Publications by authors named "Nadia Stephaniuk"

Cocrystallization of the dithiadiazolyl (DTDA) radicals p-XC F CNSSN (X=F, Cl, Br, I, CN) with TEMPO afforded the 2 : 1 cocrystals [p-XC F CNSSN] [TEMPO] (1-5) whose structures all reflect a common S ⋅⋅⋅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 [C F CNSSN] [TEMPO] supramolecular motif from [C F CNSSN] and TEMPO is substantial (-54.0 kJ mol ).

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Inclusion of the dithiadiazolyl and diselenadiazolyl radicals PhCNEEN (E = S, Se) into the porous framework, Al(bdc)(OH) [MIL-53(Al); bdc = 1,4-benzenedicarboxylate] was achieved by vacuum sublimation. PXRD studies reveal the inclusion complexes adopt the orthorhombic space group Imma. Variable temperature PXRD studies coupled with thermal analysis reveal that for PhCNSSN@MIL-53(Al), radical elimination from the pores at elevated temperatures is accompanied by an opening of the pore channels.

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Reaction of the methyl-benzodithiazolyl radical (MBDTA) with M(hfac)2 complexes (M = Mn, Co, Zn) affords the complexes M(hfac)2(MBDTA)2. Strong antiferromagnetic exchange interactions are observed between M(ii) ions and the two S = 1/2 radicals (M = Mn, Co), whereas weak antiferromagnetic interactions are observed between radicals when using the diamagnetic Zn(ii) ion. Strong intermolecular exchange coupling is also evident in Mn(hfac)2(MBDTA)2 and attributed to π*-π* contacts between MBDTA radicals which are absent for the Co and Zn derivatives.

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Formation of radical-radical cocrystals is an important step towards the design of organic ferrimagnets. We describe a simple approach to generate radical-radical cocrystals through the identification and implementation of well-defined supramolecular synthons which favor cocrystallization over phase separation. In the current paper we implement the structure-directing interactions of the E-E bond (E=S, Se) of dithiadiazolyl (DTDA) and diselenadiazolyl (DSDA) radicals to form close contacts to electronegative groups.

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