Convenient chirality transfer from organics to titania: construction and optical properties

Abstract

Polyethyleneimine (PEI) complexed with chiral d- (or l-) tartaric acid (tart) in water can self-organize into chiral and crystalline PEI/tart assemblies which can prompt titania deposition and impart their chirality to the resulting titania.

Fascinating chiral information transfer to titania/silica from near to racemic compound self-organized from polyethyleneimine and tartaric acid

“…This is the same observation as in our previously reported case, where sub-10 nm crystals of titania were uniformly located through the continuous silica phase so that the titania nanocrystals could not fuse each other to change their morphology at high temperature. 49 From the elemental mapping in the SEM images, we found that Ti, Si and O were homogeneously dispersed throughout the surface. Furthermore, the Ti content in the hybrid surfaces appears to be 28%–29% without apparent differences between the cases of enantiomeric pureness and enantiomeric excess (Fig.…”

“…Silica and titania are structural analogues when they are produced via hydrolytic polycondensation. 49 They are formed by the similar covalent bond of Si-O and Ti-O, respectively, with a tetraoxycoordinated structure. Although we have succeeded in employing the chiral crystalline complex of PEI/Tart for the construction of chiroptical minerals of silica and titania, as well as their application in developing chiroptical materials, [50][51][52][53][54][55][56][57][58][59] the relationship between the component of the catalytic templates and the chiroptical activity of the silica/titania are still not well understood.…”

“…Morphologies and phase transition of titania mediated by P/T complexes Previously, we reported that the crystalline aggregates of enantiopure P/T D and P/T L serve as a catalytic template to effectively cause the polycondensation of titanium lactate from which the chirality information of the crystalline aggregates can be efficiently transferred to the resulting titania to make the corresponding titania become chiroptical in their electronic absorption band. 49 Here, as shown in Scheme 1, we performed the preparation of chiral titania using the series of P/T complexes with different ratios of D/ L. The as-prepared products of TiO 2 @P/T were subjected to SEM, TGA, and XRD characterization.…”

Chiroptical Cross‐Linked Polymers Grown via Radical Polymerization around Chiral Nanosilica

“…[9][10][11] To begin with, it is not well reaction matrix for synthesis of chiroptical polymers although there are great achievements in both syntheses and property regarding chiral inorganic materials. [36][37][38][39][40] We have established a unique method for the synthesis of nanofiber-based chiral silica via an enantioselective pathway, by which the asymmetrical centers of silanes would be selectively generated in siliceous matrixes. [41][42][43][44][45] We revealed that polyethyleneimine (PEI) with secondary amine units (CH 2 NHCH 2 ) in the main chain could self-assemble into crystalline fibrils which can play as a catalytic template to promote the silicification exclusively on its crystalline surface.…”

Transfer of Chiral Information from Silica Hosts to Achiral Luminescent Guests: a Simple Approach to Accessing Circularly Polarized Luminescent Systems

“…Although there are lots of reports on organic and/or inorganic achiral luminophores with an outstanding luminescent property, chiral host materials for the CPL‐active system mostly come from chiral organics. In the field of chiral materials, although there are great achievements in the development of inorganic chiral materials, its potential to a chiral source for the CPL system has been rarely explored. Herein, we propose a new concept for the architecture of solid‐state CPL‐active materials based on host‐guest systems employing the inorganic chiral silica as a chiral host, which can force diverse achiral luminophores (guests) to become CPL‐active.…”