One‐Step Multicomponent Self‐Assembly of a First‐Generation Sierpiński Triangle: From Fractal Design to Chemical Reality

A novel terpyridine‐based architecture that mimics a first‐generation Sierpiński triangle has been synthesized by multicomponent assembly and features tpy? Cd^II? tpy connectivity (tpy=terpyridine). The key terpyridine ligands were synthesized by the Suzuki cross‐coupling reaction. Mixing two different terpyridine‐based ligands and Cd^II in a precise stoichiometric ratio (1:1:3) produced the desired fractal architecture in near‐quantitative yield. Characterization was accomplished by NMR spectroscopy, mass spectrometry, and transmission electron microscopy.     

Strong Stokes and Upconversion Luminescence from Ultrasmall Ln3+‐Doped BiF3 (Ln=Eu3+, Yb3+/Er3+) Nanoparticles Confined in a Polymer Matrix

Heavy metal fluorides like BiF₃ as a host for lanthanide ions are of interest as bismuth is the only heavy metal that is nontoxic. In this work, we report the synthesis of highly water‐dispersible ultrasmall BiF₃ nanoparticles about 6 nm in size within a poly(vinyl pyrrolidone) matrix by a hydrothermal method. Microscopy analysis reveals that the nanoparticles are well separated and confined within the polymer network. These nanoparticles were found to be excellent hosts for lanthanide (Ln³⁺) ions. Through suitable Ln³⁺ doping, BiF₃ exhibits strong emissions in the visible region upon both UV and near infrared (NIR) excitations. The non‐toxicity of both bismuth and PVP can be advantageous for the potential use of BiF₃ nanoparticles in drug delivery and bioimaging.     

Synthesis and photophysical study of silver nanoparticles stabilized by unsaturated dicarboxylates

Solution-phase synthesis of nanometer-sized silver particles is reported by sodium borohydride reduction of AgNO_3. Two isomeric dicarboxylates (sodium maleate and sodium fumarate) have been used as stabilizing agents. The dicarboxylate-stabilized silver nanoparticles are characterized by UV-vis spectroscopy, high-resolution transmission electron microscopy (HR-TEM) and fourier transform infrared (FT-IR) spectroscopy. A qualitative comparison is made between the UV-vis spectral characteristic of the SPR band and the simulated curve obtained from modified Mie's theory. Silver nanoparticles prepared using these two isomeric dicarboxylates show intense fluorescence in the visible region. DFT with hybrid functional (B3LYP)-based frequency (IR) calculation of both the dicarboxylates and the respective nanoparticles are in good agreement with the experimental IR frequency. On the basis of this calculation a model has been proposed for the stabilization of silver nanoparticles by these two isomeric dicarboxylate anions.     

Effect of adsorption of vapours on the electrical conductivity of lycopene crystals: Evidence of a three-stage adsorption process

Upon adsorption of various vapours, the electrical conductivity of lycopene semiconductor changes appreciably This phenomenon had been used as a probe to study the adsorption and desorption processes in these polyene crystals The adsorption and desorption kinetics have been found to follow a modified Roginsky-Zeldovich relation A three-stage adsorption process has been identified The first stage gives a Lennard-Jones potential energy curve, followed by a transition over a potential barrier to the second stage of adsorption in a potential well In the third stage a deep potential energy surface is reached by activation over a second potential barrier and strongly bound complexes between the vapour molecules and the surface molecules of the crystals are finally formed.     

Studies on nessler's reagent and nessler's precipitate part II

The composition of the precipitate formed when the Nessler's reagent is treated with ammonia, is assumed as NH_n-1Hg₂I_n, aq. and has been studied potentiometrically from iodine-hypoiodite-system. It has been observed that the value of n depends on the concentrations of [HgI₄]^-2 and OH^- ions as well as on the amount of ammonia added and it may vary from 1 to 3. The colour of the precipitate deepens from brown to chocolate as the value of n increases.