Prediction of Mefenamic Acid Crystal Shape by Random Forest Classification.

Objective: Particle shape can have a significant impact on the bulk properties of materials. This study describes the development and application of machine-learning models to predict the crystal shape of mefenamic acid recrystallized from organic solvents.

Methods: Crystals were grown in 30 different solvents to establish a dataset comprising solvent molecular descriptors, process conditions and crystal shape.

Anthracene as a Launchpad for a Phosphinidene Sulfide and for Generation of a Phosphorus-Sulfur Material Having the Composition PS, a Vulcanized Red Phosphorus That Is Yellow.

Thermolysis of a pair of dibenzo-7-phosphanorbornadiene compounds is shown to lead to differing behaviors: phosphinidene sulfide release and formation of amorphous PS. These compounds, BuP(S)A (1, A = CH or anthracene; 59% isol. yield) and HP(S)A (2; 63%), are available through thionation of BuPA and the new secondary phosphine HPA (5), prepared from MeNPA and DIBAL-H in 50% yield.

Probing covalency in halogen bonds through donor K-edge X-ray absorption spectroscopy: polyhalides as coordination complexes.

The properties of halogen bonds (XBs) in solid-state IX and IX materials (where X = Cl, Br) are explored using donor K-edge X-ray absorption spectroscopy (XAS) to experimentally determine the degree of charge transfer in such XB interactions. The degree of covalency in these bonds is substantial, even in cases where significantly weaker secondary interactions are observed. These data, in concert with previous work in this area, suggests that certain halogen bonds have covalent contributions to bonding that are similar to, and even exceed, those observed in transition metal coordinate bonds.

Evidence for halogen bond covalency in acyclic and interlocked halogen-bonding receptor anion recognition.

The synthesis and anion binding properties of novel halogen-bonding (XB) bis-iodotriazole-pyridinium-containing acyclic and [2]catenane anion host systems are described. The XB acyclic receptor displays selectivity for acetate over halides with enhanced anion recognition properties compared to the analogous hydrogen-bonding (HB) acyclic receptor. A reversal in halide selectivity is observed in the XB [2]catenane, in comparison to the acyclic XB receptor, due to the interlocked host's unique three-dimensional binding cavity, and no binding is observed for oxoanions.

Demonstration of a standard dilution technique for standard addition calibration.

A standard dilution approach to sequential (S-SAC) and conventional (C-SAC) standard addition calibration is introduced and described theoretically. The two calibration methods have then been demonstrated experimentally for chloride measurement in seawater samples. S-SAC showed superior results for such a sample as a function of the steeper extrapolation resulting from the calibration process.