Group 14 metallated 6-amino-1-azafulvene dimers : evidence for a double intramolecular nitrogen-tin interaction

The structures of group 14 C-metalated 6-amino-1-azafulvene dimers have been investigated in solution and in the solid state by NMR spectroscopy. For one of these compounds, 5,10-bis(dimethylamino)-3,8-bis(trimethylstannyl)-5H,10H-dipyrrolo[1,2-a: 1\u27,2\u27-d]-pyrazine (2c), the molecular structure in the solid state has been determined by X-ray diffractometry. The two tin centers have a distorted-trigonal-bipyramidal co-ordination geometry with the more electronegative N ligand at a pseudoaxial position, resulting in one of the longest known Sn - N interactions: 3.101 (5) A°. Moreover, the temperature-dependent 13C CP-MAS NMR spectrum of this compound shows an appreciable narrowing of the Me3Sn signal between 296 and 333 K. By comparison with nonmetalated analogs or with isomer 5c, the nonreactivity of compound 2c toward hydrolytic decomposition into corresponding 5-(trimethylstannyl)-pyrrole-2-carbaldehyde (3c) may be the result of stabilization of the dimeric form 2c by a double Sn - N interaction. In silicon and germanium analogs (2a, 2b) the Si(Ge) - N interaction is weaker

The Olfactory Threshold of Rotundone in Brandy is Ten-fold Higher than in Wine and does not Increase with the Complexity of the Matrix

Rotundone is the only known aroma compound imparting a peppery aroma to wine. Its presence hasrecently been documented in spirits, notably those aged in oak barrels. However, the sensory contributionof rotundone in such alcoholic beverages remains hard to predict, given their high ethanol level. The aimof this study was to estimate olfactory thresholds for rotundone in brandy using three different matrices.Rotundone concentrations in the unspiked samples were 50 ng/L for wine distillate and 135 ng/L for brandy,demonstrating for the first time the presence of rotundone in such spirits and a possible endogenous origin.The olfactory detection threshold was estimated at 103 ng/L in 40% (v/v) ethanol solution, while differencethresholds were 171 ng/L and 189 ng/L in fresh wine distillate and young French brandy, respectively, bothstandardised at 40% (v/v). These thresholds were 10-fold higher than in wines and did not significantlydiffer according to the complexity of the matrix. Our results, which are still preliminary and would deserveto be validated with a larger number of samples and using a higher number of panellists, open new fieldsof investigation for a deeper exploration of the concentration range of rotundone in brandies, particularlythose that underwent a longer ageing period in barrels

Group 14 metallated 6-amino-1-azafulvene dimers : evidence for a double intramolecular nitrogen-tin interaction

The structures of group 14 C-metalated 6-amino-1-azafulvene dimers have been investigated in solution and in the solid state by NMR spectroscopy. For one of these compounds, 5,10-bis(dimethylamino)-3,8-bis(trimethylstannyl)-5H,10H-dipyrrolo[1,2-a: 1',2'-d]-pyrazine (2c), the molecular structure in the solid state has been determined by X-ray diffractometry. The two tin centers have a distorted-trigonal-bipyramidal co-ordination geometry with the more electronegative N ligand at a pseudoaxial position, resulting in one of the longest known Sn - N interactions: 3.101 (5) A°. Moreover, the temperature-dependent 13C CP-MAS NMR spectrum of this compound shows an appreciable narrowing of the Me3Sn signal between 296 and 333 K. By comparison with nonmetalated analogs or with isomer 5c, the nonreactivity of compound 2c toward hydrolytic decomposition into corresponding 5-(trimethylstannyl)-pyrrole-2-carbaldehyde (3c) may be the result of stabilization of the dimeric form 2c by a double Sn - N interaction. In silicon and germanium analogs (2a, 2b) the Si(Ge) - N interaction is weaker

Towards Translational ImmunoPET/MR Imaging of Invasive Pulmonary Aspergillosis: The Humanised Monoclonal Antibody JF5 Detects Aspergillus Lung Infections In Vivo

This is the final published versionAvailable from Ivyspring International Publisher via the DOI in this recordInvasive pulmonary aspergillosis (IPA) is a life-threatening lung disease of hematological malignancy and bone marrow transplant patients caused by the ubiquitous environmental fungus Aspergillus fumigatus. Current diagnostic tests for the disease lack sensitivity as well as specificity, and culture of the fungus from invasive lung biopsy, considered the gold standard for IPA detection, is slow and often not possible in critically ill patients. In a previous study, we reported the development of a novel non-invasive procedure for IPA diagnosis based on antibody-guided positron emission tomography and magnetic resonance imaging (immunoPET/MRI) using a [64Cu]DOTA-labeled mouse monoclonal antibody (mAb), mJF5, specific to Aspergillus. To enable translation of the tracer to the clinical setting, we report here the development of a humanised version of the antibody (hJF5), and pre-clinical imaging of lung infection using a [64Cu]NODAGA-hJF5 tracer. The humanised antibody tracer shows a significant increase in in vivo biodistribution in A. fumigatus infected lungs compared to its radiolabeled murine counterpart [64Cu]NODAGA-mJF5. Using reverse genetics of the pathogen, we show that the antibody binds to the antigenic determinant 1,5-galactofuranose (Galf) present in a diagnostic mannoprotein antigen released by the pathogen during invasive growth in the lung. The absence of the epitope Galf in mammalian carbohydrates, coupled with the enhanced imaging capabilities of the hJF5 antibody, means that the [64Cu]NODAGA-hJF5 tracer developed here represents an ideal candidate for the diagnosis of IPA and translation to the clinical setting.This work was supported by the European Union Seventh Framework Programme FP7/2007-2013 under Grant 602820, the Deutsche Forschungsgemeinschaft (Grant WI3777/1-2 to SW), and the Werner Siemens Foundation. We thank Sven Krappman for use of the A. fumigatustdTomato strain, and acknowledge the Imaging Centre Essen (IMCES) for assistance with optical imaging of lungs

Investigation of the behavior of microscopic bubbles in insulating liquids: transition from the inertial regime to the viscous one

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Experimental investigation of transient pressure waves produced in dielectric liquids

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The dynamics of microscopic bubbles in viscous insulating liquids

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