Über Cyanohalogenomercurate der Alkalimetalle / On Cyanohalogenomercurates of Alkali Metals

Abstract

<jats:p>The reactions between Hg(CN)<jats:sub>2</jats:sub> and HgX<jats:sub>2</jats:sub> in aqueous solutions of alkali halides MX (M = Na, K, Rb; X = CN, Cl, Br, I) lead to mixed cyanohalogenomercurates. </jats:p><jats:p>Several compounds gained by crystallisation from aqueous solutions were characterized with X-ray, spectroscopic and thermal methods. The crystal structures of NaHg(CN)<jats:sub>2</jats:sub>Cl · H<jats:sub>2</jats:sub>O, KHg(CN)<jats:sub>2</jats:sub>Cl · H<jats:sub>2</jats:sub>O and RbHg(CN)<jats:sub>2</jats:sub>Cl · H<jats:sub>2</jats:sub>O have been determined by X-ray structure analysis with three-dimensional data. The compounds can be characterized as double salts, because the structures consist of Hg(CN)<jats:sub>2</jats:sub>-units and isolated M+ and Cl- ions. The relationship between these structures and those of the non-hydrated compounds are discussed.</jats:p>

Tuning the Structures of Mercury Cyanide-Based Coordination Polymers with Transition Metal Cations

“…14 The Hg(CN) 2 unit is also known to react with simple salts such as MX (M ) Na, K, Rb, Cs; X ) NCO, NCS, N 3 , CN, Cl, Br, I; sometimes HgX 2 is also added), to yield solid-state "double salt" arrays of the form M n+ Hg(CN) 2 X n (n ) 1, 2). 16,17 In these reactions, the Lewis-acidity of the Hg-(II) center is the key feature controlling the reactivity. Thus, the coordinately unsaturated Hg(II) center can accept compatible ligands during polymer formation to form square-planar, tetrahedral, or higher coordinate moieties in situ, in some cases increasing the structural and magnetic dimensionality of the system as result.…”

“…Our previous studies with anionic [M(CN) 2 ] - units (M = Au, Ag) have shown that these linear cyanometallates are capable of increasing structural dimensionality by forming metallophilic (M···M) interactions and also propagate significant magnetic interactions. − We are currently examining the use of mercury(II) cyanide, Hg(CN) 2 , a virtually unexplored, linear, but neutral building block, to create supramolecular architectures. , We have demonstrated that Hg(CN) 2 units can be incorporated into coordination polymers via bridging cyano groups that link to a coordinately unsaturated transition metal center as found in {Cu(tmeda)[Hg(CN) 2 ] 2 }[HgCl 4 ], a noncentrosymmetric two-dimensional layer system that shows strong optical anisotropy (tmeda = N , N , N ‘ , N ‘ -tetramethylethylenediamine) . The Hg(CN) 2 unit is also known to react with simple salts such as MX (M = Na, K, Rb, Cs; X = NCO, NCS, N 3 , CN, Cl, Br, I; sometimes HgX 2 is also added), to yield solid-state “double salt” arrays of the form M n + Hg(CN) 2 X n ( n = 1, 2). , In these reactions, the Lewis-acidity of the Hg(II) center is the key feature controlling the reactivity. Thus, the coordinately unsaturated Hg(II) center can accept compatible ligands during polymer formation to form square-planar, tetrahedral, or higher coordinate moieties in situ, in some cases increasing the structural and magnetic dimensionality of the system as result …”

Reaction of the Tricyanoborate Dianion [B(CN)3]2–with HgCl2

“…From the reaction product also small amounts of single crystals of Hg(CN) 2 •KCl•H 2 O were isolated, and its crystal structure was redetermined at low temperature. 37 Traces of Hg(CN) 2 27,28 could also be detected by 199 ). The structure of the [(NC)HgB(CN) 3 ] − anion was determined as both its K + and [PPh 4 ] + salt.…”

“…Crystals of K­[ClHgB­(CN) 3 ], [Ph 4 P] 2 [Hg­(B­(CN) 3 ) 2 ], K­[(NC)­Hg­B­(CN) 3 ], and [Ph 4 P]­[(NC)­Hg­B­(CN) 3 ] suitable for X-ray crystal structure analysis were grown by slow evaporation from aqueous solutions or dimethyl sulfoxide. From the reaction product also small amounts of single crystals of Hg­(CN) 2 ·KCl·H 2 O were isolated, and its crystal structure was redetermined at low temperature . Traces of Hg­(CN) 2 , could also be detected by 199 Hg NMR spectroscopy (−1390 ppm).…”

Anisotropic Thermal Expansion of Structurally Related Lanthanide–Mercury(II) Cyanide Coordination Polymers

“…46−59 An example of this is the reaction of Hg(CN) 2 with simple metal halides, in which the halide anions migrate to the mercury centers while the metal cations associate with the N-cyano groups of the mercury(II) cyanide; the anionic [Hg(CN) 2 Cl x ] x− moieties thereby generated then aggregate together, creating supramolecular motifs such as chains, sheets, and nets. [47][48][49][50][51]57 This strategy has previously been used in tandem with transition metal halide salts and ancillary chelating ligands to design birefringent coordination polymers; 49,57 however, mercury(II) cyanide has not yet been used in combination with f-block metals. Herein, we extend this design strategy to the lanthanides, describing the synthesis, structures, and thermal expansion of coordination polymers built from LnCl…”