Kristallstruktur des „supramolekularen“ Quecksilber(II)chlorid-thiocyanat- Hexamethylentetramin-Addukts Hg(SCN)₂ · 2HgCl₂ · 2C₆H₁₂N₄ / Crystal Structure of the “Supramolecular” Mercury(II) Chloride Thiocyanate Hexam ethylenetetram ine Adduct Hg(SCN)₂ · 2HgCl₂ · 2C₆H₁₂N₄

Abstract

Crystals of the adduct Hg(SCN)2 · 2HgCl2·2C6H12N4 were obtained from an aqueous solution containing 0.1 mol/l hexamethylenetetramine and 0.05 mol/l potassium thiocyanate and mercury(II) chloride. The compound crystallizes monoclinically; space group P21/n, a = 767.3(4), b = 1854.7(7), c = 872.5(7) pm, and β = 101.48(5)°. The structure consists of a net­ work of chains -Cl-Hg-Cl-Hg- and -(Cl-Hg-)2NCS-Hg-SCN-(Hg-Cl)2-which share common Hg atoms and form distorted hexagonal and trigonal channels. The hexamethylenetetramine molecules lie in the hexagonal channels. They act as μ3 bridging ligands, forming bonds to two Hg atoms in a given layer, and an additional bond to a Hg atom a neighbouring layer.

Hexamethylenetetramine: An old new building block for design of coordination polymers

“…In the following two decades, this chemistry developped rather slowly, since only 12 and 15 structures were published in 1980s [50][51][52][53][54][55][56][57] and 1990s [58][59][60][61][62][63][64][65][66][67][68], respectively. However, the flourishing progress of crystal engineering yielded ca.…”

“…The 3D networks 42-72 (Table 3) constitute the most interesting and diverse group of hmt-driven coordination polymers, namely [22] and 66 (b) [63] showing the formation of octahedral (a) and "parquet floor" (b) 3D skeletons formed exclusively via metal-hmt interactions (views along the c and a axes, respectively). H atoms, Cl, MeOH and NCS ligands are omitted for clarity.…”

“…[25] a Although this compound was reported [36] as a 3D polymer, it apparently features a 2D layered coordination network which, however, is extended via H-bonds to a 3D supramolecular structure. (57) [29] and [Hg 3 ( 2 -Cl) 4 ( 2 -NCS) 2 ( 3 -hmt) 2 ] n (66) [63], they represent the most notable examples of 3D hmt-driven frameworks constructed via metal-hmt interactions. Hence, compound 47 possesses an octahedral net structure composed of cross-linking ∼CdCl 2 -4 -hmt-CdCl 2 -4 -hmt∼ motifs that form square "windows" ( Fig.…”

“…Besides, the framework is further reinforced through additional -Cl interactions [22]. Another example concerns a compound 66 [63] that adopts "parquet floor" topology [2k] from the tiled rectangular Hg 6 ( 3 -hmt) 6 bricks (Fig. 4b).…”

“…Hence, the structure of [Cd 3 ( 2 -CN) 6 ( 3 -hmt) 2 ] n (65) features the formation of 2D undulating layers composed of tiled Cd 6 ( 3 -hmt) 6 bricks [65]. Although these bricks resemble those of 66 [63], the topology in 65 is slightly different and can be described [2k] as a "brick wall" (Fig. 6a).…”