过饱和乙醇溶液重结晶导致三苯基膦单斜结构到正交相的相变

Triphenylphosphine phase transition derived from a recrystallization in supersaturated ethanol solution

本文利用透射电子显微术和X-射线衍射,研究发现单斜结构三苯基膦在过饱和乙醇溶液重结晶后形成了新的三苯基膦正交相。确定该正交相的晶格常数a=0.914 nm,b=0.976 nm,c=0.532 nm1。文中提出了三苯基膦从单斜晶系到正交晶系相变过程的形成机理。三苯基膦正交相最可能的空间群类型是I212121。伴随着相变行为的发生,在新的三苯基膦正交相中发现了具有伪12次对称性的36°旋转畴微结构。

Triphenylphosphine phase transition derived from a recrystallization in supersaturated ethanol solution has been studied by means of transmission electron microscopy and X-ray diffraction.A new orthorhombic phase was found after the recrystallization of monoclinic triphenylphosphine from the supersaturated ethanol solution at 60 ℃,which was identified to have lattice parameters of a = 0.914 nm,b = 0.976 nm and c = 0.532 nm,and possible space group of I212121.The mechanism of the phase transition from monoclinic structure to orthorhombic phase of triphenylphosphine was proposed.The recrystallization from supersaturation solution can be a valuable method of manipulating organic molecular arrangements on atom scale.Along with the occurrence of this phase transition,36° rotation domains was formed in the new orthorhombic phase.SAED pattern corresponding to 36° rotation domains shows a pseudo-twelvefold symmetry,and it indicates that such quasiperiodic structures can also exist in the organic crystal,representing a new mode of organization in organic matter.