Synthesis and Characterization of Ferrocene-Chelating Heteroscorpionate Complexes of Nickel(II) and Zinc(II)

The first example of a ferrocene-chelating heteroscorpionate, [Li­(THF)₂]­[fc­(PPh₂)­(BH­[(3,5-Me)₂pz]₂)] ((fc^P,B)­Li­(THF)₂, fc = 1,1′-ferrocenediyl) is described. Starting from a previously reported compound, fcBr­(PPh₂), a series of ferrocene derivatives, fc­(PPh₂)­(B­[OMe]₂), [Li­(OEt₂)]­[fc­(PPh₂)­(BH₃)], [Li­(THF)₂]­[fc­(PPh₂)­(BH­[(3,5-Me)₂pz]₂)] (pz = pyrazole), was isolated and characterized. Compound (fc^P,B)­Li­(THF)₂ allowed the synthesis of the corresponding nickel and zinc complexes, (fc^P,B)­NiCl, (fc^P,B)­NiMe, (fc^P,B)­ZnCl, and (fc^P,B)­ZnMe. All compounds were characterized by NMR spectroscopy, while the zinc and nickel complexes were also characterized by X-ray crystallography. The redox behavior of (fc^P,B)­NiCl, (fc^P,B)­NiMe, (fc^P,B)­ZnCl, and (fc^P,B)­ZnMe was studied by cyclic voltammetry and supported by density functional theory calculations

Aromatic C–F Bond Activation by Rare-Earth-Metal Complexes

C–F bond activation is a challenging reaction with increasing importance in synthesis. The strength of the C–F bond and the shielding effect of the fluorine atom render its activation difficult. Rare-earth metals offer an exceptional opportunity for this process because the high dissociation energy of the M–F bond offsets the strength of the C–F bond. Herein we report a unique reaction for the C–F activation of aromatic bonds by rare-earth-metal complexes. The strong C–F bond of perfluorobenzene is cleaved under reducing conditions in the presence of a rare-earth-metal iodide to form initially an equimolar mixture of a metal fluoride and a metal perfluorophenyl complex; the latter eventually undergoes β-F elimination to a metal fluoride. A similar behavior is observed when inverse sandwich rare-earth-metal arene complexes react with perfluorobenzene. All compounds were characterized by X-ray crystallography, multinuclear NMR spectroscopy, and elemental analysis

Redox-Switchable Hydroelementation of a Cobalt Complex Supported by a Ferrocene-Based Ligand

The first crystallographically characterized tetrahedral cobalt salen (salen = <i>N</i>,<i>N</i>′-ethylenesalicylimine) complex was synthesized by using a 1,1′-ferrocene derivative, salfen (salfen = 1,1′- di­(2,4-di-<i>tert</i>-butyl-6-salicylimine)­ferrocene). The complex undergoes two oxidation events at low potentials, which were assigned as ligand centered by comparison to the corresponding zinc complex. The cobalt complex was found to catalyze the hydroalkoxylation of styrenes, similarly to related square planar cobalt salen complexes, likely due to its fluxional behavior in alcoholic solvents. Furthermore, the one-electron-oxidized species was found to be inactive toward hydroalkoxylation. Thus, the hydroalkoxylation reactivity could be turned on/off <i>in situ</i> by redox chemistry

Yttrium-Alkyl Complexes Supported by a Ferrocene-Based Phosphinimine Ligand

The synthesis and characterization of two yttrium alkyl complexes supported by a bisphosphinimine ferrocene ligand, <b>NP</b>^<b>fc</b> (1,1′-di­(2,4-di-<i>tert</i>-butyl-6-diphenylphosphiniminophenoxy)­ferrocene), were accomplished. Although <b>(NP</b>^<b>fc</b><b>)­Y­(CH</b>_<b>2</b><b>Ph)</b> and <b>(NP</b>^<b>fc</b>)<b>Y­(CH</b>_<b>2</b><b>SiMe</b>_<b>3</b><b>)</b> could be structurally characterized, these compounds are thermally sensitive and decompose at ambient temperature within hours. Their characterization was accomplished by NMR spectroscopy, electrochemical measurements, and elemental analysis. Reactivity studies were also carried out; however, the lack of prolonged thermal stability at ambient temperature of these molecules led to decomposition before a clean transformation to reaction products could be observed

Thrombus composition in acute coronary syndrome

Atherothrombosis and, specifically intracoronary thrombosis is a major cause of acute coronary syndromes (ACS) and consequently of morbidity and mortality throughout the world. While management of acute ST-elevation myocardial infarction (STEMI) has dramatically improved over the last years, there is still a need to find thrombosis-related biomarkers for an early identification of ischemic processes and a better stratification of patients that have suffered an ACS. In fact, the ischemia time, defined as the time from the onset of symptoms to reperfusion, has been recently suggested as the “New Gold Standard for STEMI-Care”. This thesis mainly focuses on the protein composition of the occluding coronary thrombus, occurring both in the native coronary arteries and in the commonly implanted coronary stents. The study based on the proteomic analysis of coronary thrombi, obtained after percutaneous coronary intervention (PCI), has provided consistent evidence of the dynamic composition of the coronary thrombi in relation with the time of ischemia, and has resulted in the identification of novel biomarkers of potential use to be translated to the clinical practice. Furthermore, the comparison of native and in-stent-thrombosis has allowed the identification of proteins that might serve as interesting therapeutic targets to prevent thrombosis in patients who undergo PCI with stent-implantation.La enfermedad aterotrombotica y concretamente la trombosis intracoronaria es la mayor causa de los síndromes coronarios agudos (SCA), y consecuentemente de morbilidad y mortalidad en el mundo. El manejo de los pacientes con infarto agudo de miocardio con elevación del segmento ST ha mejorado considerablemente en los últimos años, a pesar de esto sigue siendo necesario encontrar biomarcadores para la detección temprana de los procesos isquémicos y que permitan una estratificación más eficiente de los pacientes que han sufrido un evento isquémico agudo. De hecho, el tiempo de isquemia, definido como el tiempo entre el inicio del dolor y la revascularización, ha sido recientemente definido como el parámetro fundamental en el tratamiento de los pacientes con STEMI. Este trabajo de tesis está enfocado a elucidar la composición proteica de los trombos coronarios oclusivos que se forman tanto en las arterias coronarias nativas como en aquellas con stent. El estudio se basa en el análisis proteómico de trombos coronarios en relación al tiempo de isquemia, con la finalidad de encontrar nuevos biomarcadores para trasladar a la práctica clínica. Además, la comparación entre trombos nativos y trombos desarrollados sobre el stent permite la identificación de proteínas diferenciales que podrían ser futuras dianas terapéuticas para prevenir la formación del trombo en pacientes sometidos a angioplastia coronaria transluminal percutánea (ACTP) con implantación de un stent coronario

Redox-Switchable Hydroelementation of a Cobalt Complex Supported by a Ferrocene-Based Ligand

The first crystallographically characterized tetrahedral cobalt salen (salen = <i>N</i>,<i>N</i>′-ethylenesalicylimine) complex was synthesized by using a 1,1′-ferrocene derivative, salfen (salfen = 1,1′- di­(2,4-di-<i>tert</i>-butyl-6-salicylimine)­ferrocene). The complex undergoes two oxidation events at low potentials, which were assigned as ligand centered by comparison to the corresponding zinc complex. The cobalt complex was found to catalyze the hydroalkoxylation of styrenes, similarly to related square planar cobalt salen complexes, likely due to its fluxional behavior in alcoholic solvents. Furthermore, the one-electron-oxidized species was found to be inactive toward hydroalkoxylation. Thus, the hydroalkoxylation reactivity could be turned on/off <i>in situ</i> by redox chemistry

Redox Control of Aluminum Ring-Opening Polymerization: A Combined Experimental and DFT Investigation

The synthesis, characterization, and reactivity of an aluminum alkoxide complex supported by a ferrocene-based ligand, (thiolfan*)­Al­(O^<i>t</i>Bu) (<b>1</b>^<b>red</b>, thiolfan* = 1,1′-di­(2,4-di-<i>tert</i>-butyl-6-thiophenoxy)­ferrocene), are reported. The homopolymers of l-lactide (LA), ε-caprolactone (CL), δ-valerolactone (VL), cyclohexene oxide (CHO), trimethylene carbonate (TMC), and their copolymers were obtained in a controlled manner by using redox reagents. Detailed DFT calculations and experimental studies were performed to investigate the mechanism. Mechanistic studies show that, after the insertion of the first monomer, the coordination effect of the carbonyl group, which has usually been ignored in previous reports, can significantly change the energy barrier of the propagation steps, thus playing an important role in polymerization and copolymerization processes

Reduction of Diphenylacetylene Mediated by Rare-Earth Ferrocene Diamide Complexes

The synthesis and characterization of <b>Ln-C</b>_<b>4</b><b>Ph</b>_<b>4</b><b>-K</b>, [(NN^TBS)­Ln­(η²-C₄Ph₄)]­[K­(THF)_<i>x</i>] (Ln = Sc, Y, Lu), rare-earth metal complexes supported by a ferrocene diamide ligand, NN^TBS (NN^TBS = fc­(NSi^<i>t</i>BuMe₂)₂, fc = 1,1′-ferrocenediyl), were accomplished. The preparation of the half-sandwich compounds, <b>Ln-naph-K</b>, [(NN^TBS)­Ln­(μ-C₁₀H₈)]­[K­(THF)₂] (Ln = Sc, Y, Lu, La), was necessary in order to obtain high yields of rare-earth metallacyclopentadienes. Unlike Y and Lu, La did not show the same reactivity toward PhCCPh. The characterization of the new metal complexes was accomplished by NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction

Reduction of Diphenylacetylene Mediated by Rare-Earth Ferrocene Diamide Complexes

The synthesis and characterization of <b>Ln-C</b>_<b>4</b><b>Ph</b>_<b>4</b><b>-K</b>, [(NN^TBS)­Ln­(η²-C₄Ph₄)]­[K­(THF)_<i>x</i>] (Ln = Sc, Y, Lu), rare-earth metal complexes supported by a ferrocene diamide ligand, NN^TBS (NN^TBS = fc­(NSi^<i>t</i>BuMe₂)₂, fc = 1,1′-ferrocenediyl), were accomplished. The preparation of the half-sandwich compounds, <b>Ln-naph-K</b>, [(NN^TBS)­Ln­(μ-C₁₀H₈)]­[K­(THF)₂] (Ln = Sc, Y, Lu, La), was necessary in order to obtain high yields of rare-earth metallacyclopentadienes. Unlike Y and Lu, La did not show the same reactivity toward PhCCPh. The characterization of the new metal complexes was accomplished by NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction

Ferrocene-bis(phosphinimine) Nickel(II) and Palladium(II) Alkyl Complexes: Influence of the Fe–M (M = Ni and Pd) Interaction on Redox Activity and Olefin Coordination

The synthesis of several novel nickel­(II) and palladium­(II) ferrocene-bis­(phosphinimine) alkyl complexes containing iron–nickel and iron–palladium interactions is reported. The redox behavior of all complexes was evaluated electrochemically and chemically; in addition, reactions with weak nucleophiles, such as acetonitrile and olefins, were also investigated. DFT calculations were performed to understand the electronic structure of the alkyl metal complexes