Spectroscopic and Computational Evidence of Uranium Dihydrogen Complexes.

Dihydrogen complexation, a phenomenon with robust precedent in the transition metal series, is spectroscopically detected for a uranium(III) complex and thereby extended for the first time to the 5f series. The vacant coordination site and low valence of (C5H4SiMe3)3U prove to be key to the reversible formation of (C5H4SiMe3)3U-H2 (complex 1), and the paramagnetism of the f3 center facilitates the detection of complex 1 by NMR spectroscopy. Density functional theory calculations reveal that the delocalization of the 5f electron density from (C5H4SiMe3)3U onto the side-on dihydrogen ligand is crucial to complex formation, an unusual bonding situation for an actinide acid-base complex. The spectroscopic and computational results are compared to those reported for lanthanide metallocenes to yield insight into the nature of─and future possibilities for─f-element dihydrogen complexation.

The Wearable Activity Tracker Checklist for Healthcare (WATCH): a 12-point guide for the implementation of wearable activity trackers in healthcare.

Increasing physical activity in patients offers dual benefits, fostering improved patient health and recovery, while also bolstering healthcare system efficiency by minimizing costs related to extended hospital stays, complications, and readmissions. Wearable activity trackers offer valuable opportunities to enhance physical activity across various healthcare settings and among different patient groups. However, their integration into healthcare faces multiple implementation challenges related to the devices themselves, patients, clinicians, and systemic factors. This article presents the Wearable Activity Tracker Checklist for Healthcare (WATCH), which was recently developed through an international Delphi study. The WATCH provides a comprehensive framework for implementation and evaluation of wearable activity trackers in healthcare. It covers the purpose and setting for usage; patient, provider, and support personnel roles; selection of relevant metrics; device specifications; procedural steps for issuance and maintenance; data management; timelines; necessary adaptations for specific scenarios; and essential resources (such as education and training) for effective implementation. The WATCH is designed to support the implementation of wearable activity trackers across a wide range of healthcare populations and settings, and in those with varied levels of experience. The overarching goal is to support broader, sustained, and systematic use of wearable activity trackers in healthcare, therefore fostering enhanced physical activity promotion and improved patient outcomes.

Triple Inverse Sandwich versus End-On Diazenido: Bonding Motifs across a Series of Rhenium-Lanthanide and -Actinide Complexes.

While synthesizing a series of rhenium-lanthanide triple inverse sandwich complexes, we unexpectedly uncovered evidence for rare examples of end-on lanthanide dinitrogen coordination for certain heavy lanthanide elements as well as for uranium. We begin our report with the synthesis and characterization of a series of trirhenium triple inverse sandwich complexes with the early lanthanides, Ln[(µ-η5:η5-Cp)Re(BDI)]3(THF) (1-Ln, Ln = La, Ce, Pr, Nd, Sm; Cp = cyclopentadienide, BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-ß-diketiminate). However, as we moved across the lanthanide series, we ran into an unexpected result for gadolinium in which we structurally characterized two products for gadolinium, namely, 1-Gd (analogous to 1-Ln) and a diazenido dirhenium double inverse sandwich complex Gd[(µ-η1:η1-N2)Re(η5-Cp)(BDI)][(µ-η5:η5-Cp)Re(BDI)]2(THF)2 (2-Gd). Evidence for analogues of 2-Gd was spectroscopically observed for other heavy lanthanides (2-Ln, Ln = Tb, Dy, Er), and, in the case of 2-Er, structurally authenticated. These complexes represent the first observed examples of heterobimetallic end-on lanthanide dinitrogen coordination. Density functional theory (DFT) calculations were utilized to probe relevant bonding interactions and reveal energetic differences between both the experimental and putative 1-Ln and 2-Ln complexes. We also present additional examples of novel end-on heterobimetallic lanthanide and actinide diazenido moieties in the erbium-rhenium complex (η8-COT)Er[(µ-η1:η1-N2)Re(η5-Cp)(BDI)](THF)(Et2O) (3-Er) and uranium-rhenium complex [Na(2.2.2-cryptand)][(η5-C5H4SiMe3)3U(µ-η1:η1-N2)Re(η5-Cp)(BDI)] (4-U). Finally, we expand the scope of rhenium inverse sandwich coordination by synthesizing divalent double inverse sandwich complex Yb[(µ-η5:η5-Cp)Re(BDI)]2(THF)2 (5-Yb), as well as base-free, homoleptic rhenium-rare earth triple inverse sandwich complex Y[(µ-η5:η5-Cp)Re(BDI)]3 (6-Y).

Panoply of P: An Array of Rhenium-Phosphorus Complexes Generated from a Transition Metal Anion.

We expand upon the synthetic utility of anionic rhenium complex Na[(BDI)ReCp] (1, BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-ß-diketiminate) to generate several rhenium-phosphorus complexes. Complex 1 reacts in a metathetical manner with chlorophosphines Ph2PCl, MeNHP-Cl, and OHP-Cl to generate XL-type phosphido complexes 2, 3, and 4, respectively (MeNHP-Cl = 2-chloro-1,3-dimethyl-1,3,2-diazaphospholidine; OHP-Cl = 2-chloro-1,3,2-dioxaphospholane). Crystallographic and computational investigations of phosphido triad 2, 3, and 4 reveal that increasing the electronegativity of the phosphorus substituent (C < N < O) results in a shortening and strengthening of the rhenium-phosphorus bond. Complex 1 reacts with iminophosphane Mes*NPCl (Mes* = 2,4,6-tritert-butylphenyl) to generate linear iminophosphanyl complex 5. In the presence of a suitable halide abstraction reagent, 1 reacts with the dichlorophosphine iPr2NPCl2 to afford cationic phosphinidene complex 6+. Complex 6+ may be reduced by one electron to form 6•, a rare example of a stable, paramagnetic phosphinidene complex. Spectroscopic and structural investigations, as well as computational analyses, are employed to elucidate the influence of the phosphorus substituent on the nature of the rhenium-phosphorus bond in 2 through 6. Furthermore, we examine several common analogies employed to understand metal phosphido, phosphinidene, and iminophosphanyl complexes.

Applications of Low-Valent Transition Metalates: Development of a Reactive Noncarbonyl Rhenium(I) Anion.

Low-valent transition metalates─anionic, electronic-rich organometallic complexes─comprise a class of highly reactive chemical reagents that find integral applications in organic synthesis, small-molecule activation, transient species stabilization, and M-E bond formation, among others. The inherent reactivity of such electron-rich metal centers has necessitated the widespread use of strong backbonding ligands, particularly carbonyls, to aid in the isolation and handling of metalate reagents, albeit sometimes at the expense of partially masking their full reactivity. However, recent synthetic explorations into transition-metalate complexes devoid of archetypic back-bonding ligands have led to the discovery of highly reactive metalates capable of performing a variety of novel chemical transformations.Building on our group's long-standing interest in reactive organometallic species, a series of rational progressions in early-to-middle transition-metal chemistry ultimately led to our isolation of a rhenium(I) ß-diketiminate cyclopentadienide metalate that displays exceptional reactivity. We have found this Re(I) metalate to be capable of small-molecule activation; notably, the complex reversibly binds dinitrogen in solution and can be utilized to trap N2 for the synthesis of functionalized diazenido species. By employing isolobal analogues to N2 (CO and RNC), we were able to thoroughly monitor the mechanism of activation and conclude that the metalate's sodium counterion plays an integral role in promoting dinitrogen activation through a novel side-on interaction. The Re(I) metalate is also used in forming a variety of M-E bonds, including a series of uncommon rhenium-tetrylene (Si, Ge, and Sn) complexes that display varying degrees of multiple bonding. These metal tetrylenes act to highlight deviations in chemical properties within the group 14 elements. Our metalate's utility also applies to metal-metal bond formation, as demonstrated through the synthesis of a heterotetrametallic rhenium-zinc dimer. In this reaction, the Re(I) metalate performs a dual role as a reductant and metalloligand to stabilize a transient Zn22+ core fragment. Finally, the metalate displays unique reactivity with uranium(III) to yield the first transition metal-actinide inverse-sandwich bonds, in this case with three rhenium fragments bound through their Cp moieties surrounding the uranium center. Notably, throughout these endeavors we demonstrate that the metalate displays reactivity at multiple locations, including directly at the rhenium metal center, at a Cp carbon, through a Cp-sandwich mode, or through reversibly bound dinitrogen.Overall, the rhenium(I) metalate described herein demonstrates utility in diverse applications: small-molecule activation, the stabilization of reduced and/or unstable species, and the formation of unconventional M-E/M-M bonds or heterometallic complexes. Moving forward, we suggest that the continued discovery of noncarbonyl, electron-rich transition-metal anions featuring new or unconventional ligands should produce additional reactive organometallic species capable of stabilizing unique structural motifs and performing novel and unusual chemical transformations.

Porphyrinoid actinide complexes.

The diverse coordination modes and electronic features of actinide complexes of porphyrins and related oligopyrrolic systems (referred to as "porpyrinoids") have been the subject of interest since the 1960s. Given their stability and accessibility, most work with actinides has focused on thorium and uranium. This trend is also seen in the case of porphyrinoid-based complexation studies. Nevertheless, the diversity of ligand environments provided by porphyrinoids has led to the stabilization of a number of unique complexes with the early actinides that are often without structural parallel within the broader coordination chemical lexicon. This review summarizes key examples of prophyrinoid actinide complexes reported to date, including the limited number of porphyrinoid systems involving transuranic elements. The emphasis will be on synthesis and structure; however, the electronic features and reactivity pattern of representative systems will be detailed as well. Coverage is through December of 2021.

Binocular Rivalry Impact on Macroblock-Loss Error Concealment for Stereoscopic 3D Video Transmission.

Three-dimensional video services delivered through wireless communication channels have to deal with numerous challenges due to the limitations of both the transmission channel's bandwidth and receiving devices. Adverse channel conditions, delays, or jitters can result in bit errors and packet losses, which can alter the appearance of stereoscopic 3D (S3D) video. Due to the perception of dissimilar patterns by the two human eyes, they can not be fused into a stable composite pattern in the brain and hence try to dominate by suppressing each other. Thus, a psychovisual sensation that is called binocular rivalry occurs. As a result, undetectable changes causing irritating flickering effects are seen, leading to visual discomforts such as eye strain, headache, nausea, and weariness. This study addresses the observer's quality of experience (QoE) by analyzing the binocular rivalry impact on the macroblock (MB) losses in a frame and its error propagation due to predictive frame encoding in stereoscopic video transmission systems. To simulate the processing of experimental videos, the Joint Test Model (JM) reference software has been used as it is recommended by the International Telecommunication Union (ITU). Existing error concealing techniques were then applied to the contiguous lost MBs for a variety of transmission impairments. In order to validate the authenticity of the simulated packet loss environment, several objective evaluations were carried out. Standard numbers of subjects were then engaged in the subjective testing of common 3D video sequences. The results were then statistically examined using a standard Student's t-test, allowing the impact of binocular rivalry to be compared to that of a non-rivalry error condition. The major goal is to assure error-free video communication by minimizing the negative impacts of binocular rivalry and boosting the ability to efficiently integrate 3D video material to improve viewers' overall QoE.

Heterobimetallic-Mediated Dinitrogen Functionalization: N-C Bond Formation at Rhenium-Group 9 Diazenido Complexes.

We report the synthesis and characterization of rhenium-group 9 heterobimetallic diazenido species (η5-Cp)Re(µ-BDI)(µ-N2)M(η4-COD) (1-M, M = Ir or Rh, Cp = cyclopentadienide, BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-ß-diketiminate, COD = 1,5-cyclooctadiene), formed from salt elimination reactions between Na[(η5-Cp)Re(BDI)] and [MCl(η4-COD)]2. Additionally, we find that these same reagents react under an argon atmosphere to instead produce bridging hydride complexes (BDI)Re(µ-η5:η1-C5H4)(µ-H)M(η4-COD) (2-M), which undergo rearrangements upon protonation to form the alternative bridging hydrides [(η5-Cp)Re(µ-BDI)(µ-H)M(η4-COD)][(B(m-C6H3(CF3)2)4)] (3-M). Further, we demonstrate the first example of N-C bond formation at a heterobimetallic dinitrogen complex through reactions of 1-M and methyl triflate, which produces the alkylated species [(η5-Cp)Re(µ-N(Me)N)(µ-BDI)M(η4-COD)][OTf] (4-M, OTf = trifluoromethanesulfonate). A combination of spectroscopic studies, X-ray structural analysis, and computational investigations is discussed as an aid to understanding the modes of dinitrogen activation within these unique heterobimetallic complexes.

Does Reduction-Induced Isomerization of a Uranium(III) Aryl Complex Proceed via C-H Oxidative Addition and Reductive Elimination across the Uranium(II/IV) Redox Couple?

Reaction of the uranium(III) bis(amidinate) aryl complex {TerphC(NiPr)2}2U(Terph) (2, where Terph = 4,4″-di-tert-butyl-m-terphenyl-2'-yl) with a strong reductant enabled isolation of isomeric uranium(III) bis(amidinate) aryl product {TerphC(NiPr)2}2U(Terph*) (3, where Terph* = 4,4″-di-tert-butyl-m-terphenyl-4'-yl). In terms of connectivity, 3 differs from 2 only in the positions of the U-C and C-H bonds on the central aryl ring of the m-terphenyl-based ligand. A deuterium labeling study ruled out mechanisms for this isomerization involving intermolecular abstraction or deprotonation of the ligand C-H bonds activated during the reaction. Due to the complexity of this rapid, heterogeneous reaction, experimental studies could not further distinguish between two different intramolecular C-H activation mechanisms. However, high-level computational studies were consistent with a mechanism that included two sets of unimolecular, mononuclear C-H oxidative addition and reductive elimination steps involving uranium(II/IV).

[3 + 2] Cycloadditions and Retrocycloadditions of Niobium Imido Complexes: An Experimental and Computational Mechanistic Study.

We demonstrate reactivity between a ß-diketiminate-supported niobium(III) imido complex and alkyl azides to form niobatetrazene complexes (BDI)Nb(NtBu)(RNNNNR) (BDI = N,N-bis(2,6-diisopropylphenyl)-3,5-dimethyl-ß-diketiminate; R = cyclohexyl (1), benzyl (2)). Intriguingly, niobatetrazene complexes 1 and 2 can be interconverted via addition of an appropriate alkyl azide, likely through a series of concerted [3 + 2] cycloaddition and retrocycloaddition reactions in which π-loaded bis(imido) intermediates are formed. The bis(imido) intermediates were trapped upon addition of alkyl isocyanides to yield five-coordinate bis(imido) complexes (BDI)Nb(NtBu)(NCy)(CNR) (R = tert-butyl (4a), cyclohexyl (4b)). Two computational methods─density functional theory and density functional tight binding (DFTB)─were employed to calculate the lowest energy pathway across the potential energy surface for this multistep transformation. Reaction path calculations for individual cycloaddition or retrocycloaddition processes along the multistep reaction pathway showed that these transformations occur via a concerted, yet highly asynchronous mechanism, in which the two bond-breaking or -making events do not occur simultaneously. The use of the DFTB method in this work highlights its advantages and utility for studying transition metal systems.

Running-induced fatigue and impact loading in runners: A systematic review and meta-analysis.

This systematic review and meta-analysis aimed to synthesise and clarify the effect of running-induced fatigue on impact loading during running. Eight electronic databases were systematically searched until April 2021. Studies that analysed impact loading over the course of a run, in adult runners free of medical conditions were included. Changes in leg stiffness, vertical stiffness, shock attenuation, peak tibial accelerations, peak ground reaction forces (GRF) and loading rates were extracted. Subgroup analyses were conducted depending on whether participants were required to run to exhaustion. Thirty-six studies were included in the review, 25 were included in the meta-analysis. Leg stiffness decreased with running-induced fatigue (SMD -0.31, 95% CI -0.52, -0.08, moderate evidence). Exhaustive and non-exhaustive subgroups were different for peak tibial acceleration (Chi2 = 3.79, p = 0.05), with limited evidence from exhaustive subgroups showing an increase in peak tibial acceleration with fatigue. Findings for vertical GRF impact peak and peak braking force were conflicting based on exhaustive and non-exhaustive protocols (Chi2 = 3.83, p = 0.05 and Chi2 = 5.10, p = 0.02, respectively). Moderate evidence suggests leg stiffness during running decreases with fatigue. Given the non-linear relationship between leg stiffness and running economy, this may have implications for performance.

A Uranium(II) Arene Complex That Acts as a Uranium(I) Synthon.

Two-electron reduction of the amidate-supported U(III) mono(arene) complex U(TDA)3 (2) with KC8 yields the anionic bis(arene) complex [K[2.2.2]cryptand][U(TDA)2] (3) (TDA = N-(2,6-di-isopropylphenyl)pivalamido). EPR spectroscopy, magnetic susceptibility measurements, and calculations using DFT as well as multireference CASSCF methods all provide strong evidence that the electronic structure of 3 is best represented as a 5f4 U(II) metal center bound to a monoreduced arene ligand. Reactivity studies show 3 reacts as a U(I) synthon by behaving as a two-electron reductant toward I2 to form the dinuclear U(III)-U(III) triiodide species [K[2.2.2]cryptand][(UI(TDA)2)2(µ-I)] (6) and as a three-electron reductant toward cycloheptatriene (CHT) to form the U(IV) complex [K[2.2.2]cryptand][U(η7-C7H7)(TDA)2(THF)] (7). The reaction of 3 with cyclooctatetraene (COT) generates a mixture of the U(III) anion [K[2.2.2]cryptand][U(TDA)4] (1-crypt) and U(COT)2, while the addition of COT to complex 2 instead yields the dinuclear U(IV)-U(IV) inverse sandwich complex [U(TDA)3]2(µ-η8:η3-C8H8) (8). Two-electron reduction of the homoleptic Th(IV) amidate complex Th(TDA)4 (4) with KC8 gives the mono(arene) complex [K[2.2.2]cryptand][Th(TDA)3(THF)] (5). The C-C bond lengths and torsion angles in the bound arene of 5 suggest a direduced arene bound to a Th(IV) metal center; this conclusion is supported by DFT calculations.

Life-Threatening Hemoptysis in a Pediatric Referral Center.

OBJECTIVES: Hemoptysis is uncommon in children, even among the critically ill, with a paucity of epidemiological data to inform clinical decision-making. We describe hemoptysis-associated ICU admissions, including those who were critically ill at hemoptysis onset or who became critically ill as a result of hemoptysis, and identify predictors of mortality. DESIGN: Retrospective cohort study. Demographics, hemoptysis location, and management were collected. Pediatric Logistic Organ Dysfunction-2 score within 24 hours of hemoptysis described illness severity. Primary outcome was inhospital mortality. SETTING: Quaternary pediatric referral center between July 1, 2010, and June 30, 2017. PATIENTS: Medical/surgical (PICU), cardiac ICU, and term neonatal ICU admissions with hemoptysis during or within 24 hours of ICU admission. INTERVENTIONS: No intervention. MEASUREMENTS AND MAIN RESULTS: There were 326 hemoptysis-associated ICU admissions in 300 patients. Most common diagnoses were cardiac (46%), infection (15%), bronchiectasis (10%), and neoplasm (7%). Demographics, interventions, and outcomes differed by diagnostic category. Overall, 79 patients (26%) died inhospital and 109 (36%) had died during follow-up (survivor mean 2.8 ± 1.9 yr). Neoplasm, bronchiectasis, renal dysfunction, inhospital hemoptysis onset, and higher Pediatric Logistic Organ Dysfunction-2 score were independent risk factors for inhospital mortality (p < 0.02). Pharmacotherapy (32%), blood products (29%), computerized tomography angiography (26%), bronchoscopy (44%), and cardiac catheterization (36%) were common. Targeted surgical interventions were rare. Of survivors, 15% were discharged with new respiratory support. Of the deaths, 93 (85%) occurred within 12 months of admission. For patients surviving 12 months, 5-year survival was 87% (95% CI, 78-92) and mortality risk remained only for those with neoplasm (log-rank p = 0.001). CONCLUSIONS: We observed high inhospital mortality from hemoptysis-associated ICU admissions. Mortality was independently associated with hemoptysis onset location, underlying diagnosis, and severity of critical illness at event. Additional mortality was observed in the 12-month posthospital discharge. Future directions include further characterization of this vulnerable population and management recommendations for life-threatening pediatric hemoptysis incorporating underlying disease pathophysiology.

Publisher Correction: Nanoscale percolation in doped BaZrO3 for high proton mobility.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Nanoscale percolation in doped BaZrO3 for high proton mobility.

Acceptor-doped barium zirconate is a promising proton-conducting oxide for various applications, for example, electrolysers, fuel cells or methane-conversion cells. Despite many experimental and theoretical investigations there is, however, only a limited understanding as to how to connect the complex microscopic proton motion and the macroscopic proton conductivity for the full range of acceptor levels, from diluted acceptors to concentrated solid solutions. Here we show that a combination of density functional theory calculations and kinetic Monte Carlo simulations enables this connection. At low concentrations, acceptors trap protons, which results in a decrease of the average proton mobility. With increasing concentration, however, acceptors form nanoscale percolation pathways with low proton migration energies, which leads to a strong increase of the proton mobility and conductivity. Comparing our simulated proton conductivities with experimental values for yttrium-doped barium zirconate yields excellent agreement. We then predict that ordered dopant structures would not only strongly enhance the proton conductivities, but would also enable one- or two-dimensional proton conduction in barium zirconate. Finally, we show how the properties of other dopants influence the proton conductivity.

A Diverse Array of C-C Bonds Formed at a Tantalum Metal Center.

We demonstrate the formation of a diverse array of organic and organometallic products containing newly formed C-C bonds via successive methyl transfers from di-, tri-, and tetramethyl Ta(V) precursors to unsaturated small molecule substrates under mild conditions. The reactions of Ta(V) methyl complexes 1-X [H2B(MesIm)2]TaMe3X (X = Me, Cl; Im = imidazole, Mes = 2,4,6-trimethylphenyl) with CO led to oxo enolate Ta(V) products, in which the enolate ligands were constructed from Ta-Me groups and two equivalents of CO. Similarly, the reaction of 1-Me with CNXyl yielded an imido enamine Ta(V) product. Surprisingly, 1-Cl reacted with CNXyl (1 equiv) at the borate backbone of the [H2B(MesIm)2] ligand with concomitant methyl transfer from the metal center to form a new, dianionic scorpionate ligand that supported a Ta(V) dimethyl chloro complex (6). Treatment of 1-Cl with further CNXyl led to an azaallyl scorpionate complex, and an imido isocyanide scorpionate complex, along with propene and xylyl ketenimine. Complex 6 reacted with CO to yield a pinacol scorpionate complex 10-a new reaction pathway in early transition metal chemistry. Mechanistic studies revealed that this proceeded via migratory insertion of CO into a Ta-Me group, followed by methyl transfer to form an η2-acetone intermediate. Elimination of acetone furnished a CO-stabilized Ta(III) intermediate capable of rebinding and subsequently coupling two equivalents of CO-derived acetone to form the pinacol ligand in 10.

Amidinate Supporting Ligands Influence Molecularity in Formation of Uranium Nitrides.

Uranium nitride complexes are attractive targets for chemists as molecular models for the bonding, reactivity, and magnetic properties of next-generation nuclear fuels, but these molecules are uncommon and can be difficult to isolate due to their high reactivity. Here, we describe the synthesis of three new multinuclear uranium nitride complexes, [U(BCMA)2]2(µ-N)(µ-κ1:κ1-BCMA) (7), [(U(BIMA)2)2(µ-N)(µ-NiPr)(K2(µ-η3:η3-CH2CHNiPr)]2 (8), and [U(BIMA)2]2(µ-N)(µ-κ1:κ1-BIMA) (9) (BCMA = N,N-bis(cyclohexyl)methylamidinate, BIMA = N,N-bis(iso-propyl)methylamidinate), from U(III) and U(IV) amidinate precursors. By varying the amidinate ligand substituents and azide source, we were able to influence the composition and size of these nitride complexes. 15N isotopic labeling experiments confirmed the bridging nitride moieties in 7-9 were formed via two-electron reduction of azide. The tetra-uranium cluster 8 was isolated in 99% yield via reductive cleavage of the amidinate ligands; this unusual molecule contains nitrogen-based ligands with formal 1-, 2-, and 3- charges. Additionally, chemical oxidation of the U(IV) precursor U(N3)(BCMA)3 yielded the cationic U(V) species [U(N3)(BCMA)3][OTf]. Magnetic susceptibility measurements confirmed a U(IV) oxidation state for the uranium centers in the three nitride-bridged complexes and provided a comparison of magnetic behavior in the structurally related U(III)-U(IV)-U(V) series U(BCMA)3, U(N3)(BCMA)3, and [U(N3)(BCMA)3][OTf]. At 240 K, the magnetic moments in this series decreased with increasing oxidation state, i.e., U(III) > U(IV) > U(V); this trend follows the decreasing number of 5f valence electrons along this series.

The use of accelerometer-based wearable activity monitors in clinical settings: current practice, barriers, enablers, and future opportunities.

BACKGROUND: Wearable activity monitors (WAMs, e.g. Fitbits and research accelerometers) show promise for helping health care professionals (HCPs) measure and intervene on patients' activity patterns. This study aimed to describe the clinical use of WAMs within South Australia, barriers and enablers, and future opportunities for large-scale clinical use. METHODS: A descriptive qualitative study was undertaken using semi-structured interviews. Participants were HCPs with experience using WAMs in South Australian clinical settings. Commencing with participants identified through the research team's professional networks, snowball recruitment continued until all identified eligible HCPs had been invited. Semi-structured interviews were used to explore the research aims, with quantitative data analysed descriptively, and qualitative data analysed thematically. RESULTS: 18 participants (physiotherapists n = 8, exercise physiologists n = 6, medical consultants n = 2, and research personnel recommended by medical consultants n = 2), represented 12 discrete "hubs" of WAM use in clinical practice, spanning rehabilitation, orthopaedics, geriatrics, intensive care, and various inpatient-, outpatient-, community-based hospital and private-practice settings. Across the 12 hubs, five primarily used Fitbits® (various models), four used research-grade accelerometers (e.g. GENEActiv, ActivPAL and StepWatch accelerometers), one used Whoop Bands® and another used smartphone-based step counters. In three hubs, WAMs were used to observe natural activity levels without intervention, while in nine they were used to increase (i.e. intervene on) activity. Device selection was typically based on ease of availability (e.g. devices borrowed from another department) and cost-economy (e.g. Fitbits® are relatively affordable compared with research-grade devices). Enablers included device characteristics (e.g. accuracy, long battery life, simple metrics such as step count) and patient characteristics (e.g. motivation, rehabilitation population, tech-savvy), whilst barriers included the HCPs' time to download and interpret the data, multidisciplinary team attitudes and lack of protocols for managing the devices. CONCLUSIONS: At present, the use of WAMs in clinical practice appears to be fragmented and ad hoc, though holds promise for understanding patient outcomes and enhancing therapy. Future work may focus on developing protocols for optimal use, system-level approaches, and generating cost-benefit data to underpin continued health service funding for ongoing/wide-spread WAM use.

Electronic Structures of Rhenium(II) ß-Diketiminates Probed by EPR Spectroscopy: Direct Comparison of an Acceptor-Free Complex to Its Dinitrogen, Isocyanide, and Carbon Monoxide Adducts.

Electron paramagnetic resonance (EPR) studies of the rhenium(II) complex Re(η5-Cp)(BDI) (1; BDI = N,N'-bis(2,6-diisopropylphenyl)-3,5-dimethyl-ß-diketiminate) have revealed that this species reversibly binds N2 in solution: flash frozen toluene solutions of 1 disclose entirely different EPR spectra at 10 K when prepared under N2 versus Ar atmospheres. This observation was additionally verified by the synthesis of stable CO and 2,6-xylylisocyanide (XylNC) adducts of 1, which display EPR features akin to those observed in the putative N2 complex. While we found that 1 displays an extremely large gmax value of 3.99, the binding of an additional ligand leads to substantial decreases in this value, displaying gmax values of ca. 2.4. Following the generation of isotopically enriched 15N2 and 13CO adducts of 1, HYSCORE experiments allowed for the measurement of the corresponding hyperfine couplings associated with spin delocalization onto the electron-accepting ligands in these species, which proved to be small. A cumulative assessment of the EPR data, when combined with insights provided by near-infrared (NIR) spectroscopy and time-dependent density functional theory (TDDFT) calculations, indicated that while the binding of electron acceptors to 1 does lead to decreases in gmax in relative accord with the field strength (i.e., π-acidity) of the variable ligand, the magnitude of these decreases is primarily due to the changes in electronic structure at the Re center.

Reactivity of terminal imido complexes of group 4-6 metals: stoichiometric and catalytic reactions involving cycloaddition with unsaturated organic molecules.

Imido complexes of early transition metals are key intermediates in the synthesis of many nitrogen-containing organic compounds. The metal-nitrogen double bond of the imido moiety undergoes [2+2] cycloaddition reactions with various unsaturated organic molecules to form new nitrogen-carbon and nitrogen-heteroatom bonds. This review article focuses on reactivity of the terminal imido complexes of Group 4-6 metals, summarizing their stoichiometric reactions and catalytic applications for a variety of reactions including alkyne hydroamination, alkyne carboamination, pyrrole formation, imine metathesis, and condensation reactions of carbonyl compounds with isocyanates.