以卵磷脂为手性添加剂制备手性介孔二氧化硅

以十六烷基三甲基溴化铵(CTAB)的自组装体为模板,卵磷脂(PC)为手性添加剂,在n PC∶nCTAB=1∶21时,通过溶胶-凝胶法制备了螺旋介孔二氧化硅纳米棒。利用扫描电镜(FESEM)、透射电镜(TEM)、X-射线衍射以及氮气吸附-脱附等测试手段,对该纳米棒的形貌以及孔结构进行了表征。TEM显示该纳米棒的长度约为50～200 nm,直径约为30～50 nm。X-射线衍射表明孔道呈二维六方排列,虽然FESEM显示纳米棒左右手比例约为1∶1,但通过圆二色谱表征证明该纳米棒在埃尺度下倾向于形成单一手性。结果表明,卵磷脂的手性可以传递到螺旋介孔二氧化硅纳米棒中。

Preparation of Chiral Mesoporous Silica Using Phosphatidylcholine as a Chiral Additive

Helical mesoporous silica nanorods were prepared through a so-gel approach using cetyltrimethylammonium bromide (CTAB) as the template and phosphatidylcholine (PC) as a chiral additive. The molar ratio of PC and CTAB is 1:21. The morphologies and pore architectures were characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N₂ sorptions and X-ray diffraction. It was found that the mesoporous silica nanorods were about 30~50 nm in diameter and about 50~200 nm in length. The TEM images and the small-angle X-diffraction indicated that the pore channels arranged in a two-dimensional hexagonal structure. The FESEM images indicated that the ratio of the left-and right-handed nanorods is almost 1:1. However, the circular dichroism spectrum (CD) indicated that the nanorods tended to form a structure with homochirality at angstrom level. It seems that the chirality of PC has been successfully transferred to the walls of the helical mesoporous silica nanorods.