Mercury cyanide coordination

Mohamed, A.A., Abdou, H.E. and Fackler, J.P. Jr (2006) Mercury(ll) cyanide coordination polymer with dinuclear gold (1) amidinate. Structure of the 2-D [Au2(2,6-Me2-formamidinate)2]-2Hg (CN)2 2THF complex. Inorganic Chemistry, 45, 11-12. 

Metal complexes of several zinc, cadmium and mercury salts with 2-, 3- and 4-cyanopyridine have been reported.495 In none of the complexes was cyanide coordination observed. Zinc halides react with 3- and 4-cyanopyridine, but not with 2-cyanopyridine, to give 1 2 complexes which are assigned a monomeric tetrahedral structure on the basis of IR evidence. The cadmium halides also form 1 2 complexes with all the cyanopyridines, except cadmium chloride, which reacts with 2-cyanopyridine to give a 1 1 complex. The former contain... 

In the reaction of organic monocationic chlorides or coordinatively saturated metal-ligand complex chlorides with linear, neutral Hg(CN)2 building blocks, the Lewis-acidic Hg(CN)2 moieties accept the chloride ligands to form mercury cyanide/chloride double salt anions that in several cases form infinite 1-D and 2-D arrays. Hg chemical shift tensors and J( C, Hg) values measured in selected compounds reveal that the NMR properties are dominated by the Hg(CN)2 moiety. ... 

Metal ions having coordination number two occur in Hg(CN)2, [Ag(CN)2]- and [Au(CN)2]-, all derivatives of d ° species in each case the structure is linear. In K[Cu(CN)2] the copper atom is actually three-coordinated, the anion being an infinite chain each copper has a carbon atom of an unshared cyanide, and a carbon atom and a nitrogen atom of shared cyanides, as nearest neighbours in approximately planar coordination. Three-coordination also occurs in the [Hg(CN)3]- ion, but there are weak interactions between two of the nitrogen atoms and mercury atoms of other anions, giving rise to a loosely bonded chain structure. 

Each central naked Ag1 or Tl1 atom in [M TR(bzim) 2]BF4 is bonded to six Au1 centers forming a distorted trigonal prism (Fig. 28a) with Au- -M distances ranging from 2.731(2) to 2.922(2) A or from 2.9711(7) to 3.0448(7) A, respectively, indicative of appreciable metal-metal interaction. In the case of the mercury(II) derivative, the Hgn atoms interact with the Au1 centers in adjacent rings (four Au- -Hg contacts in each sandwich) with Hg---Au distances 3.2749(6) and 3.6531(6) A. Lastly, in the TCNQ derivative the cyanide groups are clearly not coordinated to the gold atoms and the distance from the centroid of the TCNQ to the centroid of the Au3 unit is 3.964 A. 

Cyanide is also an effective infrared probe (Yoshikawa et al., 1985). A drawback of this reagent as an infrared probe is its infrared intensity, which is much weaker than that of CO. However, as given in Fig. 10, the recent development in the infrared technique has solved this problem with the introduction of a mercury/cadmium/tellurium (MCT) detector (Fig. 10) (Yoshikawa et al., 1995). The C-N stretch vibrational band is sensitive to many factors, such as the oxidation state and species of the coordinating metal, the structures of porphyrin ring substituents, and the ligand trans to the cyanide and protein structure (Yoshikawa et al., 1985). This technique can be quite effectively applied for determination of the protonation state of the cyanide bound at a metal site. Possible binding modes of cyanide to a ferric iron are shown by Structures (1), (11), and (HI). Infrared spectroscopy is the best method for identihcation of these... 

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