高压拉曼光谱方法研究卟啉J-聚集体

本文利用金刚石对顶砧(DAC)和拉曼光谱技术,测量了四苯基卟啉J聚集体在13GPa内的高压拉曼光谱,根据各个拉曼谱带的频移-压强变化曲线得出在13GPa内Tpp J聚集体无相变发生,并且高波数(1010～1600cm-1)和低波数(230～330cm-1)区的斜率要远大于中等波数(380～1000cm-1)区,这表明对应于高波数和低波数区的化学键比中等波数区更具有易压缩性,并对体积的减小起着重要的作用。根据苯环ψ3C-C面内伸缩振动模式强度逐渐增强的现象提出了分子弹簧垫圈模型。此外,这种分子弹簧垫圈的劲度系数可以通过中位取代基团调控。

High Pressure Raman Investigations on Porphyrin J Aggregates

Using diamond anvil cell(DAC) microscopic Raman technique,we reported the in situ Raman measurements of Tpp J aggregates under high pressure up to 13 GPa.From the frequency-pressure relationship,no obvious evidence of phase transition can be concluded during the entire compression processes,on the whole,the slopes(dω/dP) at high-(1010~1060 cm-1) and low-frequency(230~330 cm-1) are greater than that in the middle-frequency(380~1000 cm-1) region,suggesting that the chemical bond of greater compressibility,which is associated with the high and low frequency bands,is more sensitive to compression and makes a major contribution to the reduction of the volume.Another interesting observation is the continuing intensity enhancement of phenyl ψ3 C-C stretching mode with pressure;According to this spectral phenomenon,Tpp J aggregates can be treated as a candidate for the potential application of pressure-driven molecular spring washers in parallel combinations.Additionally,the stiffness of molecular washers can be tunable by properly choice of meso-substitution.