SYNTHESIS, VIBRATION-SPECTRA AND NORMAL-C OORDINATE ANALYSIS OF 1,2-DI-TERT-BUTYLTETRAHALODISILANES

The cleavage of the silicon-phenyl bonds of 1,2-di-tert-butyltetraphen yldisilane with hydrogen halides HCl, HBr and HI produces 1,2-di-tert- butyltetrachlorodisilane, 1,2-di-tert-butyltetrabromodisilane and 1,2- di-tert-butyltetraiododisilane in good yields. tBuBr2SiSiBr2tBu easily reacts with ZnF2 in diethylether to form the tetrafluoroderivative. W ith trifluormethanesulfonicacid, two phenyl groups can be removed sele ctively from tBuPh2SiSiPh2tBu. The subsequent reaction with LiX. gives the disilanes (t)BuPhXSiSiXPh(t)Bu (X = F, Cl, Br, I). Finally, the a symmetric tert-butyldisilanes tBU2HSiSiPh2tBu, tBU2BrSiSiBr2tBu and tB uHSiSiH2tBu can be obtained from Ph2BuSiK and tBU2SiHCl, followed by b romination with HBr and reduction with LiAlH4. The infrared and Raman vibrational spectra of tBUX2SiSiX2tBu are reported and assigned with t he aid of a normal coordinate analysis.