Corruption is embedded in health systems. Throughout my life—as a researcher, public health worker, and a Minister of Health—I have been able to see entrenched dishonesty and fraud. But despite being ...one of the most important barriers to implementing universal health coverage around the world, corruption is rarely openly discussed. In this Lecture, I outline the magnitude of the problem of corruption, how it started, and what is happening now. I also outline people's fears around the topic, what is needed to address corruption, and the responsibilities of the academic and research communities in all countries, irrespective of their level of economic development. Policy makers, researchers, and funders need to think about corruption as an important area of research in the same way we think about diseases. If we are really aiming to achieve the Sustainable Development Goals and ensure healthy lives for all, corruption in global health must no longer be an open secret.
1,3-Dien-5-ynes have been extensively used as starting materials for the synthesis of a wide number of different carbo- and heterocycles. The aim of this review is to give an overview of their ...utility in organic synthesis, highlighting the variety of compounds that can be directly accessed from single reactions over these systems. Thus, cycloaromatization processes are initially commented, followed by reactions directed toward the syntheses of five-membered rings, other carbocycles and, finally, heterocycles. The diverse methodologies that have been developed for the synthesis of each of these types of compounds from 1,3-dien-5-ynes are presented, emphasizing the influence of the reaction conditions and the use of additional reagents in the outcome of the transformations.
Synergistic gold–palladium catalytic processes have been intensively sought during the past decade, because the combination of the carbophilic Lewis acidity of Au with the redox properties of Pd ...within a catalytic cycle is particularly appealing for the synthesis of novel functionalized compounds. We demonstrate here the feasibility of a Au–Pd bimetallic catalytic system based on the generation of competent Au and Pd species by anionic ligand exchange. This strategy enabled the preparation of a variety of substituted butenolides in a simple and efficient way.
4a-Aza-10a-boraphenanthrene has been synthesized in only four steps from commercially available materials with a remarkable overall yield of 62%. In contrast to other BN-isosteres of phenathrene, ...this isomer is weakly fluorescent, which has been explained by means of computational studies that found a low energy conical intersection for the nonradiative deactivation of the excited state. Moreover, a completely regioselective functionalization of 4a-aza-10a-boraphenanthrene at C-1 by reaction with activated electrophiles has been achieved.
Helically Arranged Chiral Molecular Nanographenes Izquierdo-García, Patricia; Fernández-García, Jesús M.; Fernández, Israel ...
Journal of the American Chemical Society,
08/2021, Letnik:
143, Številka:
30
Journal Article
Recenzirano
Odprti dostop
A benchtop solution-phase synthesis of molecular nanographenes composed of two orthogonal dibenzofg,ijphenanthro9,10,1,2,3-pqrstpentaphene (DBPP) moieties covalently connected through a ...tetrafluorobenzene ring is described. The helical arrangement of these three covalently linked molecular fragments leads to the existence of a chiral axis which gives rise to a racemic mixture, even with the molecular moieties being symmetrically substituted. X-ray diffraction studies show that both enantiomers cocrystallize in a single crystal, and the racemic mixture can be resolved by chiral HPLC. Asymmetric substitution in DBPP moieties affords a pair of diastereoisomers whose rotational isomerization has been studied by 1H NMR. Additionally, the electrochemical and photophysical properties derived from these new molecular nanographenes reveal an electroactive character and a significant fluorescent behavior.
Previously unknown 1,10a-dihydro-1-aza-10a-boraphenanthrene and 6a,7-dihydro-7-aza-6a-boratetraphene have been efficiently synthesized. Bromination of these BN-PAHs proceeds with complete ...regioselectivity, resulting in the formation of different substituted derivatives via cross-coupling reactions. These compounds exhibit rather high fluorescence quantum yields (up to ϕF = 0.80).
Scholl oxidation has become an essential reaction in the bottom‐up synthesis of molecular nanographenes. Herein, we describe a Scholl reaction controlled by the electronic effects on the starting ...substrate (1 a, b). Anthracene‐based polyphenylenes lead to spironanographenes under Scholl conditions. In contrast, an electron‐deficient anthracene substrate affords a helically arranged molecular nanographene formed by two orthogonal dibenzofg,ijphenanthro‐9,10,1,2,3‐pqrstpentaphene (DBPP) moieties linked through an octafluoroanthracene core. Density Functional Theory (DFT) calculations predict that electronic effects control either the first formation of spirocycles and subsequent Scholl reaction to form spironanographene 2, or the expected dehydrogenation reaction leading solely to the helical nanographene 3. The crystal structures of four of the new spiro compounds (syn 2, syn 9, anti 9 and syn 10) were solved by single crystal X‐ray diffraction. The photophysical properties of the new molecular nanographene 3 reveal a remarkable dual fluorescent emission.
The electronic nature of the starting substrate decides the fate of the reaction: Anthracene‐based polyphenylenes lead to less‐known spiro (R=H) or helical (R=F) nanographenes under mild Scholl conditions, depending upon the substitution pattern on the anthracene core. DFT calculations reveal that the formation, or not, of the trityl cation is the key issue.
Helical bilayer nanographenes (HBNGs) are chiral π-extended aromatic compounds consisting of two π–π stacked hexabenzocoronenes (HBCs) joined by a helicene, thus resembling van der Waals layered 2D ...materials. Herein, we compare 9HBNG, 10HBNG, and 11HBNG helical bilayers endowed with 9, 10, and 11helicenes embedded in their structure, respectively. Interestingly, the helicene length defines the overlapping degree between the two HBCs (number of benzene rings involved in π–π interactions between the two layers), being 26, 14, and 10 benzene rings, respectively, according to the X-ray analysis. Unexpectedly, the electrochemical study shows that the lesser π-extended system 9HBNG shows the strongest electron donor character, in part by interlayer exchange resonance, and more red-shifted values of emission. Furthermore, 9HBNG also shows exceptional chiroptical properties with the biggest values of g abs and g lum (3.6 × 10–2) when compared to 10HBNG and 11HBNG owing to the fine alignment in the configuration of 9HBNG between its electric and magnetic dipole transition moments. Furthermore, spectroelectrochemical studies as well as the fluorescence spectroscopy support the aforementioned experimental findings, thus confirming the strong impact of the helicene length on the properties of this new family of bilayer nanographenes.
Introduction: COVID-19 pandemic, declared on March 11, 2020, constitute an extraordinary health, social and economic global challenge. The impact on people's mental health is expected to be high. ...This paper sought to systematically review community-based studies on depression conducted during the COVID-19 and estimate the pooled prevalence of depression. Method: We searched for cross-sectional, community-based studies listed on PubMed or Web of Science from January 1, 2020 to May 8, 2020 that reported prevalence of depression. A random effect model was used to estimate the pooled proportion of depression. Results: A total of 12 studies were included in the meta-analysis, with prevalence rates of depression ranging from 7.45% to 48.30%. The pooled prevalence of depression was 25% (95% CI: 18%−33%), with significant heterogeneity between studies (I2=99.60%, p<.001). Conclusions: Compared with a global estimated prevalence of depression of 3.44% in 2017, our pooled prevalence of 25% appears to be 7 times higher, thus suggesting an important impact of the COVID-19 outbreak on people's mental health. Addressing mental health during and after this global health crisis should be placed into the international and national public health agenda to improve citizens’ wellbeing.
Introducción: La pandemia de COVID-19, declarada el 11 de marzo de 2020, representa un reto global extraordinario a nivel sanitario, social y económico. Se espera un impacto alto en la salud mental de las personas. Este artículo tiene como objetivo realizar una revisión sistemática de estudios transversales basados en muestras comunitarias que proporcionaban la prevalencia de depresión durante la crisis del COVID-19. Método: Se realizó una búsqueda de estudios comunitarios publicados en Pubmed y Web of Science desde el 1 de enero del 2020 al 8 de mayo del 2020 y que informaron sobre la prevalencia de depresión. Se usó un modelo de efectos aleatorios para estimar la proporción agrupada de depresión. Resultados: Un total de 12 estudios fueron incluidos en el meta-análisis, con prevalencias de depresión que oscilaban entre 7,45% y 48,30%. La prevalencia agrupada de depresión fue de 25% (95% CI: 18%-33%), con heterogeneidad significativa entre estudios (I2=99,60%, p<0,001). Conclusiones: En comparación con una estimación global de depresión en 2017 del 3,44%, nuestra prevalencia agrupada del 25% es 7 veces mayor, sugiriendo un impacto importante del brote de COVID-19 en la salud mental de las personas. El abordaje de la salud mental durante y después de esta crisis global sanitaria debe ser parte de las agendas de salud pública nacionales e internacionales para mejorar el bienestar de los ciudadanos.
PDF
