PI-COORDINATION TO MAIN-GROUP ELEMENTS - SOME NEW RESULTS

Cyclopentadienyl complexes of p-block elements in their low-oxidation state are stabilized by permethylation of the cp ring. In this context, synthesis, structure, and bonding of the group 14 decamethyl metallocenes (Me5C5)2El with EI=Si, Ge, Sn, Pb is described. Furthermore, synthesis, structure, and reactivity of the monomeric πcomplexes Me5C5GeCR{SiMe3)2 with R = H, SiMe3 is presented. - Half-sandwich cyclopentadienyl complexes of the type (Me4C5H)Me2Si(Me4C5)EI+X' with El = Ge, Sn show an additional weak metal-olefin interaction; their metallocenophane-like structure is proved by crystal structure analysis. π-Carbollyl complexes of low-valent group 13,14, and 15 elements show interesting structural features, which are discussed on the basis of NMR and x-ray crystal structure data. © 1990 IUPAC