Anion Binding Modes in <i>meso</i>-Substituted Hexapyrrolic Calix[4]pyrrole Isomers

We report on the synthesis of a new receptor for anions, <i>meso</i>-substituted hexapyrrolic calix[4]­pyrrole <b>1</b>. The calix[4]­pyrrole’s core features two additional pyrrole side-arms suspended above or below the calix[4]­pyrrole core. This hexapyrrolic calix[4]­pyrrole <b>1</b> is formed as <i>cis</i>- and <i>trans</i>-configurational isomers, the structures of which have been determined by single crystal X-ray diffraction. The anion binding experiments revealed interesting difference in the binding mode: The <i>cis</i>-<b>1</b> isomer binds anions in a mixed binding mode featuring a combination of hydrogen bonding and anion−π interactions resulting in an unexpected strong binding. On the other hand, the <i>trans</i>-<b>1</b> isomer displays only hydrogen bonding and lower affinity for anions. This is unexpected as one would assume both isomers to display the same binding modes. Overall, the titrations of <b>1</b> using UV spectrophotometry and NMR titrations by anions reveal that <i>cis</i>-isomer <b>1</b> displays higher affinity (10⁵–10⁶ M^–1) and cross-reactivity for anions, while the <i>trans</i>-isomer <b>1</b> shows a more selective response to anions. Such differences in binding mode in configurational isomers are so far unexplored and a feature deserving further study

Additional file 1: Table S1. of Prognostic roles of pathology markers immunoexpression and clinical parameters in Hepatoblastoma

The expression of stem cell markers in the tumor specimens from these 31 subjects. (DOC 46 kb

Patient profiles and endoscopic findings according to the gastroesophageal flap valve grades.

<p>Fisher exact test or chi-square test was used for categorical data. Continuous non-parametric variables were compared by Mann-Whitney u test.</p>†<p>Los Angeles classification grade.</p>‡<p>The values of pH monitor and Impedance findings were expressed as median (25%–75% range).</p><p>Patient profiles and endoscopic findings according to the gastroesophageal flap valve grades.</p

Logistic regression analysis of the association between GEFV and erosive esophagitis, pathological gatroesophageal reflux.

<p>Logistic regression analysis of the association between GEFV and erosive esophagitis, pathological gatroesophageal reflux.</p

Retroflex view of the gastroesophageal flap valve.

<p>(a) Grade I. The prominent fold of tissue along the lesser curvature apposed closely to the endoscope. (b) Grade II. The fold was present but less well defined than in grade I, and some periods of opening and rapid closing around the endoscope were found. (c) Grade III. The fold was not prominent and often failed to close around the endoscope, gripping it tightly. (d) Grade IV. There was no fold and the lumen of the esophagus was open. The squamous epithelium of the esophagus could be seen below.</p

Biscalix[4]arene Derivative As a Very Efficient Phase Selective Gelator for Oil Spill Recovery

A biscalixarene framework, without long alkyl chains, has been readily synthesized in three steps starting from the parent calix[4]arene. The biscalix[4]arene <b>1</b> was able to form organogels in various alcoholic solvents; furthermore, it exhibited an excellent phase selective gelation property that is potentially useful in oil spill recovery