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The rate constant of alkaline fading of malachite green (MG + ) was studied in alcohol-water binary mixtures. This reaction was studied under pseudo-first-order conditions at 283-303 K. It was observed that the reaction rate constants were increased in the presence of different weight percentages of methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, 1,2-propanediol, and glycerol (up to 19.3%). In aqueous glycerol solutions higher than 19.3%, the rate constant of reaction slightly decreases, which is due to high viscosity values of solvent mixtures. The fundamental rate constants of MG + fading in these solutions were obtained by using the SESMORTAC model. Owing to the charged character of activated complex, with an increase in the weight percentage of the used cosolvents or temperature, k 2 values change according to the trend of hydroxide ion nucleophilic parameter values. Also, using MG + solvatochromism, a simple test, called MAGUS, is introduced for measuring the glycerol concentration in its aqueous solutions. C 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: [508][509][510][511][512][513][514][515][516][517][518] 2010

The effect of alkali metal oxides M n O (M = Li, Na, K; n = 2, 3, 4) on the geometric, electronic, and linear and nonlinear optical properties of the Mg12O12 nanocage was investigated by density-functional-based methods. According to the computational results, these alkali metal oxides are adsorbed on the Mg12O12 nanocage because this adsorption reduces its energy gap. The static first hyperpolarizability (β 0) of the nanocage is dramatically increased in the presence of the alkali metal oxides, with the greatest increase seen in the presence of the superalkalis (i.e., M3O; M = Li, Na, and K). The highest first hyperpolarizability (β 0 ≈ 600,000 a.u.) was calculated for K3O@Mg12O12, which was considerably more than that for Mg12O12. The thermodynamic properties and relative stabilities of these inorganic compounds are discussed. Graphical Abstract Optimized structure and DOS spectrum of K3O(e@Mg12O12).

The effect of alkali metal superoxides M 3 O (M = Li, Na, K) on the electronic and optical properties of a Be 12 O 12 nanocage was studied by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The energy gaps (E g ) of all configurations were calculated. Generally, the adsorption of alkali metal superoxides on the Be 12 O 12 nanocage causes a decrease of E g . Electric dipole moment µ, polarizability α, and static first hyperpolarizability β were calculated and it was shown that the adsorption of alkali metal superoxides on Be 12 O 12 increases its polarizability. It was found that the absorption of M 3 O on Be 12 O 12 nanocluster improves its nonlinear optical properties. The highest first hyperpolarizability (β ≈ 214000 a.u.) is obtained in the K 3 O-Be 12 O 12 nanocluster. The TD-DFT calculations were performed to investigate the origin of the first hyperpolarizabilities and it was shown that a higher first hyperpolarizability belongs to the structure that has a lower transition energy.