A switchable green emitting dye and its phenomenal properties: implications for the photoluminescence features of carbon dots.

New molecular fluorophores are constantly being discovered in post-synthetic mixtures of carbon dots (CDs), prompting researchers to elucidate their role in the optical properties of these nanomaterials. It has been reported that the green-emitting fluorophore that forms during the synthesis of popular citric acid/urea CDs is HPPT (4-hydroxy-1-pyrrolo[3,4-]pyridine-1,3,6(2,5)-trione). However, due to the low concentration of HPPT-like molecules within the structure of CDs, their actual binding and contribution to the optical properties of CDs has not so far been convincingly confirmed.

Puzzling Aqueous Solubility of Guanine Obscured by the Formation of Nanoparticles.

Dissolution of guanine in neutral solutions was obscured by peculiar behavior of guanine, indicating an apparent dependence of solubility on the amount of solid guanine used. Here, we demonstrate that the problem is caused by the formation of tiny guanine nanoparticles that tend to grow forming stable particles of ca. 800 nm size.

Dissociative electron transfer in polychlorinated aromatics. Reduction potentials from convolution analysis and quantum chemical calculations.

Formal potentials of the first reduction leading to dechlorination in dimethylformamide were obtained from convolution analysis of voltammetric data and confirmed by quantum chemical calculations for a series of polychlorinated benzenes: hexachlorobenzene (-2.02 V vs. Fc(+)/Fc), pentachloroanisole (-2.

Autocatalytic cathodic dehalogenation triggered by dissociative electron transfer through a C-H···O hydrogen bond.

A combined action of the C-H···Oalkoxide hydrogen bonding and Cl···πpyrazolyl dispersive interactions facilitates intramolecular electron transfer (ET) in the transient {Mo(I)(NO)(Tp(Me2))(Oalkoxide)}˙(-)···HCCl3 adduct ([Tp(Me2)](-) = κ(3)-hydrotris(3,5-dimethylpyrazol-1-yl)borate), setting off a radical autocatalytic process, eventually leading to chloroform degradation. In the voltammetric curve, this astonishingly fast process is seen as an almost vertical drop-down. The potential at which it occurs is favorably shifted by ca.

Adsorption structures on metals--a thermodynamic description.

Thermodynamic conditions of the adsorption of gaseous molecules on metals are discussed in this work. The equilibria of the formation of surface arrays comprising several atoms, the formation of ordered structures, and the dissolution of gas atoms in the metal have been reviewed. It was found that the heat and the free energy of chemisorption is affected by the change in the number and energy of bonds between metal atoms and the adsorbate in the structures being formed.