Synthesis of stereodefined 1-aryl(heteroaryl) substituted 1,2-bis(2-bromopyridin-3-yl)ethenes by selective tandem Suzuki-Miyaura Cross-coupling reactions

In this communication we show the preparation of stereodefined trisubstituted alkenes 2 can be achieved by sequential selective Suzuki-Miyaura reactions of 2-bromo-3-(2,2-dibromovinyl)pyridines. The potentiality of this strategy to obtain 5-aryl-1,10-phenanthrolines is also demonstrated

A Solitonic Approach to Holographic Nuclear Physics

We discuss nuclear physics in the Sakai-Sugimoto model in the limit of large number $N_c$ of colors and large 't Hooft coupling $\lambda$. In this limit the individual baryons are described by classical solitons whose size is much smaller than the typical distance at which they settle in a nuclear bound state. We can thus use the linear approximation outside the instanton cores to compute the interaction potential. We find the classical geometry of nuclear bound states for baryon number up to eight. One of the interesting features that we find is that holographic nuclear physics provides a natural description for lightly bound states when $\lambda$ is large. For the case of two nuclei, we also find the topology and metric of the manifold of zero modes and, quantizing it, we find that the ground state can be identified with the deuteron state. We discuss the relations with other methods in the literature used to study Skyrmions and holographic nuclear physics. We discuss $1/{N_c}$ and $1/\lambda$ corrections and the challenges to overcome to reach the phenomenological values to fit with real QCD.Comment: 47 pages, 7 figures. v2: typos correcte

Sintesi ed applicazione in catalisi asimmetrica di derivati piridinici chiarli e non: fenantroline amino-piridine, amino-chinoline e fosfino-piridine

This thesis mainly concerns two important areas of Organic Chemistry: synthesis and catalysis. In particular our aim was to synthesize new pyridine-based ligands and to prove their ability in catalytic asymmetric reactions. Moreover we explored alternative approaches for the synthesis of molecules of interest in different fields of Chemistry. We can briefly summarize our results as follows: 1. The achievement of a new procedure to obtain optically active 1- substituted-1-(pyridin-2-yl)methylamines by diastereoselective reduction of enantiopure ketimines. 2. The synthesis of new pincer CNN ligands based on the benzo[h]quinoline framework and catalytic applications of their Ru- and Os-complexes. 3. The development of alternative approaches to the synthesis of 1,10- phenanthrolines and to compounds that are key-intermediates in the synthesis of the 1,10-phenanthroline core. 4. The synthesis of a new pyridine-based N-P ligand derived from optically active camphor and some preliminary results about its activity in catalytic reactions

Holographic computation of the nucleon-nucleon potential

In this thesis we build a model that can be used to describe baryon dynamics, and in particular we look for an interaction potential between the basic nucleons (proton and neutron). To do that, we follow an approach that mixes two ideas: the description of particles as topological solitons in nonlinear field theory and the Anti de Sitter / Conformal Field Theory (AdS/CFT) correspondence. We study large N QCD by studying the action of the low energy modes of a string theory. We see that this theory adimts topological solitons called instantons, and quantization of the degrees of freedom of an instantonic field of charge one creates a quantum system with states whose transformation properties and quantum numbers are just right to interpret them as states with a definite rest energy, an impulse, a spin and an isospin degrees of freedom. In this picture, we build a charge two field configuration by gluing together two single charge instanton solutions. Due to the non linearity of the theory, this solution is approximative, and we show that it holds in the limit of large 't Hooft coupling. In those limits, we compute the energy of this field configuration, and interpret the result as a potential of interaction between instantons. This is proposed as a classical potential for baryon interaction, and its structure as infinite sum of Yukawa monopole and dipole interactions is interpreted as the classical analogue of an exchange interaction with a meson mediator. We show how the masses of baryons and mesons can be computed in this model. After computing the potential, we quantize the coordinates of the two instanton fields, and impose physical constraints to restrict the spectrum of the system. We see that the internal degrees of freedom of the system can be rearranged and interpreted as total spin and isospin of the system, and that they assume only integer values. Among the states that are compatible with our constraints, we find a state with the right angular quantum numbers (spin one and isospin zero) and interpret it as deuteron state. We compute the stability of this state with respect to the splitting in two separated baryons, and make a similar analysis for other low energy states in the spectrum. We comment the large N and large 't Hooft coupling limit, comparing our results with the qualitative predictions of large N QCD, and extrapolate the binding energy of the deuteron

Transfer Hydrogenation from 2-propanol to Acetophenone Catalyzed by [RuCl2(eta6-arene)P] (P = monophosphine) and [Rh(PP)2] (PP = diphosphine, X = Cl-,BF4-) Complexes

The reduction of ketones through homogeneous transfer hydrogenation catalyzed by transition metals is one of the most important routes for obtaining alcohols from carbonyl compounds. The interest of this method increases when opportune catalytic precursors are able to perform the transformation in an asymmetric fashion, generating enantiomerically enriched chiral alcohols. This reaction has been extensively studied in terms of catalysts and variety of substrates. A large amount of information about the possible mechanisms is available nowadays, which has been of high importance for the development of systems with excellent outcomes in terms of conversion, enantioselectivity and Turn Over Frequency. On the other side, many mechanistic aspects are still unclear, especially for those catalytic precursors which have shown only moderate performances in transfer hydeogenation. This is the case of neutral [RuCl2(η6-arene)(P)] and cationic [Rh(PP)2]X (X = anion; P and PP = mono- and bidentate phosphine, respectively) complexes. Herein, a summary of the known information about the Transfer Hydrogenation catalyzed by these complexes is provided with a continuous focus on the more relevant mechanistic features

Behavior of Ternary Mixtures of Hydrogen Bond Acceptors and Donors in Terms of Band Gap Energies

Three ternary mixtures composed by choline chloride (ChCl), ethylene glycol (EG), and a second hydrogen bond donor (HBD) as ethanol (A), 2-propanol (B), and glycerol (C) were studied in terms of composition related to the band gap energy (BGE). A Design of Experiments (DoE) approach, and in particular a Simple Lattice three-components design, was employed for determining the variation of the BGE upon the composition of each system. UV-VIS analysis and subsequent Tauc plot methodology provided the data requested from the DoE, and multivariate statistical analysis revealed a drop of the BGE in correspondence to specific binary compositions for systems A and B. In particular, a BGE of 3.85 eV was registered for the mixtures ChCl/EtOH (1:1) and ChCl/2-propanol (1:1), which represents one of the lowest values ever observed for these systems

Nuova sintesi di 1,10-fenantroline

Proseguendo il nostro lavoro sulla chimica dei derivati fenantrolinici1 abbiamo intrapreso recentemente uno studio per sintetizzare 1,10-fenantroline a partire da piridine. Nell’affrontare questo tema abbiamo pensato sia di prepare un conveniente 1,2-di(3- piridil)alchene 2 e quindi accoppiare le piridine o alternativamente, sintetizzare un’appropriata 2,2'-bipiridina 3,3'-disostituita 3 e quindi elaborare i sostituenti in modo da formare l’anello centrale. In questa conunicazione riportiamo i risultati ottenuti affrontando questo soggetto

Sintesi stereoselettiva di piridilammine

Ammino piridine chirali hanno dimostrato la loro validità come leganti per la formazione di complessi metallici utilizzati nella catalisi asimmetrica. Tra i possibili approcci alla sintesi di questi composti noi abbiamo investigato la riduzione diastereoselettiva di N-sostituite (p-totil e tert-butil) piridil chetimmine con una serie di agenti riducenti (NaBH4, L-Selectride, DIBAL, 9-BBN) in diverse condizioni di reazione