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This paper presents a study of coherent dynamic nuclear polarization (DNP) using frequency swept pulses at 94 GHz which optimize the polarization transfer efficiency. Accordingly, an enhancement ℇ∼496 was observed using 10mM trityl-OX063 as the polarizing agent in a standard d8-glycerol:D2O:H2O :: 6:3:1 glassing matrix at 70K. At present this is the largest DNP enhancement reported at this microwave frequency and temperature. Furthermore, the frequency swept pulses enhance the nuclear magnetic resonance (NMR) signal and reduce the recycle delay, accelerating the NMR signal acquisition.

Using the 1-(

This article explores how international audiences identify with Nordic noir, and The Bridge in particular, as a way of mediating complex identity discourses and the economics of social welfare. It will be suggested that, while the influence of Scandinavian culture on the United Kingdom can be framed as an idealistic touristic projection, the appeal of Nordic noir is more complicated. On the surface, it may seem to embody positional cultural consumption and middle-class privilege; however, it is also a barometer of anxiety about dark undercurrents in UK politics at a time of change and uncertainty. At the beginning of the time of writing (2020), Britain had yet to negotiate its future relationship with the European Union following the result of the 2016 Referendum: the intervening four years having seen a rise of right-wing populism in the United Kingdom and polarization over Brexit. Overshadowing this had been the presidency of Donald Trump in the United States and an ongoing migrant crisis emanating from the war in Syria. As one respondent, invoking Shakespeare’s Hamlet, stated: ‘There’s something rotten in the state of…’. Building on the work of Creeber, Robbins Nielsen, Waade, and Alexi, it will be argued that, far from being a unique dreamland, The Bridge is a symbol of both Diaspora (Bhaba) and postmodernity (Baudrillard), and that the popularity of Scandinavian noir with international audiences is concomitant to an awareness that their own worlds are less singular.

Structural, magnetic, and spectroscopic data on a Mn spin-crossover complex with Schiff base ligand 4-OMe-Sal 323, isolated in crystal lattices with five different counteranions, are reported. Complexes of [Mn(4-OMe-Sal 323)]X where X = ClO ( ), BF ( ), NO ( ), Br ( ), and I ( ) crystallize isotypically in the chiral orthorhombic space group 2 2 2 with a range of spin state preferences for the [Mn(4-OMe-Sal 323)] complex cation over the temperature range 5-300 K. Complexes and are high-spin, complex undergoes a gradual and complete thermal spin crossover, while complexes and show stepped crossovers with different ratios of spin triplet and quintet forms in the intermediate temperature range. High-field electron paramagnetic resonance was used to measure the zero-field splitting parameters associated with the spin triplet and quintet states at temperatures below 10 K for complexes and with respective values: = +23.38(1) cm , = +2.79(1) cm , and = +6.9(3) cm , with a distribution of parameters for the = 2 state. Solid-state circular dichroism (CD) spectra on high-spin complex at room temperature reveal a 2:1 ratio of enantiomers in the chiral conglomerate, and solution CD measurements on the same sample in methanol show that it is stable toward racemization. Solid-state UV-vis absorption spectra on high-spin complex and mixed = 1/ = 2 sample reveal different intensities at higher energies, in line with the different electronic composition. The statistical prevalence of homochiral crystallization of [Mn(4-OMe-Sal 323)] in five lattices with different achiral counterions suggests that the chirality may be directed by the 4-OMe-Sal 323 ligand.

Background Ischemia-reperfusion injury remains a major clinical problem in patients with ST-elevation myocardial infarction (STEMI), leading to myocardial damage despite early reperfusion by primary percutaneous coronary intervention (PPCI). There are no effective therapies to limit ischemia-reperfusion injury, which is caused by multiple pathways activated by rapid tissue reoxygenation and the generation of reactive oxygen species (ROS). FDY-5301 contains sodium iodide, a ubiquitous inorganic halide and elemental reducing agent that can act as a catalytic anti-peroxidant. We tested the feasibility, safety and potential utility of FDY-5301 as a treatment to limit ischemia-reperfusion injury, in patients with first-time STEMI undergoing emergency PPCI. Methods STEMI patients (n = 120, median 62 years) presenting within 12 h of chest pain onset were randomized at 20 PPCI centers, in a double blind Phase 2 clinical trial, to receive FDY-5301 (0.5, 1.0 or 2.0 mg/kg) or placebo prior to reperfusion, to evaluate the feasibility endpoints. Participants underwent continuous ECG monitoring for 14 days after PPCI to address pre-specified cardiac arrhythmia safety end points and cardiac magnetic resonance imaging (MRI) at 72 h and at 3 months to assess exploratory efficacy end points. Results Intravenous FDY-5301 was delivered before re-opening of the infarct-related artery in 97% participants and increased plasma iodide levels ~1000-fold within 2 min. There was no significant increase in the primary safety end point of incidence of cardiac arrhythmias of concern. MRI at 3 months revealed median final infarct sizes in placebo vs. 2.0 mg/kg FDY-5301-treated patients of 14.9% vs. 8.5%, and LV ejection fractions of 53.9% vs. 63.2%, respectively, although the study was not powered to detect statistical significance. In patients receiving FDY-5301, there was a significant reduction in the levels of MPO, MMP2 and NTproBNP after PPCI, but no reduction with placebo. Conclusions Intravenous FDY-5301, delivered immediately prior to PPCI in acute STEMI, is feasible, safe, and shows potential efficacy. A larger trial is justified to test the effects of FDY-5301 on acute ischemia-reperfusion injury and clinical outcomes. Clinical Trial Registration: CT.gov NCT03470441 ; EudraCT 2017-000047-41

Lumpfish is utilized as a cleaner fish to biocontrol sealice infestations in Atlantic salmon farms. Aeromonas salmonicida, a Gram-negative facultative intracellular pathogen, is the causative agent of furunculosis in several fish species, including lumpfish. In this study, lumpfish were intraperitoneally injected with different doses of A. salmonicida to calculate the LD50. Samples of blood, head-kidney, spleen, and liver were collected at different time points to determine the infection kinetics. We determined that A. salmonicida LD50 is 102 CFU per dose. We found that the lumpfish head-kidney is the primary target organ of A. salmonicida. Triplicate biological samples were collected from head-kidney, spleen, and liver pre-infection and at 3- and 10-days post-infection for RNA-sequencing. The reference genome-guided transcriptome assembly resulted in 6246 differentially expressed genes. The de novo assembly resulted in 403,204 transcripts, which added 1307 novel genes not identified by the reference genome-guided transcriptome. Differential gene expression and gene ontology enrichment analyses suggested that A. salmonicida induces lethal infection in lumpfish by uncontrolled and detrimental blood coagulation, complement activation, inflammation, DNA damage, suppression of the adaptive immune system, and prevention of cytoskeleton formation.

A combination of inelastic neutron scattering (INS), far-IR magneto-spectroscopy (FIRMS), and Raman magneto-spectroscopy (RaMS) has been used to comprehensively probe magnetic excitations in Co(AsPh

Association of single nucleotide polymorphisms in the IL-23 receptor with the several auto-inflammatory diseases, led to the heterodimeric receptor and its cytokine-ligand IL-23, becoming important drug targets. Successful antibody-based therapies directed against the cytokine have been licenced and a new class of small peptide antagonists of the receptor have entered clinical trials. These peptide antagonists may offer therapeutic advantages over existing anti-IL-23 therapies, but little is known about their molecular pharmacology. In this study, we use a fluorescent version of IL-23 to characterise antagonists of the full-length receptor expressed by living cells using a NanoBRET competition assay. We then develop a cyclic peptide fluorescent probe, specific to the IL23p19:IL23R interface and use this molecule to characterise further receptor antagonists. Finally, we use the assays to study the immunocompromising C115Y IL23R mutation, demonstrating that the mechanism of action is a disruption of the binding epitope for IL23p19.

Lumpfish is utilized as a cleaner fish to biocontrol sealice infestations in Atlantic salmon farms.

Endohedral metallofullerenes (EMFs) are excellent carriers of rare-earth element (REE) ions in biomedical applications because they preclude the release of toxic metal ions. However, existing approaches to synthesize water-soluble EMF derivatives yield mixtures that inhibit precise drug design. Here we report the synthesis of metallobuckytrio (MBT), a three-buckyball system, as a modular platform to develop structurally defined water-soluble EMF derivatives with ligands by choice. Demonstrated with PEG ligands, the resulting water-soluble MBTs show superb biocompatibility. The Gd MBTs exhibit superior T

Baird’s rule predicts that molecules with 4n π electrons should be aromatic in the triplet state, but the realization of simple ring systems with such an electronic ground state has been stymied by these molecules’ tendency to distort into structures bearing a large singlet–triplet gap. Here, we show that the elusive benzene diradical dianion can be stabilized through creation of a binucleating ligand that enforces a tightly constrained inverse sandwich structure and direct magnetic exchange coupling. Specifically, we report the compounds [K(18-crown-6)(THF)2]2[M2(BzN6-Mes)] (M = Y, Gd; BzN6-Mes = 1,3,5-tris[2′,6′-(N-mesityl)dimethanamino-4′-tert-butylphenyl]benzene), which feature a trigonal ligand that binds one trivalent metal ion on each face of a central benzene dianion. Antiferromagnetic exchange in the Gd3+ compound preferentially stabilizes the triplet state such that it becomes the molecular ground state. Single-crystal X-ray diffraction data and nucleus-independent chemical shift calculations support aromaticity, in agreement with Baird’s rule. Molecules with 4n π electrons should display Baird aromaticity in the triplet state, but isolation of ring systems with this electronic ground state is stymied by structural distortion. Now, a benzene diradical dianion has been stabilized by being held rigid in a binucleating ligand as well as through magnetic exchange; single-crystal X-ray diffraction data and NICS calculations support its ground-state Baird aromaticity.

Large separation of magnetic levels and slow relaxation in metal complexes are desirable properties of single-molecule magnets (SMMs). Spin-phonon coupling (interactions of magnetic levels with phonons) is ubiquitous, leading to magnetic relaxation and loss of memory in SMMs and quantum coherence in qubits. Direct observation of magnetic transitions and spin-phonon coupling in molecules is challenging. We have found that far-IR magnetic spectra (FIRMS) of Co(PPh3)2X2 (Co-X; X = Cl, Br, I) reveal rarely observed spin-phonon coupling as avoided crossings between magnetic and u-symmetry phonon transitions. Inelastic neutron scattering (INS) gives phonon spectra. Calculations using VASP and Phonopy programs gave phonon symmetries and movies. Magnetic transitions among zero-field split (ZFS) levels of the S = 3/2 electronic ground state were probed by INS, high-frequency and -field EPR (HFEPR), FIRMS, and frequency-domain FT terahertz EPR (FD-FT THz-EPR), giving magnetic excitation spectra and determining ZFS parameters (D, E) and g values. Ligand-field theory (LFT) was used to analyze earlier electronic absorption spectra and give calculated ZFS parameters matching those from the experiments. DFT calculations also gave spin densities in Co-X, showing that the larger Co(II) spin density in a molecule is, the larger its ZFS magnitude is. The current work reveals dynamics of magnetic and phonons excitations in SMMs. Studies of such couplings in the future would help understand how spin-phonon coupling may lead to magnetic relaxation and develop guidance to control such coupling.

Overhauser dynamic nuclear polarization (ODNP) NMR of solutions at high fields is usually mediated by scalar couplings that polarize the nuclei of heavier, electron-rich atoms. This leaves

BACKGROUND AND AIMS Penetrating ulcers and cellulitis of autogenous fistulae have become significant and common complications of haemodialysis access. Their presentation can be associated with exsanguinating haemorrhage or a severe septic picture—both endangering the access and the very life of the patient. Over a 12-year period, we have seen and treated over 70 patients requiring treatment of these types of difficult complications. METHOD There were 762 autogenous fistulae and 26 prosthetic grafts performed in the 11-year period for dialysis access. In this collection of patients, there were 76 patients who presented with severe complications of infection, bleeding ulcers, exsanguinating haemorrhage, exposed graft, or massive aneurysms. In order to apply some order to these diverse complications—they were divided into five groups. There were 12 patients and 16 procedures treated with interventional techniques of covered stent placement. There were 30 patients with 34 procedures who presented with bleeding, massive, or intermittent and were treated operatively urgently or emergently depending on their stability. A total of 23 patients were presented with ulcers on their autogenous fistula or aneurysmal dilatation of the autogenous fistula. There were 11 patients who presented with obvious and significant infection in autogenous or prosthetic grafts. There were 10 patients who presented with a prosthetic graft with persistent bleeding, an ulcer with penetration to the graft, or an exposed graft. RESULTS No patient was exsanguinated from these complications at the time of operative intervention. In reviewing the 12 patients treated with stents and interventional radiology, the range of time from the repair until death or occlusion of the graft ranged from 1–89 months and an average of 15 months. In the 30 patients who presented with bleeding—the individual patients who could be primarily repaired (20) had the best results. This entailed wide excision of the ulcer/bleeding site, repair of the vein, and a two-layer closure over the repaired vein. These patients were able to resume dialysis in 24-h through their repaired fistula. In reviewing the patients who presented with large ulcers on the fistula or aneurysm with no history of bleeding—these numbered 23 patients requiring 29 procedures. There were 13 patients who had a primary repair and excision of the ulcer and these had the best results. There were two patients with large aneurysmal Cimino fistulae who had a conversion to a mid-forearm fistula, excluding the massive aneurysm. A total of 11 patients presented with severe infection and cellulitis involving the dialysis access unresponsive to antibiotics. There were 4 patients with postoperative infections from autogenous fistula construction, and these were all treated with debridement and secondary closure. There were 10 patients with a prosthetic graft who presented with an ulcer, exposed graft, or a severe infection involving the dialysis graft. These were treated with secondary closure and irrigation. As to be expected the majority (60%) were functional for only 1–2 months. CONCLUSION The results of our study continue to affirm the use of autogenous fistula in the construction of dialysis access for those patients requiring long-term haemodialysis. In each of the five groups the best results, unequivocally, were found in those patients with an autogenous fistula repaired with autogenous tissue. The fact that these autogenous fistulae were in place for several years before requiring repair allowed their walls to become thickened and have a larger diameter. It is these two characteristics, which allowed the excision of the ulcerated/bleeding area to be excised and repaired. The size of the functioning fistula allowed the closure of the defect with no compromise of the lumen and the thickened vein walls allowed a good haemostatic closure. This study emphasizes the need for autogenous tissue for both construction and repair of haemodialysis access—whether it is for ulcers on the fistula, ulcers actively haemorrhaging, or infected fistula.

The metal-metal-bonded molecule [Bu4N][(HL)2Fe6(dmf)2] (Fe6) was previously shown to possess a thermally isolated spin S = 19/2 ground state and found to exhibit slow magnetization relaxation below a blocking temperature of ∼5 K [J. Am. Chem. Soc.2015, 137, 13949-13956]. Here, we present a comprehensive spectroscopic investigation of this unique single-molecule magnet (SMM), combining ultrawideband field-swept high-field electron paramagnetic resonance (EPR) with frequency-domain Fourier-transform terahertz EPR to accurately quantify the spin Hamiltonian parameters of Fe6. Of particular importance is the near absence of a 4th-order axial zero-field splitting term, which is known to arise because of quantum mechanical mixing of spin states on account of the relatively weak spin-spin (superexchange) interactions in traditional polynuclear SMMs such as the celebrated Mn12-acetate. The combined high-resolution measurements on both powder samples and an oriented single crystal provide a quantitative measure of the isolated nature of the spin ground state in the Fe6 molecule, as well as additional microscopic insights into factors that govern the quantum tunneling of its magnetization. This work suggests strategies for improving the performance of polynuclear SMMs featuring direct metal-metal bonds and strong ferromagnetic spin-spin (exchange) interactions.

NEW FINDINGS What is the central question of this study? The pathophysiology of acute mountain sickness (AMS), involving the respiratory, renal and cerebrovascular systems, remains poorly understood. How do the early adaptations in these systems during a simulated altitude of 5000 m relate to AMS risk? What is the main finding and its importance? The rate of blood alkalosis and cerebral artery dilatation predict AMS severity during the first 10 h of exposure to a simulated altitude of 5000 m. Slow metabolic compensation by the kidneys of respiratory alkalosis attributable to a brisk breathing response together with excessive brain blood vessel dilatation might be involved in early development of AMS. ABSTRACT The complex pathophysiology of acute mountain sickness (AMS) remains poorly understood and is likely to involve maladaptive responses of the respiratory, renal and cerebrovascular systems to hypoxia. Using stepwise linear regression, we tested the hypothesis that exacerbated respiratory alkalosis, as a result of a brisk ventilatory response, sluggish renal compensation in acute hypoxia and dysregulation of cerebral perfusion predict AMS severity. We assessed the Lake Louise score (LLS, an index of AMS severity), fluid balance, ventilation, venous pH, bicarbonate, sodium and creatinine concentrations, body weight, urinary pH and cerebral blood flow [internal carotid artery (ICA) and vertebral artery (VA) blood flow and diameter], in 27 healthy individuals (13 women) throughout 10 h exposures to normobaric normoxia (fraction of inspired O2 = 0.21) and normobaric hypoxia (fraction of inspired O2 = 0.117, simulated 5000 m) in a randomized, single-blinded manner. In comparison to normoxia, hypoxia increased the LLS, ventilation, venous and urinary pH, and blood flow and diameter in the ICA and VA, while venous concentrations of both bicarbonate and creatinine were decreased (P

A pair of bimetallic compounds featuring Fe-Fe bonds, [Fe(iPrNPPh2)3FeR] (R = PMe3, ≡NtBu), have been investigated using High-Frequency Electron Paramagnetic Resonance (HFEPR) as well as field- and temperature-dependent 57Fe nuclear γ resonance (Mossbauer) spectroscopy. To gain insight into the local site electronic structure, we have concurrently studied a compound containing a single Fe(II) in a geometry analogous to that of one of the dimer sites. Our spectroscopic studies have allowed for the assessment of the electronic structure via the determination of the zero-field splitting and 57Fe hyperfine parameters for the entire series. We also report on our efforts to correlate structure with physical properties in metal-metal bonded systems using ligand field theory guided by quantum chemical calculations. Through the insight gained in this study, we discuss strategies for the design of single-molecule magnets based on polymetallic compounds linked via direct metal-metal bonds.

Background We developed a biomarker algorithm encompassing the clinical chemistry score (CCS; which includes the combination of a random glucose concentration, an estimated glomerular filtration rate and high-sensitivity cardiac troponin; hs-cTn) with the Ortho Clinical Diagnostics hs-cTnI assay (CCS-serial) and compared it to the cutoffs derived from Ortho Clinical Diagnostics 0/1 h (h) algorithm for 7-day myocardial infarction (MI) or cardiovascular (CV)-death. Methods The study cohort was an emergency department (ED) population (n = 906) with symptoms suggestive of acute coronary syndrome (ACS) who had two Ortho hs-cTnI results approximately 3 h apart. Diagnostic parameters (sensitivity/specificity/negative predictive value; NPV/positive predictive value; PPV) were derived for the CCS-serial and the 0/1 h algorithm for 7-day MI/CV-death. A safety analysis was performed for patients in the rule-out arms of the algorithms for 30-day MI/death. Results The CCS-serial algorithm yielded 100% sensitivity/NPV (32% low-risk) and 95.7% specificity/65% PPV (11% high-risk). The 0/1 h algorithm-cutoffs yielded sensitivity/NPV/specificity/PPV of 97.8%/99.4%/91.3%/50%, which classified 38% of patients as low-risk and 16% of patients as high-risk. Four patients (1.2%) in the 0/1 h algorithm-cutoff rule-out arm had a 30-day MI/death outcome as compared to zero patients in the CCS-serial rule-out arm (p = 0.06). Conclusion Both the CCS-serial and 0/1 h algorithm cutoffs yield high NPVs with a similar proportion of patients identified as low-risk. These data may be useful for sites who are unable to collect samples at 0/1 h in the emergency department.

Objectives Cystic fibrosis (CF) is a debilitating genetic disorder that benefits from early detection. CF diagnosis relies on measuring elevated sweat chloride that is difficult in neonates with low sweat rates. We introduce a new method for sweat chloride determination from volume-limited specimens, and explore the potential utility of sweat bicarbonate in neonatal CF screening. Methods A rapid assay ( 5 min) was developed to analyze chloride and bicarbonate using capillary electrophoresis with indirect UV detection (CE-iUV). Pilocarpine-stimulated sweat samples from screen-positive CF infants were collected at two hospital sites, including confirmed CF (n = 12), CF screen-positive inconclusive diagnosis (n = 4), and unaffected non-CF cases (n = 37). All sweat chloride samples were analyzed by a coulometric titrator and CE-iUV, and the viability to measure acid-labile bicarbonate was also evaluated. Results Stability studies revealed that bicarbonate can be reliably assessed in sweat if acidification and heating were avoided. Method validation demonstrated that sweat chloride and bicarbonate were quantified with acceptable accuracy (recovery of 102%), precision (CV = 3.7%) and detection limits (∼ 0.1 mM). An inter-laboratory comparison confirmed a mean bias of 6.5% (n = 53) for sweat chloride determination by CE-iUV relative to a commercial chloridometer. However, sweat bicarbonate did not discriminate between CF and non-CF infants (AUC = 0.623, p = 0.215) unlike chloride (AUC = 1.00, p = 3.00 × 10

Structural, magnetic, and spectroscopic data on a Mn

We present an extensive study of tetranuclear transition-metal cluster compounds M4(NPtBu3)4 and [M4(NPtBu3)4][B(C6F5)4] (M = Ni, Cu; tBu = tert-butyl), which feature low-coordinate metal centers and direct metal-metal orbital overlap. X-ray diffraction, electrochemical, magnetic, spectroscopic, and computational analysis elucidate the nature of the bonding interactions in these clusters and the impact of these interactions on the electronic and magnetic properties. Direct orbital overlap results in strongly coupled, large-spin ground states in the [Ni4(NPtBu3)4]+/0 clusters and fully delocalized, spin-correlated electrons. Correlated electronic structure calculations confirm the presence of ferromagnetic ground states that arise from direct exchange between magnetic orbitals, and, in the case of the neutral cluster, itinerant electron magnetism similar to that in metallic ferromagnets. The cationic nickel cluster also possesses large magnetic anisotropy exemplified by a large, positive axial zero-field splitting parameter of D = +7.95 or +9.2 cm-1, as determined by magnetometry or electron paramagnetic resonance spectroscopy, respectively. The [Ni4(NPtBu3)4]+ cluster is also the first molecule with easy-plane magnetic anisotropy to exhibit zero-field slow magnetic relaxation, and under a small applied field, it exhibits relaxation exclusively through an Orbach mechanism with a spin relaxation barrier of 16 cm-1. The S = 1/2 complex [Cu4(NPtBu3)4]+ exhibits slow magnetic relaxation via a Raman process on the millisecond time scale, supporting the presence of slow relaxation via an Orbach process in the nickel analogue. Overall, this work highlights the unique electronic and magnetic properties that can be realized in metal clusters featuring direct metal-metal orbital interactions between low-coordinate metal centers.

From global food security to textile production and biofuels, the demands currently made on plant photosynthetic productivity will continue to increase. Enhancing photosynthesis using designer, green and sustainable materials offers an attractive alternative to current genetic-based strategies and promising work with nanomaterials has recently started to emerge. Here we describe the in planta use of carbon-based nanoparticles produced by low-cost renewable routes that are bioavailable to mature plants. Uptake of these functionalised nanoparticles directly from the soil improves photosynthesis and also increases crop production. We show for the first time that glucose functionalisation enhances nanoparticle uptake, photoprotection and pigment production, unlocking enhanced yields. This was demonstrated in Triticum aestivum 'Apogee' (dwarf bread wheat) and resulted in an 18% increase in grain yield. This establishes the viability of a functional nanomaterial to augment photosynthesis as a route to increased crop productivity.

A series of trans-dicyanide vanadium(III) compounds based on acetylacetonate, (PPN)[VIII(acac)2(CN)2]·(PPN)Cl·2MeCN (1), and salen ligands, (Et4N)[VIII(salen)(CN)2] (2a), (PPN)[VIII(MeOsalen)(CN)2]·DMF·2MeCN (3), and (PPN)[VIII(salphen)(CN)2]·DMF (4) [salen = N,N'-ethylenebis(salicyl-imine), MeOsalen = N,N'-ethylenebis(methoxysalicylimine), salphen = N,N'-phenylenebis(salicyl-imine), and PPN = bis(triphenylphosphine)iminium], were prepared and structurally characterized. High-field EPR studies reveal that the complexes exhibit moderate magnetic anisotropy with positive D values of +5.70, +3.80, +4.05, and +3.99 cm-1 for 1-4, respectively.

Reactions involving reductive aggregation of MnO4- in methanol in the presence of CeIV and an excess of carboxylic acid have led to the synthesis of structurally related Ce/Mn clusters, [Ce3Mn5O8(OMe)(O2CBut)13(MeOH)] (1) and [Ce2Mn3O5(O2CPh)9(MeOH)3] (2), containing at least one {Mn2Ce2O4} cubane unit. The cores of both clusters contain Mnx units separated by three (1) or two (2) CeIV ions. Fits of variable-temperature, solid-state dc and ac magnetic susceptibility data reveal dominant ferromagnetic interactions within 1 and 2, resulting in the maximum S = 17/2 and S = 5 ground state spins, respectively, and thus suggesting significant ferromagnetic (F) interactions between the Mnx units that are ≥6 A apart and separated by four intervening bonds through diamagnetic CeIV. Fits of magnetic susceptibility data also revealed unusual long-range F interactions, and this finding was further supported by high-field EPR measurements and simulations. Density functional theory calculations and a Wannier function analysis confirm long-range interactions and indicate a Mn-Ce-Mn superexchange pathway via Mn-d/Ce-f orbital overlap/hybridization.

We report a new series of homoleptic Ni(I) bis-N-heterocyclic carbene complexes with a range of torsion angles between the two ligands from 68° to 90°. Electron paramagnetic resonance measurements revealed a strongly anisotropic g-tensor in all complexes with a small variation in g∥ ∼5.7-5.9 and g⊥ ∼0.6. The energy of the first excited state identified by variable-field far-infrared magnetic spectroscopy and SOC-CASSCF/NEVPT2 calculations is in the range 270-650 cm-1. Magnetic relaxation measured by alternating current susceptibility up to 10 K is dominated by Raman and direct processes. Ab initio ligand-field analysis reveals that a torsion angle of

We report a new series of homoleptic Ni(I) bis-N-heterocyclic carbene complexes with a range of torsion angles between the two ligands from 68° to 90°. Electron paramagnetic resonance measurements revealed a strongly anisotropic

Vibronic coupling, the interaction between molecular vibrations and electronic states, is a pervasive effect that profoundly affects chemical processes. In the case of molecular magnetic materials, vibronic, or spin-phonon, coupling leads to magnetic relaxation, which equates to loss of magnetic memory and loss of phase coherence in molecular magnets and qubits, respectively. The study of vibronic coupling is challenging, and most experimental evidence is indirect. Here we employ far-infrared magnetospectroscopy to probe vibronic transitions in in [Yb(trensal)] (where H3trensal = 2,2,2-tris(salicylideneimino)trimethylamine). We find intense signals near electronic states, which we show arise due to an “envelope effect” in the vibronic coupling Hamiltonian, and we calculate the vibronic coupling fully ab initio to simulate the spectra. We subsequently show that vibronic coupling is strongest for vibrational modes that simultaneously distort the first coordination sphere and break the C3 symmetry of the molecule. With this knowledge, vibrational modes could be identified and engineered to shift their energy towards or away from particular electronic states to alter their impact. Hence, these findings provide new insights towards developing general guidelines for the control of vibronic coupling in molecules.

Research on declines in loon populations at Squam Lake, New Hampshire, U.S.A., point to multiple potential causes since 2005, including dichlorodiphenyltrichloroethane (DDT). This study narrows down sources of DDT in a small sub-watershed by focusing mainly on collecting and analyzing soil and sediment samples, achieving rapid source area determination of DDT. We find presence of p,p’ isomers of DDT and DDE in the Bennett Brook sub-watershed arising from long-term soil and sediment storage of applications 60 years ago, plus a concentrated and current source area at a former barn. Highest concentrations, 723 μg/kg p,p’-DDT and 721 μg/kg p,p’-DDE, occur in the soils adjacent to the barn’s foundation remnants. DDT exceeds that of the metabolite, DDE, in many soils around Bennett Brook, including but not limited to the barn site. In soils where DDT>DDE, we infer mechanisms that delayed breakdown of DDT over the last 60 years. A Pb-210 dated lake sediment core, collected near the outlet of Bennet Brook, shows continuous accumulation of p,p’-DDE and p,p-DDD after 1951. These residuals likely derived from multiple sources within the sub-watershed, including orchard soils, the barn site, and from mobilized sediment deposits following extreme floods in the watershed. Although the DDT residues fall below mandatory soil remediation levels for the State of New Hampshire, Bennett Brook sediments exceed sediment quality guidelines for protection of aquatic life. Crayfish collected in Bennett Brook have significantly higher concentrations of p,p’-DDE than crayfish collected elsewhere in Squam Lake.