In situ crystalline transformation of bis(halo)mercury(II) coordination polymers to ionic chloro-bridged-bis(halo)mercury(II) species via UV irradiation in chloroform media

Self-assembly of HgX₂ (X^- = Br^- and I^-) with new 1,1,2,2-tetramethyl-1,2-di(pyridin-3-yl)disilane (L) ligand affords single crystals consisting of sinusoidal-strand coordination polymers, [HgX₂L]. Specifically, 350 nm UV irradiation of crystalline products [HgBr₂L] and [HgI₂L] in chloroform media forms in situ single crystals of extraordinary chloro-bridged mercury species, [H₂L]²⁺[Hg₂Br₄(μ-Br)(μ-Cl)]^2- and [H₂L]²⁺[HgI₂(μ-Cl)]₂^2-, respectively, in high yields that cannot be synthesized by general synthetic procedures. For all of the compounds, the coordination geometries around the Hg(ii) ions along with the mechanistic aspects of the formation of chloro-bridged species are discussed herein.