The strength of the O-O bond is of fundamental importance in a variety of chemical processes. Traditionally, a value of 34 kcal/mol has been ascribed to a generic O-O bond dissociation energy. The present, high-level ab initio calculations indicate that the average O-O bond energy is significantly higher, ca. 45 kcal/mol, and that the bond energy is sensitive to the bonding environment. Calcula...

The potential energy surfaces for the chemical reactions of lattice-framework group 14 heavy carbene species have been studied using density functional theory (B3LYP/LANL2DZ) and the Gibbs free energy method. Five lattice-framework group 14 heavy carbene species, L-F-X: , where X = C, Si, Ge, Sn, and Pb, have been chosen as model reactants in this study. Also, four kinds of chemical reactions, ...

EXPERIMENTAL AND THEORETICAL STUDIES OF BINDING INTERACTIONSIN DIVALENT TRANSITION METAL CATION-N-DONOR LIGANDCOMPLEXES: STRUCTURES, SEQUENTIAL BOND DISSOCIATION ENERGIES,MECHANISMS AND ENERGETICS OF COLLISION-INDUCED DISSOCIATION

2,2,6,6-Tetramethylpiperidinyl-masked 1,2-diols exhibited stereochemistry-dependent hydroxyl proton chemical shifts: ca. 7 ppm for the syn diastereomer and ca. 2 ppm for the anti diastereomer. A computational search for low energy geometries revealed that the syn isomer favors a six-membered ring hydrogen bond to nitrogen and the anti isomer favors a five-membered ring hydrogen bond to oxygen. ...

An energy decomposition analysis (EDA) for single chemical bonds is presented within the framework of Kohn-Sham density functional theory based on spin projection equations that are exact within wave function theory. Chemical bond energies can then be understood in terms of stabilization caused by spin-coupling augmented by dispersion, polarization, and charge transfer in competition with desta...

An improved density matrix functional [correction to Buijse and Baerends functional (BBC)] is proposed, in which a hierarchy of physically motivated repulsive corrections is employed to the strongly overbinding functional of Buijse and Baerends (BB). The first correction C1 restores the repulsive exchange-correlation (xc) interaction between electrons in weakly occupied natural orbitals (NOs) a...

In this research at the first Metoprolol drug and its fullerene derivative were optimized. Natural bond orbital (NBO), nuclear Indepndent chemical shift (NICS) and finally IR calculations, for these compounds were carried out at the B3LYP/6-31G* quantum chemistry level. Different parameters such as energy levels, the amount of chemical shift in different atoms, the amount of HOMO/LUMO, chemical...

In this research at the first Metoprolol drug and its fullerene derivative were optimized. Natural bond orbital (NBO), nuclear Indepndent chemical shift (NICS) and finally IR calculations, for these compounds were carried out at the B3LYP/6-31G* quantum chemistry level. Different parameters such as energy levels, the amount of chemical shift in different atoms, the amount of HOMO/LUMO, chemical...

When a chemical bond is broken in a direct dissociation reaction, the process is so rapid that it has generally been considered instantaneous and thus unmeasurable. However, the bond does persist for times on the order of 10(-13) seconds after the photon has been absorbed. Femtosecond (10(-15) second) laser techniques can be used to directly clock this process, which describes the dynamics of t...

Transition state theory (TST) provides a simple interpretation of many thermally activated processes. It applies successfully on timescales and length scales that differ several orders of magnitude: to chemical reactions, breaking of chemical bonds, unfolding of proteins and RNA structures and polymers crossing entropic barriers. Here we apply TST to out-of-equilibrium transport through confine...