The Spectroscopy Study Of Two Kinds Of Porphyrin Derivatives

Prophyrins（PP） is a kind of special macrocyclic compounds with many specialstructure and property characteristics such as a large conjugated structure、rigid planestructure、big conjugacy with π bond、photoelectric magnetic、the electronic buffer、as well as diverse three-dimensional structure and so on,which is widely applyied oncatalysts, optical information storage materials, anticancer drugs, superconductor,chromogenic agent field. More and more research have been developed by Prophyrinsscientific significance and wide application prospect. Porphyrin’s performance will bechanged due to their molecular structure change, so if we replace porphyrin side chainatoms with different substituents, we can change a series of optical properties ofporphyrin derivatives.This paper selects two kinds of porphyrin compounds with different substituentsT（OCH₃）₄PP and T（Cl）₄PP （four-chlorophenyl porphyrin and four-methoxyphenylporphyrin）, Which contain the group-OCH₃is the electronic donating group, thegroup-Cl is the electron withdrawing group. Due to the introduction of the two kindsof functional groups, we can optimize the photoelectric properties of porphyrincompounds.In this article, we confirmed the existence of the electron donating group-OCH₃and electron withdrawing group-Cl by Infrared Spectra(In the spectral line, appearsstretch out and draw back vibration absorption peak of the C-O around1249cm^-1and1173cm^-1; appears stretching vibration absorption peak of C-Cl in the vicinity1091cm^-1�'�490cm^-1), and point out some of the main positions of infraredabsorption peak. In the meantime, I also conducted the testing of Raman spectrum andpoint out some of the main positions of Raman vibrating peak. Through the study ofinfrared spectroscopy and Raman Spectroscopy, proved that both the electron donating group-OCH₃and the electron withdrawing group-Cl infrared activity butwithout Raman activity.For the study of the steady-state spectrum, include UV-visible absorptionspectrum and fluorescence spectroscopy.（1） UV-visible absorption spectrum: For the samples both T（OCH₃）₄PP andT（Cl）₄PP, we discovered that T（OCH₃）₄PP with the electron donating group-OCH₃would make the absorption red-shift and T（Cl）₄PP with the electron withdrawinggroup-Cl would make the absorption blue-shift in the same solvent environment. Andwhen each of the samples in solvent with the different polarity, for two of the selectedsolvents Toluene and DMSO, with the increase of the polarity of the solvent, thesamples are all have a tiny red-shift,say1²nm.（2） Fluorescence spectroscopy: For the samples both T（OCH₃）₄PP and T（Cl）₄PP,the Fluorescence peak positions of T（OCH₃）₄PP with the electron donating group-OCH₃have a6⁸nm red-shift than T（Cl）₄PP with the electron withdrawing group-Cl,which have a good corresponding to their corresponding absorption Spectra. And inthe case of each of the samples in the solvent with the different polarity, with theincrease of the polarity of the solvent, the samples are all have a tiny red-shift. For theintensity of Fluorescence peak, with the same solvent, the fluorescence intensitywould be strengthened by the substituent group-OCH₃and lessened by the thesubstituent group-Cl. In the end of this chapter, I also discussed the proportion ofeach of two fluorescence peaks, and find out that the electron donating group-OCH₃have a larger influence to rhe orbit ofα_1u（π）, the electron withdrawing group-Clhave a larger influence to rhe orbit ofα_2u（π）.For the transient absorption spectroscopy, this article conducted a study of excitedstate Dynamics on two samples T（OCH₃）₄PP and T（Cl）₄PP by the Pump-probemethod. From the experimental results, we could make the conclusion that withregard to TPP, joined electron donating group-OCH₃to the benzene rings wouldaccelerate the molecular electron transfer rate; and joined electron withdrawing group-Cl to the benzene rings would slow-down the molecular electron transfer rate. In the case of each of the samples in the different solvents, we deduced the conclusion bythe Marcus electronic transfer theory as follows: in the solvent of Toluene and DMSO,T（OCH₃）₄PP in the Marcus normal area, its time of relaxation would be decreasedwith with increasing polarity of the solvent; T（Cl）₄PP in the Marcus reverse area, itstime of relaxation would be increased with with increasing polarity of the solvent.