New ways to polysilanes

New cyclosilanes with substituents, which are functional groups, open the possibility of forming new polycyclic silanes in an aimed synthesis. This is possible on five- and six-membered rings. Also, mixed systems with different ring sizes were prepared. The UV spectra are discussed. An annelid dicycle Si₁₀Me₁₈ was also prepared. With this compound a radical anion can be formed. New aspects of the electrochemical synthesis of polysilanes are presented and a chlorine stable anode is proposed for the first time. The polymerization reaction of hydrogen-containing methyldisilanes is discussed. This reaction yields polysilanes with a general composition (SiMeH) _n and a ceramic yield over 88%. The reaction is very different from the known reaction of monosilanes. Disilanes react faster and to high polymers. Two reaction mechanisms seem to be working simultaneously, i.e., a mechanism as postulated in monosilanes and a disproportionation reaction. These mechanisms are discussed.