碘化银胶体上四苯基卟啉金属配合物的表面增强拉曼光谱研究

摘要

研究了四苯基卟啉金属配合物（MTPP,M=Ag,Mg,Cu,Pd）在AgI胶体上的表面增强拉曼光谱（SERS）。结果显示MgTPP与基底发生金属交换生成AgTPP,而在PdTPP和CuTPP上则未发现金属交换。除卟啉环的振动外，一些苯环振动带也被显著增强。在1400～1600cm-1范围，PdTPP和CuTPP的SERS与AgTPP有很大差别，可能反映了吸附分子在次甲基桥碳原子Cm附近立体构型的差异。%Surface-enhanced Raman Spectra(SERS)of four metallotetraphenylporphyrins(MTPP,M=Ag,Mg,Cu,Pd)adsorbed on AgI colloid were studied using 632.8nm excitation.It was shown that MgTPP on AgI colloid undergoes a metal exchange reaction with the substrate to form AgTPP,evidenced by appearing characteristic Raman bands of AgTPP in the SERS of MgTPP.In contrary,metal exchange reaction was not observed for CuTPP and PdTPP molecules adsorbed on AgI colloids.In addition to the porphyrin-ring related bands,several monosubstituted benzene bands are also enhanced in the SERS spectra of MTPP.The SERS enhancement patterns of PdTPP and CuTPP in the region of 1400～1600cm-1 are very different from that of AgTPP,which can be attributed to the different stereochemistry of the adsorbents around Cm atoms.The present study demonstrates that semiconductors such as AgI can be suitable SERS substrates to study the structure and chemical reactions of adsorbed molecules.