Coelectrolysis of CO2 with simple nitrogen compounds can generate molecules containing C–N bonds, which makes it an appealing method for increasing the value and scope of products obtained from CO2 electrochemical reduction (CO2ER) alone. In this study, we used density functional theory (DFT) calculations combined with a constant electrode potential model to investigate C–N formation pathways in the coreduction of CO2 and NO3 –/NO2 – to produce urea on Cu(111). Strikingly, we found that the first C–N bond is formed through coupling of gaseous CO2, rather than an intermediate of CO2ER, with the surface-bound N1 intermediates (i.e., *NO2, *NOH, *N, *NH, and *NH2) generated during NO3 –/NO2 – reduction to NH3. The reaction follows the Eley–Rideal mechanism and requires only a single active site. This result is in contrast with the literature, where the carbon species for C–N coupling were assumed to be intermediates from CO2ER to CO (i.e., *COOH and *CO). Further barrier decomposition analysis indicated that the facile kinetics of C–N coupling involving CO2 are due to the lower energy cost to deform CO2 and the N1 intermediate to the transition-state structure as well as the attractive interaction between them. For these facile and hence important CO2 + N1 reactions, we determined that the kinetic barrier of C–N coupling correlates well with the deformation energy of the N1 intermediate. Based on these insights, two strategies to improve C–N coupling have been proposed.

High-spin, late transition metal imido complexes have attracted significant interest due to their group transfer reactivity and catalytic C−H activation of organic substrates. Reaction of a new two-coordinate iron complex,...

A series of hexapole helicenes (HHs) and nonuple helicenes (NHs) were prepared from 1,3,5-tris[2-(arylethynyl)phenyl]benzene through two steps, namely, iodocyclization and subsequent palladium-catalyzed annulation with ortho-bromoaryl carboxylic acids. The crucial advantages of this synthetic method are the facile introduction of substituents, high regioselectivity, and efficient backbone extension. Three-dimensional structures of three C 1 -symmetric HHs and one C 3 -symmetric NH were elucidated using X-ray crystallography. Unlike most conventional multiple helicenes, the HHs and NHs investigated herein possess a unique structural feature where some double helical moieties share a terminal naphthalene unit. Chiral resolution of a HH and an NH was successfully achieved, and the enantiomerization barrier (ΔH ‡ ) of the HH was experimentally determined to be 31.2 kcal/mol. A straightforward method for predicting the most stable diastereomer was developed based on density functional theory calculations and structural considerations. It was found that the relative potential energies (ΔH r s) of all diastereomers for two HHs and one NH can be obtained using minimal computational effort to analyze the types, helical configurations, numbers, and ΔH (MP−MM) s [= H(M,P/P,M) − H(M,M/P,P)] of the double helicenyl fragments.

Electrochemical partial oxidation of hydrocarbons to value-added products using electricity from renewable energy resources has the potential to change the way that commodity chemicals are manufactured. In this study, we used density functional theory calculations combined with a constant electrode potential model to study the previously reported ethylene partial electro-oxidation to epoxide on RuO2(110) in an aqueous solution containing [Cl–] = 0.3 M. We found that the high selectivity toward epoxide is due to the in situ generated *OCClO* intermediate that blocks parts of the surface and leads to isolation of *O (surface adsorbed oxygen) active sites. This step turns off the pathways to over-oxidation and drives the reaction toward epoxide formation. The reaction mechanisms for ethylene over-oxidation and partial oxidation are proposed. Our theoretical study unveiled a dynamic and unique means to achieve active site isolation that can be used to improve selectivity of hydrocarbon partial electro-oxidation.

Direct methane oxidation to methanol is ideal for replacing the oxygen evolution reaction (OER) in artificial photosynthesis. This reaction requires less electricity and generates more valuable products than the OER. Moreover, it provides a better way to utilize abundant but inert methane. In this study, we have used density functional theory combined with a constant electrode potential model to evaluate the possibility of using abundant and low-cost N-doped graphene to catalyze this reaction. The active oxygen (*O) for rate-determining C−H activation is generated during the OER process. The results from our calculations show that this catalysis could be realized when graphene is doped with two nitrogen atoms in the vicinity of the reaction center so that long-lived *O is present and reacts to break strong methane C−H bonds. The minimum overall kinetic barrier is 0.91 eV at a potential of U = 1.10 V SHE , which is 0.82 eV lower than that in the absence of Us. The significant barrier reduction indicates that anodic potentials play essential roles in increasing the reactivity of N-doped graphene. During C−H activation, hydrogen is transferred from methane to *O. Analyzing this step using the Intrinsic Atomic Orbitals approach, we find that it follows a hydrogen atom transfer mechanism where the proton and electron travel together. Importantly, our analysis reveals that this transfer starts with the excitation of one electron from the *O lone pair to a surface π-orbital. This excitation increases the radical character on *O, rendering it reactive to couple with the transferred hydrogen atom. Easing this excitation is expected to further improve the reactivity of *O, as demonstrated by our calculations.

In the search for efficient and inexpensive electrocatalysts for the hydrogen evolution reaction (HER), the hydrogen binding energy (ΔG*H) is often used as a descriptor to represent the catalytic activity....