Temperature-dependent NIR-CPL spectra of chiral Yb(III) complexes.

Chiral, enantiopure Yb(III) complexes exhibit circularly polarized luminescence (CPL) in the near infrared (NIR) wavelength region. This CPL is quantified by the dissymmetry factor (). The excited state F consists of six m states degenerated in three Stark levels, due to the crystal-field splitting (CFS), which are populated in accordance with the Boltzmann distribution.

Acid/Base-Triggered Photophysical and Chiroptical Switching in a Series of Helicenoid Compounds.

A series of molecules that possess two quinolines, benzoquinolines, or phenanthrolines connected in a chiral fashion by a biaryl junction along with their water-soluble derivatives was developed and characterized. The influence of the structure on the basicity of the nitrogen atoms in two heterocycles was examined and the photophysical and chiroptical switching activity of the compounds upon protonation was studied both experimentally and computationally. The results demonstrated that changes in the electronic structure of the protonated vs.

Circularly polarized luminescence in the one-dimensional assembly of binaphtyl-based Yb(iii) single-molecule magnets.

Lanthanide ions have attracted great interest owing to their optical and magnetic properties. Single-molecule magnet (SMM) behavior has been a fascinating science for thirty years. Moreover, chiral lanthanide complexes allow the observation of remarkable circularly polarized luminescence (CPL).

Theoretical and experimental analysis of circularly polarized luminescence spectrophotometers for artifact-free measurements using a single CCD camera.

Circularly polarized luminescence (CPL) is a fast growing research field as a complementary chiroptical spectroscopy alternative to the conventional circular dichroism or in the quest of devices producing circularly polarized light for different applications. Because chiroptical signals are generally lower than 0.1%, conventional chiral spectroscopies rely on polarization time modulation requiring step-by-step wavelength scanning and a long acquisition time.

Multifunctional Helicene-Based Ytterbium Coordination Polymer Displaying Circularly Polarized Luminescence, Slow Magnetic Relaxation and Room Temperature Magneto-Chiral Dichroism.

The combination of physical properties sensitive to molecular chirality in a single system allows the observation of fascinating phenomena such as magneto-chiral dichroism (MChD) and circularly polarized luminescence (CPL) having potential applications for optical data readout and display technology. Homochiral monodimensional coordination polymers of Yb 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) units (hfac =1,1,1,5,5,5-hexafluoroacetylaconate), efficient NIR-CPL activity is observed.

Circularly polarized luminescence of Eu(III) complexes with chiral 1,1'-bi-2-naphtol-derived bisphosphate ligands.

The interest for lanthanide circularly polarized luminescence (CPL) has been quickly growing for 10 years. However, very few of these studies have involved correlation between the dissymmetry factor (g ) and the chemical modifications in a series of chiral ligands. Four polymeric compounds of Eu(III) were prepared by using a series of binaphtyl derivatives for which the size of the π system as well as the number of stereogenic elements (i.

Chiral Benzothiazole Monofluoroborate Featuring Chiroptical and Oxygen-Sensitizing Properties: Synthesis and Photophysical Studies.

Advances in personalized medicine are prompting the development of multimodal agents, that is, molecules that combine properties promoting various diagnostic and therapeutic applications. General approaches exploit chemical conjugation of therapeutic agents with contrast agents or the design of multimodal nanoplatforms. Herein, we report the design of a single molecule that exhibits potential for different diagnostic modes as well as the ability to sensitize oxygen, thus offering potential for photodynamic therapy.

Solid-State Near-Infrared Circularly Polarized Luminescence from Chiral Yb -Single-Molecule Magnet.

A field-induced chiral Yb 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 F → F emission while the NIR-CPL is associated to the f-f transitions of the Yb ion bearing chiral β-diketonate derived-camphorate ancillary ligands.

Rare-earth doped micro-emitters made by lift-off processing in pulsed laser deposited layers on Si substrate.

Rare earth emitters are promising in integrated optics but require complex integration on silicon. In this work, we have fabricated an YO:Eu micro-emitter on SiO on Si substrate without etching. Since pulsed laser deposition produces a high quality layer at room temperature, material can be locally deposited on top of substrates by lift-off processing.

Reversible Soft Mechanochemical Control of Biaryl Conformations through Crosslinking in a 3D Macromolecular Network.

Tuning the dihedral angle (DA) of axially chiral compounds can impact biological activity, catalyst efficiency, molecular motor performance, or chiroptical properties. Herein, we report gradual, controlled, and reversible changes in molecular conformation of a covalently linked binaphthyl moiety within a 3D polymeric network by application of a macroscopic stretching force. We managed direct observation of DA changes by measuring the circular dichroism signal of an optically pure BINOL-crosslinked elastomer network.

Modulation of Chiroptical Properties in a Series of Helicene-like Compounds.

We describe a large-scale synthesis of a series of helicene-like compounds based on a dibenzo[]acridine fragment by the Friedlander reaction. The series includes targeted constrained (closed) derivatives comprising 11 rings that exhibit very intense circularly polarized luminescence (CPL) ( = 8 × 10) contrary to their nonconstrained (open) 10-ring precursors that are not CPL active. The relationship between structure and chiroptical properties in the series is discussed with the aid of quantum-chemical calculations.

Au(SG): A Chiral Gold Catenane Nanocluster with Zero Confined Electrons. Optical Properties and First-Principles Theoretical Analysis.

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.

Large-Scale Synthesis of Helicene-Like Molecules for the Design of Enantiopure Thin Films with Strong Chiroptical Activity.

Helicenes are fascinating molecules owing to their unusual properties and applications in many fields from catalysis to organic electronics. Herein, we report a straightforward pathway for the synthesis of helicene-like molecules on a gram scale in an enantiopure form. Thin-film materials with good propagating optical properties and very high chiroptical responses have been grown by using pulsed laser ablation without altering the structure or the enantiopurity of the molecules.

Efficient dibenzo[c]acridine helicene-like synthesis and resolution: scaleup, structural control, and high chiroptical properties.

Herein, we describe our recent expeditious synthesis of dibenzo[c]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.

Propagation losses and gain measurements in erbium-doped fluoride glass channel waveguides by use of a double-pass technique.

We have studied Er3+, Yb3+, and Ce3+ codoped microchannel waveguides that were developed by two methods: ionic exchange for heavy metal fluoride glasses [ZrF4-BaF2-AlF3-CeF3 (ZBAC)] and vapor phase deposition for transition metal fluoride glasses [PbF2-ZnF2-GaF3 (PZG)] by using a double-pass technique. For the first time to our knowledge, the measurement of propagation losses and amplification tests were carried out by use of the same experimental setup, leading to complete characterization of the waveguides. Net gains higher than 1 dB/cm were achieved in ZBAC Er/Ce single-mode fluoride glass waveguides.