Ionic Conductivity of a Lithium-Doped Deep Eutectic Solvent: Glass Formation and Rotation-Translation Coupling

Deep eutectic solvents with admixed lithium salts are considered as electrolytes in electrochemical devices, such as batteries or supercapacitors. Compared to eutectic mixtures of hydrogen-bond donors and lithium salts, their raw-material costs are significantly lower. Not much is known about glassy freezing and rotational-translation coupling of such systems. Here, we investigate these phenomena by applying dielectric spectroscopy to the widely studied deep eutectic solvent glyceline, to which 1 and 5 mol % LiCl were added. Our study covers a wide temperature range, including a deeply supercooled state. The temperature dependences of the detected dipolar reorientation dynamics and ionic direct current (dc) conductivity reveal the signatures of glassy freezing. In comparison to pure glyceline, the lithium admixture leads to a reduction of ionic conductivity, which is accompanied by a reduction of the rotational dipolar mobility. However, this reduction is much smaller than that for deep eutectic solvents (DESs), where one main component is lithium salt, which we trace back to the lower glass-transition temperatures of lithium-doped DESs. In contrast to pure glyceline, the ionic and dipolar dynamics become increasingly decoupled at low temperatures and obey a fractional Debye-Stokes-Einstein relation, as previously found in other glass-forming liquids. The obtained results demonstrate the relevance of decoupling effects and glass transition to the enhancement of the technically relevant ionic conductivity in such lithium-doped DESs.

Rational Design of a Phosphorus-Centered Disbiradical

Phosphorus-centered disbiradicals, in which the radical sites exist as individual spin doublets with weak spin-spin interaction have not been known so far. Starting from monoradicals of the type [⋅P(μ-NTer)2 P-R], we have now succeeded in linking two such monoradical phosphorus centers by appropriate choice of a linker. To this end, biradical [⋅P(μ-NTer)2 P⋅] (1) was treated with 1,6-dibromohexane, affording the brominated species {Br[P(μ-NTer)]2 }2 C6 H12 (3). Subsequent reduction with KC8 led to the formation of the disbiradical {⋅[P(μ-NTer)]2 }2 C6 H12 (4) featuring a large distance between the radical phosphorus sites in the solid state and formally the highest biradical character observed in a P-centered biradical so far, approaching 100 %. EPR spectroscopy revealed a three-line signal in solution with a considerably larger exchange interaction than would be expected from the molecular structure of the single crystal. Quantum chemical calculations revealed a highly dynamic conformational space; thus, the two radical sites can approach each other with a much smaller distance in solution. Further reduction of 4 resulted in the formation of a potassium salt featuring the first structurally characterized P-centered distonic radical anion (5- ). Moreover, 4 could be used in small molecule activation.

Translational and reorientational dynamics in carboxylic acid-based deep eutectic solvents

The glass formation and the dipolar reorientational motions in deep eutectic solvents (DESs) are frequently overlooked, despite their crucial role in defining the room-temperature physiochemical properties. To understand the effects of these dynamics on the ionic conductivity and their relation to the mechanical properties of the DES, we conducted broadband dielectric and rheological spectroscopy over a wide temperature range on three well-established carboxylic acid-based natural DESs. These are the eutectic mixtures of choline chloride with oxalic acid (oxaline), malonic acid (maline), and phenylacetic acid (phenylaceline). In all three DESs, we observe signs of a glass transition in the temperature dependence of their dipolar reorientational and structural dynamics, as well as varying degrees of motional decoupling between the different observed dynamics. Maline and oxaline display a breaking of the Walden rule near the glass-transition temperature, while the relation between the dc conductivity and dipolar relaxation time in both maline and phenylaceline is best described by a power law. The glass-forming properties of the investigated systems not only govern the orientational dipolar motions and rheological properties, which are of interest from a fundamental point of view, but they also affect the dc conductivity, even at room temperature, which is of high technical relevance.

Rotational dynamics, ionic conductivity, and glass formation in a ZnCl2-based deep eutectic solvent

Glass formation and reorientational motions are widespread but often-neglected features of deep eutectic solvents although both can be relevant for the technically important ionic conductivity at room temperature. Here, we investigate these properties for two mixtures of ethylene glycol and ZnCl2, which were recently considered superior electrolyte materials for application in zinc-ion batteries. For this purpose, we employed dielectric spectroscopy performed in a broad temperature range, extending from the supercooled state at low temperatures up to the liquid phase around room temperature and beyond. We find evidence for a relaxation process arising from dipolar reorientation dynamics, which reveals the clear signatures of glassy freezing. This freezing also governs the temperature dependence of the ionic dc conductivity. We compare the obtained results with those for deep eutectic solvents that are formed by the same hydrogen-bond donor, ethylene glycol, but by two different salts, choline chloride and lithium triflate. The four materials reveal significantly different ionic and reorientational dynamics. Moreover, we find varying degrees of decoupling of rotational dipolar and translational ionic motions, which can partly be described by a fractional Debye-Stokes-Einstein relation. The typical glass-forming properties of these solvents strongly affect their room-temperature conductivity.

A highly versatile biopolymer-based platform for the maturation of human pluripotent stem cell-derived cardiomyocytes enables functional analysis in vitro and 3D printing of heart patches

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) represent a valuable tool for in vitro modeling of the cardiac niche and possess great potential in tissue engineering applications. However, conventional polystyrene-based cell culture substrates have adverse effects on cardiomyocytes in vitro due to the stress applied by a stiff substrate on contractile cells. Ultra-high viscosity alginates offer a unique versatility as tunable substrates for cardiac cell cultures due to their biocompatibility, flexible biofunctionalization, and stability. In this work, we analyzed the effect of alginate substrates on hPSC-CM maturity and functionality. Alginate substrates in high-throughput compatible culture formats fostered a more mature gene expression and enabled the simultaneous assessment of chronotropic and inotropic effects upon beta-adrenergic stimulation. Furthermore, we produced 3D-printed alginate scaffolds with differing mechanical properties and plated hPSC-CMs on the surface of these to create Heart Patches for tissue engineering applications. These exhibited synchronous macro-contractions in concert with more mature gene expression patterns and extensive intracellular alignment of sarcomeric structures. In conclusion, the combination of biofunctionalized alginates and human cardiomyocytes represents a valuable tool for both in vitro modeling and regenerative medicine, due to its beneficial effects on cardiomyocyte physiology, the possibility to analyze cardiac contractility, and its applicability as Heart Patches.

Heteroatom-Based Diradical(oid)s

Heteroatom-centered diradical(oid)s have been in the focus of molecular main group chemistry for nearly 30 years. During this time, the diradical concept has evolved and the focus has shifted to the rational design of diradical(oid)s for specific applications. This review article begins with some important theoretical considerations of the diradical and tetraradical concept. Based on these theoretical considerations, the design of diradical(oid)s in terms of ligand choice, steric, symmetry, electronic situation, element choice, and reactivity is highlighted with examples. In particular, heteroatom-centered diradical reactions are discussed and compared with closed-shell reactions such as pericyclic additions. The comparison between closed-shell reactivity, which proceeds in a concerted manner, and open-shell reactivity, which proceeds in a stepwise fashion, along with considerations of diradical(oid) design, provides a rational understanding of this interesting and unusual class of compounds. The application of diradical(oid)s, for example in small molecule activation or as molecular switches, is also highlighted. The final part of this review begins with application-related details of the spectroscopy of diradical(oid)s, followed by an update of the heteroatom-centered diradical(oid)s and tetraradical(oid)s published in the last 10 years since 2013.

Rational Design of Persistent Phosphorus-Centered Singlet Tetraradicals and Their Use in Small-Molecule Activation

Biradicals are important intermediates in the process of bond formation and breaking. While main-group-element-centered biradicals have been thoroughly studied, much less is known about tetraradicals, as their very low stability has hampered their isolation and use in small-molecule activation. Herein, we describe the search for persistent phosphorus-centered tetraradicals. Starting from an s-hydrindacenyl skeleton, we investigated the introduction of four phosphorus-based radical sites linked by an N-R unit and bridged by a benzene moiety. By varying the size of the substituent R, we finally succeeded in isolating a persistent P-centered singlet tetraradical, 2,6-diaza-1,3,5,7-tetraphospha-s-hydrindacene-1,3,5,7-tetrayl (1), in good yields. Furthermore, it was demonstrated that tetraradical 1 can be utilized for the activation of small molecules such as molecular hydrogen or alkynes. In addition to the synthesis of P-centered tetraradicals, the comparison with other known tetraradicals as well as biradicals is described on the basis of quantum mechanical calculations with respect to its multireference character, coupling of radical electrons, and aromaticity. The strong coupling of radical electrons enables selective discrimination between the first and the second activations of small molecules, which is shown by the example of H₂ addition. The mechanism of hydrogen addition is investigated with parahydrogen-induced hyperpolarization NMR studies and DFT calculations.

Synthesis of Stable Potassium Phosphinophosphides and Reaction with Organosilyl Halides and Chlorophosphanes

The synthesis of sterically demanding 2,6-bis(2,4,6-trimethylphenyl)phenyl (Ter)-stabilized and H-substituted diphosphanes TerHP-PR₂ (4a-4c) via conversion of the phosphide TerPHK (2) with secondary chlorophosphanes ClPR₂ (3a-3c, where R = iPr, Ph, and tBu, respectively) is described. The diphosphanes 4a-4c were deprotonated using KH in tetrahydrofuran, selectively yielding the potassium phosphinophosphides K[TerP-PR₂] (5a-5c). These phosphinophosphides are stable in solution as well as in the solid state and can be further functionalized via salt-metathesis reactions. Reaction with organosilyl halides selectively yields the silylated diphosphanes Ter(SiR¹₂R²)P-P(iPr)₂ (6a and 6b, where R¹ = R² = CH₃ and R¹ = CH₃, R² = Ph, respectively), whereas conversion with chlorophosphanes selectively yields the triphosphanes R¹₂P-P(Ter)-P(iPr)₂ (7a and 7b, where R = iPr and Ph, respectively).

On the Dynamic Behavior of Pacman Phosphanes─A Case of Cooperativity and Redox Isomerism

In solution, the Pacman chlorophosphane (2Cl) shows fast exchange of the endo/exo-orientation of the two P-Cl bonds in the molecule featuring cooperativity. Experimental and quantum mechanical investigations of the inversion on the phosphorus(III) centers reveal a crucial role of chloride ions in the dynamic process. To confirm the results, the homologous Pacman halogen-phosphanes 2X were prepared by halogen exchange reactions (X = F, Br, and I). Besides accelerated dynamic behavior for the heavier analogues, significant differences in the molecular structure are caused by the halogen exchange reactions, including the formation of an endo-endo substituted Pacman fluorophosphane as well as dicationic species by phosphorus halogen bond dissociation. The latter process can be regarded as redox isomerism since two P^III atoms in 2X become P^V centers in the dications.

Synthesis of benzene derivatives with multiple PCl2 groups

The chlorination of 1,2-diphosphinobenzene with PCl5 to 1,2-bis(dichlorophosphino)benzene (2) was performed with high yields (93%) despite the high number of P-H functions. The method was further applied to other phosphanes, enabling the first synthesis and complete characterization of 1,2,4-tris(dichlorophosphino)benzene (6) and 1,2,4,5-tetrakis(dichlorophosphino)benzene (7), valuable precursor e.g. for binuclear complexes, coordination polymers, organic wires, or metal organic frameworks.

Access to Benzo- and Naphtho-Azaphospholes via C-H Bond Activation of Aryl-Substituted Isonitriles

Differently substituted phenyl isonitriles (with C-H bonds in ortho-position) and naphthyl isonitriles were reacted with the cyclic biradical [•P(µ-N-Ter)2P•] (1). Insertion of the isonitrile formed a cyclic five-membered biradical [•P(NTer)2C(R)P•] (2R, R = phenyl, napthyl) in the first step, followed by C-H activation at the aryl substituent, resulting in novel azaphospholes (5R), which could be isolated and fully characterized. The formation of the azaphospholes can be prevented by the addition of a second equivalent of isonitrile, which causes the blocking of the radical centers in 2R by adduct formation (3R). Quantum mechanical calculations showed that a significant increase in the aromaticity of the benzo- and naphtho-azaphospholes is one of the driving forces for the activation process leading to the formation of thermodynamically favored azaphospholes. Targeted activation of C-H bonds using biradical systems represents a new synthetic approach to generate benzo- and naphtho-azaphospholes.

Hypomorphic RAG deficiency: impact of disease burden on survival and thymic recovery argues for early diagnosis and HSCT

Patients with hypomorphic mutations in the RAG1 or RAG2 gene present with either Omenn syndrome or atypical combined immunodeficiency with a wide phenotypic range. Hematopoietic stem cell transplantation (HSCT) is potentially curative, but data are scarce. We report on a worldwide cohort of 60 patients with hypomorphic RAG variants who underwent HSCT, 78% of whom experienced infections (29% active at HSCT), 72% had autoimmunity, and 18% had granulomas pretransplant. These complications are frequently associated with organ damage. Eight individuals (13%) were diagnosed by newborn screening or family history. HSCT was performed at a median of 3.4 years (range 0.3-42.9 years) from matched unrelated donors, matched sibling or matched family donors, or mismatched donors in 48%, 22%, and 30% of the patients, respectively. Grafts were T-cell depleted in 15 cases (25%). Overall survival at 1 and 4 years was 77.5% and 67.5% (median follow-up of 39 months). Infection was the main cause of death. In univariable analysis, active infection, organ damage pre-HSCT, T-cell depletion of the graft, and transplant from a mismatched family donor were predictive of worse outcome, whereas organ damage and T-cell depletion remained significant in multivariable analysis (hazard ratio [HR] = 6.01, HR = 8.46, respectively). All patients diagnosed by newborn screening or family history survived. Cumulative incidences of acute and chronic graft-versus-host disease were 35% and 22%, respectively. Cumulative incidences of new-onset autoimmunity was 15%. Immune reconstitution, particularly recovery of naïve CD4+ T cells, was faster and more robust in patients transplanted before 3.5 years of age, and without organ damage. These findings support the indication for early transplantation.

The BUrn Mortality Prediction (BUMP) Score - An improved mortality prediction score based on data of the German burn registry

BACKGROUND

Burn injuries constitute the fourth most common injuries globally. Patient outcomes must be currently assessed to provide appropriate patient care with high quality standards. However, existing mortality prediction scoring methods have been shown to lack accuracy in current burn patient populations. Therefore, this study aimed to validate existing scores using current patient data and assess whether new prediction parameters can provide better accuracy.

METHODS

A retrospective analysis of the patient data from the German Burn Registry between 2016 and 2019 was performed to evaluate all Abbreviated Burn Severity Index (ABSI) score parameters. All patients over 16 years of age who received intensive care were included. Descriptive statistics and logistic regression analysis were used to identify novel prediction parameters based on the parameters documented at admission and establish a new prediction score, the BUrn Mortality Prediction (BUMP) score. The quality of the new score was subsequently compared to that of the original ABSI, modified ABSI, Galeiras, Revised Baux score and TIMM. The new prediction score was then validated using patient data collected in the German Burn Registry in 2020.

RESULTS

In total, 7276 patients were included. Age; the presence of at least two comorbidities; burn injuries caused by work-related accidents, traffic accidents and suicide attempts; total burn surface area; inhalation trauma and full-thickness burns were identified as independent significant predictors of mortality (p < 0.001). Additionally, we evaluated new age groups to improve prediction accuracy. The number of comorbidities (p < 0.001) and the aetiology (burns occurring at work [p = 0.028], burns caused by traffic accidents [p < 0.001] or burns due to attempted suicide [p < 0.001]) had a significant influence on mortality. The BUMP score, which was developed based on these parameters, showed the best fitness and showed more accurate mortality prediction than all the above-mentioned scores (area under the receiver operating characteristic curve: 0.947 [0.939-0.954] compared to 0.926 [0.915-0.936], 0.928 [0.918-0.939], 0.937 [0.928-0.947], 0.939 [0.930-0.948], 0.940 [0.932-0.949] respectively).

CONCLUSIONS

A novel score (BUMP score) was developed for the purpose of external quality assessment of burn centres participating in the German burn registry, where observed and expected outcomes are compared on a hospital level, and for scientifically applications. The clinical impact of this score and its generalisability to other patient populations needs to be evaluated.

Aircraft noise exposure induces pro-inflammatory vascular conditioning and amplifies vascular dysfunction and impairment of cardiac function after myocardial infarction

AIMS

Traffic noise may play an important role in the development and deterioration of ischemic heart disease. Thus, we sought to determine the mechanisms of cardiovascular dysfunction and inflammation induced by aircraft noise in a mouse model of myocardial infarction (MI) and in humans with incident MI.

METHODS AND RESULTS

C57BL/6J mice were exposed to noise alone (average sound pressure level 72 dB; peak level 85 dB) up to 4d, resulting in pro-inflammatory aortic gene expression in the myeloid cell adhesion/diapedesis pathways. Noise alone promoted adhesion and infiltration of inflammatory myeloid cells in vascular/cardiac tissue, paralleled by an increased percentage of leukocytes with a pro-inflammatory, reactive oxygen species (ROS)-producing phenotype and augmented expression of Nox-2/phospho-NFκB in peripheral blood. Ligation of the LAD resulted in worsening of cardiac function, pronounced cardiac infiltration of CD11b+ myeloid cells and Ly6Chigh monocytes and induction of interleukin (IL) 6, IL-1β, CCL-2 and Nox-2, being aggravated by noise exposure prior to MI. MI induced stronger endothelial dysfunction and more pronounced increases in vascular ROS in animals preconditioned with noise. Participants of the population-based Gutenberg Health Cohort Study (median follow-up:11.4y) with incident MI revealed elevated CRP at baseline and worse LVEF after MI in case of a history of noise exposure and subsequent annoyance development.

CONCLUSION

Aircraft noise exposure before MI substantially amplifies subsequent cardiovascular inflammation and aggravates ischemic heart failure, facilitated by a pro-inflammatory vascular conditioning. Our translational results suggest, that measures to reduce environmental noise exposure will be helpful in improving clinical outcome of subjects with MI.

Coinage metal complexes of multidentate Pacman phosphane ligands

We present the extension of Pacman ligands to bidentate phosphane ligands enabling them to bind metals in their sterically protected cavity. The coordination of coinage metals shows the ability of...

Unmasking systolic impairment in HFpEF by cardiovascular magnetic resonance derived hemodynamic force assessment: insights from the HFpEF stress trial

Background

The diagnosis of heart failure with preserved ejection fraction (HFpEF) remains challenging. Exercise-stress testing is recommended in case of uncertainty; however, this approach is time-consuming and costly. Since preserved EF does not represent normal systolic function, we evaluated cardiovascular magnetic resonance (CMR) comprehensive cardiac hemodynamic forces (HDF) analyses for an in-depth characterisation of cardiac function at rest.

Methods

The HFpEF Stress Trial (DZHK-17) prospectively recruited 75 patients with exertional dyspnea, preserved EF (≥50%) and signs of diastolic dysfunction (E/e' ≥8) on echocardiography. Patients underwent right heart catheterisation, echocardiography and CMR. 68 patients entered the final study cohort (HFpEF n=34 and non-cardiac dyspnea n=34 according to pulmonary capillary wedge pressure (PCWP)). HDF assessment included left ventricular (LV) longitudinal, systolic peak and impulse, systolic/diastolic transition, E-wave deceleration as well as A-wave acceleration forces. Two patients were lost to 24 months follow-up evaluating cardiovascular mortality and hospitalisation (CVH).

Results

HDF assessment revealed impairment of LV longitudinal force in HFpEF (15.8 vs. 18.3, p=0.035) attributable to impairment of systolic peak (38.6 vs 51.6, p=0.003) and impulse (20.8 vs. 24.5, p=0.009) forces as well as late diastolic filling (−3.8 vs −5.4, p=0.029). Impairment of early diastolic filling could be observed in HFpEF patients identified at rest only but not stress (7.7 vs. 9.9, p=0.004). Impaired systolic peak was associated to CVH (HR 0.95, p=0.016) and superior for CVH prediction compared to LV global longitudinal strain (AUC 0.76 vs. 0.61, p=0.048).

Conclusions

Assessment of HDF reveals impairment of LV systolic and diastolic function in HFpEF. The value of systolic HDF assessment exceeded that of conventional deformation imaging for CVH prediction.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Centre for Cardiovascular Research

Impact of prediabetes and type 2 diabetes mellitus on cardiac function in the general population

Introduction

Prediabetes and type 2 diabetes mellitus (T2DM) are risk factors for heart failure (HF). The association of prediabetes and T2DM to different forms of functional left ventricular impairment and their impact on clinical outcome in the general population needs to be further investigated. In this context, little is known about the prevalences of prediabetes and different HF subtypes in the general population, especially in Europe.

Purpose

To investigate the prevalence and clinical impact of prediabetes and type 2 diabetes mellitus (T2DM) on functional cardiac disorder (FCD).

Methods

The participants of the Gutenberg Health Study sample (15,010 subjects, 35–74 years) were stratified in individuals with euglycaemia, prediabetes and T2DM based on clinical information and HbA1c level. FCD included asymptomatic systolic and diastolic dysfunction, symptomatic systolic and diastolic heart failure, asymptomatic diastolic dysfunction and preserved left ventricular ejection fraction (EF), asymptomatic diastolic dysfunction and reduced EF, asymptomatic preserved diastole and reduced EF, symptomatic heart failure with preserved EF (HFpEF) and symptomatic heart failure with reduced EF HFrEF). Using structured follow-up clinical outcome was assessed.

Results

Overall, 14,870 individuals were included in the present analysis. Among them, 9,426 individuals were categorized in the euglycaemia group, 4,128 participants had prediabetes and in 1,316 individuals T2DM was present. Prevalence of FCD increased from euglycaemia (19.6%) over prediabetes (33.3%) to T2DM (46.8%, p&lt;0.0001). Prevalence of symptomatic HF was increased in patients with T2DM (euglycaemia 2.8%, prediabetes 5.9%, T2DM 11.9%). T2DM was associated with reduced EF (β −0.63, 95% CI −0.99 to −0.26, P=0.00088) and elevated E/E' (β 0.08, 95% CI 0.06 to 0.10, P&lt;0.0001), whereas prediabetes was associated to elevated E/E' (β 0.02, 95% CI 0.01 to 0.03, P=0.0029). Prediabetes and T2DM revealed increased prevalences of FCD (13%, 18%), asymptomatic diastolic dysfunction with preserved EF (prediabetes: 14%, T2DM: 11%), symptomatic heart failure (prediabetes: 46%, T2DM: 70%) and HFpEF (prediabetes: 49%, T2DM: 82%). With prediabetes and T2DM all-cause mortality was elevated in presence and absence of FCD, only T2DM was also a risk factor for cardiovascular mortality with and without FCD. Within a 5-years follow-up, T2DM was an independent risk factor for the development of FCD, asymptomatic diastolic dysfunction with reduced ejection fraction, symptomatic heart failure and HFrEF. Prediabetes was not an independent risk factor for FCD.

Conclusions

In the general population, a high prevalence of asymptomatic FCD is present. Coexisting FCD and prediabetes as well as T2DM result in increased mortality elucidating the need for early detection and prevention of DM development, especially with regard to numerous asymptomatic people concerned. T2DM, but not prediabetes, is a risk factor for incident FCD.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): The Gutenberg Health Study is supported by the government of Rheinland-Pfalz (`Stiftung Rheinland-Pfalz für Innovation'), the research programmes `Wissen schafft Zukunft' and the Centre forTranslational Vascular Biology (CTVB) of the Johannes Gutenberg-University of Mainz, Germany, and its contract with Boehringer Ingelheim and Philips Medical Systems including an unrestricted grant forthe Gutenberg Health Study. P.S.W. and J.H.P. are funded by the Federal Ministry of Education and Research (BMBF 01EO1503). P.S.W. and T.M. are principal investigators of the German Center for Cardiovascular Research (DZHK). P.S.W. is principal investigator of the DIASyM research core (BMBF 161L0217A).

Main group cyanides: from hydrogen cyanide to cyanido-complexes

Homoleptic cyanide compounds exist of almost all main group elements. While the alkali metals and alkaline earth metals form cyanide salts, the cyanides of the lighter main group elements occur mainly as covalent compounds. This review gives an overview of the status quo of main group element cyanides and cyanido complexes. Information about syntheses are included as well as applications, special substance properties, bond lengths, spectroscopic characteristics and computations. Cyanide chemistry is presented mainly from the field of inorganic chemistry, but aspects of chemical biology and astrophysics are also discussed in relation to cyano compounds.

Concerted addition of aldehydes to the singlet biradical [P(μ-NTer)]2

The reaction of the singlet biradical [P(μ-NTer)]₂ with various aldehydes selectively yielded the corresponding [2.1.1]-bicyclic addition products in a very fast reaction. All products were fully characterized, including by NMR and vibrational spectroscopy as well as single-crystal X-ray diffraction. The mechanism of the addition was investigated theoretically using high-level ab initio methods (CCSD(T) with triple- and quadruple-zeta basis sets) and corresponds to a concerted cycloaddition reaction with a very low activation barrier. For comparison, the mechanisms of the literature-known cycloadditions of H₂, alkenes, and alkynes were also studied, indicating a similar reaction profile for all unsaturated reactants.

A Lewis Acid Stabilized Ketenimine in an Unusual Variant of the Electrophilic Aromatic Substitution

Electrophilic aromatic substitution (EAS) can provide a straightforward approach to the efficient synthesis of functionalized complex aromatic molecules. In general, Lewis acids serve as a beneficial stimulus for the formation of a Wheland complex, the intermediate in the classical S_E Ar mechanism of EAS, which is responsible for H/E (E=electrophile) substitution under formal H⁺ elimination. Herein, we report an unusual variant of EAS, in which a complex molecule such as the tricyanomethane, HC(CN)₃ , is activated with a strong Lewis acid (B(C₆ F₅ )₃ ) to the point where it can finally be used in an EAS. However, the Lewis acid here causes the isomerization of the tricyanomethane to the ketenimine, HN=C=C(CN)₂ , which in turn directly attacks the aromatic species in the EAS, with simultaneous proton migration of the aromatic proton to the imino group, so that no elimination occurs that is otherwise observed in the S_E Ar mechanism. By this method, it is possible to build up amino-malononitrile-substituted aromatic compounds in one step.

Radical Reactivity of the Biradical [⋅P(μ-NTer)2 P⋅] and Isolation of a Persistent Phosphorus-Cantered Monoradical [⋅P(μ-NTer)2 P-Et]

The activation of C-Br bonds in various bromoalkanes by the biradical [⋅P(μ-NTer)₂ P⋅] (1) (Ter=2,6-bis-(2,4,6-trimethylphenyl)-phenyl) is reported, yielding trans-addition products of the type [Br-P(μ-NTer)₂ P-R] (2), so-called 1,3-substituted cyclo-1,3-diphospha-2,4-diazanes. This addition reaction, which represents a new easy approach to asymmetrically substituted cyclo-1,3-diphospha-2,4-diazanes, was investigated mechanistically by different spectroscopic methods (NMR, EPR, IR, Raman); the results suggested a stepwise radical reaction mechanism, as evidenced by the in-situ detection of the phosphorus-centered monoradical [⋅P(μ-NTer)₂ P-R].< To provide further evidence for the radical mechanism, [⋅P(μ-NTer)₂ P-Et] (3Et⋅) was synthesized directly by reduction of the bromoethane addition product [Br-P(μ-NTer)₂ P-Et] (2 a) with magnesium, resulting in the formation of the persistent phosphorus-centered monoradical [⋅P(μ-NTer)₂ P-Et], which could be isolated and fully characterized, including single-crystal X-ray diffraction. Comparison of the EPR spectrum of the radical intermediate in the addition reaction with that of the synthesized new [⋅P(μ-NTer)₂ P-Et] radical clearly proves the existence of radicals over the course of the reaction of biradical [⋅P(μ-NTer)₂ P⋅] (1) with bromoethane. Extensive DFT and coupled cluster calculations corroborate the experimental data for a radical mechanism in the reaction of biradical [⋅P(μ-NTer)₂ P⋅] with EtBr. In the field of hetero-cyclobutane-1,3-diyls, the demonstration of a stepwise radical reaction represents a new aspect and closes the gap between P-centered biradicals and P-centered monoradicals in terms of radical reactivity.

Low‐Temperature Isolation of a Labile Silylated Hydrazinium‐yl Radical Cation, [(Me 3 Si) 2 N−N(H)SiMe 3 ] .+

The oxidation of silylated hydrazine, (Me₃Si)₂N−N(H)SiMe₃, with silver salts led to the formation of a highly labile hydrazinium‐yl radical cation, [(Me₃Si)₂N−N(H)SiMe₃]^.+, at very low temperatures (decomposition > −40 °C). EPR, NMR, DFT and Raman studies revealed the formation of a nitrogen‐centered radical cation along the N−N unit of the hydrazine. In the presence of the weakly coordinating anion [Al{OCH(CF₃)₂}₄]⁻, crystallization and structural characterization in the solid state were achieved. The hydrazinium‐yl radical cation has a significantly shortened N−N bond and a nearly planar N₂Si₃ framework, in contrast to the starting material. According to DFT calculations, the shortened N−N bond has a total bond order of 1.5 with a π‐bond order of 0.5. The π bond can be regarded as a three‐π‐electron, two‐center bond.

Synthesis of Bicyclic P,S-Heterocycles via the Addition of Thioketones to a Phosphorus-Centered Open-Shell Singlet Biradical

Formal addition reactions between the open-shell singlet biradical [P(μ-NTer)]₂ (1Ter) and xanthione, thioxanthione, as well as ferrocenyl naphthyl thioketone were studied in detail. Reactions were performed at room temperature and led to the formation of strained [2.1.1]-cage P,S-heterocycles (3). All addition products were isolated and fully characterized by spectroscopic methods. Furthermore, reversible cleavage of the xanthenthione-biradical addition product into the parent compounds (biradical and thioketone) could be demonstrated by ³¹P{¹H} NMR spectroscopy. The thermodynamic stability of all cyclization products with respect to the elimination of thioketone was studied by quantum-chemical computations including solvent effects. Regarding the dissociation of addition products 3 into the fragment molecules 1Ter and ketone/thioketone, calculations prove that a significantly larger distortion energy in ketones compared with thioketones causes lower thermodynamic stability of the ketone adducts.

A Cyclic Thioketone as Biradical Heterocyclopentane-1,3-diyl: Synthesis, Structure and Activation Chemistry

The reaction of the biradical [(m-NTer)P·]2 (1) with thiophosgene, SCCl2, leads to a cyclic phospha-aza thiourea derivative (7) in very good yields. This synthetic approach represents a new possibility to...

A Persistent Phosphanyl-Substituted Thioketyl Radical Anion

Alkali metal salts, M⁺[Ter(iPr)P−C(=S)−P(iPr)₂S]^.− (M=Na, K; 2_M; Ter=2,6‐bis‐(2,4,6‐trimethylphenyl)phenyl) containing a room‐temperature‐stable thioketyl radical anion were obtained by reduction of the thioketone precursor, Ter(iPr)P−C(=S)−P(iPr)₂S (1), with alkali metals (Na, K). Single‐crystal X‐ray studies as well as EPR spectroscopy revealed the unequivocal existence of a thioketyl radical anion in the solid state and in solution, respectively. The computed Mulliken spin density within 2_M is mainly located at the sulfur (49 %) and the carbonyl carbon (33 %) atoms. Upon adding [2.2.2]‐cryptand to the radical species 2_K to minimize the interionic interaction, an activation reaction was observed, yielding a potassium salt with a phosphanyl thioether based anion, [K(crypt)]⁺[Ter(iPr)P−C(−S‐iPr)−P(iPr)₂S]⁻ (3) as the product of an intermolecular shift of an iPr group from a second anion. The products were fully characterized and application of the radical anion as a reducing agent was demonstrated.

Reaction of potassium phosphide KP(iPr)Ter with chalcogens, heteroallenes and an acyl chloride

The reactivity of the secondary phosphide KP(iPr)Ter (1) (Ter = 2,6-bis-(2,4,6-trimethylphenyl)phenyl) toward small molecules is reported. Phosphide 1 displays distinct nucleophilic character and reacts selectively with chalcogens (S₈, Se_x), heteroallenes (CO₂, nPrNCS), and an acyl chloride (AdCOCl) to give the corresponding dichalcogenophosphinates (2a, 3), phosphanyl formate (5), thiocarbamoylphosphane (6a), or acylphosphane (7a), respectively. Furthermore the follow-up chemistry of these products was investigated. 2a was converted to a PSPS ligand (2b) which forms a Au(I) complex (2c) with (Me₂S)AuCl. Likewise, a gold complex of 7a was prepared. All species were isolated and fully characterized.

A Phosphorus-Based Pacman Dication Generated by Cooperative Self-Activation of a Pacman Phosphane

Formal coordination of phosphorus(III) by a calix[4]pyrrole Schiff base ligand was achieved through the reaction of this ligand with PCl₃ under basic conditions. The reaction product adopts a Pacman conformation with two P-Cl moieties, one in exo and one in endo position. It represents the first non-metal compound of calix[4]pyrrole Schiff base ligands and of Pacman ligands in general. The spatial neighborhood of the two phosphorus atoms enables cooperative reactions. As a first example, the chloride abstraction with AgOTf is presented, yielding a macrocyclic dication with two embedded phosphorus(III) monocations, which both undergo a cooperative, internal activation reaction with an adjacent C=N double bond. This intramolecular redox process affords two pentacoordinated phosphorus(V) centers within the Pacman dication. All reaction products were fully characterized and all results are supported by computations.

Patterns of pulmonary function and mortality in chronic heart failure, results from the MyoVasc study

Background

Preclinical evidence suggests that pulmonary fibrosis due to left heart disease may represent end-organ damage in heart failure (HF). Vice versa, decreased pulmonary function is related to worsening of heart failure in the absence of obstructive airway pattern.

Purpose

This study investigated the relationship between patterns of pulmonary function (i.e. obstruction and restriction) and mortality in chronic HF.

Methods

For the present analysis data from the MyoVasc-study (N=3,289) were analysed. During a five-hour examination in the dedicated study center, systematic phenotyping was performed in a highly standardized setting. Chronic HF was defined as American Heart Association HF Stage C/D. Information on pulmonary function was assessed via body plethysmography (MasterScreen Body, Carefusion, Germany). Participants with forced expiratory ratio &lt;0.7 or COPD were categorized as obstructive, while restriction was defined as reduction in total lung capacity. Information on vital status was obtained via registration offices.

Results

The analysis sample comprised 1,509 individuals with chronic heart failure and information on pulmonary function, of whom 286 had HF with reduced ejection fraction (HFrEF), 559 HF with preserved ejection fraction (HFpEF), and 333 HFpEFborderline. The mean age was 64.6±11.3 years, 38.7% were female. In the sample 124 subjects had pulmonary restriction and 400 individuals had an obstruction. During a median time to follow up of 3.70 (inter quartile range 1.25 to 4.00) years, death occurred in 170 individuals. Among clusters of pulmonary function most participants died in the restriction group (25.0%), followed by pulmonary obstruction (12.2%) and normal pulmonary function (7.3%, P for trend &lt;0.001). Cox- regression analysis adjusted for age, sex and height revealed pulmonary restriction (hazard ratio (HR) 3.00 [95% confidence interval 2.04–4.42], P&lt;0.001] and obstruction (HR 1.61 [1.11–2.35], P=0.01) as predictors of all-cause death. After additional controlling for traditional cardiovascular risk factors and the clinical profile only pulmonary restriction remained an independent predictor of mortality (HRrestriction 2.12 [1.50–3.43]; P=0.002; HRobstruction 1.35 [0.91–2.00]; P=0.10). Among HF phenotypes obstruction was only in individuals with HFpEF an independent predictor of all-cause death (HRHFpEF 2.60 [1.29–5.23]; P=0.007; HRHFpEFborderline 1.58 [0.70–3.57]; P=0.27; HRHFrEF 0.96 [0.52–1.78]; P=0.90), while pulmonary restriction was found to be predictive for death only in subjects with HFpEFborderline (HRHFpEF 2.15 [0.70–6.64]; P=0.18; HRHFpEFborderline: HR 5.47 [2.56–11.68]; P&lt;0.001; HRHFrEF 1.74 [0.88–3.46]; P=0.11)

Conclusion

In chronic heart failure, pulmonary restriction was a stronger predictor of mortality than obstructive airway pattern. The present analysis supports the hypothesis of pulmonary fibrosis as end-organ damage in HF, and may potentially represent a therapeutic target.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): German Center for Cardiovascular Research (DZHK)

Tubulin-folding cofactor E deficiency is associated with vascular dysfunction and endoplasmatic reticulum stress of vascular smooth muscle cells

Introduction

Endothelial function assessed via flow mediated dilatation (FMD) has shown to predict risk in individuals with established cardiovascular diseases, whereas its predictive value is uncertain in the setting primary prevention.

Purpose

The aim of the current work was to discover and evaluate novel mediators of vascular dysfunction in the general population and in conditional knock-out transgenic animal models.

Methods

In order to identify novel targets that were negatively correlated with FMD and investigate their contribution in vascular function, a Genome Wide Association Study (GWAS) of 5,000 participants was performed and subsequently immune cell-, endothelial- and vascular smooth muscle cell (VSMCs)-targeted conditional knockout mouse models were generated and characterized.

Results

GWAS analysis revealed that single nucleotide polymorphisms (SNPs) in the tubulin folding cofactor E (TBCE) gene were negatively correlated with FMD and TBCE expression in the peripheral blood mononuclear cells (PBMCs). Myelomonocytic cell-targeted TBCE deficiency did not lead to any vascular dysfunction in vivo in the LysM+Cre+/−TBCEfl/fl mice. Endothelial-targeted TBCE deficiency led to an NLR family pyrin domain containing 3 (NLRP3)-dependent activation of the inflammasome in the endothelial cells of Tie2-ERT2Cre+/−TBCEfl/fl mice. Importantly, VSMC-targeted TBCE deficiency was associated with endothelial dysfunction, increased aortic wall thickness and endoplasmatic reticulum (ER) stress-mediated VSMC hyperproliferation in vivo (SMMHC-ERT2Cre+/−TBCEfl/fl), paralleled by calnexin upregulation. Administration of the blood pressure hormone angiotensin II exacerbated the vascular dysfunction and phenotype. Administration of the ER stress modulator tauroursodeoxycholic acid to the SMMHC-ERT2Cre+/−TBCEfl/fl mice reversed vascular dysfunction, paralleled by induction of Raptor/Beclin-1-dependent autophagy both in vitro and in vivo.

Conclusion

TBCE and tubulin homeostasis in the vascular musculature seem to be novel markers of vascular function and represent a new druggable target for the treatment of ER-stress-mediated vascular dysfunction.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): This work was supported by grants of the German Federal Ministry for Education and Research (BMBF01EO1003 and BMBF01EO1503), the DFG Major Research Instrumentation Programme (DFG INST 371/47-1 FUGG) as well as the Boehringer Ingelheim Foundation. PW received funds from the German Research Foundation in support of his work (DFG WE4361-4-1 and WE 4361/7-1). KS, TM and PW are PIs of the DZHK.

Development of heart failure in long-term survivors of childhood cancer: results from the cvss study

Background

Long-term survivors of childhood cancer (CCS) are at increased risk for cardiovascular sequelae, including heart failure (HF) as the largest non-malignant contributor to excess death. Yet, little is known about the risk factors, mechanisms of cardiac dysfunction and prevalence of different stages of HF in these patients.

Purpose

To investigate the development and prevalence of HF phenotypes in CCS compared to the general population.

Methods

The CVSS study is a prospective single-center cohort study investigating cardiovascular sequelae of CCS. Patients were eligible for the study when they were diagnosed with a neoplasia according to the International Classification of Childhood Cancer (ICCC 3) at an age prior to 15 years between 1980 and 1990, survived more than five years after initial cancer diagnosis and received antineoplastic treatment. Between 2013 and 2016, study individuals underwent a comprehensive, standardized clinical investigation in the CVSS cohort study including echocardiographic examination. HF was categorized as stages A to D according to current HF guidelines of the American Heart Association (AHA). A population-based sample free of cancer (age- and sex matched) serves as control group.

Results

From 1,002 individuals, all CCS with history of chemo- or radiotherapy and no subsequent neoplasia (n=877) were included (mean age 34.2 (±5.5) years, 44.7% (N=392) female). Age at diagnosis was 6.28 years (±4.24) and the mean interval from the date of diagnosis of cancer to the date of completion of baseline examination 28.5±3.2 years. Based on echocardiographic examination, clinical data and biomarker assessment, 26.6% of CCS were diagnosed with HF stage A, 21.1% with HF stage B and 2.1% with symptomatic HF, i.e. HF stage C/D. Importantly, prevalence of different HF stages varied strongly by specific tumor history. Compared to the population, the prevalence ratio (PR) was 1.16 [95% confidence interval 1.02/1.31] for stage A HF and 1.91 [1.63/2.23] for the composite of stage B to D HF in an age- and sex-adjusted Poisson regression model. Multivariable linear regression with the systolic marker left ventricular ejection fraction as dependent variable and adjustment for tumor entities, age, sex, and cardiovascular risk factors (CVRF) revealed a lower EF in patients with history of bone tumors (β −6.0 [−8.1/−3.0]), soft tissue sarcoma (β −2.2 [−4.1/−0.35]), leukemia (β −0.84 [−1.8/0.08]) and renal tumors (β −1.8 [−4.0/0.27]) compared to the population. In contrast, the same model for the diastolic marker E/E', showed an association only with CVRF, but not with tumor entities.

Conclusion

The prevalence of stage B to D HF was significantly higher among long-term CCS in the 3rd to 5th age decade compared to the population and varied strongly by tumor entity. Systolic dysfunction was primarily associated with history of tumor entities, whereas diastolic dysfunction was associated with the higher burden of CVRF in CCS.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study is funded by the Deutsche Forschungsgemeinschaft (DFG) (SP 1381/2-1&2, FA 1038/2-1&2, WI 3881/2-1&2)

The software defined implantable modular platform (STELLA) for preclinical deep brain stimulation research in rodents

Context.Long-term deep brain stimulation (DBS) studies in rodents are of crucial importance for research progress in this field. However, most stimulation devices require jackets or large head-mounted systems which severely affect mobility and general welfare influencing animals' behavior.Objective.To develop a preclinical neurostimulation implant system for long-term DBS research in small animal models.Approach.We propose a low-cost dual-channel DBS implant called software defined implantable platform (STELLA) with a printed circuit board size of Ø13 × 3.3 mm, weight of 0.6 g and current consumption of 7.6µA/3.1 V combined with an epoxy resin-based encapsulation method.Main results.STELLA delivers charge-balanced and configurable current pulses with widely used commercial electrodes. Whilein vitrostudies demonstrate at least 12 weeks of error-free stimulation using a CR1225 battery, our calculations predict a battery lifetime of up to 3 years using a CR2032. Exemplary application for DBS of the subthalamic nucleus in adult rats demonstrates that fully-implanted STELLA neurostimulators are very well-tolerated over 42 days without relevant stress after the early postoperative phase resulting in normal animal behavior. Encapsulation, external control and monitoring of function proved to be feasible. Stimulation with standard parameters elicited c-Fos expression by subthalamic neurons demonstrating biologically active function of STELLA.Significance.We developed a fully implantable, scalable and reliable DBS device that meets the urgent need for reverse translational research on DBS in freely moving rodent disease models including sensitive behavioral experiments. We thus add an important technology for animal research according to 'The Principle of Humane Experimental Technique'-replacement, reduction and refinement (3R). All hardware, software and additional materials are available under an open source license.

Ethanol inactivation of orthonairoviruses in ixodid ticks

Ixodid ticks represent vectors and reservoirs for a broad range of zoonotic pathogens. Collected ticks from field studies are therefore usually stored in ethanol, which in higher concentrations effectively inactivates most of the known tick-borne pathogens. Although commonly practiced as gold standard for inactivation, hardly any scientific data demonstrate that ethanol sufficiently penetrates the comparatively thick cuticula of ticks. Therefore, Amblyomma hebraeum tick pools were stored for 21 days in ethanol (96%). Afterwards, the ethanol was removed and the ticks were homogenized. Quantitative ¹H-NMR spectroscopic analysis was applied to determine the residual concentration of ethanol inside the ticks. ¹H-NMR spectroscopic analysis revealed that ethanol constituted 28.3-42.6 mg of the total weight of three ticks in the pools (89.9-121.5 mg). In addition, the low-pathogenic Hazara orthonairovirus (HAZV) was used as a cell culture model for this study. The virus was exposed to ethanol concentrations between 0 and 60% and incubated under various temperature conditions for four time periods. Afterwards, the residual virus infectivity was determined by titration. Following ethanol exposure, HAZV did not grow in cells after 9 h of exposure to an ethanol concentration of 25%. These results demonstrate an extremely low ethanol resistance of the virus, which was generally in line with previously reported ethanol inactivation data for Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV). After prolonged storage and impregnation, comparable ethanol concentrations are achieved in the ticks, indicating the suitability of this inactivation method also for Bunyaviruses in ticks. At the very least, a massive virus inactivation can be assumed. Definitive proof of virus inactivation would require a bioassay of ethanol-treated infected ticks under appropriate biosafety conditions.

Insertion of CS2 into a Phosphorus-Arsenic Single Bond and Investigations on Phosphane Arsanyldithiocarboxylates

The synthesis and reactivity of sterically demanding phosphaarsanes TerR¹P-AsR² (3) is described. These species were selectively synthesized via metathesis reactions of Ter-stabilized [Ter = 2,6-bis(2,4,6-trimethylphenyl)phenyl] potassium phosphides TerR¹PK (1) with the N-heterocyclic chloroarsane ClAs{N(tBu)CH₂}₂ (2). Conversion of the n-butyl-substituted phosphaarsane 3c with the reactive heterocumulene CS₂ leads to an insertion into the P-As bond, yielding the phosphane arsanyldithiocarboxylate TerR¹P-C(S)S-AsR² (4c) as a new structural motif. Because full conversion of 3c with CS₂ requires long reaction times, an alternative synthetic route is reported herein, involving the conversion of 2 with phosphane dithiocarboxylates TerR¹-C(S)SK (5), enabling synthetic access to a wider range of phosphane arsanyldithiocarboxylates. These interpnictogen dithiocarboxylates show an interesting bonding situation with a significantly elongated As-S bond due to negative hyperconjugation within the molecule. All products along the reaction path were fully characterized.