Effect of High Pressure on the Internal Vibrations of all-trans-Hexaphenylcyclohexasilane

Abstract

Infrared and Raman spectra have been recorded with the aid of diamond anvil cells for all-transhexaphenylcyclohexasilane, [Si(H)Ph] 6 (I), at various pressures up to ∼40 kbar. The pressure dependences (dν/dP) and relative pressure dependences (d ln ν/dP) of the internal vibrations (ν SiH , ν SiSi , ν SiC , ν CH , etc.) have been determined. Two pressure-induced structural transitions were detected at ∼5 kbar (phase I→phase II) and ∼18 kbar (phase I→phase III), in which the conformation of the Si 6 skeleton and the orientation of the phenyl groups about the SiC bonds are changed