Mohammad Asad

In this study, a novel ternary nanocatalytic system TiO ₂ /ZnO/NiO was synthesized via sol gel method and characterized using UV–visible DRS, XPS, XRD, and SEM techniques. This nanocatalyst promoted the solvent‐free, eco‐friendly synthesis of pyrazole heterocycles through a one pot reaction of aldehyde, active methylene compounds and phenyl hydrazine, which involves Knoevenagel condensation followed by Michael addition reactions. This approach notably leads to excellent yields, shorter reaction times, simple work‐up procedures and eminent reusability of catalyst for up to five successive reaction cycles. These pyrazoles were characterized using FT‐IR, ¹ HNMR, ¹³ CNMR, and MALDI‐MS spectroscopic techniques. Fluorescence studies established that all pyrazoles showed good emission properties and selective metal ion sensing behavior through effective pyrazole‐metal ion complexation. Compound 4c was characterized by fluorescence enhancement and selective detection of Co ²⁺ ions. Density functional theory studies including frontier‐molecular‐orbital and molecular‐electrostatic‐potential analyses, supported the reaction mechanism and revealed orbital controlled cyclization with a narrowed HOMO–LUMO gap at the rate‐limiting transition state. MEP analysis locates complementary π‐hole/π‐well pairs that pre‐organize the phenyl‐hydrazine nucleophile, reducing the entropic barrier and affording a 72% yield. Combined experimental and theoretical results emphasize the potential of this catalytic system for sustainable heterocyclic synthesis and development of metal‐ion responsive pyrazole fluorophores.

C ₂₃ H ₁₈ Br ₂ N ₂ O ₃ , Monoclinic, P 2 ₁ / n (no. 14), a = 20.2284(17) Å, b = 4.0250(3) Å, c = 25.612(2) Å, β = 92.435(8)°, V = 2083.4(3) Å ³ , Z = 4, R _gt ( F ) = 0.0564, w R _ref ( F ² ) = 0.1287, T = 296(3) K.

This review highlights mechanochemical strategies for CO ₂ reduction catalysis, enabling sustainable pathways toward carbon-neutral products and environmental remediation.

Context In this work, a series of heterocyclic alkenes were prepared by the reaction of 2-hydroxy-1-naphthaldehyde with various heterocyclic active methylene compounds via Knoevenagel condensation reaction using mesoporous silica, MCM 41, supported perchloric acid as an efficient green catalytic system under solvent-free conditions. A comparative study of the conventional method vs the green method was also reported with the same raw materials. ¹H NMR, ¹³C NMR, IR, and mass spectroscopic techniques were used for the characterization of synthesized compounds. Methods Computational study was performed for these compounds by applying density functional theory (DFT) at M06 functional and 6-311G (d,p) basis set to interpret the electronic structures and counter check the experimental findings. The frequency analysis with aforementioned levels of DFT was performed to confirm the stability associated with optimized geometries. The true minimum for the optimized geometries for 1, 2, and 3 was achieved as indicated by the absence of negative eigenvalues in all the calculated frequencies. Additionally, natural bond orbitals (NBOs) and nonlinear optical (NLO) properties were explored utilizing the aforementioned level and basis set combination via DFT, whereas the frontier molecular orbitals (FMOs) evaluation was done at time-dependent density functional theory TDDFT at M06/6-311G(d,p). The global reactivity parameters were also calculated using the FMO data. These computation-based outcomes were found in good agreement with the experimental findings.

Currently, polymer organic solar cells (POSCs) are widely utilized due to their significant application, such as low-cost power conversion efficiencies (PCEs). Therefore, we designed a series of photovoltaic materials (D1, D2, D3, D5 and D7) by the incorporation of selenophene units (n = 1–7) as π₁-spacers by considering the importance of POSCs. Density functional theory (DFT) calculations were accomplished at MPW1PW91/6-311G (d, p) functional to explore the impact of additional selenophene units on the photovoltaic behavior of the above-mentioned compounds. A comparative analysis was conducted for designed compounds and reference compounds (D1). Reduction in energy gaps (∆E = 2.399 − 2.064 eV) with broader absorption wavelength (λ_max = 655.480 − 728.376 nm) in chloroform along with larger charge transference rate was studied with the addition of selenophene units as compared to D1. A significantly higher exciton dissociation rate was studied as lower values of binding energy (E_b = 0.508 − 0.362 eV) were noted in derivatives than in the reference (E_b = 0.526 eV). Moreover, transition density matrix (TDM) and density of state (DOS) data also supported the efficient charge transition origination from HOMOs to LUMOs. Open circuit voltage (V_oc) was also calculated for all the aforesaid compounds to check the efficiency, and significant results were seen (1.633–1.549 V). All the analyses supported our compounds as efficient POSCs materials with significant efficacy. These compounds might encourage the experimental researchers to synthesize them due to proficient photovoltaic materials.