Circular dichroism

  • Article
    | Open Access

    The stereoselective analysis of mixtures of chiral compounds typically requires time-consuming chromatography. Here, the authors combine reaction based chiroptical sensing and chemometric tools to directly determine the absolute configuration, enantiomeric composition and concentration of convoluted samples without physical separation.

    • Diandra S. Hassan
    •  & Christian Wolf
  • Article
    | Open Access

    Polymer thin films that emit and absorb circularly polarised light are promising in achieving important technological advances, but the origin of the large chiroptical effects in such films has remained elusive. Here the authors demonstrate that in non-aligned polymer thin films, large chiroptical effects are caused by magneto-electric coupling, not structural chirality as previously assumed.

    • Jessica Wade
    • , James N. Hilfiker
    •  & Matthew J. Fuchter
  • Article
    | Open Access

    Chirality of nanostructures may be determined by ensemble measurements in solution or on single immobilized nanoparticles, with loss of detail or interference from the substrate. Here the authors demonstrate that circular differential scattering intensity spectra of freely diffusing single nanoparticles provide chiroptical spectra which reflect their intrinsic chirality.

    • Johannes Sachs
    • , Jan-Philipp Günther
    •  & Peer Fischer
  • Article
    | Open Access

    Room temperature phosphorescence (RTP) is a topic which is currently widely studied, but a study on the correlation between types of molecular solid and RTP properties is lacking. Here the authors show that RTP is enhanced in the racemic form of axial chiral molecules due to its denser R- and S- cross packing arrangement.

    • Xiugang Wu
    • , Chun-Ying Huang
    •  & Pi-Tai Chou
  • Article
    | Open Access

    Spin-information transport or transfer is essential for spintronics applications and often relies on high purity and quality materials. Here, the authors report on the defect-tolerant solution-processed Ruddlesden–Popper halide perovskites, where a spin propagation length of 600 nm was achieved via spin funneling.

    • David Giovanni
    • , Jia Wei Melvin Lim
    •  & Tze Chien Sum
  • Article
    | Open Access

    Chiroptical sensing in complex mixtures remains a challenging task. Here, the authors report an efficient coumarin probe for chiroptical click chirality sensing of absolute configuration, concentration and enantiomeric excess of several compound classes. The method can be directly applied to crude asymmetric reaction mixtures.

    • F. Yushra Thanzeel
    • , Kaluvu Balaraman
    •  & Christian Wolf
  • Article
    | Open Access

    Molecular aggregation is a widespread and important process in physiological metabolism, but details regarding conformational changes during the process are hard to probe. Here, the authors use circular dichroism to monitor in-situ the conformational changes occurring during molecular aggregation.

    • Haoke Zhang
    • , Xiaoyan Zheng
    •  & Ben Zhong Tang
  • Article
    | Open Access

    Molecular details that underlie mechanical properties of spider silk are of great interest to material scientists. Here, the authors report a previously unknown three-state mechanism of folding and an expanded structure of a spider silk protein that may contribute to elasticity of spider silk.

    • Charlotte Rat
    • , Julia C. Heiby
    •  & Hannes Neuweiler
  • Article
    | Open Access

    The ability to spectroscopically pinpoint whether nanoparticles are located inside or outside of cells represents an overarching need in biology and medicine. Here, the authors show that the chirality of DNA-bridged particle dimers reverses when they cross the cell membrane, providing a real-time chiroptical signature of their intra- or extracellular location.

    • Maozhong Sun
    • , Liguang Xu
    •  & Chuanlai Xu
  • Article
    | Open Access

    The experimental determination of band structure of single wall carbon nanotubes (SWCNTs) is a challenging task, and often must be theoretically predicted. Here, the authors separate SWCNTs in high purity and experimentally determine their excitonic band structures using circular dichroism spectra.

    • Xiaojun Wei
    • , Takeshi Tanaka
    •  & Hiromichi Kataura
  • Article
    | Open Access

    Protein subunits on the capsids of icosahedral viruses can form patterns with rotational symmetry, which are difficult to recreate in the laboratory. Here the authors report a strategy to construct 3D chiral polyhedra with rotational faces from 2D chiral truxene-based units through dynamic covalent chemistry.

    • Xinchang Wang
    • , Yu Wang
    •  & Xiaoyu Cao
  • Article
    | Open Access

    Analysis and detection of circularly polarized light involves the use of multiple optical elements. Here, the authors demonstrate an ultracompact circularly polarized light detector using chiral plasmonic metamaterials with hot electron injection, realizing its implementation on an integrated photonic platform.

    • Wei Li
    • , Zachary J. Coppens
    •  & Jason Valentine
  • Article
    | Open Access

    The transfer of chirality from surfaces to molecular species may have implications in areas from the origin of homochirality to heterogeneous catalysis. Here, the authors show that a chiral gold cluster can transfer its inherent chirality to adsorbed, achiral molecules, causing them to adopt chiral conformations.

    • Igor Dolamic
    • , Birte Varnholt
    •  & Thomas Bürgi
  • Article |

    Three-dimensional helical chiral metamaterials are required for nanophotonics but lack of full rotational symmetry has limited their use. Here, Esposito et al. combine chirality and isotropy, fabricating intertwined helical nanowires with 37% broadband circular dichroism with a high signal to noise ratio.

    • Marco Esposito
    • , Vittorianna Tasco
    •  & Adriana Passaseo
  • Article |

    High-harmonic generation is now capable of delivering high-energy X-ray pulses with short duration, but achieving elliptical polarization remains challenging. Here, Lambert et al. use a cross-polarized two-colour laser field to produce elliptically polarized X-rays and measure magnetic circular dichroism in nickel.

    • G. Lambert
    • , B. Vodungbo
    •  & M. Fajardo
  • Article |

    The differential absorption of left and right handed light, circular dichroism, is typically observed only in chiral objects. Here, the authors demonstrate that giant circular dichroism can be induced in non-chiral objects when the left and right handed circularly polarized modes used are vortex beams.

    • Xavier Zambrana-Puyalto
    • , Xavier Vidal
    •  & Gabriel Molina-Terriza
  • Article
    | Open Access

    Plasmonic resonances in nanoparticle helices arranged by the DNA origami method can give rise to strong circular dichroism at visible wavelengths. Schreiber et al. show that aligning and then toggling the orientation of such nanoparticle helices enables reversible switching of the dichroic response.

    • Robert Schreiber
    • , Ngoc Luong
    •  & Tim Liedl
  • Article
    | Open Access

    The monolayer transition-metal dichalcogenide molybdenum disulphide has recently attracted attention owing to its distinctive electronic properties. Cao and co-workers present numerical evidence suggesting that circularly polarized light can preferentially excite a single valley in the band structure of this system.

    • Ting Cao
    • , Gang Wang
    •  & Ji Feng