Strukturchemische Aspekte der Organozinnchemie

Abstract

In a short survey the fundamental difference between organometallic and organometalloid chemistry is related to the reverse polarity of carbon-metal bonds in comparison with bonds between carbon and other elements. The several types of carbon-metal bonds are discussed with special emphasis on the elements of the fourth main group of the periodic system (Si, Ge, Sn and Pb).
The body of this paper is devoted to a description of the preparation and structure of a newly developed class of organotin compounds. These compounds have the general structure R₃SnR' in which R stands for an aliphatic or aromatic hydrocarbon radical and R' for a group that is bound by means of a tin-nitrogen bond. Compounds of this class are exceptionally stable when R' is an unsaturated group containing two nitrogen atoms in 1,3 position, e. g. imidazole, triazole or the hydrazoic anion. It is shown that these substances are hydrolysed in aqueous solution, but are stabilized in the crystalline state. The infrared spectra in the 500 cm^-1 region point to the presence of planar R₃Sn groups. From this combined evidence a new type of structure is proposed for these compounds in which the second nitrogen of the group R' is co-ordinated intermolecularly to a neighbouring tin atom. Thus each metal atom becomes five-co-ordinated with its axial positions bound to nitrogen and its equatorial positions to the hydrocarbon radicals.
The structure described above probably has a more general validity. It is proposed also for trialkyltin acylates, the physical properties of which can be explained by its aid.