Silicon, the Sister Element of Carbon

Herbert W. Roesky


University of Goettingen , Institute of Inorganic Chemistry,Tammannstrase 4,

37077 Goettingen, Germany


For the preparation of compounds with low valent silicon new methods were developed to generate these molecules in high yield. This was an important target, because otherwise the development of this class of compounds on a broader scale would not be possible. The preparation of NHC•SiCl2 (NHC = N-heterocyclic carbene) results from the HCl elimination of NHC•SiHCl3 with N-heterocyclic carbene to yield NHC•SiCl2 and NHC•HCl. The latter compound is hardly soluble in organic solvents, and can be removed by filtration. The base stabilized NHC•SiCl2 turned out to be an interesting precursor for the preparation of various types of silicon compounds. The bissilylene forms a four-membered N2Si2: ring. So far a carbon analogous compound is not known. Furthermore the preparation of LSiCl and LSiN(SiMe3)2 will be reported (L = PhC(NtBu)2). They are precursors for the preparation of a number of silicon-phosphorus compounds using P4 as a phosphorus source. Moreover, it is shown that the P4 can be converted to a Si=P-P=P-P=Si chain using a silylene.