Effect of Pressure on 4-Toluenesulfonyl Azide Studied by Raman Scattering and Synchrotron X-ray Diffraction

Abstract

The effect of high pressure on the phase transition behaviors of 4-toluenesulfonyl azide (C7H7N3O2S, 4-TsN3) have been investigated by Raman scattering and angle-dispersive X-ray diffraction (ADXRD) measurements in diamond anvil cells up to ∼15.6 GPa at room temperature. The liquid 4-TsN3 (phase I) begins to transform into solid state (phase II) at 0.7 GPa, and turns to phase III at about 2.7 GPa, then going to phase IV at about 6.3 GPa. The phase IV of 4-TsN3 finally starts to turn into an amorphous state above 10.6 GPa. The first phase transition (phase I to phase II) of 4-TsN3 is triggered by the rearrangement of C—H···π interaction, and the second phase transition (phase II to phase III) is attributed to the conformational change, then the rotation of sulfonyl leads to the third phase transition (phase III to phase IV). The variation of sulfonyl has an influence on the behavior of azide group which will bend and further decompose upon compression. In the process of amorphization, the lattice structure...