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The description of two novel double-hybrid functionals, B2K-PLYP and mPW2K-PLYP, is presented. The proposed functionals depict excellent results for main-group thermochemistry, main-group thermochemical kinetics, and late transition metal reactions.

An extensive ab initio and density functional theory (DFT) methods are applied to characterize and study Rozen's epoxidation reagent, C[H.sub.3]CN.HOF, and a prototype epoxidation reaction employing it. The formation of alternative hydrogen bond networks is considered and DFT anharmonic force fields of the C[H.sub.3]CN.HOF dimer and its monomers are obtained for further spectroscopic studies on the dimer.

The glutathione S-transferase (GST) family plays an important role in the adaptation of herbivorous insects to new host plants and other environmental constrains. The family codes for enzymes that neutralize reactive oxygen species and phytotoxins through the conjugation of reduced glutathione. Here, we studied the molecular evolution of the GST family in Bemisia tabaci , a complex of >35 sibling species, differing in their geographic and host ranges. We tested if some enzymes evolved different functionality, by comparing their sequences in six species, representing five of the six major genetic clades in the complex. Comparisons of the nonsynonymous to synonymous substitution ratios detected positive selection events in 11 codons of 5 cytosolic GSTs. Ten of them are located in the periphery of the GST dimer, suggesting a putative involvement in interactions with other proteins. Modeling the tertiary structure of orthologous enzymes, identified additional 19 mutations in 9 GSTs, likely affecting the enzymes' functionality. Most of the mutation events were found in the environmentally responsive classes Delta and Sigma, indicating a slightly different delta/sigma tool box in each species. At a broader genomic perspective, our analyses indicated a significant expansion of the Delta GST class in B. tabaci and a general association between the diet breadth of hemipteran species and their total number of GST genes. We raise the possibility that at least some of the identified changes improve the fitness of the B. tabaci species carrying them, leading to their better adaptation to specific environments. [ABSTRACT FROM AUTHOR]