Thionitrosyl Complexes of Rhenium and Technetium with PPh3 and Chelating Ligands - Synthesis and Reactivity

In contrast to corresponding nitrosyl compounds, thionitrosyl complexes of rhenium and technetium are rare. Synthetic access to the thionitrosyl core is possible by two main approaches: (i) the treatment of corresponding nitrido complexes with S2Cl2 and (ii) by reaction of halide complexes with trithiazyl chloride. The first synthetic route was applied for the synthesis of novel rhenium and technetium thionitrosyls with the metals in their oxidation states “+1” and “+2”. [MVNCl2(PPh3)2], [MVNCl(PPh3)(LOMe)] and [MVINCl2(LOMe)] (M = Re, Tc; {LOMe}− = (η5-cyclopentadienyl)tris(dimethyl phosphito-P)cobaltate(III)) complexes have been used as starting materials for the synthesis of [ReII(NS)Cl3(PPh3)2] (1), [ReII(NS)Cl3(PPh3)(OPPh3)] (2), [ReII(NS)Cl(PPh3)(LOMe)]+ (4a), [ReII(NS)Cl2(LOMe)] (5a), [TcII(NS)Cl(PPh3)(LOMe)]+ (4b) and [TcII(NS)Cl2(LOMe)] (5b). The triphenylphosphine complex 1 is partially suitable as a precursor for ongoing ligand exchange reactions and has been used for the synthesis of [ReI(NS)(PPh3)(Et2btu)2] (3a) (HEt2btu = N,N-diethyl-N′-benzoyl thiourea) containing two chelating benzoyl thioureato ligands. The novel compounds have been isolated in crystalline form and studied by X-ray diffraction and spectroscopic methods including IR, NMR and EPR spectroscopy and (where possible) mass spectrometry. A comparison of structurally related rhenium and technetium complexes allows for conclusions about similarities and differences in stability, reaction kinetics and redox behavior between these 4d and 5d transition metals

Nitrosyl and Thionitrosyl Complexes of Technetium and Rhenium and Their Reactions with Hydrotris(pyrazolyl)borates

The very limited number of structurally known thionitrosyl complexes of technetium was increased by the synthesis of [TcII(NS)Cl3(PPh3)2] (3) and [TcII(NS)Cl3(PPh3)(OPPh3)] (4) and their reaction products with hydrotris(pyrazolyl)borates, {HB(pzR)3}−. Similar reactions were conducted with [TcI(NO)Cl2(PPh3)2(CH3CN)] and related rhenium thionitrosyls. Remarkably, most such reactions result in a rapid cleavage of the boron–nitrogen bonds of the ligands and the formation of pyrazole complexes of the two group 7 metals. Only one compound with an intact {HB(pzR)3}− ligand could be isolated: the technetium(I) complex [TcI(NO)Cl(PPh3){HB(pz)3}] (2). Other products show the coordination of one or four neutral pyrazole ligand(s) in the coordination spheres of technetium generated by thermal decomposition of the pyrazolylborates [TcI(NO)Cl2(PPh3)2(pzH)] (1) and [TcI(NS)Cl(pzHMe2)4]+ (5). Reactions with the corresponding thionitrosylrhenium complex [ReII(NS)Cl3(PPh3)2] require higher temperatures and only compounds with one pyrazole ligand, [ReI(NS)Cl2(PPh3)(pzHR)] (6a–6c), were isolated. The products were studied spectroscopically and by X-ray diffraction

Modifications of the CZTSe/Mo Back-Contact Interface by Plasma Treatments

Molybdenum (Mo) is the most commonly used back-contact material for copper zinc tin selenide (CZTSe)-based thin-film solar cells. For most fabrication methods, an interfacial molybdenum diselenide (MoSe2) layer with an uncontrolled thickness is formed, ranging from a few tens of nm up to ≈1 μm. In order to improve the control of the back-contact interface in CZTSe solar cells, the formation of a MoSe2 layer with a homogeneous and defined thickness is necessary. In this study, we use plasma treatments on the as-grown Mo surface prior to the CZTSe absorber formation, which consists of the deposition of stacked metallic layers and the annealing in selenium (Se) atmosphere. The plasma treatments include the application of a pure argon (Ar) plasma and a mixed argon–nitrogen (Ar–N2) plasma. We observe a clear impact of the Ar plasma treatment on the MoSe2 thickness and interfacial morphology. With the Ar–N2 plasma treatment, a nitrided Mo surface can be obtained. Furthermore, we combine the Ar plasma treatment with the application of titanium nitride (TiN) as back-contact barrier and discuss the obtained results in terms of MoSe2 formation and solar cell performance, thus showing possible directions of back-contact engineering for CZTSe solar cells

Contribution of ecosystem services to air quality and climate change mitigation policies : the case of urban forests in Barcelona, Spain

Mounting research highlights the contribution of ecosystem services provided by urban forests to quality of life in cities, yet these services are rarely explicitly considered in environmental policy targets. We quantify regulating services provided by urban forests and evaluate their contribution to comply with policy targets of air quality and climate change mitigation in the municipality of Barcelona, Spain. We apply the i-Tree Eco model to quantify in biophysical and monetary terms the ecosystem services "air purification," "global climate regulation," and the ecosystem disservice "air pollution" associated with biogenic emissions. Our results show that the contribution of urban forests regulating services to abate pollution is substantial in absolute terms, yet modest when compared to overall city levels of air pollution and GHG emissions. We conclude that in order to be effective, green infrastructure-based efforts to offset urban pollution at the municipal level have to be coordinated with territorial policies at broader spatial scales

Field programmable gate array based reconfigurable scanning probe/optical microscope

The increasing popularity of nanometrology and nanospectroscopy has pushed researchers to develop complex new analytical systems. This paper describes the development of a platform on which to build a microscopy tool that will allow for flexibility of customization to suit research needs. The novelty of the described system lies in its versatility of capabilities. So far, one version of this microscope has allowed for successful near-field and far-field fluorescence imaging with single molecule detection sensitivity. This system is easily adapted for reflection, polarization (Kerr magneto-optical (MO)), Raman, super-resolution techniques, and other novel scanning probe imaging and spectroscopic designs. While collecting a variety of forms of optical images, the system can simultaneously monitor topographic information of a sample with an integrated tuning fork based shear force system. The instrument has the ability to image at room temperature and atmospheric pressure or under liquid. The core of the design is a field programmable gate array (FPGA) data acquisition card and a single, low cost computer to control the microscope with analog control circuitry using off-the-shelf available components. A detailed description of electronics, mechanical requirements, and software algorithms as well as examples of some different forms of the microscope developed so far are discussed

Non-targeted urine metabolomics and associations with prevalent and incident type 2 diabetes

Better risk prediction and new molecular targets are key priorities in type 2 diabetes (T2D) research. Little is known about the role of the urine metabolome in predicting the risk of T2D. We aimed to use non-targeted urine metabolomics to discover biomarkers and improve risk prediction for T2D. Urine samples from two community cohorts of 1,424 adults were analyzed by ultra-performance liquid chromatography/mass spectrometry (UPLC-MS). In a discovery/replication design, three out of 62 annotated metabolites were associated with prevalent T2D, notably lower urine levels of 3-hydroxyundecanoyl-carnitine. In participants without diabetes at baseline, LASSO regression in the training set selected six metabolites that improved prediction of T2D beyond established risk factors risk over up to 12 years' follow-up in the test sample, from C-statistic 0.866 to 0.892. Our results in one of the largest non-targeted urinary metabolomics study to date demonstrate the role of the urine metabolome in identifying at-risk persons for T2D and suggest urine 3-hydroxyundecanoyl-carnitine as a biomarker candidate.Peer reviewe

Analysis of the In Vivo Transcriptome of Bordetella pertussis during Infection of Mice

Bordetella pertussis causes the disease whooping cough through coordinated control of virulence factors by the Bordetella virulence gene system. Microarrays and, more recently, RNA sequencing (RNA-seq) have been used to describe in vitro gene expression profiles of B. pertussis and other pathogens. In previous studies, we have analyzed the in vitro gene expression profiles of B. pertussis, and we hypothesize that the infection transcriptome profile in vivo is significantly different from that under laboratory growth conditions. To study the infection transcriptome of B. pertussis, we developed a simple filtration technique for isolation of bacteria from infected lungs. The work flow involves filtering the bacteria out of the lung homogenate using a 5-μm-pore-size syringe filter. The captured bacteria are then lysed to isolate RNA for Illumina library preparation and RNA-seq analysis. Upon comparing the in vitro and in vivo gene expression profiles, we identified 351 and 255 genes as activated and repressed, respectively, during murine lung infection. As expected, numerous genes associated with virulent-phase growth were activated in the murine host, including pertussis toxin (PT), the PT secretion apparatus, and the type III secretion system. A significant number of genes encoding iron acquisition and heme uptake proteins were highly expressed during infection, supporting iron acquisition as critical for B. pertussis survival in vivo. Numerous metabolic genes were repressed during infection. Overall, these data shed light on the gene expression profile of B. pertussisduring infection, and this method will facilitate efforts to understand how this pathogen causes infection

Contribución del verde de Barcelona a la calidad del aire y la mitigación del cambio climático

[ES] Cada vez más estudios científicos destacan la contribución de los servicios ecosistémicos generados por el verde urbano en relación a la calidad de vida en las ciudades. En este estudio cuantificamos en valores biofísicos y monetarios, los servicios ecosistémicos de regulación ‘filtración del aire’ y ‘secuestro de carbono’ proporcionados por el verde urbano (principalmente arbolado) del municipio de Barcelona mediante la aplicación del modelo iTree Eco. Asimismo, también evaluamos la contribución de estos servicios en relación a los objetivos de calidad del aire y mitigación del cambio climático de la ciudad. Los resultados muestran que la contribución del verde urbano en la reducción de la contaminación atmosférica es relevante en términos absolutos, pero moderada si se compara con los niveles totales de contaminación del aire y emisiones de gases de efecto invernadero (GEI) de la ciudad. Nuestra conclusión principal es que, para ser eficaces, las políticas basadas en la mejora de la infraestructura verde urbana en relación a la calidad ambiental de Barcelona se tienen que coordinar conjuntamente con medidas de reducción de emisiones.Baró, F.; Chaparro, L.; Gómez-Baggethun, E.; Langemeyer, J.; Nowak, DJ.; Terrades, J. (2014). Contribución del verde de Barcelona a la calidad del aire y la mitigación del cambio climático. En XVI CONGRESO NACIONAL DE ARBORICULTURA. Editorial Universitat Politècnica de València. 15-30. http://hdl.handle.net/10251/91324OCS153