Ravinder Pawar

Acid-size-aware Voronoi mapping identifies accessible FLP pockets in base-functionalized 3D COFs. ML surrogates and genetic exploration navigate the design space, prioritizing porous hosts with high pocket capacity for prospective CO ₂ utilization.

The cycloaddition behavior of 3-azacyclopentadienone depends strongly on reaction-partner identity, but how this dependence reshapes post-transition-state dynamics remains unclear. Herein, we investigate the endocycloadditions of 3-azacyclopentadienone with furan and cyclopentadiene using density functional theory, DLPNO-CCSD(T) single-point calculations, quasi-classical molecular dynamics trajectories, and complementary orbital analyses. The results show that reaction-partner identity reshapes both the transition-state region and the downstream reaction landscape. In the furan system, one endo pathway proceeds through a highly asynchronous ambimodal transition structure but exhibits a strong dynamic preference for one product channel, whereas the competing pathway follows a conventional single-valley route. In contrast, both endo pathways with cyclopentadiene access bifurcating post-transition-state surfaces and display substantial two-product dynamic competition. Solvation-model-based SMD calculations in dichloromethane, tetrahydrofuran, and acetonitrile indicate that solvation produces only modest changes in barrier heights and does not alter the qualitative kinetic ordering. Intrinsic bond orbital and electron density of delocalized-bond analyses further support these contrasting behaviors in terms of post-transition-state bond reorganization and cyclic electron delocalization. These results demonstrate that reaction-partner identity can switch 3-azacyclopentadienone cycloadditions among single-valley descent, biased ambimodal branching, and persistent post-transition-state bifurcation.

Development of calcium-ion batteries (CIBs) is strongly hindered by the limited availability of electrolytes that enable reversible plating and stripping of Ca²⁺ ions while maintaining interfacial and electrochemical stability. Motivated by this need for chemically distinct and less fluorinated weakly coordinating anions, we present a density functional theory (DFT) evaluation of hexacoordinated phosphate/phosphorate anions as prospective electrolyte components for CIBs. Surface electrostatic analysis indicates diffuse negative potential distributions consistent with weakly coordinating anion (WCA)-like behavior, broadly comparable to fluorinated alkoxy borate and aluminate anions. Their electrochemical viability was further assessed using frontier molecular orbital (HOMO/LUMO) descriptors, binding energies, and oxidation/reduction limits to estimate electrochemical stability windows (ESW) in representative solvents. Across the series, oxygen-rich chelating frameworks generally exhibit weaker Ca²⁺-anion association and enhanced oxidative robustness, which is consistent with the calculated ESW values. Overall, the phosphate-based anions fall within the performance window of previously investigated WCA families, supporting their potential as a chemically distinct class of electrolyte additives for CIBs. Among the anions examined, TOP and TCP show higher ESW, with TOP in ethylene carbonate (EC) emerging as the best combination under the descriptors considered, making it a viable electrolyte component.

The design of new molecules from known structural motifs via [3 + 2] cycloaddition is a widely used strategy in modern drug discovery.

Bifurcating reactions yield multiple products from a single transition state (TS) without intervening minima, rendering product selectivity a formidable challenge, which is governed by dynamic effects rather than TS energetics. Herein, we report a rare instance of product selectivity in a bifurcating dimerization pathway of 2,3-diazacyclopentadienone. The reaction proceeds through two sequential unsymmetric bifurcations on the potential energy surface via a stepwise mechanism involving an intermediate, ultimately yielding a selectively dimerized product. The adduct formed via the N═N moiety acting as the dienophile is kinetically favored and proceeds through a closed-shell TS, while the thermodynamically controlled adduct where the C═C moiety serves as the dienophile is accessed through a singlet biradicaloid TS. The work further rationalizes the intricate interplay of the electronic structure and behavior that modulates electron flow and drives the dimerization that ultimately originates unprecedented product selectivity in a complex bifurcating landscape.

This study investigates the interaction of methanol (CH ₃ OH) with transition metal dichalcogenides (TMDCs), focusing particularly on the effect of thorium (Th) doping on the methanol oxidation reaction (MOR).

The ambimodal cycloaddition between pentafulvene and a homologous series of [n]radialenes (n = 3-6) was systematically investigated using density functional theory, DLPNO-CCSD(T) calculations, and quasi-classical molecular dynamics (QCMD) simulations to elucidate the geometric and electronic origins of periselectivity. Despite their intrinsic instability, these π-rich systems enable the formation of multiple products through bifurcated potential energy surfaces (PESs). Two distinct ambimodal transition states were identified, corresponding to bispericyclic (exo) and trispericyclic (endo) pathways. The reaction revealing [5]-radialene exhibits the most pronounced ambimodal character, driven by favorable exocyclic π-overlap, extensive charge delocalization, and the lowest activation barrier. Intrinsic bond orbital and interaction region indicator analyses reveal asynchronous σ-bond formation and progressive orbital reorganization that govern dynamic branching behavior. QCMD simulations further confirm that product distributions are dictated by PES topography rather than static transition-state energetics, underscoring the significance of dynamic effects in determining selectivity. This comprehensive study establishes a unified mechanistic framework linking geometry and electronic delocalization to dynamic selectivity control in cross-conjugated π-systems, offering predictive insights into ambimodal bis- and trispericyclic reactivity with potential implications for synthetic and biosynthetic design.

The cycloaddition of 2-azacyclopentadienone (2-AzaCPD) with furan follows a single product-forming pathway in the gas phase, whereas acetonitrile reduces transition-state asymmetry and enables competing post-transition-state pathways.

Boronium cation structure indirectly tunes the solvation shell of Ca ²⁺ , influencing its mobility in ionic-liquids.

Synthesis of a water splitting catalyst from Vitex negundo leaves.