FWF - Aktivierung der Si-Si Bi - Co-mediated Si-Si bond activation

Project: Research project

Description

Cobalt carbonyl compounds have been found useful in organic chemistry as protecting groups for alkynes, as
catalyst for a number of interesting reactions and even as stoichiometric reagents (see f.i. cyclotrimerization of
alkynes and the Pausen Khand reaction). In organosilicon chemistry cobalt complexed alkynylsilanes and even
compounds containing silicon cobalt bond have been known for some while. Nevertheless, many aspects of the
chemistry of these compounds have not even been addressed so far.
In preliminary studies to this project a number of new cobalt complexed alkynyloligosilanes could be prepared.
These compounds exhibited an unusually streng activation of Si-Si bonds within the oligosilyl fragment. This
reactivity was responsible for the formation of a number of unexpected rearrangement products containing bridging
silylene ligands. Within the framework of the planned project the chemistry of metal complexed
alkynyloligosilanes will systematically be investigated. Especiall the Si-Si bond activation process, which is caused
by the complexation will be studied in some detail. Also some focus will be put an the rearrangement process
which is likely to be caused by the bond activation. Another rearrangement reaction which occurs when
oligosilylhydrides are treated with dicobaltoctacarbonyl was observed. The structural similarty of the the
rearrangement products obtained from the two reactions point at some related mechanisms.
Investigations conceming the chemistry of cobalt carbonyl complexes with bridging silylene ligands will be another
focus point of the planned research. Their structural similarity with dicobaltoctacarbonyl calls for the investigation
of addition reactions to unsaturated substrates. Also further reactions with hydrosilanes and hydrogen may be of
interest. In addition a screening for possible catalytic activity of the compounds will be carried out. Silylene
transfer ability may be another potentially useful feature of these compounds. Finally, it should be made clear that
all new compounds shall be investigated for their electrochemical, electronic and physical properies in -eneral,
especially in light of possible interesting material properties.
StatusFinished
Effective start/end date1/10/051/10/08