This paper presents a systematic study of the reactivity of polycyclic aromatic hydrocarbons (PAH), identifying crosslinks that permit the combination of physical π-stacking interactions and covalent bonding. Hybrid density functional theory was used to identify the location of reactive sites on PAHs using the average local ionization potential. The bond energies formed between these various reactive sites were then computed. σ-Radicals were found to be the most reactive, forming bonds with other radicals and some reactive closed shell edge types. Partially saturated rim-based pentagonal rings were found to form localized π-radicals with high reactivity. This site, in addition to resonantly stabilized π-radicals, was found to be capable of bonding and stacking, which is explored for a variety of larger species. Localized π-radicals on rim-based pentagonal rings, in particular, were found to form strongly bound stacked complexes, indicating a potentially important role in soot formation.
High-fidelity computer-aided
experimentation is becoming more accessible
with the development of computing power and artificial intelligence
tools. The advancement of experimental hardware also empowers researchers
to reach a level of accuracy that was not possible in the past. Marching
toward the next generation of self-driving laboratories, the orchestration
of both resources lies at the focal point of autonomous discovery
in chemical science. To achieve such a goal, algorithmically accessible
data representations and standardized communication protocols are
indispensable. In this perspective, we recategorize the recently introduced
approach based on Materials Acceleration Platforms into five functional
components and discuss recent case studies that focus on the data
representation and exchange scheme between different components. Emerging
technologies for interoperable data representation and multi-agent
systems are also discussed with their recent applications in chemical
automation. We hypothesize that knowledge graph technology, orchestrating
semantic web technologies and multi-agent systems, will be the driving
force to bring data to knowledge, evolving our way of automating the
laboratory.
Curvature in polyaromatic hydrocarbons (PAHs), due to pentagon inclusion, produces a dipole moment that contributes significantly to self-assembly processes and adsorption at the surface of carbon materials containing curved structures. This work presents electronic structure calculations of the dipole moment for 18 different curved PAH molecules for various numbers of pentagons and the total number of aromatic rings. A significant dipole moment was found that depends strongly on the number of aromatic rings (4-6.5 debye for ring count 10-20). The main cause for the dipole is shown to be the π-electron flexoelectric effect. An atom-centered partial charge representation of the charge distribution in these molecules is insufficient to correctly describe their electrostatic potential; distributed multipoles were required instead.
20Biomass-based power generation combined with CO 2 capture and storage (Biopower CCS) currently represents one of the few practical and economic means of removing large quantities of CO 2 from the atmosphere, and the only approach that involves the generation of electricity at the same time. emissions.
Flame-made TiO2 nanoparticles with tunable polymorphs, including the metastable TiO2-II phase, were prepared and a phase formation mechanism was proposed.
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