Rubén Meana-Pañeda

  • Citations Per Year
Learn More
Nucleoside-based cofactors are presumed to have preceded proteins. The Rossmann fold is one of the most ancient and functionally diverse protein folds, and most Rossmann enzymes utilize nucleoside-based cofactors. We analyzed an omnipresent Rossmann ribose-binding interaction: a carboxylate side chain at the tip of the second β-strand (β2-Asp/Glu). We(More)
This work reports a detailed theoretical study of the hydrogen abstraction reactions from ethanol by atomic hydrogen. The calculated thermal rate constants take into account torsional anharmonicity and conformational flexibility, in addition to the variational and tunneling effects. Specifically, the kinetics calculations were performed by using multi-path(More)
The classical trajectory method (also called molecular dynamics) is the most widely used method for ensemble averaging and calculating rate constants of complex dynamical systems; however it has the serious drawback of not allowing tunneling. Here, we show how to include tunneling efficiently in realtime classical trajectories by using the army ants(More)
The thermal isomerization reaction converting previtamin D to vitamin D is an intramolecular [1,7]-sigmatropic hydrogen shift with antarafacial stereochemistry. We have studied the dynamics of this reaction by means of the variational transition-state theory with multidimensional corrections for tunneling in both gas-phase and n-hexane environments. Two(More)
The utility of chloroform as both a solvent and a hydrogen atom donor in Barton reductive decarboxylation of a range of carboxylic acids was recently demonstrated (Ko, E. J. et al. Org. Lett. 2011, 13, 1944). In the present work, a combination of electronic structure calculations, direct dynamics calculations, and experimental studies was carried out to(More)
For electronically nonadiabatic processes in all but the simplest systems, the most practical multidimensional simulation method is a semiclassical approximation in which a trajectory or the center of a wave packet follows a classical path governed by an effective potential energy function. Here, we show how such simulations can be made more realistic by(More)
Direct-dynamics canonical variational transition-state theory calculations with microcanonically optimized multidimensional transmission coefficient (CVT/muOMT) for tunneling were carried out at the MPWB1K/6-31+G(d,p) level to study the [1,7] sigmatropic hydrogen rearrangement in 7-methylocta-1,3(Z),5(Z)-triene. This compound has seven conformers, of which(More)
We present quasiclassical trajectory simulations of the high-energy collision-induced O((3)P) + N2 reaction. The simulation results show that reactive scattering may proceed on both the (3)A' and (3)A″ potential energy surfaces, but the reaction on (3)A″ surface overwhelmingly dominates. At total energies of collision slightly above the threshold, the(More)
Isobutanol is a prototype biofuel, and sorting out the mechanism of its combustion is an important objective where theoretical modeling can provide information that is unavailable and not easily obtained by experiment. In the present work the rate constants and branching ratios for the hydrogen abstraction reactions from isobutanol by hydroxyl radical have(More)
A fully stereocontrolled 1,3-diol orthoesterification and a water-promoted intramolecular Henry addition, combined with the previously reported formal (3 + 3) annulation of α-nitro-α,β-enals and 2,2-dimethyl-1,3-dioxan-5-one, provided for a short convergent pathway to the dioxaadamantane core of (±)-tetrodotoxin.