Full Polarization Control of Optical Planar Waveguides with Chiral Material

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

Efficient Dibenzo[<i>c</i>]acridine Helicene-like Synthesis and Resolution: Scaleup, Structural Control, and High Chiroptical Properties

Herein, we describe our recent expeditious synthesis of dibenzo[<i>c</i>]acridine helicene-like compounds on a large scale in pure enantiomeric form. This flexible synthesis allows for variation at several positions on the skeleton. Geometrical parameters related to these compounds have been obtained from monocrystal X-ray structure resolution. Additionally, chiroptical parameters have been recorded, highlighting the versatility of this family showing for example optical rotation at 589 nm varying between 135 and 150 deg g^–1cm²

Efficient Dibenzo[<i>c</i>]acridine Helicene-like Synthesis and Resolution: Scaleup, Structural Control, and High Chiroptical Properties

Herein, we describe our recent expeditious synthesis of dibenzo[<i>c</i>]acridine helicene-like compounds on a large scale in pure enantiomeric form. This flexible synthesis allows for variation at several positions on the skeleton. Geometrical parameters related to these compounds have been obtained from monocrystal X-ray structure resolution. Additionally, chiroptical parameters have been recorded, highlighting the versatility of this family showing for example optical rotation at 589 nm varying between 135 and 150 deg g^–1cm²

Efficient Dibenzo[<i>c</i>]acridine Helicene-like Synthesis and Resolution: Scaleup, Structural Control, and High Chiroptical Properties

Herein, we describe our recent expeditious synthesis of dibenzo[<i>c</i>]acridine helicene-like compounds on a large scale in pure enantiomeric form. This flexible synthesis allows for variation at several positions on the skeleton. Geometrical parameters related to these compounds have been obtained from monocrystal X-ray structure resolution. Additionally, chiroptical parameters have been recorded, highlighting the versatility of this family showing for example optical rotation at 589 nm varying between 135 and 150 deg g^–1cm²

Sulfoxidation inside a <i>C</i>₃‑Vanadium(V) Bowl-Shaped Catalyst

The confined enantiopure oxido-vanadium complex <i>SSS-RRR-</i><b>1</b> was synthesized and tested as a catalyst for the oxidation of sulfides into sulfoxides. This catalyst is very efficient with a reaction rate more than 300 times higher than that of the model compound <i>SSS-RRR-</i><b>3</b>, and a turnover number (TON) close to 10⁵ was reached in combination with a good selectivity (more than 90%) in the sulfoxide product. Moreover, enantiomerically enriched sulfoxide can be obtained, breaking through the major limitation of the previous chiral vanatrane catalysts that show no detectable enantiomeric excess (ee). Further investigations revealed that the complex <i>SSS-RRR-</i><b>1</b> adopts a bowl-shaped structure with an open hydrophobic pocket. The microenvironment of the chiral pocket above the metal center accounts for the strong improvement in catalytic activity and enantioselectivity

Efficient Dibenzo[<i>c</i>]acridine Helicene-like Synthesis and Resolution: Scaleup, Structural Control, and High Chiroptical Properties

Herein, we describe our recent expeditious synthesis of dibenzo[<i>c</i>]acridine helicene-like compounds on a large scale in pure enantiomeric form. This flexible synthesis allows for variation at several positions on the skeleton. Geometrical parameters related to these compounds have been obtained from monocrystal X-ray structure resolution. Additionally, chiroptical parameters have been recorded, highlighting the versatility of this family showing for example optical rotation at 589 nm varying between 135 and 150 deg g^–1cm²

Efficient Dibenzo[<i>c</i>]acridine Helicene-like Synthesis and Resolution: Scaleup, Structural Control, and High Chiroptical Properties

Herein, we describe our recent expeditious synthesis of dibenzo[<i>c</i>]acridine helicene-like compounds on a large scale in pure enantiomeric form. This flexible synthesis allows for variation at several positions on the skeleton. Geometrical parameters related to these compounds have been obtained from monocrystal X-ray structure resolution. Additionally, chiroptical parameters have been recorded, highlighting the versatility of this family showing for example optical rotation at 589 nm varying between 135 and 150 deg g^–1cm²

Cyclotriveratrylene-BINOL-Based Host Compounds: Synthesis, Absolute Configuration Assignment, and Recognition Properties

New host compounds combining a cyclotriveratrylene (CTV) unit and three binaphthol moieties have been synthesized enantiomerically and diastereomerically pure. The use of a chemical correlation allows for the assignment of their absolute configuration. The energy barrier of epimerization was measured, suggesting that no intramolecular hydrogen bonding occurs between the hydroxyl groups of the binaphthols. These open-shell host compounds were then tested in the recognition of carbohydrates; a preferential binding of mannose toward glucose was observed, and good diastereoselectivities were reached (up to 1:10). This recognition of sugar derivatives by open-shell CTV-based host compounds is unprecedented and opens up the way for a wider use of this easily accessible class of molecules as chiral sensors