Quantum-mechanical calculations on molecular substructures involved in nanosystems

Area of Science:

• Computational chemistry
• Materials science
• Nanotechnology

Background:

• Fullerenes, polybenzenes, and P-type crystal networks are key areas in molecular nanostructure research.
• Exotic carbon allotropes like D5 diamond and hyper-graphenes present unique structural possibilities.
• Understanding aromaticity and stability is crucial for designing novel molecular systems.

Purpose of the Study:

• To review and analyze the aromaticity and stability of various hypothetical molecular nanostructures.
• To investigate the construction, energetic, and vibrational properties of novel carbon-based networks.
• To evaluate the potential of theoretical molecular nanostructures to exist as real molecules.

Main Methods:

• Hartree-Fock (HF) and Density Functional Theory (DFT) calculations were employed for aromaticity assessment using HOMA and NICS criteria.
• Quantum-mechanical calculations were performed on repeat units of P-type crystal networks.
• Density Functional Tight Binding (DFTB) level of theory was used for construction and stability evaluation of exotic diamond allotropes.

Main Results:

• Aromaticity in functionalized fullerenes with 6- and 8-membered rings was analyzed.
• Energetic and vibrational spectra of polybenzene networks were computed.
• The construction and stability of D5 diamond allotropes within hyper-graphenes were evaluated.

Conclusions:

• Several discussed hypothetical molecular nanostructures demonstrate characteristics suggesting they could be synthesized.
• The theoretical studies provide a foundation for future experimental investigations into these novel materials.
• Computational chemistry plays a vital role in predicting and guiding the discovery of new molecular entities.