4-[(4-Methyl­benz­yl)amino]-3-[(4-methyl­benz­yl)imino­meth­yl]-2H-chromen-2-one

The title compound, C26H24N2O2, was prepared from the reaction of 4-chloro-3-formyl­coumarin with p-methyl­benzyl­amine. Even though there are no strong and specific inter­actions in the crystal structure, the translationally related mol­ecules form chains along the b axis. The coumarin moieties are stacked through π–π inter­actions [centroid–centroid distance = 3.5275 (7) Å], forming layers perpendicular to the stacking direction

Structural basis for bending of organic crystals

Bending is observed in organic crystals when the packing is anisotropic in such a way that strong and weak interaction patterns occur in nearly perpendicular directions

Asymmetric rotations and dimerization driven by normal to modulated phase transition in 4-biphenylcarboxy coupled L-phenylalaninate

Amongst the derivatives of 4-biphenylcarboxylic acid and amino acid esters, the crystal structure of 4-biphenylcarboxy-(L)-phenylalaninate is unusual owing to its monoclinic symmetry within a pseudo-orthorhombic lattice. The distortion is described by disparate rotational property around the chiral centers ($\varphi_{\mathrm{chiral}}$ $\simeq$ -129 degrees and 58 degrees) of the two molecules in the asymmetric unit. Each of these molecules comprise of planar biphenyl moieties ($\varphi_{\mathrm{biphenyl}}$ = 0 degrees). Using temperature dependent single crystal X-ray diffraction experiments we show that the compound undergoes a phase transition below $T$ $\sim$ 124 K that is characterized by a commensurate modulation wave vector, $\mathbf{q}$ = $\delta(101)$, $\delta$ = $\frac{1}{2}$. The (3+1) dimensional modulated structure at $T$ = 100 K suggests that the phase transition drives the biphenyl moieties towards non coplanar conformations with significant variation of internal torsion ($\varphi^{\mathrm{max}}_{\mathrm{biphenyl}}$ $\leq$ $20$ degrees). These intramolecular rotations lead to dimerization of the molecular stacks that are described predominantly by intermolecular tilts and small variations in intermolecular distances. Atypical of modulated structures and superstructures of biphenyl and other polyphenyls, the rotations of individual molecules are asymmetric ($\Delta$$\varphi_{\mathrm{biphenyl}}$ $\approx$ 5 degrees) while $\varphi_{\mathrm{biphenyl}}$ of one independent molecule is two to four times larger than the other. Crystal-chemical analysis and phase relations in superspace suggest multiple competing factors involving intramolecular steric factors, intermolecular H--C${\cdot}{\cdot}{\cdot}$C--H contacts and weak C--H${\cdot}{\cdot}{\cdot}$O hydrogen bonds that govern the distinctively unequal torsional property of the molecules

Mild and Highly Efficient Stereoselective Synthesis of 2,3-Unsaturated Glycopyranosides using La(NO3)3 · 6H2O as a Catalyst: Ferrier Rearrangement

A mild and highly efficient stereoselective reaction of 3,4,6-tri-O-acetyl-D-glucal with a variety of nucleophiles, viz. alcohols, phenols, thiols, thiophenols, and allyl trimethyl silane (TMS), in the presence of 5 mol% of lanthanum(III) nitrate hexahydrate under solvent-free conditions yielded the corresponding 2,3-unsaturated glycopyranosides (pseudoglycals) in excellent yields

Structural Basis for Mechanical Anisotropy in Polymorphs of Caffeine-Glutaric Acid Cocrystal

YesInsights into structure–mechanical property correlations in molecular and multicomponent crystals have recently attracted significant attention owing to their practical applications in the pharmaceutical and specialty fine chemicals manufacturing. In this contribution, we systematically examine the mechanical properties of dimorphic forms, Forms I and II of 1:1 caffeine-glutaric acid cocrystal on multiple faces using nanoindentation to fully understand their mechanical anisotropy and mechanical stability under applied load. Higher hardness, H, and elastic modulus, E, of stable Form II has been rationalized based on its corrugated layers, higher interlayer energy, lower interlayer separation, and presence of more intermolecular interactions in the crystal structure compared to metastable Form I. Our results show that mechanical anisotropy in both polymorphs arises due to the difference in orientation of the same 2D structural features, namely the number of possible slip systems, and strength of the intermolecular interactions with respect to the indentation direction. The mechanical properties results suggest that 1:1 caffeine-glutaric acid cocrystal, metastable form (Form I) could be a suitable candidate with desired tablet performance to that of stable Form II. The overall, it demonstrates that the multiple faces of nanoindentation is critical to determine mechanical anisotropy and structure- mechanical property correlation. Further, the structural-mechanical property correlations aids in the selection of the best solid phase for macroscopic pharmaceutical formulation

Bio-inoculated Nutrient Management Influence on Soil Nutrient Availability Pattern and Growth of Hybrid Pigeonpea (ICPH 2740) under Establishment Methods and Crop Geometry

Background A two-year field study was conducted at the ICRISAT research farm during the rainy seasons of 2021 and 2022 to investigate the impact of crop geometry, crop establishment method and sustainable nutrient management practices on nutrient availability pattern and growth of hybrid pigeon pea. Methods The experiment followed a split-split plot design. The collected data was analysed using radar graph and heat maps for nutrient availability and dry matter respectively. Result Data revealing that transplanted plots registered higher nutrient availability and proportionate root and total dry matter production at various growth stages. Among plant geometry the root and total dry matter production was higher with 100×100 cm. when considering planting methods, transplanting with a square system of 100×100 cm, combined with an integrated nutrient management approach consisting of 150% (or) 100% soil test based NPK, vermicompost at a rate of 5 t ha-1, phosphate-solubilizing bacteria (PSB) and seed treatment with Rhizobium, resulted in average of 31.5% higher dry matter production over alone inorganic nutrient management practices. Thus, a square geometry of 100×100 cm, along with sustainable integrated nutrient management (100% soil test based NPK, vermicompost at a rate of 5 t ha-1, PSB and seed treatment with Rhizobium), resulted in higher nutrient availability and dry matter production. These findings highlight the importance of careful selection of planting methods, crop geometry and nutrient management practices for maximizing the nutrient mining for production of high dry matter production of hybrid pigeonpea

Temperature-dependent structural properties, phase transition behavior, and dynamic properties of a benzene derivative in the solid state

We report the solid-state structural properties and phase transition behavior of 1,4-dibromo-2,3,5,6-tetramethylbenzene, demonstrating that this material undergoes an order–disorder phase transition below ambient temperature (at ca. 154 K on cooling and ca. 160 K on heating). In both the high-temperature and low-temperature phases, the crystal structure is based on π-stacking of the molecules. In the crystal structure of the high-temperature phase, the bromine occupancy in each substituent site is ca. 1/3 and the methyl group occupancy in each substituent site is ca. 2/3, consistent with statistical orientational disorder of the molecule between six distinct orientations. Natural-abundance solid-state 2H NMR spectroscopy confirms that, at ambient temperature, this disorder is dynamic via rapid molecular reorientation about an axis perpendicular to the aromatic ring. In the low-temperature phase, the bromine and methyl substituents occupy preferred sites within the crystal structure, with the distribution of site occupancies becoming progressively more ordered on decreasing temperature

Three new hydrochlorothiazide cocrystals: Structural analyses and solubility studies

YesHydrochlorothiazide (HCT) is a diuretic BCS class IV drug with poor aqueous solubility and low permeability leading to poor oral absorption. The present work explores the cocrystallization technique to enhance the aqueous solubility of HCT. Three new cocrystals of HCT with water soluble coformers phenazine (PHEN), 4-dimethylaminopyridine (DMAP) and picolinamide (PICA) were prepared successfully by solution crystallization method and characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), fourier transform –infraredspectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Structural characterization revealed that the cocrystals with PHEN, DMAP and PICA exists in P21/n, P21/c and P21/n space groups, respectively. The improved solubility of HCT-DMAP (4 fold) and HCT-PHEN (1.4 fold) cocrystals whereas decreased solubility of HCT-PICA (0.5 fold) as compared to the free drug were determined after 4 h in phosphate buffer, pH 7.4, at 25 °C by using shaking flask method. HCT-DMAP showed a significant increase in solubility than all previously reported cocrystals of HCT suggest the role of a coformer. The study demonstrates that the selection of coformer could have pronounced impact on the physicochemical properties of HCT and cocrystallization can be a promising approach to improve aqueous solubility of drugs

The Opinions of Italian Psychology Students About People Diagnosed with Depression and Schizophrenia: A Comparative Study

This study explored the opinions about depression and schizophrenia among Italian psychology students, and whether students’ opinions changed during education. Of the 705 students who read a description of depression (N = 275) or schizophrenia (N = 430) and then completed a questionnaire on their opinions about the disorder, 490 made a correct diagnosis (depression = 243/275; schizophrenia: 247/430) and were included in the study. Compared to schizophrenia-group students, depression-group students: more frequently mentioned psychosocial factors and less frequently heredity among the causes; were more convinced about the usefulness of psychological therapies and less about pharmacotherapies; had more prognostic optimism; had lower perception of unpredictability and dangerousness. Compared to first-year students, fifth-year students (depression = 105; schizophrenia = 162): in both diagnostic groups more frequently cited heredity among the causes; in depression group, had lower perception of unpredictability; in schizophrenia group, had higher perception of dangerousness and more prognostic pessimism. More education about stigma should be provided to psychology students