The pyndazine hexafluorophosphate[C4H5N2]~＋[PF6]^-（1） undergoes a reversible phase transition around140 K,which was confirmed by the DSC measurement.Variable-temperature crystal structures determined at 293 K and 9...The pyndazine hexafluorophosphate[C4H5N2]~＋[PF6]^-（1） undergoes a reversible phase transition around140 K,which was confirmed by the DSC measurement.Variable-temperature crystal structures determined at 293 K and 93 K show that the compound crystallizes in the same space group P21/c,indicating that 1 undergoes an iso-structural phase transition.As the temperature decreases,dielectric measurement of the title compound shows no significant change around the phase transition temperature.Classic hydrogen bonds are found between molecules at 293 K and 93 l〈 with similar packing arrangement.The most distinct difference between the low temperature and room temperature structures is the order-disorder transition of the hexafluorophosphate anion,which is probably the driving force of the phase transition.展开更多
基金financially supported by the National Natural Science Foundation of China(No.91222101)
文摘The pyndazine hexafluorophosphate[C4H5N2]~＋[PF6]^-（1） undergoes a reversible phase transition around140 K,which was confirmed by the DSC measurement.Variable-temperature crystal structures determined at 293 K and 93 K show that the compound crystallizes in the same space group P21/c,indicating that 1 undergoes an iso-structural phase transition.As the temperature decreases,dielectric measurement of the title compound shows no significant change around the phase transition temperature.Classic hydrogen bonds are found between molecules at 293 K and 93 l〈 with similar packing arrangement.The most distinct difference between the low temperature and room temperature structures is the order-disorder transition of the hexafluorophosphate anion,which is probably the driving force of the phase transition.
