CRYSTAL CHEMISTRY OF COMPLEX AND ORGANOMETALIC COMPOUNDS WITH POLYATOMIC Hg_n-GROUPS

G.V. Romanenko, N.V. Pervukhina, S.A. Magarill

Institute of Inorganic Chemistry, Sib. Br. of RAS, Lavrentiev Av., 3, 630090 Novosibirsk, Russia

Compounds of formally univalent mercury Hg(I) contain characteristic metal - metal bond, usually have stable structural unit - Hg₂²⁺ dumbbell, which is stable in solutions and in a solids of compounds of different chemical classes. However, a number of clusters with polynuclear groups Hg_n (n= 3-9) is known.

On the basis of data on 125 crystal structures, taken from CCSDB and DB PME [1], a crystal chemical analysis of structures of coordination and organometallic Hg(I) compounds with organic ligands has been carried out.

The presence of a linear fragment ...X-Hg-Hg-X.. (X= O, Hal, S) with distance Hg-Hg 2.48-2.56 A is characteristic for the complexes with organic ligands. Nearest environment of mercury atom usually includes two atoms (Hg and X), but it can be added by other atoms, being on large distances.

Mercury - containing clusters can be divided on two groups : two- (flat polygones) and three-dimensional (Hg-polyhedra). The value of Hg-Hg bond lengths in Hg- and heterometallic clusters lay within an interval 2,65-3,45 A, that is longer than Hg-Hg bond lengths in complex Hg(I) compounds and is related to the type of Hg_n-group and the role of second type metal atoms in the formation of metal frame.

The analysis of Hg-Hg distances allows to make a conclusion that the increase of the number of coordinated ligands results in weakening (and lengthening) of the Hg-Hg bond.

This work was financially supported by the Russian Fundamental Research Fund (grant 98-05-65223).

1. Magarill S.A. et al. //J. Struct. Chem., v. 36, N3, pp. 510-513.