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Chiral SiO 2 and Ag@SiO 2 Materials Templated by Complexes Consisting of Comblike Polyethyleneimine and Tartaric Acid
Author(s) -
Yao DongDong,
Murata Hiroki,
Tsunega Seiji,
Jin RenHua
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201502290
Subject(s) - tartaric acid , materials science , chirality (physics) , calcination , metal , crystallography , chemical engineering , catalysis , micrometer , nanotechnology , chemistry , organic chemistry , chiral symmetry breaking , physics , optics , quantum mechanics , nambu–jona lasinio model , engineering , metallurgy , citric acid , quark
A facile avenue to fabricate micrometer‐sized chiral ( L ‐, D ‐) and meso ‐like ( dl ‐) SiO 2 materials with unique structures by using crystalline complexes (cPEI/tart), composed of comblike polyethyleneimine (cPEI) and L ‐, D ‐, or dl ‐tartaric acid, respectively, as catalytic templates is reported. Interestingly, both chiral crystalline complexes appeared as regularly left‐ and right‐twisted bundle structures about 10 μm in length and about 5 μm in diameter, whereas the dl ‐form occurred as circular structures with about 10 μm diameter. Subsequently, SiO 2 @cPEI/tart hybrids with high silica content (>55.0 wt %) were prepared by stirring a mixture containing tetramethoxysilane (TMOS) and the aggregates of the crystalline complexes in water. The chiral SiO 2 hybrids and calcined chiral SiO 2 showed very strong CD signals and a nanofiber‐based morphology on their surface, whereas dl ‐SiO 2 showed no CD activity and a nanosheet‐packed disklike shape. Furthermore, metallic silver nanoparticles (Ag NPs) were encapsulated in each silica hybrid to obtain chiral ( D and L forms) and meso ‐like ( dl form) Ag@SiO 2 composites. Also, the reaction between L ‐cysteine (Lcys) and these Ag@SiO 2 composites was preliminarily investigated. Only chiral L ‐ and D ‐Ag@SiO 2 composites promoted the reaction between Lcys and Ag NPs to produce a molecular [Ag–Lcys] n complex with remarkable exciton chirality, whereas the reaction hardly occurred in the case of meso ‐like ( dl ‐) Ag@SiO 2 composite.