脂肪醇对杂多酸P_2Mo_(18)^(6-)激发态的还原作用

REDUCTION OF P_2Mo_(18)^(6-) EXCITATION STATE BY ALIPHATIC ALCOHOLS

近年来,杂多酸和氧化物催化剂表面的类似性引起了人们的广泛兴趣。钼杂多酸具有光化学活性,在不同种类有机溶剂存在下,紫外或可见光辐照就形成杂多蓝还原产物及相应的有机物氧化产物。从乙醇或1,4-二噁烷中沉淀出来的杂多酸化合物(简称HPC)在日光下也变成蓝色。HPC还原时形成多电子还原产物—杂多蓝(简称HPB)。这种多个还原电子体系可能作为还原N_2,CO和H_2O的还原剂。杂多酸光催化大量有机物的氧化反应,以及水放氢的还原反应,是一个活跃的研究领域之一。本文研究了Dawson结构P_2Mo_(18)^(6-)

In this paper, the kinectics and quantum yields of heteropolyanion P_2Mo_(18)O_(62)^(6-) excitation state reduced by methanol, ethanol, n-propanol, 2-propanol, ethylene glycol, and tert-butyl alcohol are reported.We have measured the conversion rate of HPC to its reduced form HPB under the irradiation of Xe lamp when mixed with aliphatic alcohol. By a good linear relation between the concentration of HPB and the reaction time (Figure 2), a zero -order reaction was shown. The quantum yield of HPB was measured in the presence of aliphatic alcohol, the rate constants k_r defined by d(HPB)/dt=k_r(HPC~*) (Aliphatic alcohol) were also estimated. The sequence of the k_r is as follows:ethylene glycol>2-propanol>n-propanol～ethanol>methano tert-butyl alcoholIn addition, the spectra and properties of both HPC and HPB have been compared.