Performance of Particle Swarm Optimization in Predicting the Orientation of π-Conjugated Molecules Inside Carbon Nanotubes Compared with Density Functional Theory Calculations.

Particle swarm optimization (PSO) was employed to obtain the global minimum of host-guest structures consisting of a triiodobenzene molecule (BzI) inside an armchair (,) nanotube (BzI@(,)), whose host-guest interactions are approximated by Lennard-Jones (LJ) potentials. The host-guest structures obtained using the PSO-LJ method were then compared with those obtained through dispersion-corrected density functional theory (DFT) calculations to evaluate the performance of the PSO-LJ approach in predicting the guest orientation inside a tube. When the inner space of the host tube is limited for guest encapsulation, the PSO-LJ method can reproduce the DFT results of BzI@(,) in terms of the guest orientation.

Experimental and Computational Insights into the Catalytic Mechanism of YBaCoO Perovskite Oxides with a Controlled Crystal Structure.

The crystal structure of Co-based perovskite oxides (ACoO) can be controlled by adjusting the A-site elements. In this study, we synthesized YBaCoO ( = 0, 0.5, and 1.

Roles of Carbon Nanotube Confinement in Modulating Regioselectivity of 1,3-Dipolar Cycloadditions.

DFT-based calculations were employed to investigate mechanisms of 1,3-dipolar cycloadditions between phenylacetylene and an azide (phenylazide or benzylazide) inside carbon nanotubes, whose diameters range from 10 to 14 Å, by obtaining their reaction species (reactant complex, transition state (TS), and product (Pro)). The reactions yield 1,4- and 1,5-triazoles, whose paths are denoted by 1,4- and 1,5-approaches, respectively. We found different geometrical features of reaction species between 1,4- and 1,5-approaches.

Theoretical understanding of stability of mechanically interlocked carbon nanotubes and their precursors.

Dispersion-corrected DFT calculations were performed on (,) nanotubes ( = 5-10) attached by a U-shaped functional group consisting of -xylene-linked double 9,10-di(1,3-dithiol-2-ylidene)-9,10-dihydro anthracene terminated by CH chains ( = 6, 8, and 9), and their ring-closing macrocycles containing tubes. The reactant precursors and macrocycles are denoted by UP--(,) and (,)@Cycle-, respectively. We found that UP--(,) are energetically preferable relative to the dissociation limit toward a U-shaped functional group (UP-) and a tube (initial state) due to the attractive CH-π and π-π interactions.

Ultralong Distance Hydrogen Spillover Enabled by Valence Changes in a Metal Oxide Surface.

Hydrogen spillover is a phenomenon in which hydrogen atoms generated on metal catalysts diffuse onto catalyst supports. This phenomenon offers reaction routes for functional materials. However, due to difficulties in visualizing hydrogen, the fundamental nature of the phenomenon, such as how far hydrogen diffuses, has not been well understood.