Hexa-Fe(III) Carboxylate Complexes Facilitate Aerobic Hydrocarbon Oxidative Functionalization: Rh Catalyzed Oxidative Coupling of Benzene and Ethylene to Form Styrene.

Fe(II) carboxylates react with dioxygen and carboxylic acid to form Fe6(µ-OH)2(µ3-O)2(µ-X)12(HX)2 (X = acetate or pivalate), which is an active oxidant for Rh-catalyzed arene alkenylation. Heating (150-200 °C) the catalyst precursor [(η2-C2H4)2Rh(µ-OAc)]2 with ethylene, benzene, Fe(II) carboxylate, and dioxygen yields styrene >30-fold faster than the reaction with dioxygen in the absence of the Fe(II) carboxylate additive. It is also demonstrated that Fe6(µ-OH)2(µ3-O)2(µ-X)12(HX)2 is an active oxidant under anaerobic conditions, and the reduced material can be reoxidized to Fe6(µ-OH)2(µ3-O)2(µ-X)12(HX)2 by dioxygen. At optimized conditions, a turnover frequency of ∼0.2 s-1 is achieved. Unlike analogous reactions with Cu(II) carboxylate oxidants, which undergo stoichiometric Cu(II)-mediated production of phenyl esters (e.g., phenyl acetate) as side products at temperatures ≥150 °C, no phenyl ester side product is observed when Fe carboxylate additives are used. Kinetic isotope effect experiments using C6H6 and C6D6 give k H/k D = 3.5(3), while the use of protio or monodeutero pivalic acid reveals a small KIE with k H/k D = 1.19(2). First-order dependencies on Fe(II) carboxylate and dioxygen concentration are observed in addition to complicated kinetic dependencies on the concentration of carboxylic acid and ethylene, both of which inhibit the reaction rate at a high concentration. Mechanistic studies are consistent with irreversible benzene C-H activation, ethylene insertion into the formed Rh-Ph bond, ß-hydride elimination, and reaction of Rh-H with Fe6(µ-OH)2(µ3-O)2(µ-X)12(HX)2 to regenerate a Rh-carboxylate complex.

Improving co-electrocatalytic carbon dioxide reduction by optimizing the relative potentials of the redox mediator and catalyst.

The effects of fixing the redox mediator (RM) reduction potential relative to a series of Cr-centered complexes capable of the reduction of CO2 to CO are disclosed. The greatest co-electrocatalytic activity enhancement is observed when the reduction potentials of the catalyst and RM are identical, implying that controlling the speciation of the Cr complex relative to RM activation is essential for improving catalytic performance. In all cases, the potential where co-catalytic activity is observed matches the reduction potential of the RM, regardless of the relative reduction potential of the Cr complex.

Mono- and Bis-Phosphine Promoted Incorporation of Boron, Nitrogen, and Phosphorus into Heterocycles via Staudinger Reactions of Borafluorene Azides.

We report the synthesis and characterization of a series of BNP-incorporated borafluorenate heterocycles formed via thermolysis reactions of pyridylphosphine and bis(phosphine)-coordinated borafluorene azides. The use of diphenyl-2-pyridylphosphine (PyPh2P), trans-1,2-bis(diphenylphosphino)ethylene (Ph2P(H)C═C(H)PPh2), and bis(diphenylphosphino)methane (Ph2PC(H2)PPh2) as stabilizing ligands resulted in Staudinger reactions to form complex heterocycles with four- (BN2P, BNPC, P2N2) and five-membered (BNP2C and BN2PC) rings, which were successfully isolated and fully characterized by multinuclear NMR and X-ray crystallography. However, when bis(diphenylphosphino)benzene (Ph2P-Ph-PPh2) was used as the ligand in a reaction with 9-bromo-9-borafluorene (BF-Br), due to the close proximity of the donor P atoms, the diphosphine-stabilized borafluoronium ion with an unusual borafluorene dibromide anion was formed. Reaction of the borafluoronium ion with trimethylsilyl azide left the cation intact, and the dibromide anion was substituted by a diazide. Density functional theory calculations were used to provide mechanistic insight into the formation of these new boracyclic compounds. This work highlights a new method in which donor phosphine ligands may be used to promote dimerization, cyclization, and ring contraction reactions to produce boracycles via Staudinger reactions.

Mortality attributable to PM2.5 from wildland fires in California from 2008 to 2018.

In California, wildfire risk and severity have grown substantially in the last several decades. Research has characterized extensive adverse health impacts from exposure to wildfire-attributable fine particulate matter (PM2.5), but few studies have quantified long-term outcomes, and none have used a wildfire-specific chronic dose-response mortality coefficient. Here, we quantified the mortality burden for PM2.5 exposure from California fires from 2008 to 2018 using Community Multiscale Air Quality modeling system wildland fire PM2.5 estimates. We used a concentration-response function for PM2.5, applying ZIP code-level mortality data and an estimated wildfire-specific dose-response coefficient accounting for the likely toxicity of wildfire smoke. We estimate a total of 52,480 to 55,710 premature deaths are attributable to wildland fire PM2.5 over the 11-year period with respect to two exposure scenarios, equating to an economic impact of $432 to $456 billion. These findings extend evidence on climate-related health impacts, suggesting that wildfires account for a greater mortality and economic burden than indicated by earlier studies.

Synthesis of 1-Azatriene Complexes of Tungsten: Metal-Promoted Ring-Opening of Dihydropyridine.

For nearly a century, chemists have explored how transition-metal complexes can affect the physical and chemical properties of linear conjugated polyenes and heteropolyenes. While much has been written about higher hapticity complexes (η4-η6), less is known about the chemistry of their η2 analogues. Herein, we describe a general method for synthesizing 5,6-η2-(1-azatriene) tungsten complexes via a 6π-azaelectrocyclic dihydropyridine ring-opening that is promoted by the π-basic nature of {WTp(NO)(PMe3)}. This study includes detailed spectroscopic and crystallographic data for the η2-dihydropyridine and η2-1-azatriene complexes, both of which were prepared as single regio- and stereoisomers.

Controlling product selectivity during dioxygen reduction with Mn complexes using pendent proton donor relays and added base.

The catalytic reduction of dioxygen (O2) is important in biological energy conversion and alternative energy applications. In comparison to Fe- and Co-based systems, examples of catalytic O2 reduction by homogeneous Mn-based systems is relatively sparse. Motivated by this lack of knowledge, two Mn-based catalysts for the oxygen reduction reaction (ORR) containing a bipyridine-based non-porphyrinic ligand framework have been developed to evaluate how pendent proton donor relays alter activity and selectivity for the ORR, where Mn(p-tbudhbpy)Cl (1) was used as a control complex and Mn(nPrdhbpy)Cl (2) contains a pendent -OMe group in the secondary coordination sphere. Using an ammonium-based proton source, N,N'-diisopropylethylammonium hexafluorophosphate, we analyzed catalytic activity for the ORR: 1 was found to be 64% selective for H2O2 and 2 is quantitative for H2O2, with O2 binding to the reduced Mn(ii) center being the rate-determining step. Upon addition of the conjugate base, N,N'-diisopropylethylamine, the observed catalytic selectivity of both 1 and 2 shifted to H2O as the primary product. Interestingly, while the shift in selectivity suggests a change in mechanism for both 1 and 2, the catalytic activity of 2 is substantially enhanced in the presence of base and the rate-determining step becomes the bimetallic cleavage of the O-O bond in a Mn-hydroperoxo species. These data suggest that the introduction of pendent relay moieties can improve selectivity for H2O2 at the expense of diminished reaction rates from strong hydrogen bonding interactions. Further, although catalytic rate enhancements are observed with a change in product selectivity when base is added to buffer proton activity, the pendent relays stabilize dimer intermediates, limiting the maximum rate.

Unlocking Biradical Character in Diborepins.

Systems that possess open- and closed-shell behavior attract significant attention from researchers due to their inherent redox and charge transport properties. Herein, we report the synthesis of the first diborepin biradicals. They display tunable biradical character based on the steric and electronic profile of the stabilizing ligand and the resulting geometric deviation of the diborepin core from planarity. While there are numerous all-carbon-based biradical systems, boron-based biradical compounds are comparatively rare, particularly ones in which the radical sites are disjointed. Calculations using density functional theory (DFT) and multireference methods demonstrate that the fused diborepin scaffold exhibits high biradical character, up to 95%. Use of a nonsterically demanding diaminocarbene promotes the planarization of the pentacyclic framework, resulting in the synthetic realization of a diborepin containing a dibora-quinoidal core, which possesses a closed-shell ground state and thermally accessible triplet state. The biradicals were structurally authenticated and characterized by both solution and solid-state electron paramagnetic resonance (EPR) spectroscopy. Half-field transitions were observed at low temperatures (about 170 K), confirming the presence of the triplet state. Initial reactivity studies of the biradicals led to the isolation and structural characterization of bis(borepin hydride) and bis(borepin dianion).

Unveiling Three Interconvertible Redox States of Boraphenalene.

Neutral 1-boraphenalene displays the isoelectronic structure of the phenalenyl carbocation and is expected to behave as an attractive organoboron multi-redox system. However, the isolation of new redox states have remained elusive even though the preparation of neutral boron(III)-containing phenalene compounds have been extensively studied. Herein, we have adopted an N-heterocyclic carbene ligand stabilization approach to achieve the first isolation of the stable and ambipolar 1-boraphenalenyl radical 1•. The 1-boraphenalenyl cation 1+ and anion 1- have also been electrochemically observed and chemically isolated, representing new redox forms of boraphenalene for the study of non-Kekulé polynuclear benzenoid molecules. Experimental and theoretical investigations suggest that the interconvertible three-redox-state species undergo reversible electronic structure modifications, which primarily take place on the polycyclic framework of the molecules, exhibiting atypical behavior compared to known donor-stabilized organoboron compounds. Initial reactivity studies, aromaticity evaluations, and photophysical studies show redox-state-dependent trends. While 1+ is luminescent in both the solution and solid states, 1• exhibits boron-centered reactivity and 1- undergoes substitution chemistry on the boraphenalenyl skeleton and serves as a single-electron transfer reductant.

Tungsten-anisole complex provides 3,6-substituted cyclohexenes for highly diversified chemical libraries.

Medicinal chemists use vast combinatorial molecular libraries to develop leads for new pharmaceuticals. The syntheses of these compounds typically rely on coupling molecular fragments through atoms with planar (sp2) geometry. These so-called flat molecules often lack the protein binding site specificity needed to be an effective drug. Here, we demonstrate a coupling strategy in which a cyclohexene is used as a linker to connect two diverse molecular fragments while forming two new tetrahedral (sp3) stereocenters. These connections are made with the aid of a tungsten complex that activates anisole toward an unusual double protonation, followed by sequential nucleophilic additions. As a result, either cis- or trans-disubstituted cyclohexenes can be prepared with a range of chemical diversity unparalleled by other dearomatization methods.

Geminal bimetallic coordination of a carbone to main-group and transition metals.

The non-bonding carbone lone pair in geometrically-constrained antimony and bismuth carbodiphosphorane complexes readily complexed AuCl to afford rare examples of geminal bimetallic carbone coordination featuring a main-group metal.

Air- and photo-stable luminescent carbodicarbene-azaboraacenium ions.

Substitution of a C=C bond by an isoelectronic B-N bond is a well-established strategy to alter the electronic structure and stability of acenes. BN-substituted acenes that possess narrow energy gaps have attractive optoelectronic properties. However, they are susceptible to air and/or light. Here we present the design, synthesis and molecular structures of fully π-conjugated cationic BN-doped acenes stabilized by carbodicarbene ligands. They are luminescent in the solution and solid states and show high air and moisture stability. Compared with their neutral BN-substituted counterparts as well as the parent all-carbon acenes, these species display improved quantum yields and small optical gaps. The electronic structures of the azabora-anthracene and azabora-tetracene cations resemble higher-order acenes while possessing high photo-oxidative resistance. Investigations using density functional theory suggest that the stability and photo-physics of these conjugated systems may be ascribed to their cationic nature and the electronic properties of the carbodicarbene.

A virtual mother-infant postpartum psychotherapy group for mothers with a history of adverse childhood experiences: open-label feasibility study.

OBJECTIVES: Mothers with a history of adverse childhood experiences (ACE) are at elevated risk for postpartum mental illness and impairment in the mother-infant relationship. Interventions attending to maternal-infant interactions may improve outcomes for these parents and their children, but barriers to accessing in-person postpartum care limit uptake. We adapted a postpartum psychotherapy group for mothers with mental illness (e.g., mood, anxiety, trauma-related disorders) and ACE for live video-based delivery, and evaluated feasibility, acceptability, and preliminary efficacy in an open-label pilot study. METHODS: We recruited adults with children (6-18 months) from a perinatal psychiatry program in Toronto, Canada. The intervention was a live video-based 12-week interactive psychotherapy group focused on maternal symptoms and maternal-infant relationships. The primary outcome was feasibility, including feasibility of recruitment and retention, fidelity of the intervention, and acceptability to patients and group providers. Maternal clinical outcomes were compared pre- to post-intervention, as secondary outcomes. RESULTS: We recruited 31 participants (mean age 36.5 years (SD 3.9)) into 6 groups; 93.6% (n = 29) completed post-group questionnaires, and n = 20 completed an optional post-group acceptability interview. Mean weekly group attendance was 83% (IQR 80-87); one participant (3.2%) dropped out. All group components were implemented as planned, except for dyadic exercises where facilitator observation of dyads was replaced with unobserved mother-infant exercises followed by in-group reflection. Participant acceptability was high (100% indicated the virtual group was easy to access, beneficial, and reduced barriers to care). Mean maternal depressive [Edinburgh Postnatal Depression Scale: 14.6 (SD 4.2) vs. 11.8 (SD 4.2), paired t, p = 0.005] and post-traumatic stress [Posttraumatic Stress Disorder Checklist for DSM-5: 35.5 (SD 19.0) vs. 27.1 (SD 16.7)], paired t, p = 0.01] symptoms were significantly lower post vs. pre-group. No differences were observed on mean measures of anxiety, emotion regulation or parenting stress. CONCLUSIONS: Recruitment and retention met a priori feasibility criteria. There were significant pre- to post-group reductions in maternal depressive and post-traumatic symptoms, supporting proceeding to larger-scale implementation and evaluation of the intervention, with adaptation of dyadic exercises.

The Tungsten-Promoted Synthesis of Piperidyl-Modified erythro-Methylphenidate Derivatives.

Due to its efficacy as a dopamine receptor agonist, methylphenidate (MPH) is of interest as a potential therapeutic for cocaine addiction. While numerous derivatives of MPH have been investigated for their potential medicinal value, functionalization of the piperidine ring has not been explored. The pyridine borane ligand in WTp(NO)(PMe3)(η2-pyBH3) is dearomatized by the metal and can be elaborated to the analogous η2-mesylpyridinium complex. Installing a methyl phenylacetate moiety at the C2' position via a Reformatsky reaction followed by a tandem protonation/nucleophilic addition sequence results in a library of erythro MPH analogues functionalized at the piperidyl C5' position. The functional group is added chemoselectively to C5', cis to the methyl phenylacetate. Repeating this procedure with an enantioenriched source of the tungsten reagent results in enantioenriched MPH derivatives. All identities of the newly reported compounds are supported by comprehensive 2D NMR and HRMS data or crystallographic data.

Evolution and impact of a dedicated ultrasound clinic on clinical rheumatology practice at an academic medical center.

BACKGROUND: Rheumatologic ultrasonography (RhUS) has grown in scope and application over the past 20 years. While many studies have shown the benefits of RhUS, few have investigated the efficacy of a dedicated clinic. This study explores the impact of a dedicated ultrasound clinic on patients and rheumatologists at an academic medical center (AMC). METHODS: We analyzed claims data for patient visits, X-rays (XR), magnetic resonance imaging (MRI), and RhUS from an AMC with an established RhUS clinic, alongside two affiliated community medical practices (CMPs) without RhUS. We also analyzed RhUS clinic records on referral indication, procedures, results, and follow-up treatment changes. Pre- and post-RhUS visit patient surveys and referring physician (RP) surveys assessed experience and impact of the RhUS clinic. RESULTS: From 2018 to 2021, referrals to the RhUS clinic substantially increased. In parallel, XR and MRI orders changed by -76 % and -43 % respectively, compared with 163 % and -24 % at CMPs. Discordance between RP pre-RhUS assessments and RhUS results were common. Patient surveys showed RhUS led to increased disease understanding and impacted thoughts and decisions about their therapy. RPs found utility in RhUS across a range of indications and were confident with RhUS results. CONCLUSIONS: These findings suggest a dedicated RhUS clinic can be a valuable resource in clinical rheumatology practice. Implementation of a RhUS clinic at this AMC spurred rapid adoption of RhUS into clinical decision-making with notable benefits for patients and physicians alike. This may serve as a model for implementation of similar clinics at other institutions.

Photochemically and Thermally Generated BN-Doped Borafluorenate Heterocycles via Intramolecular Staudinger-Type Reactions.

A series of BN-incorporated borafluorenate heterocycles, bis(borafluorene-phosphinimine)s (11-15), have been formed via intramolecular Staudinger-type reactions. The reactions were promoted by light or heat using monodentate phosphine-stabilized 9-azido-9-borafluorenes (R3P-BF-N3; 6-10) and involve the release of dinitrogen (N2), migration of phosphine from boron to nitrogen, and oxidation of the phosphorus center (PIII to PV). Density functional theory (DFT) calculations provide mechanistic insight into the formation of these compounds. Compounds 11-15 are blue emissive in the solution and solid states with absolute quantum yields (ΦF) ranging from 12 to 68%.

Bis(9-Boraphenanthrene) and Its Stable Biradical.

Selective and site-specific boron-doping of polycyclic aromatic hydrocarbon frameworks often give rise to redox and/or photophysical properties that are not easily accessible with the analogous all-carbon systems. Herein, we report ligand-mediated control of boraphenanthrene closed- and open-shell electronic states, which has led to the first structurally characterized examples of neutral bis(9-boraphenanthrene) (2-3) and its corresponding biradical (4). Notably, compounds 2 and 3 show intramolecular charge transfer absorption from the 9-boraphenanthrene units to p-quinodimethane, exhibiting dual (red-shifted) emission in solution due to excited state conjugation enhancement (ESCE). Moreover, while boron-centered monoradicals are ubiquitous, biradical 4 represents a rare type of open-shell singlet compound with 95% biradical character, among the highest of any reported boron-based polycyclic species with two radical sites.

Framing the work: A coparenting model for guiding infant mental health engagement with families.

When working with families of infants and toddlers, intentionally looking beyond dyadic child-parent relationship functioning to conceptualize the child's socioemotional adaptation within their broader family collective can enhance the likelihood that clinical gains will be supported and sustained. However, there has been little expert guidance regarding how best to frame infant-family mental health therapeutic encounters for the adults responsible for the child's care and upbringing in a manner that elevates their mindfulness about and their resolve to strengthen the impact of their coparenting collective. This article describes a new collaborative initiative organized by family-oriented infant mental health professionals across several different countries, all of whom bring expansive expertise assessing and working with coparenting and triangular family dynamics. The Collaborative's aims are to identify a means for framing initial infant mental health encounters and intakes with families with the goal of assessing and raising family consciousness about the relevance of coparenting. Initial points of convergence and growing points identified by the Collaborative for subsequent field study are addressed.

Cuando se trabaja con familias de infantes y niños pequeñitos, el mirar intencionalmente más allá del funcionamiento de la relación diádica niño-progenitor para conceptualizar la adaptación socioemocional del niño dentro de la amplitud del colectivo familiar puede mejorar la posibilidad de que los logros clínicos sean apoyados y mantenidos. Sin embargo, ha habido poca guía de expertos acerca de cómo enmarcar mejor los encuentros terapéuticos infante-familia de salud mental para los adultos que son responsables del cuidado y crianza del niño de una manera que se eleve su estado consciente acerca de y su determinación de reforzar el impacto del colectivo en el proceso de la crianza compartida. Este artículo describe una nueva iniciativa colaborativa organizada por profesionales de la salud mental infantil orientados hacia la familia en varios diferentes países, todos los cuales aportan su conocimiento amplio evaluando y trabajando con las dinámicas familiares de crianza compartida y triangular. Las metas de este esfuerzo Colaborativo son identificar un medio para enmarcar los encuentros y la proporción de salud mental infantil con familias que se proponen evaluar y crear consciencia familiar acerca de la relevancia de la crianza compartida. Se abordan los puntos iniciales de convergencia y puntos de crecimiento identificados por el esfuerzo Colaborativo para subsecuentes estudios en el campo.

En travaillant avec des familles de nourrissons et de petits enfants, le fait de regarder délibérément au- delà du fonctionnement de la relation dyadique enfant-parent afin de conceptualisation l'adaptation socio émotionnelle de l'enfant, au sein de leur collectif familial plus large, peut accroître la probabilité que les gains cliniques seront bien soutenus et prolongés. Cependant il y a eu peu de directive experte concernant la meilleure manière d'encadrer les rencontres thérapeutiques nourrisson-famille de santé mentale pour les adultes responsables du soin de l'enfant et de son éducation d'une manière qui élève la pleine conscience et la détermination qu'il y a à renforcer l'impact de leur coparentage collectif. Cet article décrit une nouvelle initiative collaborative organisée par des professionnels de la santé mentale du nourrisson centrés sur la famille au travers de plus pays différents, tous étant de grands experts évaluant et travaillant avec des dynamiques de coparentage et de famille triangulaire. Les buts de cette collaboration sont d'identifier un moyen d'encadrer des rencontres de santé mentale initiales et les apports des familles avec le but d'évaluer et d'améliorer la conscience de la famille quant à la pertinence du coparentage. Les premiers points de convergence et de développement identifiés par la collaboration pour des études sur le terrain à venir sont discutés.

Making Advance Care Planning a part of cancer patients' end-of-life care in Rwanda.

After the devastating damage inflicted by the 1994 Genocide against the Tutsi, Rwanda made great strides in reconstructing its healthcare system from scratch. Although cancer mortality rates continue to rise, there is still a dearth of qualified healthcare workers for advance care planning (ACP) for terminally ill patients. I will draw on lessons learned through the literature search for the initiation of ACP and reflect on their adaptation to the existing policies, healthcare systems, and workforce in Rwanda. We hope to introduce advance care planning into the clinical package given to patients with cancers in terminal illness and their families in Rwanda. The introduction of ACP by skilled, qualified, and specialized healthcare professionals in Rwanda will help establish a practical ACP strategy at the hospital and in the community to benefit patients and their loved ones for an enhanced quality of life in end-of-life care. There is a need for training, policy-making, and community mobilization for the awareness of ACP.

The double protonation of dihapto-coordinated benzene complexes enables dearomatization using aromatic nucleophiles.

Friedel-Crafts Arylation (the Scholl reaction) is the coupling of two aromatic rings with the aid of a strong Lewis or Brønsted acid. This historically significant C-C bond forming reaction normally leads to aromatic products, often as oligomeric mixtures, dictated by the large stabilization gained upon their rearomatization. The coordination of benzene by a tungsten complex disrupts the natural course of this reaction sequence, allowing for Friedel-Crafts Arylation without rearomatization or oligomerization. Subsequent addition of a nucleophile to the coupled intermediate leads to functionalized cyclohexenes. In this work, we show that by coordinating benzene to tungsten through two carbons (dihapto-coordinate), a rarely observed double protonation of the bound benzene is enabled, allowing its subsequent coupling to a second arene without the need of a precious metal or Lewis acid catalyst.