The 1:1 (arene)mercury complexes [HgR2(arene)] [R = C 6F4-o-NO2, C6F4-m-NO 2, 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, C6F 4-o-H, C6F5) and PhMe (R = C6F 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 fluoroarenearene stacking). For the TMB complex with R = C6F 4-m-NO2 the 2D array is distorted into a herringbone motif by weak C-H···O interactions. The 1:2 complex [Hg(C 6F4-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, C6F 4-m-NO2) are consistent with the findings from the observed crystal structures.
ASJC Scopus subject areas
- Inorganic Chemistry