Volume 34, Issue 2

Metalloid cluster compounds of tin of the general formulae Sn n R m with n>m (R=organic ligand), where beside ligand-bound tin atoms also “naked” tin atoms, that only bind to other tin atoms, are present, represent a novel class of cluster compounds in tin chemistry. As the “naked” tin atoms inside these clusters exhibit an oxidation state of 0, the average oxidation state of the tin atoms within such metalloid tin clusters is in between 0 and 1. Thus, these cluster compounds may be seen as intermediates on the way to the elemental state. Therefore, interesting properties are expected for these compounds, which might complement results from nanotechnology. During the last years, different syntheses of such novel cluster compounds have been introduced, leading to several metalloid tin cluster compounds, which exhibit new and partly unusual structure and bonding properties. In this review, recent results in this novel field of group 14 chemistry are discussed, whereby special attention is focused on the novel synthetic route applying a disproportionation reaction of metastable Sn(I) halides.

Complexes of transition metals with heavy analogs of carbenes (tetrylenes) as ligands have been studied now for some 40 years. The current review attempts to provide an overview about complexes with non-stabilized (having no π-donating substituents) germylenes, stannylenes, and plumbylenes. Complexes are known for groups 4–11. For groups 6–10 not only examples of monodentate tetrylene ligands, but also of bridging ones are known. While this review covers almost 200 complexes, the field in general has been approached only very selectively and real attempts for systematic studies are very scarce. Although some isolated reports exist which deal with the reactivity of the tetrylene complexes most of the so far published work concentrates on synthesis and characterization.