Cyclopropenimine-Mediated CO2 Activation for the Synthesis of Polyurethanes and Small-Molecule Carbonates and Carbamates.

Carbon dioxide (CO2) is an abundant C1 feedstock with tremendous potential to produce versatile building blocks in synthetic applications. Given the adverse impact of CO2 on the atmosphere, it is of paramount importance to devise strategies for upcycling it into useful materials, such as polymers and fine chemicals. To activate such stable molecule, superbases offer viable modes of binding to CO2. In this study, a superbase cyclopropenimine derivative was found to exhibit exceptional proficiency in activating CO2 and mediating its polymerization at ambient temperature and pressure for the synthesis of polyurethanes. The versatility of this reaction can be extended to monofunctional amines and alcohols, yielding a variety of functional carbonates and carbamates.

Breaking the tert-Butyllithium Contact Ion Pair: A Gateway to Alternate Selectivity in Lithiation Reactions.

The effects of Lewis basic phosphoramides on the aggregate structure of t-BuLi have been investigated in detail by NMR and DFT methods. It was determined that hexamethylphosphoramide (HMPA) can shift the equilibrium of t-BuLi to include the triple ion pair (t-Bu-Li-t-Bu)-/HMPA4Li+ which serves as a reservoir for the highly reactive separated ion pair t-Bu-/HMPA4Li+. Because the Li-atom's valences are saturated in this ion pair, the Lewis acidity is significantly decreased; in turn, the basicity is maximized which allowed for the typical directing effects within oxygen heterocycles to be overridden and for remote sp3 C-H bonds to be deprotonated. Furthermore, these newly accessed lithium aggregation states were leveraged to develop a simple γ-lithiation and capture protocol of chromane heterocycles with a variety of alkyl halide electrophiles in good yields.

Attitudes towards COVID-19 vaccination among incarcerated persons in the Federal Bureau of Prisons, June-July 2021.

OBJECTIVE: To understand the attitudes towards COVID-19 vaccination and trusted sources of vaccination-related information among persons incarcerated in the Federal Bureau of Prisons. METHODS: From June-July 2021, persons incarcerated across 122 facilities operated by the Federal Bureau of Prisons were invited to participate in a survey asking their reasons for receiving or declining COVID-19 vaccination and the information sources they relied upon to make these decisions. Descriptive analyses were conducted. RESULTS: A total of 130,789 incarcerated persons with known vaccination status were invited to participate in the survey. At the time of survey, 78,496 (62%) were fully vaccinated; 3,128 (3%) were partially vaccinated and scheduled to complete their second dose, and 44,394 (35%) had declined either a first or second dose. 7,474 (9.5%) of the fully vaccinated group and 2,302 (4.4%) of the group declining either a first or second dose chose to participate in the survey; an overall survey return rate of 7.6% (n = 9,905). Among vaccinated respondents, the most common reason given for accepting vaccination was to protect their health (n = 5,689; 76.1%). Individuals who declined vaccination cited concerns about vaccine side effects (n = 1,304; 56.6%), mistrust of the vaccine (n = 1,256; 54.6%), and vaccine safety concerns (n = 1,252; 54.4%). Among those who declined, 21.2% (n = 489) reported that they would choose to be vaccinated if the vaccine was offered again. Those who declined also reported that additional information from outside organizations (n = 1128; 49.0%), receiving information regarding vaccine safety (n = 841; 36.5%), and/or speaking with a trusted medical advisor (n = 565; 24.5%) may influence their decision to be vaccinated in the future. CONCLUSION: As the COVID-19 pandemic continues, it is important to increase vaccine confidence in prisons, jails, and detention facilities to reduce transmission and severe health outcomes. These survey findings can inform the design of potential interventions to increase COVID-19 vaccine uptake in these settings.

Preparation of Highly Reactive Lithium Metal Dendrites for the Synthesis of Organolithium Reagents.

A long-standing problem in the area of organolithium chemistry has been the need for a highly reactive Li-metal source that mimics Li-powders but has the advantage of being freshly prepared from inexpensive and readily available Li-sources. Here, we report a simple and convenient activation method using liquid ammonia that furnishes a new Li-metal source in the form of crystalline Li-dendrites. The Li-dendrites were shown to have ca. 100 times greater surface area than conventional Li-sources created by prototypical mechanical activation methods. Concomitant with the surface area increase, the Li-dendrites were shown to exhibit significant rate enhancements over Li-powders, which are currently the industry standard for the preparation of organolithium compounds. These features were leveraged for the reproducible synthesis of organolithium reagents over a range of common laboratory scales.

COVID-19 vaccination in the Federal Bureau of Prisons, December 2020-April 2021.

OBJECTIVES: To describe COVID-19 vaccine distribution operations in United States Federal Bureau of Prisons (BOP) institutions and offices from December 16, 2020-April 14, 2021, report vaccination coverage among staff and incarcerated people, and identify factors associated with vaccination acceptance among incarcerated people. METHODS: The BOP COVID-19 vaccination plan and implementation timeline are described. Descriptive statistics and vaccination coverage were calculated for the BOP incarcerated population using data from the BOP electronic medical record. Coverage among staff was calculated using data from the Centers for Disease Control and Prevention Vaccination Administration Management System. Vaccination coverage in the BOP versus the overall United States adult population was compared by state/territory. Univariate and multivariable logistic regression models were developed to identify demographic, health-related, and institution-level factors associated with vaccination acceptance among incarcerated people, using hierarchical linear modeling to account for institution-level clustering. RESULTS: By April 14, 2021, BOP had offered COVID-19 vaccination to 37,870 (100%) staff and 88,173/126,413 (69.8%) incarcerated people, with acceptance rates of 50.2% and 64.2%, respectively. At the time of analysis, vaccination coverage in BOP was comparable to coverage in the overall adult population in the states and territories where BOP institutions and offices are located. Among incarcerated people, factors associated with lower vaccination acceptance included younger age, female sex, non-Hispanic Black and Asian race/ethnicity, and having few underlying medical conditions; factors associated with higher acceptance included having a prior SARS-CoV-2 infection, being born outside the United States, and being assigned to a Federal Detention Center. CONCLUSIONS: Early COVID-19 vaccination efforts in BOP have achieved levels of coverage similar to the general population. To build on this initial success, BOP can consider strategies including re-offering vaccination to people who initially refused and tailoring communication strategies to groups with lower acceptance rates.

Thiolate-Thione Redox-Active Ligand with a Six-Membered Chelate Ring via Template Condensation and Its Pt(II) Complexes.

A new template condensation reaction has been discovered in a mixture of Pt(II), thiobenzamide, and base. Four complexes of the general form [Pt(ctaPhR)2], R = CH3 (1a), H (1b), F (1c), Cl (1d), cta = condensed thioamide, have been prepared under similar conditions and thoroughly characterized by 1H NMR and UV-vis-NIR spectroscopy, (spectro)electrochemistry, elemental analysis, and single-crystal X-ray diffraction. The ligand is redox active and can be reduced from the initial monoanion to a dianionic and then trianionic state. Chemical reduction of 1a with [Cp2Co] yielded [Cp2Co]2[Pt(ctaPhCH3)2], [Cp2Co]2[1a], which has been similarly characterized with the addition of EPR spectroscopy and SQUID magnetization. The singly reduced form containing [1a]1-, (nBu4N)[Pt(ctaPhCH3)2], has been generated in situ and characterized by UV-vis and EPR spectroscopies. DFT studies of 1b, [1b]1-, and [1b]2- confirm the location of additional electrons in exclusively ligand-based orbitals. A detailed analysis of this redox-active ligand, with emphasis on the characteristics that favor noninnocent behavior in six-membered chelate rings, is included.

Reversible PCET and Ambient Catalytic Oxidative Alcohol Dehydrogenation by {V=O} Perfluoropinacolate Complexes.

A new air-stable catalyst for the oxidative dehydrogenation of benzylic alcohols under ambient conditions has been developed. The synthesis and characterization of this compound and the related monomeric and dimeric V(IV)- and V(V)-pinF (pinF = perfluoropinacolate) complexes are reported herein. Monomeric V(IV) complex (Me4N)2[V(O)(pinF)2] (1) and dimeric (µ-O)2-bridged V(V) complex (Me4N)2[V2(O)2(µ-O)2(pinF)2] (3a) are prepared in water under ambient conditions. Monomeric V(V) complex (Me4N)[V(O)(pinF)2] (2) may be generated via chemical oxidation of 1 under an inert atmosphere, but dimerizes to 3a upon exposure to air. Complexes 1 and 2 display a perfectly reversible VIV/V couple at 20 mV (vs Ag/AgNO3), whereas a quasi-reversible VIV/V couple at -865 mV is found for 3a. Stoichiometric reactions of 3a with both fluorenol and TEMPOH result in the formation of (Me4N)2[V2(O)2(µ-OH)2(pinF)2] (4a), which contains two V(IV) centers that display antiferromagnetic coupling. In order to structurally characterize the dinuclear anion of 4a, {K(18C6)}+ countercations were employed, which formed stabilizing K···O interactions between the counterion and each terminal oxo moiety and H-bonding between the oxygen atoms of the crown ether and µ-OH bridges of the dimer, resulting in {K(18C6)}2[V2(O)2(µ-OH)2(pinF)2] (4b). The formal storage of H2 in 4a is reversible and proton-coupled electron transfer (PCET) from crystals of 4a regenerates 3a upon exposure to air over the course of several days. Furthermore, the reaction of 3a (2%) under ambient conditions with excess fluorenol, cinnamyl alcohol, or benzyl alcohol resulted in the selective formation of fluorenone (82% conversion), cinnamaldehyde (40%), or benzaldehyde (7%), respectively, reproducing oxidative alcohol dehydrogenation (OAD) chemistry known for VOx surfaces and demonstrating, in air, the thermodynamically challenging selective oxidation of alcohols to aldehydes/ketones.

Rational Design of an Iron-Based Catalyst for Suzuki-Miyaura Cross-Couplings Involving Heteroaromatic Boronic Esters and Tertiary Alkyl Electrophiles.

Suzuki-Miyaura cross-coupling reactions between a variety of alkyl halides and unactivated aryl boronic esters using a rationally designed iron-based catalyst supported by ß-diketiminate ligands are described. High catalyst activity resulted in a broad substrate scope that included tertiary alkyl halides and heteroaromatic boronic esters. Mechanistic experiments revealed that the iron-based catalyst benefited from the propensity for ß-diketiminate ligands to support low-coordinate and highly reducing iron amide intermediates, which are very efficient for effecting the transmetalation step required for the Suzuki-Miyaura cross-coupling reaction.

Iron-Catalyzed Suzuki-Miyaura Cross-Coupling Reactions between Alkyl Halides and Unactivated Arylboronic Esters.

An iron-catalyzed cross-coupling reaction between alkyl halides and arylboronic esters was developed that does not involve activation of the boronic ester with alkyllithium reagents nor requires magnesium additives. A combination of experimental and theoretical investigations revealed that lithium amide bases coupled with iron complexes containing deprotonated cyanobis(oxazoline) ligands were best to obtain high yields (up to 89%) in catalytic cross-coupling reactions. Mechanistic investigations implicate carbon-centered radical intermediates and highlight the critical importance of avoiding conditions that lead to iron aggregates. The new iron-catalyzed Suzuki-Miyaura reaction was applied toward the shortest reported synthesis of the pharmaceutical Cinacalcet.

Carbohydrate/DBU Cocatalyzed Alkene Diboration: Mechanistic Insight Provides Enhanced Catalytic Efficiency and Substrate Scope.

A mechanistic investigation of the carbohydrate/DBU cocatalyzed enantioselective diboration of alkenes is presented. These studies provide an understanding of the origin of stereoselectivity and also reveal a strategy for enhancing reactivity and broadening the substrate scope.

Sulfur-Limonene Polysulfide: A Material Synthesized Entirely from Industrial By-Products and Its Use in Removing Toxic Metals from Water and Soil.

A polysulfide material was synthesized by the direct reaction of sulfur and d-limonene, by-products of the petroleum and citrus industries, respectively. The resulting material was processed into functional coatings or molded into solid devices for the removal of palladium and mercury salts from water and soil. The binding of mercury(II) to the sulfur-limonene polysulfide resulted in a color change. These properties motivate application in next-generation environmental remediation and mercury sensing.

Reconstructing the early evolution of Fungi using a six-gene phylogeny.

The ancestors of fungi are believed to be simple aquatic forms with flagellated spores, similar to members of the extant phylum Chytridiomycota (chytrids). Current classifications assume that chytrids form an early-diverging clade within the kingdom Fungi and imply a single loss of the spore flagellum, leading to the diversification of terrestrial fungi. Here we develop phylogenetic hypotheses for Fungi using data from six gene regions and nearly 200 species. Our results indicate that there may have been at least four independent losses of the flagellum in the kingdom Fungi. These losses of swimming spores coincided with the evolution of new mechanisms of spore dispersal, such as aerial dispersal in mycelial groups and polar tube eversion in the microsporidia (unicellular forms that lack mitochondria). The enigmatic microsporidia seem to be derived from an endoparasitic chytrid ancestor similar to Rozella allomycis, on the earliest diverging branch of the fungal phylogenetic tree.

Assembling the fungal tree of life: progress, classification, and evolution of subcellular traits.

Based on an overview of progress in molecular systematics of the true fungi (Fungi/Eumycota) since 1990, little overlap was found among single-locus data matrices, which explains why no large-scale multilocus phylogenetic analysis had been undertaken to reveal deep relationships among fungi. As part of the project "Assembling the Fungal Tree of Life" (AFTOL), results of four Bayesian analyses are reported with complementary bootstrap assessment of phylogenetic confidence based on (1) a combined two-locus data set (nucSSU and nucLSU rDNA) with 558 species representing all traditionally recognized fungal phyla (Ascomycota, Basidiomycota, Chytridiomycota, Zygomycota) and the Glomeromycota, (2) a combined three-locus data set (nucSSU, nucLSU, and mitSSU rDNA) with 236 species, (3) a combined three-locus data set (nucSSU, nucLSU rDNA, and RPB2) with 157 species, and (4) a combined four-locus data set (nucSSU, nucLSU, mitSSU rDNA, and RPB2) with 103 species. Because of the lack of complementarity among single-locus data sets, the last three analyses included only members of the Ascomycota and Basidiomycota. The four-locus analysis resolved multiple deep relationships within the Ascomycota and Basidiomycota that were not revealed previously or that received only weak support in previous studies. The impact of this newly discovered phylogenetic structure on supraordinal classifications is discussed. Based on these results and reanalysis of subcellular data, current knowledge of the evolution of septal features of fungal hyphae is synthesized, and a preliminary reassessment of ascomal evolution is presented. Based on previously unpublished data and sequences from GenBank, this study provides a phylogenetic synthesis for the Fungi and a framework for future phylogenetic studies on fungi.