Metalloporphyrin-capped calix[4]pyrroles: heteroditopic receptor models for anion recognition and ligand fixation

Diametrically strapped calix[4]pyrrole-metalloporphyrin conjugates, potential hosts for anionic guests, have been synthesized and characterized. The syntheses rely on the acid-catalyzed condensation of two dipyrromethane bearing Ni(II) porphyrins with acetone. An (1)H NMR spectroscopic titration experiment indicated that the resulting receptors selectively trapped fluoride anions in organic media but not other, larger halide anions. The experimental results from titration and Job plots indicated that the bound fluoride anion must reside inside the cavity. The current systems provide a well-defined illustration of how size-selective anion receptors may be synthesized by incorporating recognition functions, such as Lewis acidity, hydrogen bonding, and encapsulating moieties into established recognition motifs, calix[4]pyrrole in the present instance.     

Meso-diacylated calix[4]pyrrole: structural diversities and enhanced binding towards dihydrogenphosphate ion

Meso-diacylated calix[4]pyrrole was obtained via acid catalysed condensation of meso-acylated dipyrromethane with acetone. Selective presence of flexible substituents at the calix[4]pyrrole periphery led to interesting structural motifs in the solid state along with enhanced binding towards anions, especially dihydrogenphosphate ion via anchoring.     

Synthesis of bis(pyrrol-2-yl)arenes by Pd-catalyzed cross coupling

2-Borylpyrrole was prepared from 2-iodopyrrole almost quantitatively and then reacted with dihaloarenes under typical reaction conditions of Suzuki-Miyaura cross coupling to give bis(pyrrol-2-yl)arenes in good yields, while the cross coupling reaction of 2-iodopyrrole with 1,4-phenylenebisboronic acid was susceptible to oxidative self-coupling to produce 4,4′-bis(pyrrol-2-yl)biphenyl as a byproduct. These bis(pyrrol-2-yl)arenes showed strong fluorescence.     

Image-Feature Based Deep Learning Model for Plant Leaf Disease Detection

Currently, everyone is facing significant difficulties with food scarcity. There may be several causes for this, but food loss is a well-known issue. Specifically, crop losses bring on by plant and leaf diseases during farming operations. Plant disease is typically identified visually or through laboratory testing, which delays detection and reduces crop yields by the time it is finished. The wide use of smartphones along with recent advancements in computer vision has made it viable to diagnose any ailment by applying machine learning techniques. Smartphone-assisted disease diagnosis is now a reality. In this study, a multi-Support Vector Machine (SVM) model is used to detect four different diseases as well as healthy conditions of plant leaves. Using 13 feature vectors for each input, a total of 2400 leaves representing four distinct classes (four varieties) have been used to train and test the model. The experimental results give an average accuracy of 91.25% for diseased leaves detection and 99% accuracy for healthy leaves detection.     

Colorimetric sensing of fluoride ion by new expanded calix[4]pyrrole through anion-π interaction

Three new expanded calix[4]pyrroles were synthesized, where the two dialkylldipyrromethane units are linked via C-C double bonds. One of them, calix[2]bispyrrolylethene, colorimetrically senses fluoride ion only, owing to anion-π interaction in polar aprotic solvents.     

Calix[4]pyrrole-capped metalloporphyrins as ditopic receptor models for anions

Strapped calix[4]pyrrole-metalloporphyrin conjugates, potential hosts for anionic guests, have been synthesized and characterized. The condensation unexpectedly resulted in the formation of the two conformational isomers of calix[4]pyrrole-capped porphyrins 6 and 7. The anion binding studies revealed that only isomer 6 showed strong binding with fluoride anion in organic solvent, and neither isomer showed any appreciable binding with Cl-, Br-, and I-. [structure: see text]