Assembly of a new family of mercury(II) zwitterionic thiolate complexes from a preformed compound [Hg(Tab)2](PF6)2 [Tab = 4-(trimethylammonio)benzenethiolate]

Article abstract of DOI:10.1021/ic051875n

Reactions of Hg(OAc)₂ with 2 equiv of TabHPF₆ [TabH = 4-(trimethylammonio)benzenethiol] in MeCN/MeOH afforded a mononuclear linear complex [Hg(Tab)₂](PF₆)₂ (1). By using 1 as a precursor, a new family of mercury(II) zwitterionic thiolate complexes, [Hg ₂(Tab)₆](PF₆)₄·2MeCN (2·2MeCN), [Hg(Tab)₂(SCN)](PF₆) (3), [Hg(Tab) ₂(SCN)₂] (4), [Hg-(Tab)I₂] (5), {[Hg(Tab) ₂]₄[HgI₂][Hg₂I₆]}(PF ₆)₂(NO₃)₄ (6), [Hg(Tab) ₂][HgI₄] (7), [Hg(Tab)₂][HgCl ₂(SCN)₂] (8), [Tab-Tab]₂[Hg₃Cl ₁₀] (9), and [Hg₂(Tab)₆]₃(PF ₆)Cl₁₁ (10), were prepared and characterized by elemental analysis, IR spectra, UV-vis spectra, ¹H-NMR, and single-crystal X-ray crystallography. The [Hg₂(Tab)₆]⁴⁺ tetracation of 2 or 10 contains an asymmetrical Hg₂S₂ rhomb with an inversion center lying on the midpoint of the Hg...Hg line. The Hg atom of the [Hg(Tab)₂]²⁺ dication of 3 is coordinated to one SCN^-, forming a rare T-shaped coordination geometry, while in 4, the Hg atom of [Hg(Tab)₂]²⁺ is coordinated to two SCN^-, forming a seesaw-shaped coordination geometry. Through weak secondary Hg...S coordinations, each cation in 3 is further linked to afford a one-dimensional zigzag chain. The trigonal [Hg(Tab)I₂] molecules in 5 are held together by weak secondary Hg...I and Hg...S interactions, forming a one-dimensional chain structure. In 6, the four [Hg(Tab)₂]²⁺ dications, one HgI₂ molecule, one [Hg₂I₆]^2- dianion, one PF₆^-, and four NO₃^- anions are interconnected by complicated secondary Hg...I and Hg...O interactions, forming a scolopendra-like chain structure. The secondary Hg...I interactions, [Hg(Tab)₂]²⁺ and [HgI ₄]^2- in 7, are combined to generate a one-dimensional chain structure, while [Hg(Tab)₂]²⁺ and [HgCl ₂(SCN)₂]^2- in 8 are interconnected by secondary Hg...N interactions to form a one-dimensional zigzag chain structure. Compound 9 consists of two [Tab-Tab]²⁺ dications and one [Hg ₃Cl₁₀]^4- tetraanion. The facile approach to the construction of 2-8 and 10 from 1 may be applicable to the mimicking of a coordination sphere of the Hg sites of metallothioneins.