Isolation of Key Organometallic Aryl-Co(III) Intermediates in Cobalt-Catalyzed C(sp2)–H Functionalizations and New Insights into Alkyne Annulation Reaction Mechanisms

The selective annulation reaction of alkynes with substrates containing inert C–H bonds using cobalt as catalyst is currently a topic attracting significant interest. Unfortunately, the mechanism of this transformation is still relatively poorly understood, with little experimental evidence for intermediates, although an organometallic Co(III) species is generally implicated. Herein, we describe a rare example of the preparation and characterization of benchtop-stable organometallic aryl-Co(III) compounds (NMR, HRMS, XAS, and XRD) prepared through a C(sp2)–H activation, using a model macrocyclic arene substrate. Furthermore, we provide crystallographic evidence of an organometallic aryl-Co(III) intermediate proposed in 8-aminoquinoline-directed Co-catalyzed C–H activation processes. Subsequent insights obtained from the application of our new organometallic aryl-Co(III) compounds in alkyne annulation reactions are also disclosed. Evidence obtained from the resulting regioselectivity of the annulation reactions and DFT studies indicates that a mechanism involving an organometallic aryl-Co(III)-alkynyl intermediate species is preferred for terminal alkynes, in contrast to the generally accepted migratory insertion pathway

Stereoselective Formation of Chiral Metallopeptides

This is the peer reviewed version of the following article: Rama, G., Ardá, A., Maréchal, J., Gamba, I., Ishida, H., Jiménez‐Barbero, J., Vázquez, M. E. and Vázquez López, M. (2012), Stereoselective Formation of Chiral Metallopeptides. Chem. Eur. J., 18: 7030-7035, which has been published in final form at https://doi.org/10.1002/chem.201201036. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsPlaying into our hands: The achiral bipyridine amino acid fluorenylmethyloxycarbonyl 5‐amino‐3‐oxapentanoic acid (Fmoc‐O1PenBpy‐OH) has been used for the solid‐phase synthesis of metallopeptides. Circular dichroism, molecular modeling, and NMR spectroscopic studies show that the chirality of the resulting metal complexes in aqueous solution is determined, and can thus be controlled, by the stereochemistry of one proline residue in the loop between the two coordinating O1PenBpy residuesConsolider Ingenio. Grant Number: CSD2007‐00006 Xunta de Galicia. Grant Numbers: INCITE09 209 084PR, GRC2010/12, PGIDIT08CSA‐047209PR PRESTO Program of JST Grant‐in‐Aid for Scientific Research (C) from the Ministry of Education, Culture, Sports, Science, and Technology. Grant Number: 21550163 International Iberian Nanotechnology Laboratory (INL)S

Programmed stereoselective assembly of DNA-binding helical metallopeptides

A flexible and versatile synthetic approach for the construction of water-stable DNA-binding chiral peptide helicates based on the solid phase peptide synthesis (SPPS) methodology is reportedWe are thankful for the support given by the Spanish grants SAF2010-20822-C02, CTQ2012-31341, CTQ2011-23336, CCTQ2010-16959 Consolider Ingenio 2010 CSD2007-00006, the Xunta de Galicia, GRC2010/12, GRC2013-041, PGIDIT08CSA-047209PR, and the Generalitat de Catalunya, 2009SGR68. Support of COST Action CM1105 is kindly acknowledged. G.R. thanks the INL for his PhD fellowship and E. O. the UAB for her PhD grantS

Generation, Spectroscopic, and Chemical Characterization of an Octahedral Iron(V)-Nitrido Species with a Neutral Ligand Platform

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The folding of a metallopeptide

We have applied solid-phase synthesis methods for the construction of tris(bipyridyl) peptidic ligands that coordinate Fe(II) ions with high affinity and fold into stable mononuclear metallopeptides. The main factors influencing the folding pathway and chiral control of the peptidic ligands around the metal ions have been studied both by experimental techniques (CD, UV-vis and NMR) and molecular modeling tools. Amongst the numerous molecular variables that have been studied, this study clearly illustrates how the chirality of a given set of aminoacids (proline in this case) of the peptide dictates the chirality of the metal center of the resulting metallopeptide. Moreover, the relatively hydrophobic peptidic models used in this work show that the most stable structures present reduced solvent contacts and, in counterpart, stabilize the cis configuration of the proline residuesWe are thankful for the support given by the Spanish grants SAF2013-41943-R, CTQ2012-31341, CTQ2011-23336 and CTQ2013-49317-EXP; the ERDF and the European Research Council (Advanced Grant 340055); the Xunta de Galicia grants GRC2013-041 and PGIDIT08CSA-047209PR and the Generalitat de Catalunya grant 2009SGR68. Support of COST Action CM1105 is kindly acknowledged. G.R. thanks the INL for his PhD fellowshipS

Membrane-disrupting iridium(III) oligocationic organometallopeptides

NOTICE: This is the peer reviewed version of the following article: Salvadó, I, Gamba, I, Montenegro J, Martínez-Costas J, Brea JM, Loza MI, Vázquez López M, Vázquez M.E. Membrane-disrupting iridium(III) oligocationic organometallopeptides. Chem. Commun., 2016,52, 11008-11011. DOI: 10.1039/C6CC05537K. This article may be used for non-commercial purposes in accordance with RSC Terms and Conditions for self-archivingA series of oligoarginine peptide derivatives containing cyclometallated iridium(III) units display remarkable cytotoxicity, comparable to that of cisplatin. In vitro studies with unilamellar vesicles support a membrane-disrupting mechanism of actionWe are thankful for the support given by the Spanish grants SAF2013-41943-R, CTQ2015-70698-R, CTQ2013-49317-EXP,CTQ2014-59646-R, and BFU2013-43513-R, and the Xunta de Galicia GRC2013-041. Support from COST Action CM1105 and the orfeo-cinqa network (CTQ2014-51912-REDC) is kindly acknowledgedS

High-affinity sequence-selective DNA binding by iridium(III) polypyridyl organometallopeptides

We demonstrate the application of solid-phase peptide synthesis methods for the straightforward assembly of polynuclear Ir(III) organometallopeptides, and show that their oligoarginine derivatives exhibit high DNA binding affinity, sequence selectivity, and high cytotoxicity towards a set of cancer cell lines

Dal collezionismo privato alle istituzioni pubbliche

Il progetto, nato all\u2019interno di corso di Museologia e collezionismo della Scuola di Specializzazione in Beni storico-artistici \u2013 DAR, riguarda la schedatura di opere conservate in istituzioni molto diverse l'una dall'altra e costituiscono una testimonianza della variet\ue0 di approcci e di fonti relative alla storia del collezionismo. Con introduzione di M. Pigozzi e schede di A. Barbanti, G. Cali, I. Carozza, I. Chia, L. Coppa, A. Di Maio, Cristina Elia, C. Forconi, F. Gamba, A. Lisbona, M. Mariano, S. Mauro, F. Passerini, L. Regano, G.M. Sassoli de\u2019 Bianchi Strozzi, I. Siboni, S. Zugni

Imaging features and ultraearly hematoma growth in intracerebral hemorrhage associated with COVID-19

Purpose: Intracerebral hemorrhage (ICH) is an uncommon but deadly event in patients with COVID-19 and its imaging features remain poorly characterized. We aimed to describe the clinical and imaging features of COVID-19-associated ICH. Methods: Multicenter, retrospective, case-control analysis comparing ICH in COVID-19 patients (COV19\u2009+) versus controls without COVID-19 (COV19\u2009-). Clinical presentation, laboratory markers, and severity of COVID-19 disease were recorded. Non-contrast computed tomography (NCCT) markers (intrahematoma hypodensity, heterogeneous density, blend sign, irregular shape fluid level), ICH location, and hematoma volume (ABC/2 method) were analyzed. The outcome of interest was ultraearly hematoma growth (uHG) (defined as NCCT baseline ICH volume/onset-to-imaging time), whose predictors were explored with multivariable linear regression. Results: A total of 33 COV19\u2009+\u2009patients and 321 COV19\u2009-\u2009controls with ICH were included. Demographic characteristics and vascular risk factors were similar in the two groups. Multifocal ICH and NCCT markers were significantly more common in the COV19\u2009+\u2009population. uHG was significantly higher among COV19\u2009+\u2009patients (median 6.2 mL/h vs 3.1 mL/h, p\u2009=\u20090.027), and this finding remained significant after adjustment for confounding factors (systolic blood pressure, antiplatelet and anticoagulant therapy), in linear regression (B(SE)\u2009=\u20090.31 (0.11), p\u2009=\u20090.005). This association remained consistent also after the exclusion of patients under anticoagulant treatment (B(SE)\u2009=\u20090.29 (0.13), p\u2009=\u20090.026). Conclusions: ICH in COV19\u2009+\u2009patients has distinct NCCT imaging features and a higher speed of bleeding. This association is not mediated by antithrombotic therapy and deserves further research to characterize the underlying biological mechanisms