello di aiutare le persone a “semplificarla”, attraverso l'identificazione di ciò che rimane costante, a fronte delle componenti accessorie. In questo modo, l'educazione recupera
la sua funzione di sapere pratico-progettuale in grado di fornire ai soggetti coinvolti strumenti efficaci per l'interpretazione e la trasformazione del mondo
The CNGS project and OPERA experiment at LNGS
No full textThe OPERA (CNGS1) experiment will study neutrino oscillations, in particular it was designed to observe @n_@m->@n_@t oscillation signal via the direct observation of @n_@t interactions in a target of nuclear emulsions films and lead. The experiment will make use of a high energy @n_@m beam (CNGS) produced at CERN and of a detector placed in the Gran Sasso Underground laboratory (LNGS), the sub-micron spatial resolution provided by nuclear emulsions will allow to identify oscillation signal with a very low background level. In these months the OPERA collaboration is carrying out the detector assembly and the physical data acquisition is expected to start in August 2006. In order to cope with the expected neutrino interaction rate and allow a quasi-online analysis of the events, the emulsion read out have to be very fast, the limited number of signal events expected requires to the system high efficiency, purity and precision
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