Facile Decoration of Polyaniline Fiber with Ag Nanoparticles for Recyclable SERS Substrate

Facile synthesis of polyaniline@Ag composite has been successfully demonstrated by a simple solution-dipping method using high-aspect-ratio benzene tetracarboxylic acid-doped polyaniline (BDP) fiber as a nontoxic reducing agent as well as template cum stabilizer. In BDP@Ag composite, BDP fibers are decorated with spherical Ag nanoparticles (Ag NPs), and the population of Ag NPs on BDP fibers is controlled by changing the molar concentration of AgNO₃. Importantly, Ag-NP-decorated BDP fibers (BDP@Ag composites) have been evolved as a sensitive materials for the detection of trace amounts of 4-mercaptobenzoic acid and rhodamine 6G as an analyte of surface-enhanced Raman scattering (SERS), and the detection limit is down to nanomolar concentrations with excellent recyclability. Furthermore, synthesized BDP@Ag composites are applied simultaneously as an active SERS substrate and a superior catalyst for reduction of 4-nitrothiophenol

Reduced Graphene Oxide/Fe₃O₄/Polyaniline Nanostructures as Electrode Materials for an All-Solid-State Hybrid Supercapacitor

We have synthesized a ternary rGO/Fe₃O₄/PANI (rGFP) composite for binder-free, semiflexible, thin, all-solid-state supercapacitor device fabrication. A scalable soft-template technique has been adopted for the preparation of three-dimensional Fe₃O₄-decorated reduced graphene oxide (rGO)-doped polyaniline (PANI) nanorods that are unambiguously investigated under electron microscopes (FESEM and HRTEM). The presence of PANI in the nanocomposite is overwhelmingly supported by the absorption and vibration studies. Raman spectra convincingly show the presence of rGO in the nanocomposites, and the formation of Fe₃O₄ nanoparticles is confirmed by XRD and XPS results. The specific capacitance value that has been achieved for synthesized ternary rGFP nanocomposite is ∼283.4 F/g at 1.0 A/g current density and exhibited a maximum energy density of 47.7 W h/kg at a power density of 550 W/kg. Interestingly, after 5000 cycles the composite shows excellent life stability that is a 78% retention of the electrochemical property. To demonstrate the portable energy storage applicability, a binder-free rGFP-based supercapacitor device was fabricated, which illustrated the operation of an LED bulb for 30 min when fully charged. These results indicate that synthesized ternary nanocomposites are worth their potential as an electrode material and would be used in next-generation high-rate energy storage systems

One-Dimensional Anhydrous Proton Conducting Channel Formation at High Temperature in a Pt(II)-Based Metallo-Supramolecular Polymer and Imidazole System

One dimensional (1D) Pt­(II)-based metallo-supramolecular polymer with carboxylic acids (polyPtC) was synthesized using a new asymmetrical ditopic ligand with a pyridine moiety bearing two carboxylic acids. The carboxylic acids in the polymer successfully served as apohosts for imidazole loaded in the polymer interlayer scaffold to generate highly ordered 1D imidazole channels through the metallo-supramolecular polymer chains. The 1D structure of imidazole loaded polymer (polyPtC-Im) was analyzed in detail by thermogravimetric analysis, powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and ultraviolet–visible and photoluminescence spectroscopic measurements. PolyPtC-Im exhibited proton conductivity of 1.5 × 10^–5 S cm^–1 at 120 °C under completely anhydrous conditions, which is 6 orders of magnitude higher than that of the pristine metallo-supramolecular polymer

Azo Anion Radical Complex of Rhodium as a Molecular Memory Switching Device: Isolation, Characterization, and Evaluation of Current–Voltage Characteristics

Two rare examples of azo anion diradical complexes of Rh­(III) are reported. These complexes showed excellent memory switching properties with a large ON/OFF ratio and are suitable for RAM/ROM applications. Their electronic structures have been elucidated using a host of physical methods, including X-ray crystallography, variable-temperature magnetic susceptibility measurement, cyclic voltammetry, electron paramagnetic resonance spectroscopy, and density functional theory. The results indicate a predominant triplet state description of the systems with two ferromagnetically coupled radicals

Azo Anion Radical Complex of Rhodium as a Molecular Memory Switching Device: Isolation, Characterization, and Evaluation of Current–Voltage Characteristics

Two rare examples of azo anion diradical complexes of Rh­(III) are reported. These complexes showed excellent memory switching properties with a large ON/OFF ratio and are suitable for RAM/ROM applications. Their electronic structures have been elucidated using a host of physical methods, including X-ray crystallography, variable-temperature magnetic susceptibility measurement, cyclic voltammetry, electron paramagnetic resonance spectroscopy, and density functional theory. The results indicate a predominant triplet state description of the systems with two ferromagnetically coupled radicals

Selective DNA Recognition and Cytotoxicity of Water-Soluble Helical Metallosupramolecular Polymers

Water-soluble helical Fe­(II)-based metallosupramolecular polymers ((<i>P</i>)<b>-</b> and (<i>M</i>)-polyFe) were synthesized by 1:1 complexation of Fe­(II) ions and bis­(terpyridine)­s bearing a (<i>R</i>)- and (<i>S</i>)-BINOL spacer, respectively. The binding affinity to calf thymus DNA (ct-DNA) was investigated by titration measurements. (<i>P</i>)-PolyFe with the same helicity as B-DNA showed 40-fold higher binding activity (<i>K</i>_b = 13.08 × 10⁷ M^–1) to ct-DNA than (<i>M</i>)-polyFe. The differences in binding affinity were supported by electrochemical impedance spectroscopy analysis. The charge-transfer resistance (<i>R</i>_ct) of (<i>P</i>)-polyFe increased from 2.5 to 3.9 kΩ upon DNA binding, while that of (<i>M</i>)-polyFe was nearly unchanged. These results indicate that ionically strong binding of (<i>P</i>)-polyFe to DNA chains decreased the mobility of ions in the conjugate. Unique rod-like images were obtained by atomic force microscopy measurement of the DNA conjugate with (<i>P</i>)-polyFe, likely because of the rigid binding between DNA chains and the polymer. Differences in polymer chirality lead to significantly different cytotoxicity levels in A549 cells. (<i>P</i>)-PolyFe showed higher binding affinity to B-DNA and much higher cytotoxicity than (<i>M</i>)-polyFe. The helicity in metallosupramolecular polymer chains was important not only for chiral recognition of DNA but also for coordination to a biological target in the cellular environment