Publications

The structural, electro-optical and charge-transport properties of compound trans -3-(3,4-dimethoxyphenyl)-2-(4-nitrophenyl)prop-2-enenitrile (DMNPN) were studied using quantum chemical methods. The neutral, cation and anion molecular geometries were optimized in the ground state using density functional theory (DFT) at the restricted and unrestricted B3LYP/6-31G** level of theory. The excited state geometries were optimized by applying time-dependent DFT at the TD-B3LYP/6-31G** level of theory. The absorption and fluorescence wavelengths were calculated at the TD-CAM-B3LYP/6-31G** and TD-LC-BLYP/6-31G** levels of theory. The distribution pattern of the charge densities on the highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) are discussed. Intramolecular charge transfer was observed from the dimethoxyphenyl to (nitrophenyl)prop-2-enenitrile moieties. The detailed charge-transport behavior of the DMNPN molecule is investigated based on its ionization potential, electron affinity, hole and electron reorganization energies, hole and electron-transfer integrals, and hole and electron intrinsic mobilities. The total/partial densities of states and structure–property relationship are discussed in detail. The higher computed hole intrinsic mobility than electron intrinsic mobility reveals that DMNPN is an efficient hole-transport material.

Abstract A simple method to prepare cobalt nanoparticles (CoNPs) in an aqueous environment was developed utilizing 4-aminophenol as a reducing agent and the gemini surfactant (14-4-14)/polyvinylpyrrolidone (PVP) as a stabilizer. The localized surface plasmon resonance band of cobalt nanoparticles in the UV-Vis spectrum was used to determine the rate of formation of cobalt nanoparticles and to assess the beginning of the oxidation process. The effect of the concentration cobalt nitrate, 4-aminophenol, 14-4-14 and PVP was investigated on the growth rate of CoNPs. The data obtained in this work provide valuable information on the rate of reaction at the nanoscale.

A Pd site initiates hydrogen peroxide decomposition by adsorbing one ‘O’ followed by splitting of O–H bond. Meanwhile, a Pt site finally completes the decomposition process by enabling desorption of the incipient O₂species.

Ni₂P nanoflake arrays on carbon cloth act as an efficient and durable catalyst electrode for the urea oxidation reaction (UOR) and hydrogen evolution reaction (HER). Its two-electrode alkaline electrolyzer needs 1.35 V for 50 mA cm⁻², which is 0.58 V less than that required for pure water splitting.

The human nasopharynx-associated lymphoid tissue (NALT) and bronchus-associated lymphoid tissue (BALT) could successfully limit the spread of several respiratory pathogens. However, in the case of MERS-CoV infection, limited research has been conducted in humans with regard to immunopathogenesis and mucosal immune responses due to the lack of relevant tissues. A better understanding of the immune mechanisms of the URT and LRT is vital for the design and development of effective MERS-CoV vaccines.

A novel strategy was developed for microRNA detection based on the fluorescence quenching of polydopamine (PDA)-coated reduced graphene oxide (RGO) nanosheets (RGO@PDA). Compared with graphene oxide (GO), the reduction of GO and modification of the surface of RGO by PDA not only improve the stability, dispersity, biocompatibility, and cellular uptake without degeneration of the unique electronic properties of graphene, but also add an electron gate for harvesting electrons, as well as enabling efficient and forward electron transfer to avoid unwanted electron transfer and realize highly sensitive miRNA detection; thus a lower detection limit can be achieved in this sensing system. Remarkably, nanoprobes consisting of RGO@PDA and fluorescein-labeled single-stranded DNA can naturally enter cancer cells without the aid of transfection agents, as well as resisting enzymatic lysis and showing almost no effect on the cell viability. More importantly, intense and time-dependent fluorescence responses were observed from the important tumor marker microRNA-21 (miR-21) in living cells; thus suggesting that the proposed sensing platform shows great promise for applications in disease diagnosis and fundamental research into biochemistry.

Fullerene-based organic compounds have been reported as useful materials with some limitations; nonetheless, fullerene-free compounds are primarily considered to be the most substantial materials for the development of modern technology. Therefore, in this study, a series of compounds (<b>NFBC2</b>-<b>NFBC7</b>) having an A<i>-</i>π-D architecture were designed for the first time from a synthesized nonfullerene (<b>O-IDTBR</b>) compound by changing different acceptor groups. The synthesized nonfullerene (<b>O-IDTBR1</b>) compound and its designed derivatives were optimized with frequency analyses at the M06/6-311G(d,p) level. These optimized structures were further characterized by different quantum chemical approaches. The study required that the designed compounds possess a low energy gap in comparison to that of <b>O-IDTBR1</b> (2.385 eV). Moreover, density of state (DOS) calculations supported the FMO analysis and displayed charge transfers from the HOMO to the LUMO in an effective manner. The λ_max values of the investigated chromophores were observed to be greater than that of the reference compound. Amazingly, the highest amplitude of linear polarizability ⟨α⟩ and first (β_tot) and second hyperpolarizability values were achieved by <b>NFBC6</b> at 1956.433, 2155888.013, and 7.868 × 10⁸ au, respectively, among all other derivatives. Effective NLO findings revealed that nonfullerene-based derivatives may contribute significantly to NLO technology.

Quantum dots (QDs) are semiconducting inorganic nanoparticles, tiny molecules of 2-10 nm sizes to strength the quantum confinements of electrons. The QDs are good enough to emit light onto electrons for exciting and returning to the ground state. Here, CdSe/ZnS core/shell QDs have been prepared and applied for electrochemical sensor development in this approach. Flat glassy carbon electrode (GCE) was coated with CdSe/ZnS QDs as very thin uniform layer to result of the selective and efficient sensor of 3-CP (3-chlorophenol). The significant analytical parameters were calculated from the calibration plot such as sensitivity (3.6392 µA µM^-1 cm^-2) and detection limit (26.09 ± 1.30 pM) with CdSe/ZnS/GCE sensor probe by electrochemical approach. The calibration curve was fitted with the regression co-efficient r² = 0.9906 in the range of 0.1 nM ∼ 0.1 mM concentration, which denoted as linear dynamic range (LDR). Besides these, it was performed the reproducibility in short response time and successfully validated the fabricated sensor for 3-CP in the real environmental and extracted samples. It is introduced as a noble route to detect the environmental phenolic contaminants using CdSe/ZnS QDs modified sensor by electrochemical method for the safety of healthcare and environmental fields at broad scales.