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

Polyethyleneimine (PEI) complexed with chiral d- (or l-) tartaric acid (tart) in water can self-organize into chiral and crystalline PEI/tart assemblies. It has been previously confirmed that the complexes of PEI/tart could work as catalytic/chiral templates to induce the deposition of SiO nanofibres with optical activity but without outwards shape chirality such as helices. In this work, we found that the templating functions of PEI/tart were still effective to prompt the deposition of TiO to form chiral PEI/tart@TiO hybrid nanofibres under aqueous and room temperature conditions within two hours. Furthermore, the co-deposition of TiO and SiO was also fulfilled to yield chiral PEI/tart@TiO/SiO nanofibres. These TiO-containing hybrid nanofibres showed non-helical shapes on the length scale; however, chiroptical signals with mirror relation around the UV-Vis absorption band of TiO remarkably appeared on their circular dichroism (CD) spectra. By means of the protocols of XRD, TEM, SEM, UV-Vis, CD and XPS, structural features and thermoproperties of the chiral TiO and SiO/TiO were investigated.