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

The 1:1 (arene)mercury complexes [HgR 2 (arene)] [R = C 6 F 4 ‐ o ‐NO 2 , C 6 F 4 ‐ m ‐NO 2 , C 6 F 4 ‐ o ‐H, C 6 F 5 ; 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 CH 2 Cl 2 or CH 2 Cl 2 /hexane. Analogous 1:1 complexes are also formed from Hg(C 6 F 5 ) 2 and PhMe, whereas novel 1:2 complexes [HgR 2 (arene) 2 ] result from Hg(C 6 F 4 ‐ o ‐NO 2 ) 2 and PhMe or TMO (1,2,4‐trimethoxybenzene) and from Hg(C 6 F 5 ) 2 and TMO. In the crystalline state, the 1:1 [HgR 2 (arene)] complexes exist as canted columns of alternating planar HgR 2 and arene layers linked by weak (Hg ··· C 3.2–3.5 Å) η 1 or η 2 π‐arene–mercury interactions. For the TMB (R = C 6 F 4 ‐ o ‐NO 2 , C 6 F 4 ‐ o ‐H, C 6 F 5 ) and PhMe (R = C 6 F 5 ) 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 = C 6 F 4 ‐ m ‐NO 2 the 2D array is distorted into a herringbone motif by weak C–H ··· O interactions. The 1:2 complex [Hg(C 6 F 4 ‐ o ‐NO 2 ) 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 HgR 2 with two PhMe units per HgR 2 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 HgR 2 and pairs of TMO. Theoretical calculations for the 1:2 [HgR 2 (TMB) 2 ] complexes (R = C 6 F 4 ‐ o ‐NO 2 , C 6 F 4 ‐ m ‐NO 2 ) are consistent with the findings from the observed crystal structures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)