Photoactivated Artificial Molecular Motors

Accurate control of long-range motion at the molecular scale holds great potential for the development of ground-breaking applications in energy storage and bionanotechnology. The past decade has seen tremendous development in this area, with a focus on the directional operation away from thermal equilibrium, giving rise to tailored man-made molecular motors. As light is a highly tunable, controllable, clean, and renewable source of energy, photochemical processes are appealing to activate molecular motors. Nonetheless, the successful operation of molecular motors fueled by light is a highly challenging task, which requires a judicious coupling of thermal and photoinduced reactions. In this paper, we focus on the key aspects of light-driven artificial molecular motors with the aid of recent examples. A critical assessment of the criteria for the design, operation, and technological potential of such systems is provided, along with a perspective view on future advances in this exciting research area

Radical Relatives: Facile Oxidation of Hetero-Diarylmethene Anions to Neutral Radicals

Furan and thiophene diarylmethenes are potential redox-active ligands for metal centers that could be exploited in the development of nontraditional, stoichiometric, and catalytic redox reactions. As such, we describe here the selective <i>meso</i>-deprotonations of dithiophene, difuran, and diimine–difuran diarylmethanes to form the π-conjugated anions, for which only the diimino–difuryl anion is truly isolable and studied by X-ray crystallography. In all cases, facile one-electron oxidation of these anions occurs, which allows the isolation of the neutral dithienyl and diimino–difuryl radicals. UV–Visible and time-dependent density functional theory studies reveal that the oxidation of the dithienyl anion to its radical is associated with an increase in the highest (singly) occupied molecular orbital–lowest unoccupied molecular orbital gap, evident through a hypsochromic shift of the main absorption band in the electronic spectrum, whereas oxidation of the diimino–difuryl anion causes only minor spectroscopic changes. Electrochemical studies support the stability of the radicals with respect to the anion, showing strongly negative oxidation potentials. The control of the redox activity of these diarylmethene carbanions through variation of the nature of the substituents, donor-atom, and the conjugated π-system and their potential as ligands for redox-inert metal centers makes them intriguing candidates as noninnocent partners for redox reactions

Rotavirus Quantification in Children with Acute Gastroenteritis

Introduction: Most intractable diarrheas are treated with antibiotics, irrespective of the causative agent. This study aimed to quantify rotavirus (RV) with TaqMan real-time PCR in fecal samples of children with acute gastroenteritis (AGE) in accordance with the program of reduction of drug resistance and use of antibiotics. Methods: A total of 190 fecal specimens were collected from under-5-year-old children with AGE in pediatric Hospital Regina Margherita of Turin in Italy in 2017. A total of 38 out of 67 (56.7%) episodes of AGE were associated with RV genomic detection with a multiplex commercial kit. Results: All fecal specimens were tested for the presence of RV and other GE viruses. The most commonly detected virus was norovirus (41%), astrovirus (15.8%), human bocavirus (8.9%), sapovirus (7.9%), human parechovirus (5.8%), rhinovirus (4.2%), and adenovirus (1%). In 66 out of 190 (34.7%), RV was detectable with the median viral load 7.2E + 11 ± 60E + 11 genomes/mg fecal specimens. Discussion/Conclusions: Our results showed that RV was present in around 34.7% of children hospitalized for AGE, a rate similar to those reported in previous studies conducted elsewhere which were in the range of 33–75%. Our protocols are able to quantify the absolute number of viral particle/mg of feces. The clinical utility of quantitative molecular assays, such as RV viral load, will be markedly improved

Photoinduced Autonomous Nonequilibrium Operation of a Molecular Shuttle by Combined Isomerization and Proton Transfer Through a Catalytic Pathway

We describe a [2]rotaxane whose recognition sites for the ring are a dibenzylammonium moiety, endowed with acidic and H-bonding donor properties, and an imidazolium center bearing a photoactive phenylazo substituent. Light irradiation of this compound triggers a network of E/Z isomerization and proton transfer reactions that enable autonomous and reversible ring shuttling away from equilibrium

Dicerium letterbox-shaped tetraphenolates : f-block complexes designed for two-electron chemistry

Rare examples of molecular, dinuclear CeIII and PrIII complexes with robust Ln-coordination are accessible by use of the tetraphenolate pTP as a supporting, chelating O-donor ligand platform, pTP = [{2-(OC6H2R2-2,4)2CH}-C6H4-1,4]4− that favours the higher formal oxidation states accessible to rare earths. Two classes of complexes have been made from the platforms; one metallacyclic 2 + 2 [Ln2(pTP)2] framework with a rigid, letterbox-shaped geometry and [Ln(aryloxide)4] core, and one more flexible [(LnX)2(pTP)] with one rare earth ion at either end of the platform. The LnIII letterbox complexes have two K+ counter-cations, one of which sits inside the letterbox, binding the two central arenes of the platform sufficiently strongly that it cannot be displaced by solvent molecules (THF and pyridine) or crown ethers. Oxidation of the CeIII lettterboxes is facile and forms the unusual neutral molecular (CeIV)2 letterbox in which the CeIV reduction potential is −1.83 V vs. Fc/Fc+. The electronic structure of the Ce(III/IV) complexes was investigated using HERFD-XAS (high energy resolution fluorescence detection X-ray absorption spectroscopy).Publisher PDFPeer reviewe

Earth-Abundant Mixed-Metal Catalysts for Hydrocarbon Oxygenation

The oxygenation of aliphatic and aromatic hydrocarbons using earth-abundant Fe and Cu catalysts and “green” oxidants such as hydrogen peroxide is becoming increasingly important to atom-economical chemical processing. In light of this, we describe that dinuclear Cu^II complexes of pyrrolic Schiff-base macrocycles, in combination with ferric chloride (FeCl₃), catalyze the oxygenation of π-activated benzylic substrates with hydroperoxide oxidants at room temperature and low loadings, representing a novel design in oxidation catalysis. Mass spectrometry and extended X-ray absorption fine structure analysis indicate that a cooperative action between Cu^II and Fe^III occurs, most likely because of the interaction of FeCl₃ or FeCl₄^– with the dinuclear Cu^II macrocycle. Voltammetric measurements highlight a modulation of both Cu^II and Fe^III redox potentials in this adduct, but electron paramagnetic resonance spectroscopy indicates that any Cu–Fe intermetallic interaction is weak. High ketone/alcohol product ratios, a small reaction constant (Hammett analysis), and small kinetic isotope effect for H-atom abstraction point toward a free-radical reaction. However, the lack of reactivity with cyclohexane, oxidation of 9,10-dihydroanthracene, oxygenation by the hydroperoxide MPPH (radical mechanistic probe), and oxygenation in dinitrogen-purge experiments indicate a metal-based reaction. Through detailed reaction monitoring and associated kinetic modeling, a network of oxidation pathways is proposed that includes “well-disguised” radical chemistry via the formation of metal-associated radical intermediates

Il CNR e i risultati della ricerca scientifica_ Le nuove procedure di controllo interno Attività di AUDIT Progetti PRIN e FIRB

Nel presente volume sono evidenziate le procedure relative alla nuova disciplina dei controlli interni a valere sulle spese di progetto. Tale disciplina, dettata dal MIUR, ha fornito lo spunto per l’implementazione e la sperimentazione di un coordinamento interno CNR volto alla certificazione delle spese effettuate dalla Rete Scientifica

Convenzione CNR-MiSE fondo per la crescita sostenibile

Nel presente documento vengono illustrate in dettaglio le finalità del FCS e le attività rea- lizzate dal RTI nell’ambito del servizio realizzato per il primo intervento che il MiSE ha bandito sul Fondo con Decreto del 20 giugno 2013 e attuato con procedura valutativa “a sportello”, definita nel Decreto del 25 luglio 2014. In particolare, oltre alle caratteristiche principali dei progetti di ricerca che il MiSE intende finanziare attraverso tale intervento, nel presente documento viene altresì descritta l’attività che l’Ufficio Supporto alla Programmazione Operativa della Direzione Centrale alla Rete Scientifica e Infrastrutture del CNR ha condotto per coordinare e gestire il processo di valutazione delle proposte progettuali. Viene infatti descritta la compagine di valutazione del CNR, che è stata attivata grazie alla partecipazione dei ricercatori e tecnologi della rete scientifica dell’Ente, e le attività che questi, in veste di esperti valutatori, hanno condotto per determinare la qualità tecnico-scientifica delle proposte progettuali presentate

Vinorelbine plus 3-weekly trastuzumab in metastatic breast cancer: a single-centre phase 2 trial

BACKGROUND: After two studies reporting response rates higher than 70% in HER2-positive metastatic breast cancer with weekly trastuzumab and vinorelbine, we planned a phase 2 study to test activity of the same combination, with trastuzumab given every 3 weeks. METHODS: Patients with HER2-positive metastatic breast cancer (3+ at immunohistochemistry or positive at fluorescence in situ hybridization), PS ≤2, normal left-ventricular ejection fraction (LVEF) and no more than one chemotherapy line for metastatic disease were eligible. Vinorelbine (30 mg/m(2)) was given on days 1&8 every 21 and trastuzumab (8 mg/kg day 1, then 6 mg/kg) every 21 days). A single-stage phase 2 design, with p(0 )= 0.45, p(1 )= 0.65, type I and II error = 0.10, was applied; 22 objective responses were required in 39 patients. RESULTS: From Nov 2002 to May 2005, 50 patients were enrolled, with a median age of 54 years (range 31–81). Among 40 patients eligible for response assessment, there were 7 complete and 13 partial responses (overall response rate 50%; 95% exact CI 33.8–66.2); 11 patients had disease stabilization, lasting more than 6 months in 10 cases. Response rate did not vary according to patients and tumor characteristics, type and amount of previous chemotherapy. Within the whole series, median progression-free survival was 9.6 months (95% CI 7.3–12.3), median overall survival 22.7 months (95% CI 19.5-NA). Fifteen patients (30%) developed brain metastases at a median time of 12 months (range 1–25). There was one toxic death due to renal failure in a patient receiving concomitant pamidronate. Twenty-three patients (46%) had grade 3–4 neutropenia, 2 (4%) grade 3 anemia, 4 (8%) febrile neutropenia. Two patients stopped treatment because of grade 2 decline of LVEF and one patient because of grade 2 liver toxicity concomitant with a grade 1 decline of LVEF. One patient stopped trastuzumab after 50 cycles because of grade 1 decline of LVEF. CONCLUSION: Although lower than in initial studies, activity of 3-weekly trastuzumab plus vinorelbine fell within the range of results reported with weekly schedules. Toxicity was prevalently manageable. This combination is safe and active for metastatic breast cancer patients who received adjuvant taxanes with anthracyclines