The selective reduction of O2, typically with the goal forming H2O, represents a long-standing challenge in field catalysis. Macrocyclic transition-metal complexes, and cobalt porphyrins particular, have been focus extensive study as catalysts for this reaction. Here, we show that mononuclear Co-tetraarylporphyrin complex, Co(porOMe) (porOMe = meso-tetra(4-methoxyphenyl)porphyrin), catalyzes either 2e-/2H+ or 4e-/4H+ O2 high selectivity simply by changing identity Brønsted acid...

A soluble, bis-ketiminate-ligated Co complex [Co(N2O2)] was recently shown to catalyze selective reduction of O2 H2O2 with an overpotential as low 90 mV. Here we report experimental and computational mechanistic studies the Co(N2O2)-catalyzed reaction (ORR) decamethylferrocene (Fc*) reductant in presence AcOH MeOH. Analysis Co/O2 binding stoichiometry kinetic support pathway involving a mononuclear cobalt species. The catalytic rate exhibits first-order dependence on [AcOH], but no [Fc*] or...

The recently developed real-time nuclear–electronic orbital (RT-NEO) approach provides an elegant framework for treating electrons and selected nuclei, typically protons, quantum mechanically in nonequilibrium dynamical processes. However, the RT-NEO neglects motion of other preventing a complete description coupled dynamics spectroscopy. In this work, interactions between nuclei electron–proton subsystem are described with mixed quantum–classical Ehrenfest method. NEO-Ehrenfest propagates...

Multicomponent density functional theory (DFT) allows the consistent quantum mechanical treatment of both electrons and nuclei. Recently epc17 electron-proton correlation was derived using a multicomponent extension Colle-Salvetti formalism implemented within nuclear-electronic orbital (NEO) framework for treating specified protons mechanically. Herein another functional, denoted epc18, is different form parameter interpreted as representing length interactions. The epc18 shown to perform...

A significant challenge for multicomponent quantum chemistry methods is the calculation of vibrational frequencies comparison to experiment. The nuclear–electronic orbital (NEO) approach treats specified nuclei, typically key protons, mechanically. Born–Oppenheimer separation between and classical nuclei prevents direct corresponding modes composed both types nuclei. Herein an effective strategy calculating entire molecule within NEO framework devised implemented. This requires...

Coordination of the tridentate ligand bis(2-diphenylphosphinoethyl)phenylphosphine (P3) to cobalt forms [(CH3CN)2CoIIP3](BF4)2 (CoIIP3). In presence Brönsted base iPr2EtN, CoIIP3 electrocatalytically oxidizes benzyl alcohol (BnOH) benzaldehyde at an applied potential −630 mV vs Fc+/0 with a TON 19.9. noncatalytic reaction excess BnOH and is reduced by one electron [(CH3CN)2CoIP3]BF4 (CoIP3) concomitant formation half equivalent benzaldehyde. This stoichiometric oxidation suggests transfer...

The nuclear–electronic orbital (NEO) method is a multicomponent quantum chemistry theory that describes electronic and nuclear effects simultaneously while avoiding the Born–Oppenheimer approximation for certain nuclei. Typically specified hydrogen nuclei are treated mechanically at same level as electrons, NEO potential energy surface depends on classical coordinates. This approach includes such zero-point delocalization directly into surface. An extended depending expectation values of...

The nuclear-electronic orbital (NEO) approach treats all electrons and specified nuclei, typically protons, on the same quantum mechanical level. Proton vibrational excitations can be calculated using multicomponent time-dependent density functional theory (NEO-TDDFT) for fixed classical nuclei. Recently NEO-DFT(V) was developed to enable calculation of molecular frequencies modes composed both This uses input from NEO-TDDFT construct an extended NEO Hessian that depends expectation values...

The computational investigation of photochemical processes often entails the calculation excited-state geometries, energies, and energy gradients. nuclear–electronic orbital (NEO) approach treats specified nuclei, typically protons, quantum mechanically on same level as electrons, thereby including associated nuclear effects non-Born–Oppenheimer behavior into chemistry calculations. multicomponent density functional theory (NEO-DFT) time-dependent DFT (NEO-TDDFT) methods allow efficient...

The nuclear-electronic orbital (NEO) method treats specified nuclei, typically protons, quantum mechanically on the same level as electrons. This approach invokes Born-Oppenheimer separation between and classical well conventional electrons nuclei. To test validity of this additional adiabatic approximation, herein diagonal correction (DBOC) within NEO framework is derived, analyzed, calculated numerically for a set eight molecules. Inclusion DBOC found to change equilibrium bond lengths by...

Hydrogen tunneling plays a critical role in many biologically and chemically important processes. The nuclear-electronic orbital multistate density functional theory (NEO-MSDFT) method was developed to describe hydrogen transfer systems. In this approach, the transferring proton is treated quantum mechanically on same level as electrons within multicomponent DFT, nonorthogonal configuration interaction scheme used produce delocalized vibronic states from localized states. NEO-MSDFT has been...

The computational investigation of photochemical processes often entails the calculation excited state geometries, energies, and energy gradients. nuclear-electronic orbital (NEO) approach treats specified nuclei, typically protons, quantum mechanically on same level as electrons, thereby including associated nuclear effects non-Born-Oppenheimer behavior into chemistry calculations. multicomponent density functional theory (NEO-DFT) time-dependent DFT (NEO-TDDFT) methods allow efficient...