We report facile synthesis of the Au(SG) nanoclusters, where SG stands for glutathione, found to be promising as a new class of radiosensitizers for cancer radiotherapy. The homoleptic catenane structure with two AuSG interconnected rings, among different isomer structures, gives the best agreement between theoretical and experimental optical spectra and XRD patterns. This catenane structure exhibits a centrosymmetry-broken structure, resulting in enhanced second harmonic response and new characteristic circular dichroism signals in the spectral region of 250-400 nm. This is the first determination of the nonlinear optical properties of a ligated cluster with an equal Au-to-ligand ratio, thus without a metallic core and therefore zero confined electrons. Insight into the nonlinear and chiroptical efficiencies arising from interplay between structural and electronic properties is provided by the TD-DFT approach.

The electronic structure of a chiral Yb(III)-based complex is fully determined by taking advantage of experimental magnetic, luminescence, and chiroptical (NIR-ECD and CPL) characterizations in combination with ab-initio wavefunction calculations....

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A field‐induced chiral YbIII Single‐Molecule Magnet (SMM) displayed an unprecedented near‐infrared circularly polarized luminescence (NIR‐CPL) in the solid‐state. The bridging bis(1,10‐phenantro[5,6b])tetrathiafulvalene triad (L) allowed an efficient sensitization of the NIR 2F5/2→2F7/2 emission while the NIR‐CPL is associated to the f‐f transitions of the YbIII ion bearing chiral β‐diketonate derived‐camphorate ancillary ligands.

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Starting from a microscopic description, we show the analogy between photon avalanche and second-order phase transition. This justifies the validity of the mean-field approximation. Then we show that the rate equations reproduce quantitatively the experimental results as soon as the Gaussian intensity profile of the input beam is taken into account. Moreover, we apply the general Landau theory to the photon avalanche: the absorption between the excited state is the control parameter of the transition whereas the ground-state absorption is an external field. By this way the impact of the residual nonresonant ground-state absorption is clarified.

The combination of physical properties sensitive to molecular chirality in a single system allows the observation of fascinating phenomena such as magnetochiral dichroism (MChD) and circularly polarized luminescence (CPL) having potential applications for optical data readout and display technology. Homochiral monodimensional coordination polymers of Yb III were designed from a 2,15-bis-ethynyl-hexahelicenic scaffold decorated with two terminal 4-pyridyl units. Thanks to the coordination of the chiral organic chromophore to Yb(hfac) 3 units (hfac À = 1,1,1,5,5,5-hexafluoroacetylaconate), efficient NIR-CPL activity is observed. Moreover, the specific crystal field around the Yb III induces a strong magnetic anisotropy which leads to a singlemolecule magnet (SMM) behaviour and a remarkable room temperature MChD. The MChD-structural correlation is supported by computational investigations.

Circularly polarized (CP) light is attracting growing interest in photonics, however it is not possible to use regular planar waveguides for the transmission of such CP light. While keeping the planar geometry, we conceived devices where the chirality of the propagation medium overcomes the planar symmetry. Thus, we report on the fabrication of chirowaveguides arising from the stacking of three layers of a new hybrid chiral organic modified silica (OrMoSil). A flexible strategy allows the control of the two main parameters impacting the ellipticity of the propagated waves. First, the high chirality of the transparent material is based on cheap and easy to access binaphthyl precursors simply shaped as films by dip-coating. Second, the refractive index (RI) contrast between the layers is finely tuned by TriEthOxySilane (TEOS) doping. The polarization of the two fundamental guided modes is measured on 2 cm long waveguides. We demonstrated that the polarization can be modulated from linear to nearly circular (80% ellipticity) depending on the RI contrast and the core thickness. These unprecedented achievements in the area of both optical materials and guided optics, open the way to fully integrated photonic devices dealing with CP light propagation.