Deepak Chopra

BACKGROUND: Widespread resistance among malaria vectors to conventional insecticides, coupled with the limited availability of insecticides with novel mechanisms of action, necessitates the discovery of new chemical scaffolds for vector control. Anopheles arabiensis is an important malaria vector in sub‐Saharan Africa and poses additional control challenges due to its behavioral adaptability and rising insecticide resistance. This study aimed to design, synthesize, characterize, and evaluate novel 6‐(4‐substituted phenyl)imidazo[2,1‐ b ][1,3,4]thiadiazole‐2‐carboxamide derivatives ( 6a–6i ) as potential larvicidal agents. RESULTS: Novel derivatives were synthesized and evaluated against third‐instar A. arabiensis larvae. At 4 μg/ mL , mortality ranged from 18% to 97% after 48 h. Compound 6e , bearing a sulfolane substituent, was the most active, producing 93% and 97% mortality at 24 and 48 h, respectively, comparable to temephos (99% at both time points). Its median lethal concentration ( LC ₅₀ ) values were 1.17 and 1.03 μg/ mL , respectively, compared with 1.41 and 1.21 μg/ mL for temephos, corresponding to an efficiency ratio of 0.9 at both time points. Structure–activity relationship ( SAR) analysis indicated that the C‐6 trifluoromethyl group and polar hydrogen‐bond‐accepting substituents were favorable. Molecular docking identified adenosine kinase as a potential target, with recurrent interactions involving Gly64, Asn221, and Leu133. CONCLUSION: The findings identify imidazo[2,1‐ b ][1,3,4]thiadiazole as a promising scaffold for developing new larvicidal chemotypes. Compound 6e represents the most promising lead and provides a basis for further optimization and validation of this scaffold for innovative malaria‐vector control strategies. © 2026 Society of Chemical Industry.

Azo-urea molecular photoswitches form chloride-templated supramolecular channel-like architectures that allow reversible photomodulation of self-assembly and transport activity, enabling light-controlled chloride transport across lipid membranes.

The current highlight intends to unravel the historical developments in the field of in situ cryocrystallization.

Noncovalent interactions involving thiol molecules remain poorly characterized, despite their ubiquity in biological systems and materials. In particular, the nature of S–H–donor involved in weak hydrogen bonding in thiols remains underexplored. Herein, we investigate the intermolecular interactions in two in situ cryocrystallized thiols (liquids at room temperature), 4-fluorothiophenol (1) and benzyl thiol (2), wherein the crystal structures were determined from single-crystal X-ray diffraction data, the measurements being performed at 210 K for (1) and at 200 K for (2). Quantitative insights into these interactions are derived from electron-density topological parameters and pairwise interaction energies using the models based on quantum crystallography (QCr). Hirshfeld atom refinement (HAR) yields accurate S–H bond lengths, which are comparable to neutron data. These studies reveal directional, stabilizing S–H···S/π hydrogen bonds with lattice-energy contributions rivaling or surpassing those of π···π, C–H···π, C–H···S, and C–H···F motifs. Molecular dynamics simulations show that these interactions weaken significantly at ambient temperature, rationalizing the low melting behavior of these thiol compounds. Together, these results provide a quantitative picture of thiol-based noncovalent interactions across solid–liquid regimes and establish their pivotal role in dictating the physical properties of liquid thiols.

The phenomenon of polymorphism and isostructurality, though conceptually distinct, is governed by the role of intermolecular interactions that are of importance in crystal packing. Here, we report the synthesis and structural characterization of mono‐ and di‐substituted chloro/bromo phenyl benzimidamides to explore these phenomena. Extensive screening of the compounds resulted in ( Z )‐ N '‐(4‐bromophenyl)benzimidamide existing as dimorphs, which, despite differences in crystal density and thermal stability, exhibit nearly isostructural packing, as confirmed by structure similarity analysis. Interaction energy calculations confirmed their isoenergetic nature and established them as being ‘quasi‐isostructural polymorphs’, an intermediate state between polymorphism and isostructurality. Other halogen‐substituted derivatives displayed similar unit cell parameters, and their structural similarity analysis confirmed the same. Three‐dimensional isostructurality with a low dissimilarity index value, yielding isomorphous chloro/bromo pairs. The crystal packing analysis and intermolecular interaction energy calculations further revealed comparable interaction topologies and energetic contributions across these isostructural pairs. Quantitative investigation demonstrated consistent intermolecular interaction motifs, dominated by strong N…H hydrogen bonds, together with Cl/Br…H interactions. Together, these results provide deep insights into how subtle changes in the position of the same or different functional groups govern crystal packing and energetics in halogen‐substituted molecules.

Herein we report the design, synthesis, and self‐assembly behaviour of a chiral, fluorescent macrocycle (CFM) based on a pyridine‐2,6‐dicarboxamide (PDC) core, incorporating cyclohexane‐1,2‐diamine as a chiral linker. Single crystal x‐ray diffraction (SCXRD) structural analysis confirmed that CFM adopts a rigid helically twisted conformation stabilized through intramolecular H‐bonding. The CFM self‐assembled into twisted‐ribbons in 50% DMF/water mixture. The helical‐twist direction of these ribbons was governed by the molecular chirality of the enantiomeric macrocycles ( R , R )‐CFM and ( S , S )‐CFM. These ribbon‐shaped assemblies displayed increased circular dichroism (CD) and circular polarized luminescence (CPL) signal with g _lum up to 7 × 10 ⁻³ at λ = 490 nm. Furthermore, CFM showed charge transfer interaction (CTI) with tetracyanobenzene (TCNB), resulting in distinct red‐shifted chiroptical signals in both the solution and the solid states. The formation of the CT complex induced a distinct morphological transition, disrupting the twisted ribbon structures and yielding microspheres at higher ratios of TCNB. Remarkably, the CT coassembly exhibited CPL in the orange‐reddish region with g _lum 3 × 10 ⁻⁴ at λ = 650 nm. SCXRD further revealed that TCNB molecules were intercalated between the pyrene wings of two CFM molecules, stabilized through strong intermolecular interactions such as π–π stacking and C─H···O interactions with the amide oxygen.

Thermally activated delayed fluorescence (TADF) in metal nanoclusters (MNCs) is an effective strategy to harvest the emission from the excited-triplet states. However, the applications of these TADF-active MNCs are limited by the use of hydrophobic ligands, which generally make these MNCs insoluble. Herein, we report the NIR-TADF emitting CuNCs that are highly water-soluble and display intense-red emission in the solid state. The atomic connectivity of the CuNCs was determined by SC-XRD technique. The delayed fluorescence phenomenon is validated by temperature-dependent photoluminescence studies, and the excited singlet–triplet energy gap (ΔE_ST) was experimentally estimated to be ∼98 meV, thereby substantiating the TADF mechanism. DFT calculations performed on the crystal geometry of the CuNCs further attested to the TADF mechanism along with the associated charge-transfer dynamics. Additionally, the CuNCs demonstrate excellent catalytic activity involving the reduction of ferricyanide and Methylene Blue, highlighting their multifunctional applications in the aqueous phase.