Details

Autor(en) / Beteiligte

• Stephaniuk, Nadia T.
• Nascimento, Mitchell A.
• Nikoo, Sahar
• Heyer, Elodie
• Watanabe, Lara K.
• Rawson, Jeremy M.

Titel

Robust S4⋅⋅⋅O Supramolecular Synthons: Structures of Radical‐Radical Cocrystals [p‐XC6F4CNSSN]2[TEMPO] (X=F, Cl, Br, I, CN)

Ist Teil von

• Chemistry : a European journal, 2022-03, Vol.28 (15), p.e202103846-n/a

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2022

Quelle

Wiley Online Library - AutoHoldings Journals

Beschreibungen/Notizen

• Cocrystallization of the dithiadiazolyl (DTDA) radicals p‐XC6F4CNSSN (X=F, Cl, Br, I, CN) with TEMPO afforded the 2 : 1 cocrystals [p‐XC6F4CNSSN]2[TEMPO] (1–5) whose structures all reflect a common S4⋅⋅⋅O supramolecular motif. The nature of this interaction was probed by DFT calculations (M06/aug‐cc‐pVDZ) on 1 which revealed that the enthalpy of formation of the [C6F5CNSSN]2[TEMPO] supramolecular motif from [C6F5CNSSN]2 and TEMPO is substantial (−54.0 kJ mol−1). Electronic structure calculations revealed a TEMPO‐based doublet S=1/2 configuration as the ground state with limited spin density on the DTDA rings (2.4 %). The corresponding spin quartet state is +78.9 kJ mol−1 higher in energy. An atoms‐in‐molecules analysis reveals four bond critical points (BCPs) between the TEMPO O and the DTDA S atoms as well as additional BCPs between selected DTDA S atoms and methyl H atoms of the TEMPO molecule. Herein, the structures of 2–5 are considered within the context of a hierarchical view of competing and complementary intermolecular interactions; in particular, the established supramolecular CN⋅⋅⋅S−S synthon is sacrificed in order to form the new S4⋅⋅⋅O interaction. Cocrystallization of TEMPO with a series of dithiadiazolyl (DTDA) radicals, p‐XC6F4CNSSN (X=F, Cl, Br, I, CN), led to the isolation of 2 : 1 radical‐radical cocrystals [p‐XC6F4CNSSN]2[TEMPO] that exhibit a common S4⋅⋅⋅O structural motif. Computational studies reflect the robust nature of this interaction and identify a well‐isolated S=1/2 spin ground state, largely localized on the TEMPO radical.