芘在离子液体及常规溶剂中的激光闪光光解研究

Laser Photolysis Studies on Pyrene in Ionic Liquids and Conventional Solvents

利用纳秒级时间分辨激光光解装置,以Nd∶YAG激光器三倍频后的355 nm激光作为激发光源,研究了芘在常规溶剂乙腈、丙酮、环己烷、1-丁基-3-甲基咪唑六氟磷酸离子液体([Bmim][PF6])、N-丁基吡啶四氟硼酸离子液体([BuPy][BF4])以及三乙基庚基铵双三氟甲磺酰亚胺(R4NNTf2)的瞬态光解行为,比较了芘在各类体系中的瞬态光谱及反应动力学行为。研究表明芘在离子液体中各类瞬态物种的寿命均较常规溶剂延长,且反应速率常数随着离子液体的类型的变化而不同。与[Bmim][PF6]和R4NNTf2相比,[BuPy][BF4]最为活泼,认为主要是由于[BuPy][BF4]自身参加了反应。

The photochemistry of pyrene in conventional solvents（acetone,acetonitrile,cyclohexane） and ionic liquids ,,R4NNTf2 was investigated by time-resolved laser photolytic techniques.The transient absorption spectra of the excited pyrene and other radical species were compared.The absorption band of pyrene cation radical was observed in the acetone,acetronitrile and pyridinium ionic liquid systems.Only excited triplet pyrene was observed in cyclohexane and and R4NNTf2.The result demonstrates that there was an interaction between pyrene and solvents,and the pyrene cation radical was formed by electron transfer from the excited state of pyrene to acetonitrile,acetone and .The possible mechanisms of the six systems were suggested.