Spread of a SARS-CoV-2 variant through Europe in the summer of 2020.

Following its emergence in late 2019, the spread of SARS-CoV-21,2 has been tracked by phylogenetic analysis of viral genome sequences in unprecedented detail3–5. Although the virus spread globally in early 2020 before borders closed, intercontinental travel has since been greatly reduced. However, travel within Europe resumed in the summer of 2020. Here we report on a SARS-CoV-2 variant, 20E (EU1), that was identified in Spain in early summer 2020 and subsequently spread across Europe. We find no evidence that this variant has increased transmissibility, but instead demonstrate how rising incidence in Spain, resumption of travel, and lack of effective screening and containment may explain the variant’s success. Despite travel restrictions, we estimate that 20E (EU1) was introduced hundreds of times to European countries by summertime travellers, which is likely to have undermined local efforts to minimize infection with SARS-CoV-2. Our results illustrate how a variant can rapidly become dominant even in the absence of a substantial transmission advantage in favourable epidemiological settings. Genomic surveillance is critical for understanding how travel can affect transmission of SARS-CoV-2, and thus for informing future containment strategies as travel resumes. © 2021, The Author(s), under exclusive licence to Springer Nature Limited

Unsymmetrical 1,1-diborated multisubstituted sp3-carbons formed via a metal-free concerted-asynchronous mechanism

author can archive pre-print (ie pre-refereeing). 12 meses de embargo DOI: 10.1039/c5ob01523e URL: http://pubs.rsc.org/en/content/articlelanding/2015/ob/c5ob01523e#!divAbstract Filiació URV: SIWe have experimentally proved the unsymmetrical 1,1-diboration of diazo compounds, formed in situ from aldehydes and cyclic and non-cyclic ketones, in the absence of any transition metal complex. The heterolytic cleavage of the mixed diboron reagent, Bpin-Bdan, and the formation of two geminal C-Bpin and C-Bdan bonds has been rationalised based on DFT calculations to occur via a concerted-asynchronous mechanism. Diastereoselection is attained on substituted cyclohexanones and DFT studies provide understanding on the origin of the selectivity. The alkoxide-assisted selective deborylation of Bpin from the multisubstituted sp3-carbon and generation of a Bdan stabilized carbanion, easily conducts a selective protodeboronation sequenc

A Clear-Cut Example of Selective Bpin-Bdan Activation and Precise Bdan Transfer on Boron Conjugate Addition

author can archive pre-print (ie pre-refereeing). 12 meses de embargo DOI: 10.1002/chem.201304615 URL: http://onlinelibrary.wiley.com/doi/10.1002/chem.201304615/abstract Filiació URV: SIA Clear-Cut Example of Selective Bpin-Bdan Activation and Precise Bdan Transfer on Boron Conjugate Additio

Understanding α,β-unsaturated imine formation from amine additions to α,β-unsaturated aldehydes and ketones: an analytical and theoretical investigation

A combination of in situ IR spectroscopy (ReactIR) and DFT calculations have been used to understand what factors govern the selectivity in the addition of primary amines to α,β-unsaturated aldehydes and ketones, i.e., 1,2- versus 1,4-addition. It has been found that the 1,2-addition products (α,β-unsaturated imines following addition and elimination) usually predominate for most systems. However, exceptions, such as methyl vinyl ketone, selectively give 1,4-addition products. This has been rationalized by DFT calculations that show that major conformational effects are involved, controlled mainly by steric effects of carbonyl substituents, resulting in a model that provides simple and predictable preparation of α,β-unsaturated imines for in situ utilization in synthesis

Redox-Active Behavior of the [{Ti(η5-C5Me5)(μ-NH)}3(μ3-N)] Metalloligand

10.1021/ic400463aTreatment of [Cl3Y{(µ3-NH)3Ti3(?5-C5Me5)3(µ3-N)}] with [K(C5Me5)] in toluene gives C10Me10 and the paramagnetic [K(µ-Cl)3Y{(µ3-NH)3Ti3(?5-C5Me5)3(µ3-N)}] (3) derivative. Crystallization of 3 in pyridine affords the potassium-free [Cl2(py)2Y{(µ3-NH)3Ti3(?5-C5Me5)3(µ3-N)}] (4) complex. Whereas the reaction of 3 with 1 equiv of 18-crown-6 leads to the molecular complex [(18-crown-6)K(µ-Cl)3Y{(µ3-NH)3Ti3(?5-C5Me5)3(µ3-N)}] (5), the analogous treatment of 3 with cryptand-222 affords the ion pair [K(crypt-222)][Cl3Y{(µ3-NH)3Ti3(?5-C5Me5)3(µ3-N)}] (6). The X-ray crystal structures of 4, 5, and 6 have been determined. Density functional theory (DFT) calculations have elucidated the electronic structure of these species, which should be regarded as containing trivalent Y bonded to the {(µ3-NH)3Ti3(?5-C5Me5)3(µ3-N)} metalloligand radical anion

The rate-determining step in the rhodium-Xantphos-catalyzed hydroformylation of 1-octene

The rate-determining step in the hydroformylation of 1-octene, catalysed by the rhodium-Xantphos catalyst system, was determined by using a combination of experimentally determined H-1/H-2 and C-12/C-13 kinetic isotope effects and a theoretical approach. From the rates of hydroformylation and deuterioformylation, a small H-1/H-2 isotope effect of 1.2 was determined for the hydride moiety of the rhodium catalyst. C-12/C-13 isotope effects of 1.012(1) and 1.012(3) for the a-carbon and beta-carbon atoms of 1-octene were determined, respectively. Both quantum mechanics/molecular mechanics (QM/MM) and full quantum mechanics calculations were carried out on the key catalytic steps, for "real-world" ligand systems, to clarify whether alkene coordination or hydride migration is the rate-determining step. Our calculations (21.4 kcal mol(-1)) quantitatively reproduce the experimental energy barrier for CO dissociation (20.1 kcal mol(-1)) starting at the (bisphosphane)RhH(CO)(2) resting state. The barrier for hydride migration lies 3.8 kcal mol(-1) higher than the barrier for CO dissociation (experimentally determined trend similar to 3 kcal mol(-1)). The computed H-1/H-2 and C-12/C-13 kinetic isotope effects corroborate the results of the energy analysis

A fast metal-metal bonded water oxidation catalyst

10.1016/j.jcat.2014.04.010The metal-metal bonded diruthenium (II, II) tetraacetate compound, [Ru 2(µ-O2CCH3)4], is a water oxidation catalyst (WOC) that exhibits oxygen evolution rates as high as 77 s-1 at ambient conditions, exhibiting comparable catalytic activity over a wide pH range (1 < pH < 10). The turnover conditions of the catalyst remain active for several hours with oxidative deactivation eventually occurring at a slow rate. DFT calculations support a single-site mechanism via water nucleophilic attack, with the most energy demanding process being the very first one electron oxidation step. This is one of the fastest WOCs reported, and the first WOC found in the field of metal-metal bonded chemistry

Synthetic strategy for metallophthalocyanine covalent organic frameworks for electrochemical water oxidation

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