Mercury complexes cluster compounds

A silver- mercury centered cluster compound was prepared by Peringer etal. [96] (Scheme 12.41). The multi-component reaction led to quantitative formation of the complex 141, which was analyzed by X-ray single crystal diffraction. The Hg-Ag distances in this compound are 2.853(2) and 2.805(2) A, and the Hg-Hg distance is 2.6598(14) A. 

Mercury will bond directly to certain metal atoms including Co, Ru, Rh, Fe, Pt, and Mn. Such Hg-metal bonds are usually part of linear M-Hg-M or M-Hg-X linkages, and some clusters containing mercury-metal bonds are also known. These compounds are prepared by the reaction of mercury(II) halides with carbonyhnetallates. A rare example of trigonal prismatic (see Trigonal Prism) coordination in a mercury complex is exhibited by [Hg Pt3(2,6-Me2C6H3NC)6 2], which contains Pt-Hg bonds. These types of compound have been reviewed. ... 

Another area of major interest in the field is that of mixed metal cluster systems. Hieber very early in the study of metal carbonyl chemistry was able to prepare mercury complexes of the type Fe(CO)4(HgCl)2. The related gold ° compounds were prepared in the 1960s by reaction of phosphine gold halides with carbonyl anions. 

Gold-mercury cluster compounds have been obtained by different groups. Fackler et al. first prepared two Au-Hg-bonded complexes 143 and 145 in 1988 (Scheme 12.42) [97]. The two complexes are isomeric and the Au-Hg bond lengths are 3.088(1) and 2.989(1) A, respectively. Compound 144 could also be converted into 146 by treating with Au(THT)Cl (THT = tetrahydrothiophene) without T1 salt. The solid structure of 146 showed the Hg-Au distances of 3.310(1) and 3.361(1) A. 

Tetracarbonylcobaltate(l —) forms ionic complexes with group 1 elements. However, compounds of the type M[Co(CO)4] , where 2 and M = zinc, cadmium, mercury, indium, etc., are covalent, possessing M —Co bonds in which the main group metal has normal coordination number. These compounds are monomeric in the solid state. Ag[Co(CO)4] and Cu[Co(CO)4] are tetrameric clusters in which the metal atoms form planar, eight-membered rings. Each of the distorted [Co(CO)4] tetrahedrons is bonded to two atoms of silver or copper. 

The first example of a solid compound (Na3Hg2 amalgam) containing doubly cr- and 7T-aromatic transition metal cluster Hg " was discovered by Kuznetsov et al. [27]. Formation of the Hg " cluster was puzzling since mercury has a closed shell electron configuration (6s ), and therefore a neutral Hg4 cluster is expected to be a van der Waals complex. The stability of the Hg " building block can be explained due to the fact that it is isoelectronic to the first all-metal aromatic cluster. 

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