PUB - Publikationen an der Universität Bielefeld

The title compound 2 can be synthesized either by reaction of ([C5H5SiMe2SiMe2C5H5]2- 2 Li+) with XSiMe2SiMe2X or by an intermolecular nucleophilic substitution reaction between two molecules of ([XSiMe2SiMe2C5H5]- Li+). Isomers of 2 with allylic hydrogen atoms arise from silatropic rearrangements and therefore show "cyclopentadiene reactivity". Reaction of the monoanion of 2 with FeCl2 yields the ferrocene 4. From the reaction of the dianion of 2 with Me5C5RuCl, the binuclear ruthenium complex 7 with Si - Si bridges in 1,2-position can be isolated; reactions with FeCl2 or Me5C5Fe(acac), with Me5C5GeCl, with SnCl2, and with PbCl2, lead to the metallocenes 6, 7, 8, and 9; in all these complexes the disilane bridges are in 1,2-position. The binuclear cobalt complex 10, in which the cyclopentadienyl rings are connected with each other by disilane bridges in 1,3-position, can be synthesized by the reaction of 2 with Co2(CO)8. The results of single-crystal X-ray structure analyses of 6 and 10 are presented. The possible conformations of the dianion of 2 are discussed.