Spectroscopic and kinetic studies of photochemical reaction of magnesium tetraphenylporphyrin with oxygen.
Magnesium tetraphenylporphyrin (MgTPP) was synthesized from meso-tetraphenylporphyrin (H(2)TPP) in N,N-dimethylformamide (DMF). The photochemical properties of MgTPP in the presence of oxygen were investigated in dichloromethane (CH(2)Cl(2)) by conventional fluorescence, UV-vis, (1)H NMR, MALDI-TOF-MS, FTIR, and XPS spectroscopic techniques. Spectral analyses showed that under irradiation, MgTPP molecules reacted with O(2) molecules, and a stable 1:1 adduct was produced. During the photochemical reaction process, one oxygen molecule was bound to the pyrrolenine nitrogens in the MgTPP molecule, and the characteristic N-O bonds were identified using the FTIR and XPS techniques. The kinetics of the photochemical reaction of MgTPP with O(2) has been studied in an oxygen-saturated solution. Under irradiation conditions, the experimental rate follows a pseudo-first-order reaction for MgTPP, having a half-life from 40 to 130 min under various irradiation intensities. The kinetic rate constant of photochemical reaction of MgTPP with O(2) showed a linear dependence.
Zhang
Jianbin
J
Department of Applied Chemistry, College of Chemistry & Molecular Engineering, Peking University, Beijing 100190, China. tadzhang@126.com
Zhang
Pengyan
P
Zhang
Zhengfu
Z
Wei
Xionghui
X
D002384:Catalysis; D002734:Chlorophyll / Q000737:chemistry; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010100:Oxygen / Q000737:chemistry*; D055668:Photochemical Processes; D011166:Porphyrins / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
D011166:Porphyrins; C409084:tetraphenylporphyrin; D002734:Chlorophyll; D010100:Oxygen