Thiadiazole-containing expanded heteroazaporphyrinoids: a gas-phase electron diffraction and computational structural...

Area of Science:

• * Computational Chemistry
• * Molecular Spectroscopy
• * Materials Science

Background:

• * Expanded heteroazaporphyrinoids are complex macrocyclic compounds with potential applications in various fields.
• * Understanding their precise molecular structure is crucial for predicting and optimizing their properties.
• * Thiadiazole moieties introduce unique electronic and structural characteristics to these macrocycles.

Purpose of the Study:

• * To determine the gas-phase molecular structure of a thiadiazole-containing expanded heteroazaporphyrinoid.
• * To elucidate the equilibrium geometry and symmetry of the molecule.
• * To investigate the orientation of the thiadiazole rings and sulfur atoms within the macrocycle.

Main Methods:

• * Synchronous gas electron diffraction (GED) and mass spectrometry (MS) experiments.
• * Density Functional Theory (DFT) calculations employing the B3LYP hybrid method and cc-pVTZ basis sets.
• * Development of an algorithm for constructing internal coordinates for vibrational corrections.

Main Results:

• * The molecule (C42H39N15S3) exhibits an equilibrium structure with C3h symmetry.
• * A planar macrocycle was identified, with thiadiazole rings positioned such that sulfur atoms face outwards.
• * DFT computations were also performed on the unsubstituted macrocycle (C30H15N15S3).

Conclusions:

• * The study successfully determined the detailed gas-phase molecular structure of the target heteroazaporphyrinoid.
• * The findings provide valuable structural data for this class of compounds.
• * The outward orientation of sulfur atoms may influence intermolecular interactions and material properties.