Study of stacking interactions between two neutral tetrathiafulvalene molecules in Cambridge Structural Database crystal structures and by quantum chemical calculations

• Published in: Acta crystallographica Section B, Structural science, crystal engineering and materials Structural science, crystal engineering and materials, 2019-02, Vol.75 (1), p.1-7
• Main Authors: Antonijević, Ivana S., Malenov, Dušan P., Hall, Michael B., Zarić, Snežana D.
• Format: Article
• Language: English
• Subjects: Cambridge Structural Database; CCSD(T)/CBS; Conductors; Crystal structure; Crystals; Data bases; interaction energies; Mathematical analysis; Organic chemistry; Potential energy; Quantum chemistry; Stacking; tetrathiafulvalene
• ISSN: 2052-5206; 2052-5192; 2052-5206
• DOI: 10.1107/S2052520618015494

Tetrathiafulvalene (TTF) and its derivatives are very well known as electron donors with widespread use in the field of organic conductors and superconductors. Stacking interactions between two neutral TTF fragments were studied by analysing data from Cambridge Structural Database crystal structures and by quantum chemical calculations. Analysis of the contacts found in crystal structures shows high occurrence of parallel displaced orientations of TTF molecules. In the majority of the contacts, two TTF molecules are displaced along their longer C2 axis. The most frequent geometry has the strongest TTF–TTF stacking interaction, with CCSD(T)/CBS energy of −9.96 kcal mol−1. All the other frequent geometries in crystal structures are similar to geometries of the minima on the calculated potential energy surface. Stacking interactions in which two TTF molecules are displaced along their longer C2 axis are dominant in crystal structures. The most frequent geometry has the strongest stacking interaction (−9.96 kcal mol−1), calculated at very accurate CCSD(T)/CBS level. The other frequent geometries in crystal structures are also similar to very stable geometries of the minima on the calculated potential energy surface.