Noncovalent Interactions between Tetrazole and an <i>N</i>,<i>N</i>‘-Diethyl-Substituted Benzamidine

Amidines have long been known to form strong noncovalent complexes with carboxylates and phosphates. However, their interaction with tetrazoles, which are acidic heterocycles and important bioisosteric replacements for carboxylic acids in medicinal chemistry, has remained unexplored so far. The binding of a tetrazole to an N,N‘-diethyl-substituted benzamidine has been studied for the first time by X-ray crystallography, solution NMR methods, and electrospray mass spectrometry. The amidinium group of model complex 3 was found to prefer an E,Z configuration in the crystal. Benzamidinium and tetrazolate groups alternate along an infinite chain of hydrogen bonds and salt bridges between the amidine-NH groups and the two tetrazole-N atoms next to the ring carbon. In solution, a 1:1 complex was evident from Job's method of continuous variation, and an association constant of 4.0 × 103 ± 1.6 × 103 M-1 (in CDCl3/CD3CN, 6:1) could be determined by 1H NMR dilution experiments. Tetrazolate was not only found to be a weaker ligand than carboxylates but, surprisingly, the binding mode also changed with concentration in neat CDCl3. At low concentrations, the amidine group in complex 3 adapted an E,E configuration as it does in a related carboxylic acid complex 4. With increasing concentration, the E,Z isomer starts to predominate. A free activation enthalpy ΔG298⧧ of 64 ± 1 kJ mol-1 for the E,E to E,Z isomerization was determined by line shape analysis at different magnetic fields. Binding strength was further probed in a competition experiment between a bisamidine, a carboxylate, and a tetrazolate by electrospray mass spectrometry

Direct Synthesis of Cubic ZrMo₂O₈ Followed by Ultrafast In Situ Powder Diffraction

Direct Synthesis of Cubic ZrMo2O8 Followed by Ultrafast In Situ Powder Diffractio

Data_Sheet_2_A Spectroscopic Investigation of Eu3+ Incorporation in LnPO4 (Ln = Tb, Gd1-xLux, X = 0.3, 0.5, 0.7, 1) Ceramics.zip

We have investigated the incorporation of the luminescent Eu3+ cation in different LnPO4 (Ln = Tb, Gd1−xLux, x = 0.3, 0.5, 0.7, 1) host phases. All samples were analyzed with powder X-ray diffraction (PXRD), Raman spectroscopy, and site-selective time-resolved laser-induced luminescence spectroscopy (TRLFS) directly after synthesis and after an aging time of one year at ambient conditions. The PXRD investigations demonstrate the formation of a TbPO4 phase in an uncommon anhydrite-like crystal structure evoked by a pressure-induced preparation step (grinding). In the Gd1−xLuxPO4 solid solution series, several different crystal structures are observed depending on the composition. The TRLFS emission spectra of LuPO4, Gd0.3Lu0.7PO4, and Gd0.5Lu0.5PO4 indicate Eu3+–incorporation within a xenotime-type crystal structure. TRLFS and PXRD investigations of the Gd0.7Lu0.3PO4 composition show the presence of anhydrite, xenotime, and monazite phases, implying that xenotime no longer is the favored crystal structure due to the predominance of the substantially larger Gd3+–cation in this solid phase. Eu3+–incorporation occurs predominantly in the anhydrite-like structure with smaller contributions of Eu3+ incorporated in monazite and xenotime. The electronic levels of the Eu3+–dopant in Gd0.3Lu0.7PO4 and Gd0.5Lu0.5PO4 xenotime hosts are strongly coupled to external lattice vibrations, giving rise to high-energy peaks in the obtained excitation spectra. The coupling becomes stronger after aging to such an extent that direct excitation of Eu3+ in the xenotime structure is strongly suppressed. This phenomenon, however, is only visible for materials where Eu3+ was predominantly incorporated within the xenotime structure. Single crystals of Eu3+–doped LuPO4 show no changes upon aging despite the presence of vibronically coupled excitation peaks in the excitation spectra measured directly after synthesis. Based on this observation, we propose a lattice relaxation process occurring in the powder samples during aging, resulting in Eu3+ migration within the crystal structure and Eu3+ accumulation at grain boundaries or xenotime surface sites.</p

Phenomenological Determinisms

The arrow of time is revisited. It is proposed that it arises from the existence in the cosmos of a phenomenological determinism within the fundamental determinism expressed by the Liouville or Liouville-von Neumann equations. The latter link exactly the fundamental information present in the cosmos at any different times. The proposed phenomenological determinism is expressed by phenomenological laws which allow the observers to deduce, from the phenomenological fraction of the fundamental information accessible to observation at a time t, the same phenomenological information at a times t', but only along the arrow of time t'>t. It is first shown, in a simplified cosmos, that this phenomenological determinism can exist under two conditions : an initial condition weighing on the fundamental information at a primordial time of the cosmos, which introduces the arrow of time aimed from the primordial time to the observers' times ; a structural condition specifying in fine the nature of the phenomenological information, which imposes that any information which does not become phenomenological very rapidly becomes disconnected forever. It is then shown that these conditions are fulfilled, and the phenomenological determinism exists, thanks to a canonical representation of the phase space in the vicinity of the hamiltonian trajectories, which highlights purely hyperbolic or elliptic motions of the cosmos

Argentophilicity-Dependent Colossal Thermal Expansion in Extended Prussian Blue Analogues

Argentophilicity-Dependent Colossal Thermal Expansion in Extended Prussian Blue Analogue

Pearson’s rank correlation coefficient for the WT and WA% on inspiration for all bronchial generations (1^st−10^th).

<p>For the airway parameters no statistically significant correlation with the lung function parameters was found (all r<0.5 except PEF and the ratio of PEF/PEF_predicted with WT insp in generation 10).</p

Pearson’s rank correlation coefficient for the WT and WA% on expiration for all bronchial generations and subdivided into bronchial generations (1^st8^th).

<p>No statistically significant correlation with the lung function parameters was found between morphometric analysis of the airway parameters on expiration and PFT.</p

Results (mean values) of the pulmonary function tests for the entire study population and subdivided according to male/female patients and those with/without BOS.

<p>Results (mean values) of the pulmonary function tests for the entire study population and subdivided according to male/female patients and those with/without BOS.</p

The mean lumen diameter (LD) in millimeter in patients with and without BOS.

<p>The LD is increased in the peripheral bronchial generations in patients with BOS indicating the development of bronchiectasis. although it failed to demonstrate statistical significance with the exception of 7^th generation which we regard as an accidental occurrence (the standard deviation values are in parentheses).</p

Bronchial wall measurements using the MeVis Airway Examiner.

<p>A three-dimensional display of the tracheobronchial tree (B) allowed the selection of the bronchus that should be evaluated (yellow border). For visualization, curved mulitplanar reformation (D) and cross-sectional images perpendicular to the central path, were used (C) and with the viewing direction along the bronchial path. The original dataset is shown in (A) and the selected bronchus is tagged with a cross-line. The location for measurements of the bronchial wall was visualized with a yellow line for the inner and a red line for the outer borderline of the bronchial wall (C).</p