Synthesis and characterization of [Ru(eta(6)-C10H14)(dppf)X][PF6] (X = Cl, Br, I, SnF3) compounds: The X-ray structure of [Ru(eta(6)-C10H14)(dppf)Cl][SnCl3]center dot 0.45CH(2)Cl(2)

The arene-ruthenium complex [Ru(eta(6)-C10H14)(dppf)Cl]PF6 (1) was used as a precursor for the syntheses of the [Ru(eta(6)-C10H14)(dppf)Br]PF6 (2), [Ru(eta(6)-C10H14)(dppf)I]PF6 (3). [Ru(eta(6)-C10H14)(dppf)SnF3]PF6 (4) and [Ru(eta(6)-C10H14)(dppf)Cl][SnCl3]center dot 0.45CH(2)Cl(2) (5) complexes by its reactions with KBr, Kl, SnF2 and SnCl2. respectively. All of the compounds were characterized by NMR, IR, Fe-57 and Sn-119-Mossbauer spectroscopy, and cyclic voltammetry. The single-crystal X-ray structure analysis of the [Ru(eta(6)-C10H14)(dppf)Cl] [SnCl3]center dot 0.45CH(2)Cl(2) complex revealed the expected piano-stool geometry. Cyclic voltammograms of the complexes showed only one quasi-reversible electrochemical process, involving the oxidation of Fe(II) and Ru(II) at the same potential, which was confirmed by exhaustive electrolysis experiments. Fe-57-Mossbauer parameters obtained for the complexes (1-5) were fitted with one doublet corresponding to a site of one iron(II). The Sn-119-Mossbauer parameters of the complex (4) indicate that tin is tetra covalent. (c) 2012 Elsevier Ltd. All rights reserved.

Isolation and characterisation of aerobic endospore forming Bacilli from sugarcane rhizosphere for the selection of strains with agriculture potentialities

Eighteen aerobic endospore forming strains were isolated from sugarcane rhizosphere in N-free medium. A phenotypic description and analysis of the 5' end hypervariable region sequences of 16S rRNA revealed a high diversity of Bacillus and related genera. Isolates were identified, and four genera were obtained: seven strains belonged to Bacillus (Bacillaceae family), four belonged to Paenibacillus, six belonged to Brevibacillus and one strain was identified as Cohnella (Paenibacillaceae family). Four Brevibacillus strains showed in vitro inhibitory activity against plant pathogens fungi Curvularia and Fusarium. Seventy-four percent of the isolated bacteria grew on pectin as the only carbon source, showing polygalacturonase activity. Pectate lyase activity was detected for the first time in a Brevibacillus genus strain. All isolates showed endoglucanase activity. Calcium phosphate solubilisation was positive in 83.3% of the isolates, with higher values than those reported for Bacillus inorganic phosphate solubilising strains. High ethylene plant hormone secretion in the culture medium was detected in 22% of the bacteria. This is the first report of ethylene secretion in Paenibacillaceae isolates. Indole-3-acetic acid production was found in a Brevibacillus genus isolate. It was reported for the first time the presence of Cohnella genus strain on sugarcane rhizosphere bearing plant growth promoting traits. The sugarcane isolate Brevibacillus B65 was identified as a plant growth inoculant because it showed wider spectra of plant stimulation capabilities, including an antifungal effect, extracellular hydrolases secretion, inorganic phosphate solubilisation and plant hormone liberation. In this work, sugarcane was shown to be a suitable niche for finding aerobic endospore forming 'Bacilli' with agriculture biotechnological purposes.

Synthesis and properties of substituted Hg-based superconductors

This thesis is focused on studies of substituted Hg-based superconducting copper oxides ((Hg1-xMx)Ba2Can-1CunO2n+2+δ). These compounds are promising objects of investigation, not only from a fundamental point of view but also because of their high values of superconducting transition temperature (Tc) and irreversibility field (Hirr). The first part of the thesis is devoted to optimization of the synthesis procedure for Hg-based cuprates. The influence of different parameters (T, t, p(Hg), p(O2)) on the synthesis of these compounds in sealed silica tubes was studied. Optimal conditions yielded samples containing up to 95% of HgBa2Ca2Cu3O8+δ (Hg-1223). The formation of solid solutions with the formula (Hg1-xCux)Ba2Ca2Cu3O8+δ (where x <= 0.5) was also established. Another technique was developed, using LiF as a flux, for synthesis of samples containing up to 90% of the HgBa2CaCu2O6+δ (Hg-1212) phase. The second part concerns synthesis and studies of oxyfluorides using Hg-1212 and Hg-1223 as starting materials together with XeF2 as a fluorinating agent. It was found that oxyfluorides of both phases have a parabolic dependence of Tc vs. a parameter as well as enhanced Tc values (ΔT ≈ 3-4 K) in comparison with optimally doped non-fluorinated analogues. The crystal structure of Hg-1223 oxyfluoride was studied by X-ray powder and neutron diffraction methods. It is suggested that chemical modification of the crystal structure leads to a decrease in Cu-O distance without noticeable change in Cu-O-Cu angle (in the (CuO2) layers), which may be the significant factors influencing this Tc increase. Hg-1223 oxyfluoride was also studied under high pressure for first time. It was found that this compound has a record-high Tc value (≈ 166 K) at P ≈ 23 GPa. The last part describes the investigation of substituted Hg-based superconductors in the series (Hg0.9M0.1)Ba2CuO4+δ {(Hg,M)-1201}, where M = Tl, Pb, W, Mo, Nb and V. A comprehensive study of these compounds by various methods (X-ray powder diffraction, EDX, IR-, EXAFS- and XANES -spectroscopy) indicated that the change of charge carrier doping level is a crucial factor determining the irreversibility line. (Hg0.9Mo0.1)Ba2CuO4+δ showed the most improved irreversibility line position among the (Hg,M)-1201 compounds studied in this series.

Synthesis and characterization of implants for bone substitutions made of biomedical apatites containing silicon

In the last decades the development of bone substitutes characterized by a superior biomimetism has become of particular interest, owing to the increasing economic and societal impact of the bone diseases. In the present work of research the development of bone substitutes characterized by improved biomimetism, has been faced in a chemical, structural and morphological perspective. From a chemical point of view, it has been developed the synthesis of hydroxyapatite powders, exhibiting multiple ionic substitutions in both cationic and anionic sites, so to simulate the chemical composition of the natural bone. Particular emphasis has been given to the effect of silicon on the chemical-physical and solubility properties of the obtained hydroxyapatites. From a structural point of view, it has been developed the synthesis of ceramic composite materials, based on hydroxyapatite and calcium silicates, employed both as a reinforcing phase, to raise the mechanical strength of the composite compared to hydroxyapatite, and as a bioactive phase, able to increase the bioactivity properties of the whole ceramic. Finally the unique morphological features of the bone were mimicked by taking inspiration by Nature, so that native wood structures were treated in chemical and thermal way to obtain hydroxyapatite porous materials characterized by the same morphology as the native wood. The results obtained in the present work were positive in all the three different areas of investigation, so to cover the three different aspects of biomimetism, chemical, structural and morphological. Anyway, only at the convergence of the three different fields it is possible to find out the best solutions to develop the ideal bone-like scaffold. Thus, the future activity should be devoted to solve the problems at the borderline between the different research lines, which hamper this convergence and in consequence, the achievement of a bone scaffold able to mimic the various aspects exhibited by the bone tissue

Synthesis and application of new ion-tagged ligands and organocatalysts

We report the synthesis and application of some ion-tagged catalysts in organometallic catalysis and organocatalysis. With the installation of an ionic group on the backbone of a known catalyst, two main effects are generally obtained. i) a modification of the solubility of the catalyst: if judicious choice of the ion pair is made, the ion-tag can confer to the catalyst a solubility profile suitable for catalyst recycling. ii) the ionic group can play a non-innocent role in the process considered: if stabilizing interaction between the ionic group and the developing charges in the transition state are established, the reaction can speed up. We describe the use of ion-tagged diphenylprolinol as Zn ligand. The chiral ligand grafted onto an ionic liquid (IL) was recycled 10 times with no loss of reactivity and selectivity, when it was employed in the first example of enantioselective addition of ZnEt2 to aldehydes in ILs. An ammonium-tagged phosphine displayed the capability to stabilize Pd catalysts for the Suzuki reaction in ILs. The ionic phase was recycled 6 times with no detectable loss of activity and very low Pd leaching in the organic phase. This catalytic system was also employed for the functionalization of the challenging substrate 5,11-dibromotetracene. In the field of organocatalysis, we prepared two ion-tagged derivatives of the McMillan imidazolidinone. The results of the asymmetric Diels-Alder reaction between trans-cinnamaldehyde and cyclopentadiene exhibited great dependence on the position and nature of the ionic group. Finally, when O-TMS-diphenylprolinol was tagged with an imidazolium ion, exploiting a silyl ether linker, an efficient catalyst for the asymmetric addition of aldehydes to nitroolefins was achieved. The catalyst displayed enhanced reactivity and the same high level of selectivity of the untagged parent catalyst and it could be employed in a wide range of reaction conditions, included use of water as solvent.

Synthesis and characterization of novel poly(imino ketone)s via palladium-catalyzed aryl amination

The challenge of the present work was to synthesize and to characterize new classes of N-containing polymers via palladium-catalyzed aryl amination. This work was inspired by a desire to combine the properties of high-performance polymers such as PEKs with those of N-containing conductive polymers such as polyaniline (PANI), poly(aromatic amides) (PAAs), and the ready synthesis of N-containing simple aromatic compound by the Buchwald-Hartwig reaction. Careful investigation of a model reaction was carried out to provide insights into the formation of side products which will have a negative effect upon the molecular weight or upon the materials properties of the desired polymers in the polycondensation reaction. In this thesis, five new different polymer classes namely, poly(imino ketone)s (PIKs), poly(imino acridine)s (PIAcs), poly(imino azobenzene)s (PIAzos), poly(imino fluorenone)s (PIFOs), and poly(imino carbazole)s (PICs) were synthesized and fully characterized by means of 1H-NMR, elemental analysis, UV, FT-IR, X-ray, GPC, TGA, DSC, DMA, and dielectric spectroscopy. To optimize the polycondensation process, the influence of the concentration, temperature, ligands and the reactivity of the halogen containing monomers were investigated. A temperature of 100-165 °C and a concentration of 30-36 % were found to be optimal for the palladium-catalyzed polycondensation to produce polymer with high molecular weight (Mn = 85 900, Mw = 474 500, DP = 126). Four different ligands were used successfully in the Pd-catalyzed process, of which the Pd/BINAP system was found to be the most effective catalyst, producing the highest yield and highest molecular weight polymers. It was found that the reactivity decreases strongly with increasing electronegativity of the halogen atoms, for example better yields, and higher molecular weights were obtained by using dibromo compounds than dichloro compounds while difluoro compounds were totally unreactive. Polymer analogous transformations, such as the protonation reaction of the ring nitrogens in PIAcs, or of the azobenzene groups of PIAzos, the photo and thermal cis-trans-isomerization of PIAzos, and of poly(imino alcohol)s were also studied. The values of the dielectric constants of PIKs at 1 MHz were in the range 2.71-3.08. These low values of the dielectric constant are lower than that of "H Film", a polyimide Kapton film which is one of the most preferred high-performance dielectrics in microelectronic applications having a dielectric constant of 3.5. In addition to the low values of the dielectric constants, PIKs have lower and glass transition temperatures (Tgs) than arimides such as Kapton which may make them more easily processable. Cyclic voltammetry showed that PICs exhibited low oxidation and reduction potentials and their values were shifted to low values with increasing degree of polymerization i.e. with increasing of the carbazole content in backbone of PICs (PIC-7, 0.44, 0.33 V, DP= 37, PIC-5, 0.63, 0.46, DP= 16, respectively).

Synthesis and characterization of polyelectrolyte brushes

On the pathway to synthesizing synthetic model systems for human cartilage, macroinitiators for the ATRP of styrene sulfonate esters with different chain lengths and initiation site densities from 10 % to 100 % were synthesized. Polymer brushes from styrene sulfonate ethyl ester and styrene sulfonate dodecyl ester with varying grafting density, backbone length and side chain length were synthesized and characterized by 1H-NMR, AUC, AFM, TEM, and in the case of the ethyl esters, GPC-MALLS. Polyelectrolyte brushes from styrene sulfonate were synthesized from the corresponding esters. These brushes were characterized in solution (GPC-MALLS, static and dynamic light scattering, SANS, 1H-NMR) and on solid interfaces (AFM and TEM). It was shown that these brushes may form extended aggregates in solution. The aggregation behavior and the size and shape of the aggregates depend on the side chain length and the degree of saponification. For samples with identical backbone and side chain length, but varying degrees of ester hydrolysis, marked differences in the aggregation behavior were observed. A functionalized ATRP macroinitiator with a positively charged head group was synthesized and employed for the synthesis of a functionalized polyelectrolyte brush. These brushes were found to form complexes with negatively charged latex particles and are thus suitable as proteoglycan models in the proteoglycan-hyaluronic acid complex.

Synthesis and characterization of Poly(vinylphosphonic acid) for proton exchange membranes in fuel cells

Vinylphosphonic acid (VPA) was polymerized at 80 ºC by free radical polymerization to give polymers (PVPA) of different molecular weight depending on the initiator concentration. The highest molecular weight, Mw, achieved was 6.2 x 104 g/mol as determined by static light scattering. High resolution nuclear magnetic resonance (NMR) spectroscopy was used to gain microstructure information about the polymer chain. Information based on tetrad probabilities was utilized to deduce an almost atactic configuration. In addition, 13C-NMR gave evidence for the presence of head-head and tail-tail links. Refined analysis of the 1H NMR spectra allowed for the quantitative determination of the fraction of these links (23.5 percent of all links). Experimental evidence suggested that the polymerization proceeded via cyclopolymerization of the vinylphosphonic acid anhydride as an intermediate. Titration curves indicated that high molecular weight poly(vinylphosphonic acid) PVPA behaved as a monoprotic acid. Proton conductors with phosphonic acid moieties as protogenic groups are promising due to their high charge carrier concentration, thermal stability, and oxidation resistivity. Blends and copolymers of PVPA have already been reported, but PVPA has not been characterized sufficiently with respect to its polymer properties. Therefore, we also studied the proton conductivity behaviour of a well-characterized PVPA. PVPA is a conductor; however, the conductivity depends strongly on the water content of the material. The phosphonic acid functionality in the resulting polymer, PVPA, undergoes condensation leading to the formation of phosphonic anhydride groups at elevated temperature. Anhydride formation was found to be temperature dependent by solid state NMR. Anhydride formation affects the proton conductivity to a large extent because not only the number of charge carriers but also the mobility of the charge carriers seems to change.

Synthesis and characterization of new discotic polycyclic aromatic hydrocarbons and related pyrolytic nanostructures

Diskotische Hexa-peri-hexabenzocoronene (HBC) als molekulare, definierte graphitische Substrukturen sind bereits seit langem Gegenstand von Untersuchungen zu der Delokalisierung von π-Elektronen. In dieser Arbeit wurden zusätzlich Platin-Komplexe in das periphere Substitutionsmuster von HBC eingeführt. Dies führte zu einer Verbesserung der Emission von dem angeregten Triplett-Zustand in den Singulett-Grundzustand mit einer zusätzlichen Verlängerung der Lebensdauer des angeregten Zustandes. Zusätzlich erlaubte diese Konfiguration ein schnelles Intersystem-Crossing mittels einer verstärkten Spin-Orbit Kopplung, die sowohl bei tiefen Temperaturen, als auch bei Raumtemperatur exklusiv zu Phosphoreszenz (T1→S0) führte. Das Verständniss über solche Prozesse ist auch essentiell für die Entwicklung verbesserter opto-elektronischer Bauteile. Die Erstellung von exakt definierten molekularen Strukturen, die speziell für spezifische Interaktionen hergestellt wurden, machten eine Inkorporation von hydrophoben-hydrophilen, wasserstoffverbrückten oder elektrostatischen funktionalisierten Einheiten notwendig, um damit den supramolekularen Aufbau zu kontrollieren. Mit Imidazolium-Salzen funktionalisierte HBC Derivate wurden zu diesem Zwecke hergestellt. Eine interessante Eigenschaft dieser Moleküle ist ihre Amphiphilie. Dies gestattete die Untersuchung ihrer Eigenschaften in einem polaren Solvens und sowohl der Prozessierbarkeit als auch der Faserbildung auf Siliziumoxid-Trägern. Abhängig vom Lösungsmittel und der gewählten Konditionen konnten hochkristalline Fasern erhalten werden. Durch eine Substitution der HBCs mit langen, sterisch anspruchsvollen Seitenketten, konnte durch eine geeignete Prozessierung eine homöotrope Ausrichtung auf Substraten erreicht werden, was dieses Material interessant für photovoltaische Applikationen macht. Neuartige Polyphenylen-Metall-Komplexe mit diskotischen, linearen und dendritischen Geometrien wurden mittels einer einfachen Reaktion zwischen Co2(CO)8 und Ethinyl-Funktionalitäten in Dichlormethan hergestellt. Nach der Pyrolyse dieser Komplexe ergaben sich unterschiedliche Kohlenstoff-Nanopartikel, inklusive Nanoröhren, graphitischen Nanostäben und Kohlenstoff/Metall Hybrid Komplexe, die durch Elektronenmikroskopie untersucht wurden. Die resultierenden Strukturen waren dabei abhängig von der Zusammensetzung und Struktur der Ausgangssubstanzen. Anhand dieser Resultate ergeben sich diverse Möglichkeiten, um den Mechanismus, der zur Herstellung graphitischer Nanopartikel führt, besser zu verstehen.

Synthesis and characterization of structurally well-defined polymer-layered silicate nanocomposites

Zusammenfassung Nanokomposite aus Polymeren und Schichtsilikaten werden zumeist auf der Basis natürlicher Tone wie Montmorillonit hergestellt. Für NMR- und EPR-Untersuchungen der Tensidschicht, die das Silikat mit dem Polymer kompatibilisiert, ist der Eisengehalt natürlicher Tone jedoch abträglich, weil er zu einer Verkürzung der Relaxationszeiten und zu einer Linienverbreiterung in den Spektren führt. Dieses Problem konnte überwunden werden, indem als Silikatkomponente eisenfreies, strukturell wohldefiniertes Magadiit hydrothermal synthetisiert und für die Kompositbildung eingesetzt wurde. Die Morphologie des Magadiits wurde durch Rasterelektronenmikroskopie charakterisiert und der Interkalationsgrad von schmelzinterkalierten Polymer-Nanokompositen wurde durch Weitwinkelröntgenstreuung bestimmt. Polymere mit Carbonylgruppen scheinen leichter zu interkalieren als solche ohne Carbonylgruppen. Polycaprolacton interkalierte sowohl in Oragnomagadiite auf der Basis von Ammoniumtensiden als auch in solche auf der Basis von Phosphoniumtensiden. Die Dynamik auf einer Nanosekundenzeitskala und die Struktur der Tensidschicht wurden mittels ortsspezifisch spinmarkierter Tensidsonden unter Nutzung von Dauerstrich- (CW) und Puls-Methoden der elektronenparamagnetischen Resonanzspektroskopie (EPR) untersucht. Zusätzlich wurde die statische 2H-Kernmagnetresonanz (NMR) an spezifisch deuterierten Tensiden angewendet, um die Tensiddynamik auf einer komplementären Zeitskala zwischen Mikrosekunden und Millisekunden zu erfassen. Sowohl die CW-EPR- als auch die 2H-NMR-Ergebnisse zeigen eine Beschleunigung der Tensiddynamik durch Interkalation von Polycaprolacton auf, während sich in den nichtinterkalierten Mikrokompositen mit Polystyrol die Tensiddynamik verlangsamt. Die Rotationskorrelationszeiten und Aktivierungsenergien offenbaren verschiedene Regime der Tensiddynamik. In Polystyrol-Mikrokompositen entspricht die Übergangstemperatur zwischen den Regimen der Glasübergangstemperatur von Polystyrol, während sie in Polycaprolacton-Nanokompositen bei der Schmelztemperatur von Polycaprolacton liegt. Durch die erhebliche Verlängerung der Elektronenspin-Relaxationszeiten bei Verwendung von eisenfreiem Magadiit können Messdaten hoher Qualität mit Puls-EPR-Experimenten erhalten werden. Insebsondere wurden die Vier-Puls-Elektron-Elektron-Doppelresonanz (DEER), die Elektronenspinechoenveloppenmodulation (ESEEM) und die Elektronen-Kern-Doppelresonanz (ENDOR) an spinmarkierten sowie spezifisch deuterierten Tensiden angewandt. Die ENDOR-Ergebnisse legen ein Model der Tensidschicht nahe, in dem zusätzlich zu den Oberflächenlagen auf dem Silikat eine wohldefinierte mittlere Lage existiert. Dieses Modell erklärt auch Verdünnungseffekte durch das Polymer in Kompositen mit Polycaprolacton und Polystyrol. Die umfangreiche Information aus den Magnetresonanztechniken ergänzt die Information aus konventionellen Charakterisierungstechniken wie Röntgendiffraktion und Transmissionselektronenmikroskopie und führt so zu einem detaillierteren Bild der Struktur und Dynamik der Tensidschicht in Nanokompositen aus Polymeren und Schichtsilikaten.

A molecular approach towards tethered bilayer lipid membranes: synthesis and characterization of novel anchor lipids

Tethered bilayer lipid membranes (tBLMs) are a promising model system for the natural cell membrane. They consist of a lipid bilayer that is covalently coupled to a solid support via a spacer group. In this study, we developed a suitable approach to increase the submembrane space in tBLMs. The challenge is to create a membrane with a lower lipid density in order to increase the membrane fluidity, but to avoid defects that might appear due to an increase in the lateral space within the tethered monolayers. Therefore, various synthetic strategies and different monolayer preparation techniques were examined. Synthetical attempts to achieve a large ion reservoir were made in two directions: increasing the spacer length of the tether lipids and increasing the lateral distribution of the lipids in the monolayer. The first resulted in the synthesis of a small library of tether lipids (DPTT, DPHT and DPOT) characterized by 1H and 13C NMR, FD-MS, ATR, DSC and TGA. The synthetic strategy for their preparation includes synthesis of precursor with a double bond anchor that can be easily modified for different substrates (e.g. metal and metaloxide). Here, the double bond was modified into a thiol group suitable for gold surface. Another approach towards the preparation of homogeneous monolayers with decreased two-dimensional packing density was the synthesis of two novel anchor lipids: DPHDL and DDPTT. DPHDL is “self-diluted” tether lipid containing two lipoic anchor moieties. DDPTT has an extended lipophylic part that should lead to the preparation of diluted, leakage free proximal layers that will facilitate the completion of the bilayer. Our tool-box of tether lipids was completed with two fluorescent labeled lipid precursors with respectively one and two phytanyl chains in the hydrophobic region and a dansyl group as a fluorophore. The use of such fluorescently marked lipids is supposed to give additional information for the lipid distribution on the air-water interface. The Langmuir film balance was used to investigate the monolayer properties of four of the synthesized thiolated anchor lipids. The packing density and mixing behaviour were examined. The results have shown that mixing anchor with free lipids can homogeneously dilute the anchor lipid monolayers. Moreover, an increase in the hydrophylicity (PEG chain length) of the anchor lipids leads to a higher packing density. A decrease in the temperature results in a similar trend. However, increasing the number of phytanyl chains per lipid molecule is shown to decrease the packing density. LB-monolayers based on pure and mixed lipids in different ratio and transfer pressure were tested to form tBLMs with diluted inner layers. A combination of the LB-monolayer transfer with the solvent exchange method accomplished successfully the formation of tBLMs based on pure DPOT. Some preliminary investigations of the electrical sealing properties and protein incorporation of self-assembled DPOT and DDPTT-based tBLMs were conducted. The bilayer formation performed by solvent exchange resulted in membranes with high resistances and low capacitances. The appearance of space beneath the membrane is clearly visible in the impedance spectra expressed by a second RC element. The latter brings the conclusion that the longer spacer in DPOT and the bigger lateral space between the DDPTT molecules in the investigated systems essentially influence the electrical parameters of the membrane. Finally, we could show the functional incorporation of the small ion carrier valinomycin in both types of membranes.

Design, Synthesis and Characterization of N-Containing Organic Compounds

The needed of new intermediates/products for screening in the fields of drug discovery and material science is the driving force behind the development of new methodologies and technologies. Organic scaffolds are privileged targets for this scouting. Among them a priority place must be attributed to those including nitrogen functionalities in their scaffolds. It comes out that new methodologies, allowing the introduction of the nitrogen atom for the synthesis of an established target or for the curiosity driven researches, will always be welcome. The target of this PhD Thesis’ work is framed within this goal. Accordingly, Chapter 1 reports the preparation of new N-Heteroarylmethyl 3-carboxy-5-hydroxy piperidine scaffold, as potential and selective α-glucosidase inhibitors. The proposed reversible uncompetitive mechanism of inhibition makes them attractive as interesting candidate for drug development. Chapter 2 is more environmentally method-driven research. Eco-friendly studies on the synthesis of enantiomerically pure 1,4-dihydropyridines using “solid” ammonia (magnesium nitride) is reported via classical Hantzch method. Chapter 3 and Chapter 4 may be targeted as the core of the Thesis’s research work. Chapter 3 reports the studies addressed to the synthesis of N-containing heterocycles by using N-trialkylsilylimine/hetero-Diels–Alder (HAD) approach. New eco-friendly methodology as MAOS (Microwave Assisted Organic Synthesis) has been used as witness of our interest to a sustainable chemistry. Theoretical calculations were adopted to fully clarify the reaction mechanism. Chapter 4 is dedicated to picture the most recent studies performed on the application of N-Metallo-ketene imines (metallo= Si, Sn, Al), relatively new intermediates which are becoming very popular, in the preparation of highly functionalized N-containing derivatives, accordingly to the Thesis’ target. Derivatives obtained are designed in such a way that they could be of interest in the field of drug and new material chemistry.