PHOSPHORESCENCE QUENCHING BY MOLECULAR-OXYGEN - ZINC TETRAPHENYLPORPHIN ON SOLID SUPPORTS
PHOSPHORESCENCE QUENCHING BY MOLECULAR-OXYGEN - ZINC TETRAPHENYLPORPHIN ON SOLID SUPPORTS
复制标题
DOI：
10.1021/j100304a024
复制
发表时间：
1987-09-24
影响因子：
--
通讯作者：
GOOD, L
中科院分区：
文献类型：
--
作者：
TWAROWSKI, AJ;GOOD, L
研究了分子氧对四苯基卟啉锌（ZnTPP）磷光的猝灭作用，发现负载于硅胶和氯化钠晶体上的ZnTPP磷光猝灭作用明显不同。对于后一种基质，氧猝灭缩短了磷光寿命，并遵守Stern-Volmer动力学。在室温下，猝灭速率常数约为1100 Torr ~（-1）s ~（-1），对温度没有明显的依赖性。在硅胶上ZnTPP磷光猝灭发生在较低的氧气压力，并不伴随着发光速率常数的变化。磷光猝灭的数据同意与修改后的Langmuir吸附模型，该模型假设，只有吸附在硅胶表面上的ZnTPP分子旁边的氧将淬灭发光。如果假设氧与水分子竞争衬底表面上的吸附位点，则由吸附模型来解释猝灭对硅胶衬底的温度依赖性。水和氧之间的吸附能的平均差Em是发光猝灭模型中的拟合参数，并且被发现为：
The quenching of zinc tetraphenylporphin (ZnTPP) phosphorescence by molecular oxygen is found to be markedly different for dye supported on silica gel and on NaCl crystals. With the latter substrate quenching by oxygen shortens the phosphorescence lifetime and obeys Stern-Volmer kinetics. The quenching rateconstant is approximately 1100 Torr'1 s'1 at room temperature and shows no dramatic dependence on temperature. On silica gel quenching of ZnTPP phosphorescence takes place at lower oxygen pressure and is not accompanied by a change in the luminescence rate constant. The phosphorescence quenching data agree with a modified Langmuir adsorption model which assumes that only oxygen adsorbed on the silica gel surface next to a ZnTPP molecule will quench luminescence. The temperature dependence of quenching on the silica gel substrate is explained by the adsorption model if it is assumed that oxygen competes with water molecules for adsorption sites on the substrate surface. The mean difference in adsorption energy betweenwater and oxygen, Em, is a fitting parameter in the luminescence quenching model and is found to be