非平面扭曲构象对1，3－二苯基吡唑啉衍生物荧光性质的影响

研究了１，３－二苯基吡唑啉（ＤＰＰ）和１－苯基－３－（４－硝基苯基）吡唑啉（ＰＮＰ）在室温及７７Ｋ时不同溶剂中的荧光光谱，发现在非极性溶剂中７７Ｋ时ＤＰＰ的荧光强度远比其在室温时的低，而ＰＮＰ则完全没有荧光，表明这些化合物激发态的构象松驰，形成非平面扭曲构象对分子的发光性质十分重要。同时发现这两个化合物具有不同的关键性扭曲部位，形成各自有利于发光的构象，Ｎ－１上及Ｃ－３上苯环的扭曲分别对ＤＰＰ和ＰＮＰ的发光态的形成起着重要作用。

Influence of Twisted Conformation on Fluorescent Properties of 1,3-Diphenyl Pyrazoline Derivatives

The fluorescent properties of 1,3-diphenyl pyrazoline(DPP) and 1-phenyl-3-(4-nitrophenyl) pyrazoline(PNP) were studied at room temperature(293 K) and 77 K respectively.In non-polar solvents the intensity of the fluorescence of DPP at 77 K was much lower than that at room temperature and PNP showed no emission at 77 K.These phenomena indicate that it is very important for luminescent properties of the compounds that in excited state the conformation of the molecules relaxes from a planar to a twisted one.The studies of the modified compounds,inhibiting the rotation of the phenyl groups at different positions in DPP and PNP,verified the expression above.From experimental results it can also be concluded that there are different key twisting positions to form luminescent conformation between DPP and PNP.It is very important for forming the luminescent state of DPP to twist the phenyl at N-1 position,in contrast with that,twisted phenyl at C-3 is more important for establishing the luminescent state in PNP.