The effect of fluorinated aryl substituents on the crystal structures of 1,2,3,5-dithiadiazolyl radicals

Molecular Electrostatic Potential as a Predictor of Supramolecular Synthons in Non‐Hydrogen‐Bonded Systems: Application to Heavier p‐Block Systems

“…Details of the synthesis of radicals 1 – 7 , and the attempted synthesis of 8 , are provided in the experimental section. Results from mass spectrometry and EPR spectroscopy, which are comparable to results reported for related DTDA radicals, are also reported in the Supporting Information, as well as PXRD to confirm phase purity. Crystals suitable for single‐crystal X‐ray diffraction were obtained for 1 – 3 , 6 , and 7 .…”

“…There is also always a region of negative potential at both nitrogen atoms which is associated with the N atom lone pair and localised in the plane of the heterocycle, as confirmed by recent high‐resolution X‐ray diffraction studies on DTDAs . It is well‐established that S ··· N interactions are significant in the structures of DTDA radicals , . When there is a fluorine atom in the ortho position ( 1 , 2 and 3 ), the region of negative potential around the N atom is enhanced.…”

“…In this context we previously examined the polymorphic radical (ClCNSSN) 2 and related DTDA structures and reviewed common non‐covalent structure‐directing motifs . Pertinent to the current work are studies by Cole et al on monofluorophenyl DTDA radicals which employed Hirshfeld surfaces to analyse intermolecular interactions and our previous studies on a series of di‐ and trifluoro‐substituted aryl DTDAs in which simple semi‐empirical calculations of ESP were able to effectively rationalise the crystal structures of a number of DTDA derivatives. It was shown that, aside from the strong dimerisation interaction, the crystal structures of di‐ and trifluorinated DTDAs were largely determined by electrostatic interactions.…”

“…This minimises intramolecular N ··· F contacts, which has been shown to assist in suppressing dimerisation , , . We noted that a fluorine atom ortho to the DTDA nitrogen, or two or more fluorine atoms that are positioned mutually ortho to one another, generate regions of negative potential which has a significant structure‐directing effect, and identified that molecular electrostatic potential maps could be a useful qualitative tool for rationalising the intermolecular interactions between DTDA dimers in the solid state …”

Magnetostructural Investigation of Orthogonal 1‐Aryl‐3‐Phenyl‐1,4‐Dihydrobenzo[e][1,2,4]triazin‐4‐yl Derivatives

“…In both cases there are noticeable closec ontacts between the Fa toms, which suggests that fluorous interactions may be driving, in part, such molecular arrangements. [30] Magnetic measurements demonstrated that solids with double co-facial p-p dimer motifs (eitherh omoa si n1d or hetero as in 1c and 1h)e xhibit weak antiferromagnetic exchange interactions. In the case of the hetero-dimeric systems this is presumably duet ot he lacko fd irect p-p interactions of high-spinc entres and essentially magnetic isolation of the spin-containing BT units.…”