Density functional investigations on 2-naphthalenecarbonitrile dimerization within cucurbit[8]uril cavitand

Area of Science:

• Supramolecular Chemistry
• Computational Chemistry
• Physical Chemistry

Background:

• 2-naphthalenecarbonitrile (2-NpCN) can form dimers.
• Cucurbit[8]uril (CB[8]) is a macrocyclic host known for molecular encapsulation.
• Understanding host-guest interactions is crucial for molecular assembly.

Purpose of the Study:

• To investigate the dimerization of 2-NpCN mediated by CB[8].
• To elucidate the structural and energetic properties of 2-NpCN dimers within CB[8].
• To correlate computational findings with experimental spectroscopic data.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Exploration of different 2-NpCN dimer configurations (anti-head-to-head, anti-head-to-tail, syn-head-to-tail).
• Analysis of (1)H NMR and infrared (IR) spectra.

Main Results:

• The anti-head-to-head dimer (A) was identified as the lowest energy structure within CB[8].
• Calculated (1)H NMR spectra showed significant shielding for aromatic protons and down-field signals for cubane protons.
• IR spectroscopy indicated a frequency up-shift (blue shift) in methylene stretching vibrations.

Conclusions:

• CB[8] effectively mediates the dimerization of 2-NpCN into stable, rigid structures.
• Computational results are consistent with experimental NMR and IR spectroscopic observations.
• This study provides insights into host-mediated dimerization and its spectral consequences.