Optically Active Chiral CuO “Nanoflowers”

Abstract

Helical symmetry can be found in most flowers with a rotation of contort petal aestivation. For micro- and nanoscale analogies, flower mimicking structures have been reproduced; however, the conceptual chirality of "nanoflowers" has not yet been defined. Here, the chirality of the "flower" was defined by its nanosized chiral structure and consequent optical activity (OA), opening new horizons for the physical theory and chiral materials. We report the surfactant-mediated hydrothermal synthesis of chiral CuO nanoflowers using sodium dodecyl sulfate (SDS) as a structure-directing agent, an amino alcohol as a symmetry-breaking agent, and cupric salt as the inorganic source. Two levels of hierarchical chirality exist for a CuO nanoflower including primary helically arranged "nanoflakes" and secondary helical "subnanopetals" that form "nanopetals". The nanoflowers exhibited a prominent optical response to circularly polarized light (CPL) at the absorption bands characteristic of CuO.

Enhanced visible-light activities for PEC water reduction of CuO nanoplates by coupling with anatase TiO2 and mechanism

“…In particular, it can be observed from the HRTEM image inset Fig. 2C, that the lattice fringes of (1 0 1) planes with interplanar distance (d 101 = 0.35 nm) correspond to nanocrystalline anatase TiO 2 [22], whereas the interplanar distance (d 111 = 0.25 nm) correspond to CuO NPC [21]. The HRTEM image of the heterojunction TiO 2 /CuO NPC reveals that the material is highly crystalline, as evidenced by the well-defined lattice fringes.…”

“…The steady-state surface photovoltage spectra (SS-SPS) instrument was a home-built apparatus as discussed elsewhere [20]. [16,21]. But no peaks of TiO 2 can be seen in the composites even for the 15T/C NPC, one reason is that the crystallinity of CuO NPs is much higher than TiO 2 ; another is that the TiO 2 nanoparticles are uniformly scattered on CuO NPs.…”

Self‐Assembly of 1D Helical Nanostructures into Higher Order Chiral Nanostructures in Supramolecular Systems

“…CuO is a kind of achiral inorganic oxide. However, when sodium dodecyl sulfate (SDS) was used as a structure‐directing agent and an amino alcohol as a symmetry‐breaking agent, the cupric salt could self‐assemble into chiral CuO nanoflowers by surfactant‐mediated hydrothermal synthesis (Figure B) . The CuO nanoflower had two levels of hierarchical chirality including primary helically arranged “nanoflakes” and secondary helical “subnanopetals”, which exhibited a prominent optical response to circularly polarized light (CPL).…”

CuO nanoparticle‐catalyzed diaminations for synthesis of benzimidazole derivatives

“…Nanoparticles have emerged as robust and high‐surface‐area heterogeneous catalysts, which serve as sustainable alternatives to conventional materials . CuO nanoparticles have drawn attention due to their stability and availability . For example, Punniyamurthy and co‐workers reported the synthesis of substituted benzimidazoles via CuO nanoparticle‐catalyzed intramolecular C–N coupling .…”