Experimental and theoretical charge density assessments for the 4-perfluoropyridyl- and 4-perflurophenyl-1,2,3,5-dithiadiazolyl radicals

• Published in: CrystEngComm 2016-01, Vol.18 (37), p.7116-7125
• Main Authors: Domaga a, S awomir, Haynes, Delia A
• Format: Article
• Language: English
• Subjects: Bonding strength; Carbon; Chemical bonds; Density; Dimers; Electron density; Radicals; Sulfur
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/c6ce01095d

The results of an experimental density analysis of 4-perfluoropyridyl-1,2,3,5-dithiadiazolyl (NF-radical) are presented and compared with the previously reported analysis of the related 4-perfluorophenyl-1,2,3,5-dithiadiazolyl (F-radical). Both the NF- and F-radicals form dimers in their crystal lattice. The strong interaction between sulfur atoms in the dimers is confirmed by the high values of the electron density at the bond critical points. Some additional bond paths relating to weaker interactions are also observed in the dimers, notably between carbon atoms and between F and N atoms. For both radicals, the spin density is almost entirely located on the nitrogen and sulfur atoms of the dithiadiazolyl ring. However, the values of the spin density are higher in the case of the NF-radical, which may result in stronger interactions between sulfur atoms in the dimers. The electron density derived properties from the experimental and theoretical multipolar models are in fairly good agreement. Both NF- and F-radicals form dimers in their crystal lattice. The strong interaction between sulfur atoms in the dimers is confirmed by the high values of electron density between these atoms. Analysis of the electron density makes it clear that these interactions are distinct from both covalent bonds and intermolecular interactions.