Synthesis, Characterization, and Computational Study of Three-Coordinate SNS Copper(I) Complexes Based on Bis-Thione Ligand Precursors

A series of tridentate pincer ligands, each possessing two sulfur and one nitrogen donor (SNS), based on bis-imidazolyl or bis-triazolyl salts were metallated with CuCl2 to give new tridentate SNS pincer copper(I) complexes [(SNS)Cu]+. These orange complexes exhibit a three-coordinate pseudo-trigonal-planar geometry in copper. During the formation of these copper(I) complexes, disproportionation is observed as the copper(II) salt precursor is converted into the Cu(I) [(SNS)Cu]+ cation and the [CuCl4]2– counteranion. The [(SNS)Cu]+ complexes were characterized with single crystal X-ray diffraction, electrospray mass spectrometry, EPR spectroscopy, attenuated total reflectance infrared spectroscopy, UV–Vis spectroscopy, cyclic voltammetry, and elemental analysis. The EPR spectra are consistent with anisotropic Cu(II) signals with four hyperfine splittings in the lower-field region (g||) and g values consistent with the presence of the tetrachlorocuprate. Various electronic transitions are apparent in the UV–Vis spectra of the complexes and originate in the copper-containing cations and anions. Density functional calculations support the nature of the SNS binding, allowing assignment of a number of features present in the UV–Vis and IR spectra and cyclic voltammograms of these complexes

Syntheses and characterization of three-and five-coordinate copper(II) complexes based on SNS pincer ligand precursors

A series of tridentate pincer ligands, each possessing two sulfur- and one nitrogen-donor functionalities (SNS), based on a bis-imidazolyl precursor were metallated with CuCl2 to give new tridentate SNS pincer copper(II) complexes [(SNS)CuCl2]. These purple complexes exhibit a five-coordinate pseudo-square pyramidal geometry at the copper center. The [(SNS)CuCl2] complexes were characterized with single crystal X-ray diffraction, electrospray mass spectrometry, EPR spectroscopy, attenuated total reflectance infrared spectroscopy, UV–Vis spectroscopy, cyclic voltammetry, and elemental analysis. The EPR spectra are consistent with typical anisotropic Cu(II) signals with four hyperfine splittings in the lower-field region (g||). Various electronic transitions are apparent in the UV–Vis spectra of the complexes and originate from d-to-d transitions or various charge transfer transitions. We preformed computational studies to understand the influence that structural constraints internal to our tridentate SNS ligand precursors have on the oxidation state of the resulting bound copper complex. We have determined that a d9 copper(II) metal center is better situated than a d10 copper(I) center to bind our tridentate SNS ligand set when it does not contain an internal CH2 group. Without this methylene linker, the SNS ligand forces the N and S atoms into a T-shaped arrangement about the metal center

Synthesis, characterization, and computational study of three-coordinate SNS-copper(I) complexes based on bis-thione precursors

<div><p>A series of tridentate pincer ligands, each possessing two sulfur and one nitrogen donor (SNS), based on bis-imidazolyl or bis-triazolyl salts were metallated with CuCl₂ to give new tridentate SNS pincer copper(I) complexes [(SNS)Cu]⁺. These orange complexes exhibit a three-coordinate pseudo-trigonal-planar geometry in copper. During the formation of these copper(I) complexes, disproportionation is observed as the copper(II) salt precursor is converted into the Cu(I) [(SNS)Cu]⁺ cation and the [CuCl₄]^2– counteranion. The [(SNS)Cu]⁺ complexes were characterized with single crystal X-ray diffraction, electrospray mass spectrometry, EPR spectroscopy, attenuated total reflectance infrared spectroscopy, UV–Vis spectroscopy, cyclic voltammetry, and elemental analysis. The EPR spectra are consistent with anisotropic Cu(II) signals with four hyperfine splittings in the lower-field region (<i>g</i>_||) and <i>g</i> values consistent with the presence of the tetrachlorocuprate. Various electronic transitions are apparent in the UV–Vis spectra of the complexes and originate in the copper-containing cations and anions. Density functional calculations support the nature of the SNS binding, allowing assignment of a number of features present in the UV–Vis and IR spectra and cyclic voltammograms of these complexes.</p></div

NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data

Evolution over Time of Ventilatory Management and Outcome of Patients with Neurologic Disease∗

OBJECTIVES: To describe the changes in ventilator management over time in patients with neurologic disease at ICU admission and to estimate factors associated with 28-day hospital mortality. DESIGN: Secondary analysis of three prospective, observational, multicenter studies. SETTING: Cohort studies conducted in 2004, 2010, and 2016. PATIENTS: Adult patients who received mechanical ventilation for more than 12 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the 20,929 patients enrolled, we included 4,152 (20%) mechanically ventilated patients due to different neurologic diseases. Hemorrhagic stroke and brain trauma were the most common pathologies associated with the need for mechanical ventilation. Although volume-cycled ventilation remained the preferred ventilation mode, there was a significant (p &lt; 0.001) increment in the use of pressure support ventilation. The proportion of patients receiving a protective lung ventilation strategy was increased over time: 47% in 2004, 63% in 2010, and 65% in 2016 (p &lt; 0.001), as well as the duration of protective ventilation strategies: 406 days per 1,000 mechanical ventilation days in 2004, 523 days per 1,000 mechanical ventilation days in 2010, and 585 days per 1,000 mechanical ventilation days in 2016 (p &lt; 0.001). There were no differences in the length of stay in the ICU, mortality in the ICU, and mortality in hospital from 2004 to 2016. Independent risk factors for 28-day mortality were age greater than 75 years, Simplified Acute Physiology Score II greater than 50, the occurrence of organ dysfunction within first 48 hours after brain injury, and specific neurologic diseases such as hemorrhagic stroke, ischemic stroke, and brain trauma. CONCLUSIONS: More lung-protective ventilatory strategies have been implemented over years in neurologic patients with no effect on pulmonary complications or on survival. We found several prognostic factors on mortality such as advanced age, the severity of the disease, organ dysfunctions, and the etiology of neurologic disease

The value of open-source clinical science in pandemic response: lessons from ISARIC

International audienc

Characteristics and outcomes of an international cohort of 600 000 hospitalized patients with COVID-19

Background: We describe demographic features, treatments and clinical outcomes in the International Severe Acute Respiratory and emerging Infection Consortium (ISARIC) COVID-19 cohort, one of the world's largest international, standardized data sets concerning hospitalized patients. Methods: The data set analysed includes COVID-19 patients hospitalized between January 2020 and January 2022 in 52 countries. We investigated how symptoms on admission, co-morbidities, risk factors and treatments varied by age, sex and other characteristics. We used Cox regression models to investigate associations between demographics, symptoms, co-morbidities and other factors with risk of death, admission to an intensive care unit (ICU) and invasive mechanical ventilation (IMV). Results: Data were available for 689 572 patients with laboratory-confirmed (91.1%) or clinically diagnosed (8.9%) SARS-CoV-2 infection from 52 countries. Age [adjusted hazard ratio per 10 years 1.49 (95% CI 1.48, 1.49)] and male sex [1.23 (1.21, 1.24)] were associated with a higher risk of death. Rates of admission to an ICU and use of IMV increased with age up to age 60&nbsp;years then dropped. Symptoms, co-morbidities and treatments varied by age and had varied associations with clinical outcomes. The case-fatality ratio varied by country partly due to differences in the clinical characteristics of recruited patients and was on average 21.5%. Conclusions: Age was the strongest determinant of risk of death, with a ∼30-fold difference between the oldest and youngest groups; each of the co-morbidities included was associated with up to an almost 2-fold increase in risk. Smoking and obesity were also associated with a higher risk of death.&nbsp;The size of our international database and the standardized data collection method make this study a comprehensive international description of COVID-19 clinical features. Our findings may inform strategies that involve prioritization of patients hospitalized with COVID-19 who have a higher risk of death