The Supramolecular Architecture of Arene Complexes of Bis(polyfluorophenyl)mercurials

Abstract

AbstractThe 1:1 (arene)mercury complexes [HgR2(arene)] [R = C6F4‐o‐NO2, C6F4‐m‐NO2, C6F4‐o‐H, C6F5; arene = TMB (1,2,4,5‐tetramethylbenzene), PMB (1,2,3,4,5‐pentamethylbenzene)] are readily formed when mixtures of the mercurial and arene are crystallised from CH2Cl2 or CH2Cl2/hexane. Analogous 1:1 complexes are also formed from Hg(C6F5)2 and PhMe, whereas novel 1:2 complexes [HgR2(arene)2] result from Hg(C6F4‐o‐NO2)2 and PhMe or TMO (1,2,4‐trimethoxybenzene) and from Hg(C6F5)2 and TMO. In the crystalline state, the 1:1 [HgR2(arene)] complexes exist as canted columns of alternating planar HgR2 and arene layers linked by weak (Hg···C 3.2–3.5 Å) η1 or η2 π‐arene–mercury interactions. For the TMB (R = C6F4‐o‐NO2, C6F4‐o‐H, C6F5) and PhMe (R = C6F5) complexes, the packing of neighbouring columns shows aligned, alternating fluoroarene and arene ring planes resulting in a 2D brick‐wall motif with potential supramolecular components (fluoroarene–fluoroarene and fluoroarene–arene stacking). For the TMB complex with R = C6F4‐m‐NO2 the 2D array is distorted into a herringbone motif by weak C–H···O interactions. The 1:2 complex [Hg(C6F4‐o‐NO2)2(PhMe)2] has an analogous mercury environment to the 1:1 complexes, and the packing shows a distinct layer structure of alternating rows of PhMe and HgR2 with two PhMe units per HgR2 unit but with no inter‐stack interactions. The TMO complexes have long Hg···O contacts (3.2 Å) rather than Hg···C and similarly show a layered structure, but in this case, with a single column of alternating HgR2 and pairs of TMO. Theoretical calculations for the 1:2 [HgR2(TMB)2] complexes (R = C6F4‐o‐NO2, C6F4‐m‐NO2) are consistent with the findings from the observed crystal structures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)