A supramolecular twist to the structures of bis(polyfluorophenyl) mercurials

The crystal structure of Hg(C6F4-o-NO2)21 is planar with intramolecular Hg–O coordination whereas those of the polymorphs of Hg(C6F4-m-NO2)22a and 2b have the two aryl rings rotated relative to each other (87° and 59°). At a supramolecular level, both complexes exhibit weak HgO interactions. Theoretical calculations (B3LYP and MP2) for gas-phase Hg(C6F4-o-NO2)2 and Hg(C6F4-m-NO2)2 molecules predict non-planar conformations in both complexes corresponding to one polymorph of the latter (2a). However, when the supramolecular HgO interactions are included, using a dimeric model, the calculations more accurately predict the observed structures of 1 and 2b