Optically Active Research Articles

Enhanced photocatalytic removal of tetracycline by ZnO/NiCo2O4 through the construction of a p-n heterojunction

A new ZnO/NiCo2O4 photocatalyst was synthesized to develop systems for removing pharmaceutical pollutants. Various properties of the synthesized nanocomposite such as crystal structure, morphology, optical activity, chemical composition, electrochemical functions, and energy band structure were investigated. The study on tetracycline removal showed that the catalytic activity of the ZnO/NiCo2O4 nanocomposite (0.0426 min−1) is significantly higher compared to ZnO and NiCo2O4 individually. Morphology images confirmed the creation of a heterojunction between rice-shaped ZnO and NiCo2O4 nanoparticles. In photoluminescence and electrochemical impedance analyses, the nanocomposite displayed the weakest signal among its components, suggesting effective control of recombination and charge carrier transfer. The combination of NiCo2O4 with ZnO resulted in increased light absorption in the visible spectrum, contributing to its photocatalytic performance. The energy band structure of ZnO and NiCo2O4 was examined, presenting a detailed explanation of the most likely mechanism for the improved photocatalytic activity.

A Multiwavelength Survey of Nearby M Dwarfs: Optical and Near-ultraviolet Flares and Activity with Contemporaneous TESS, Kepler/K2, Swift, and HST Observations

We present a comprehensive multiwavelength investigation into flares and activity in nearby M dwarf stars. We leverage the most extensive contemporaneous data set obtained through the Transiting Exoplanet Sky Survey, Kepler/K2, the Neil Gehrels Swift Observatory, and the Hubble Space Telescope, spanning the optical and near-ultraviolet (NUV) regimes. In total, we observed 213 NUV flares on 24 nearby M dwarfs, with ∼27% of them having detected optical counterparts, and found that all optical flares had NUV counterparts. We explore NUV/optical energy fractionation in M dwarf flares. Our findings reveal a slight decrease in the ratio of optical to NUV energies with increasing NUV energies, a trend in agreement with prior investigations on G–K stars’ flares at higher energies. Our analysis yields an average NUV fraction of flaring time for M0–M3 dwarfs of 2.1%, while for M4–M6 dwarfs it is 5%. We present an empirical relationship between NUV and optical flare energies and compare to predictions from radiative hydrodynamic and blackbody models. We conducted a comparison of the flare frequency distribution (FFDs) of NUV and optical flares, revealing that the FFDs of both NUV and optical flares exhibit comparable slopes across all spectral subtypes. NUV flares on stars affect the atmospheric chemistry, the radiation environment, and the overall potential to sustain life on any exoplanets they host. We find that early and mid-M dwarfs (M0–M5) have the potential to generate NUV flares capable of initiating abiogenesis.

Tailoring structural and optical properties of Cu(II)-induced MgAl2O4 nanoparticles and their response to toxic dyes under solar illumination.

Worldwide environmental challenges pose critical problems with the growth of the global economy. Addressing these issues requires the development of an eco-friendly and sustainable catalyst for degrading organic dye pollutants. In this study, copper-doped magnesium aluminates (CuxMg1-xAl2O4) with x = 0.0-0.8 were synthesized using a citrate-based combustion route. The inclusion of Cu(II) significantly impacted the structural, microstructural, optical, and photocatalytic activity of the catalyst. Rietveld analysis of X-ray diffraction powder profiles revealed single-phase spinels crystallized in the face-centered cubic unit cell with space group. Chemical states of the ions, surface morphology, and elemental investigation were analyzed by X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy, respectively. UV-visible and diffuse reflectance spectroscopies confirmed the reduction of the band gap due to Cu(II) doping, validated by first-principle investigations using the WIEN2k code. The catalyst with x = 0.8 showed higher photocatalytic efficacy (90% and 93%) for removing two azo organic dye pollutants, rhodamine B and methyl orange, respectively, within 120min. Degradation kinetics followed a pseudo-first-order mechanism. The doped (0.8) sample was structurally and morphologically stable and reusable under visible irradiation, retaining performance after three runs. Scavenger studies confirmed hydroxyl and superoxide radicals' involvement in the degradation. This work presents an effective approach to enhancing CuxMg1-xAl2O4 catalysts' photodegradation performance, with potential applications in pharmaceuticals and wastewater remediation.

Synthesis of Isotypic Giant Polymolybdate Cages for Efficient Photocatalytic C-C Coupling Reactions.

The construction of isotypic high-nuclearity inorganic cages with identical pristine parent structure and increasing nuclearity is highly important for molecular growth and structure-property relationship study, yet it still remains a great challenge. Here, we provide an in situ growth approach for successfully synthesizing a series of new giant hollow polymolybdate dodecahedral cages, Mo250, Mo260-I, and Mo260-E, whose structures are growth based on giant polymolybdate cage Mo240. Remarkably, they show two pathways of nuclear growth based on Mo240, that is, the growth of 10 and 20 Mo centers on the inner and outer surfaces to afford Mo250 and Mo260-I, respectively, and the growth of 10 Mo centers both on the inner and outer surfaces to give Mo260-E. To the best of our knowledge, this is the first study to display the internal and external nuclear growth of a giant hollow polyoxometalate cage. More importantly, regular variations in structure and nuclearity confer these polymolybdate cages with different optical properties, oxidative activities, and hydrogen atom transfer effect, thus allowing them to exhibit moderate to excellent photocatalytic performance in oxidative cross-coupling reactions between different unactivated alkanes and N-heteroarenes. In particular, Mo240 and Mo260-E with better comprehensive abilities can offer the desired coupling product with yield up to 92% within 1 h.

Oxygen vacancy-riched NdVO4/BiVO4 heterojunction with infrared absorption feature for efficient water oxidation

Bismuth vanadate (BiVO4) has been recognized as a favorable photocatalyst for generating oxygen from water decomposition using solar energy. While, BiVO4’s optical activity is limited due to its low charge mobility, high photo-generated electron hole recombination rate and low infrared light response. Herein, an oxygen vacancy-riched NdVO4/BiVO4 heterojunction with infrared absorption feature is successfully prepared by a two-step cation-exchange method using Na5V12O32 nanowire as a precursor. The in-situ growth of BiVO4 on NdVO4 forms a close contact interface, forming a heterojunction structure and generating an internal electric field, and the oxygen vacancies generated during cation-exchange can serve as electron traps, promoting the separation of photogenerated electron-hole pairs at the heterojunction. Furthermore, the enhanced infrared absorption properties of NdVO4, which forms the heterojunction, broaden the spectral response range. As a result, the synergistic effect of improved heterojunctions due to oxygen vacancies and enhanced infrared absorption, the photocatalyst exhibits enhanced photocatalytic oxygen evolution activity under visible and near-infrared light irradiation, with an oxygen evolution rate of 1543.16 μmol h−1 g−1 under visible light, which is 3 times higher than that of bare BiVO4. Oxygen can be generated even under near-infrared light.

Classification of BLL Blazars by Optical Activity Types

Classification of BLL Blazars by Optical Activity Types

Chirality conferral enables the observation of hyper-Raman optical activity

Chirality conferral is fundamental for understanding the origin of life, and it is of direct importance for synthesizing new pharmaceuticals in the face of growing antibiotic resistance. Human-made, self-assembling nanostructures replicate the biological chirality conferral processes utilizing covalent and non-covalent bonds. However, chirality conferral from one form of matter to another via electromagnetic fields is more subtle and less explored. Here we report chirality conferral between gold nanohelices and achiral molecules (crystal violet). This conferral enables the experimental observation of a physical effect predicted in 1979—hyper-Raman optical activity. To benefit from Fermi’s golden rule, the chirality conferral system was designed as doubly resonant, with the nanohelices and molecules resonating at the fundamental frequency and at the second-harmonic, respectively. We provide a theoretical framework for our results that expands the original mathematical formalism to include surface-enhanced hyper-Raman scattering and the chirality conferral process. Our results demonstrate that field-driven chirality conferral mechanisms are opening up entire fields of research, as exemplified by the discovery of a physical phenomenon.

Improving light harvesting and charge carrier separation enabling enhanced photoelectrochemical hydrogen production by Sb2S3-decorated TiO2 nanotube arrays on porous Ti-photoanodes

The Ag + ions doped TiO2 nanotube arrays fabricated on Ti mesh through an electrochemical anodization process, and n/n heterostructure formed by coating the TiO2 nanotube array photoanode with an n-type stibnite (Sb2S3) layer improve photoelectrochemical water splitting reaction by enhancing light harvesting and charge carrier separation. Sb2S3 is chosen because of its suitable band gap position and strong visible light response. The Ag + ion incorporated TiO2 nanotube array coated with Sb2S3 exhibits a photocurrent density of 6.5 mA cm−2 vs. RHE, whereas bare TiO2 nanotube array coated with Sb2S3 and pristine TiO2 nanotube array exhibit photocurrent densities of 3.6 and 0.27 mA cm−2, respectively, under the same conditions, which is nearly 1.8 and 24 times greater than the TiO2 nanotube array coated with Sb2S3 and pristine TiO2 nanotube array photoanodes. The applied bias photon-to-current efficiency of Ag + ion incorporated TiO2 nanotube array coated with Sb2S3 is 3.6% and the improved Photoelectrochemical performance of Ag + ion doped TiO2 nanotube array coated with Sb2S3 is attributable to higher conductivity of TiO2 nanotube array caused by increased oxygen vacancies and broad optical activity of Sb2S3. The 1-dimensional TiO2 nanotube array device structure in the Ti mesh improves charge separation and light harvesting while reducing photogenerated charge carrier recombination and the potential of this novel device structure for advanced energy conversion applications is highlighted in this study.

Synthesis, biological properties, drug-likeness, In silico ADME studies and theoretical studies on 1,3,2λ5-diazaphosphinane derivatives: A DFT investigation

Under various reaction conditions, Tetraphosphorus decasulphide P4S10 and Lawesson's reagent LR interacted with 2-cyano-N-[(2-hydroxyphenyl) methylidene] acetohydrazide (1) to synthesize a new 1,3,2λ5-diazaphosphinane derivatives 2–4. The three novel compounds 2−4 have been synthesized and characterized by elemental and spectral analyses (UV–Vis, FT-IR, MS, and 1H–NMR) throughout the current inquiry. The ground state energies, harmonic vibrational wavenumbers, and ground state geometries of the investigated compounds 2−4 were optimized by applying the density functional theory (DFT) at the B3LYP level, utilizing 6–311++G (d, p) basis sets. The first principal study has been investigated for the electronic properties, molecular electrostatic potentials, and quantum chemical identities. There was a noticeable shift in intramolecular charge from the occupied to the empty molecular orbitals. Time-dependent density functional theory (TD-DFT) and the CAM-B3LYP/6–311++G (d, p) function was used to conduct the UV–Vis analysis. A few bacterial and fungal strains were used to test the antimicrobial activities. The stability of the molecule resulting from hyper conjugative interactions that cause its nonlinear optical activity and charge delocalization was investigated using a natural bond orbital approach. The Mullikan atomic charge and molecular electrostatic potential are also anticipated. The value of the HOMO-LUMO energy gap indicates the possibility of charge transfer within the molecule. Compound 4 is the most reactive, with an energy difference between the border orbital of ΔEgap = 2.97 eV, according to analysis of the global descriptors. In addition, compared to the other 2 and 3 compounds under study, compound 4 is the softest, least stable, and has the largest electronic exchange capacity. Examined the structure-activity relationship using DFT calculations (SAR) and compared the findings with real-world antimicrobial outcomes for compounds 2–4. Also, Drug-likeness and In silico ADME studies were performed.

Synthesis of Zn0.87(Fe, Al)0.065O – MO (MO = NiO, Fe2O3, CuO, and CoO) nanocomposites: Structural, vibrational, optical and antibacterial studies

One of the most effective strategies for achieving high-performance antibacterial activity is the synthesis of nanocomposites by combining different nanoparticles. Hence, Zn0.87(Fe, Al)0.065O – MO (NiO, Fe2O3, CuO and CoO) nanocomposites (NCs) with a 7:3 molar ratio were synthesized via the solution combustion method. The produced NCs structural, vibrational, and optical characteristics were investigated using XRD, FTIR, UV–Vis, and PL spectroscopies. The standard disc diffusion method was used to evaluate the antibacterial efficacy of the NCs. The lattice constant, crystallite size, bond length, dislocation density, and other relevant parameters of the NCs were also evaluated. XRD analysis revealed a well-defined mixed-phase structure for all 0.7Zn0.87(Fe, Al)0.065O – 0.3NiO (ZFA-Ni), 0.7Zn0.87(Fe, Al)0.065O – 0.3Fe2O3 (ZFA-Fe), 0.7Zn0.87(Fe, Al)0.065O – 0.3CuO (ZFA-Cu) and 0.7Zn0.87(Fe, Al)0.065O – 0.3CoO (ZFA-Co) NCs, indicating successful mixing of each metal oxide with the ZnO matrix. The average crystallite size within the NCs ranged from 14.21 to 18.10 nm, suggesting a degree of nanocrystallinity nature of all NCs. FTIR confirmed the presence of characteristic functional groups within the NCs. Moreover, all the synthesized NCs exhibited significant optical activation in the ultraviolet radiation range but visible light absorption was also observed when the composite formed with CuO and Fe2O3 nanoparticles. The band gap energy values exhibited variation between 2.72 eV for ZFA-Co NC and 2.90 eV for ZFA-Ni NC. Photoluminescence (PL) emission in the composite formation of ZnO NPs with other metal oxide were significantly influenced by the absorption range of the composite with pn-junction formation in a notable enhancement of antibacterial efficacy against bacterial strains of Escherichia coli and Staphylococcus aureus. Particularly, ZFA-Co NC exhibited an excellent antibacterial performance against both bacterial strains.

Ultrasensitive Raman Detection of Biomolecular Conformation at the Attomole Scale using Chiral Nanophotonics.

Understanding the function of a biomolecule hinges on its 3D conformation or secondary structure. Chirally sensitive, optically active techniques based on the differential absorption of UV-vis circularly polarized light excel at rapid characterisation of secondary structures. However, Raman spectroscopy, a powerful method for determining the structure of simple molecules, has limited capacity for structural analysis of biomolecules because of intrinsically weak optical activity, necessitating millimolar (mM) sample quantities. A breakthrough is presented for utilising Raman spectroscopy in ultrasensitive biomolecular conformation detection, surpassing conventional Raman optical activity by 15 orders of magnitude. This strategy combines chiral plasmonic metasurfaces with achiral molecular Raman reporters and enables the detection of different conformations (α-helix and random coil) of a model peptide (poly-L/D-lysine) at the ≤attomole level (monolayer). This exceptional sensitivity stems from the ability to detect local, molecular-scale changes in the electromagnetic (EM) environment of a chiral nanocavity induced by the presence of biomolecules using molecular Raman reporters. Further signal enhancement is achieved by incorporating achiral Au nanoparticles. The introduction of the nanoparticles creates highly localized regions of extreme optical chirality. This approach, which exploits Raman, a generic phenomenon, paves the way for next-generation technologies for the ultrasensitive detection of diverse biomolecular structures.

Photocatalytic activities of Fe2O3 coated ZnO nanowires grown by electrochemical anodization method

In this study, the visible light photocatalytic activities of the ZnO and ZnO/Fe2O3 structures were investigated. Anodization of Zn plates to obtain ZnO nanowires was carried out by applying 35 V between 1 and 30 min durations. Fe2O3 layers were coated on initially obtained ZnO nanowires through a sol-gel spin-coating process. All samples were examined for morphological, structural, optical, and photocatalytic activities in detail. The results showed that the conducted anodization process was successful where up to micrometer-length nanowires were obtained. SEM images confirmed the presence of Fe2O3 deposits surrounding the nanowires, while UV and visible absorption spectra indicated increased absorption due to Fe2O3, leading to enhanced photocatalytic performance. The best-performing ZnO nanowire anodized for 5 min almost doubled its photocatalytic activity after Fe2O3 coating, in which an apparent reaction rate of 12.24 × 10−3 min−1 and degrading 90.32 % of the initial MB concentration was recorded.

Optical Activity of Nonactin and Its Cation Complexes.

Nonactin is a non-enantiomorphous (S4 symmetric), optically active natural product with a specific rotation of zero in solutions at all frequencies and temperatures. All optically active, non-enantiomorphous natural products have specific rotations of zero as a consequence of the spatial average of bisignate chiroptical (magnetoelectric or gyration) tensors with equal and opposite eigenvalues. Zeros that arise in the spatial average are distinct in principle, though not necessarily in practice, from zeros that arise in optical inactivity-chiroptical tensors with zero values for all elements as in centric molecules. Nonactin would be measurably optically active when oriented. The anisotropy of the optical activity of nonactin and its cation complexes, likewise S4 symmetric, are studied here by computation to emphasize the infelicitous linkage between optical activity and chirality. Computations show that changes in the conformation of the nonactin macrocycle upon complexation principally are responsible for diminishing the computed optical activity; the metals are incidental.

Synthesis, characterization and evaluation of new alternative ruthenium complex for dye sensitized solar cells

For first time, new innovative ruthenium N3-Dye anchored with selenium (Se) and N3 dye anchored with sulphur atoms were synthesized in a good yield. Dyes are applied and evaluated in performance of dye sensitized solar cell. N3–Se dye showed superior photochemical& electrochemical behavior and high rate electron transfer across anode surface than N3–S dye. The better optical and electrochemical activities would make Se-dye a candidate for applications in solar cells. Half life time of N3–S showed a single exponential decay with an average lifetime of 0.8 ns. For N3–Se dye, decay curve was fitted by sum two exponential functions with 75% and 25% counts have 2.5 ns and 30 ns respectively. Solar cells were fabricated and analyzed to determine their solar-to-electric conversion efficiency under standard AM 1.5 sunlight. Commercial N3 dyes showed current density (Jsc) of 17.813 mA cm−2, open circuit potential (Voc) of 0.678 V, filling factor (FF) of 0.607 and conversion efficiencies (η) of 7.3%. Corresponding values for N3–S dye, Jsc 11.2 mA cm−2, Voc 0.650 V, FF 0.681 and η 5%. Se–N3 dye, showed Jsc = 6.670 mA cm−2, Voc = 0.6004 V, FF = 0.77 and η = 3.09%. Long lifetime of N3–Se caused low practical performance.

Giant chiral magnetoelectric oscillations in a van der Waals multiferroic

Helical spin structures are expressions of magnetically induced chirality, entangling the dipolar and magnetic orders in materials1–4. The recent discovery of helical van der Waals multiferroics down to the ultrathin limit raises prospects of large chiral magnetoelectric correlations in two dimensions5,6. However, the exact nature and magnitude of these couplings have remained unknown so far. Here we perform a precision measurement of the dynamical magnetoelectric coupling for an enantiopure domain in an exfoliated van der Waals multiferroic. We evaluate this interaction in resonance with a collective electromagnon mode, capturing the impact of its oscillations on the dipolar and magnetic orders of the material with a suite of ultrafast optical probes. Our data show a giant natural optical activity at terahertz frequencies, characterized by quadrature modulations between the electric polarization and magnetization components. First-principles calculations further show that these chiral couplings originate from the synergy between the non-collinear spin texture and relativistic spin–orbit interactions, resulting in substantial enhancements over lattice-mediated effects. Our findings highlight the potential for intertwined orders to enable unique functionalities in the two-dimensional limit and pave the way for the development of van der Waals magnetoelectric devices operating at terahertz speeds.

Intense Circularly Polarized Luminescence Induced by Chiral Supramolecular Assembly: The Importance of Intermolecular Electronic Coupling

Herein we report on circularly polarized luminescence (CPL) emission originating from supramolecular chirality of organic microcrystals with a |glum| value up to 0.11. The microcrystals were prepared from highly emissive difluoroboron β‐diketonate (BF2dbk) dyes R‐1 or S‐1 with chiral binaphthol (BINOL) skeletons. R‐1 and S‐1 exhibit undetectable CPL signals in solution but manifest intense CPL emission in their chiral microcrystals. The chiral superstructures induced by BINOL skeletons were confirmed by XRD analysis. Spectral analysis and theoretical calculations indicate that intermolecular electronic coupling, mediated by the asymmetric stacking in the chiral superstructures, effectively alters excited‐state electronic structures and facilitates electron transitions perpendicular to BF2bdk planes. The coupling increases cosθµ,m from 0.05 (monomer) to 0.86 (tetramer) and triggers intense optical activity of BF2bdk. The results demonstrate that optical activity of chromophores within assemblies can be regulated by both orientation and extent of intermolecular electronic couplings.

Intense Circularly Polarized Luminescence Induced by Chiral Supramolecular Assembly: The Importance of Intermolecular Electronic Coupling.

Herein we report on circularly polarized luminescence (CPL) emission originating from supramolecular chirality of organic microcrystals with a |glum| value up to 0.11. The microcrystals were prepared from highly emissive difluoroboron β-diketonate (BF2dbk) dyes R-1 or S-1 with chiral binaphthol (BINOL) skeletons. R-1 and S-1 exhibit undetectable CPL signals in solution but manifest intense CPL emission in their chiral microcrystals. The chiral superstructures induced by BINOL skeletons were confirmed by single-crystal XRD analysis. Spectral analysis and theoretical calculations indicate that intermolecular electronic coupling, mediated by the asymmetric stacking in the chiral superstructures, effectively alters excited-state electronic structures and facilitates electron transitions perpendicular to BF2bdk planes. The coupling increases cosθμ,m from 0.05 (monomer) to 0.86 (tetramer) and triggers intense optical activity of BF2bdk. The results demonstrate that optical activity of chromophores within assemblies can be regulated by both orientation and extent of intermolecular electronic couplings.

Interdisciplinary insights into (1′R,3S,3′R)-1'-(4-chlorobenzoyl)-5′,6′,7′,7a′-tetrahydro-1′H dispiro[indoline-3,2′-pyrrolizine-3′,3″-indoline]-2,2″-dione: Structural, electronic, and molecular dynamics perspectives

In the field of heterocyclic compounds, the spiro-pyrrolidine and oxindole ring systems are highly esteemed due to their distinctive structural scaffold that is present in numerous pharmacologically significant alkaloids. Interdisciplinary research has been increasingly important in recent years for deciphering the intricate characteristics and behaviors of novel organic compounds. The current work uses quantum chemical computational techniques to study the structural stability and nonlinear optical (NLO) activity of (1′R,3S,3′R)-1'-(4-chlorobenzoyl)-5′,6′,7′,7a′-tetrahydro-1′H dispiro[indoline-3,2′-pyrrolizine-3′,3″-indoline]-2,2″-dione (DSOIP-Cl). The study combines molecular biology, computational chemistry, and theoretical chemistry knowledge to create a comprehensive picture of this fascinating organic compound. This study employed the density functional theory (DFT) B3LYP method to compute the electronic properties and molecular geometry. The basis set for the computations was 6–311++G(d,p). The IEFPCM solvation method is used to investigate the behavior of the head compound in different solvents. Understanding the interaction between organic compounds and the solvent phase is crucial because the majority of interactions in biological systems occur in solution. UV–Vis spectral analysis of the molecule in different solvents is performed using the TD-DFT method. The compound exhibits more excellent absorption in polar solvents such as water, while its absorption is lower in the gaseous phase. Assessing NLO properties revealed optoelectronics applications. DSOIP-Cl has 5.25 times the first-order hyperpolarizability of urea. Different solvents have higher dipole moments and first-order hyperpolarizability than gases. To identify the inter- and intramolecular charge transfer interactions, intermolecular hydrogen bonding, and hyperconjugative interactions that stabilize the structure, natural bond orbital (NBO) analysis is performed. A stabilization energy of 9.99 kcal/mol is obtained for π(C32–C33) → σ*(C33–C34) due to strong intramolecular hyperconjugative interactions. Frontier molecular orbital (FMO) analysis helps determine the global reactivity parameters and the charge transfer interaction. The van der Waals interaction and steric effect within the molecule are identified using RDG analysis. The pharmacokinetic properties, adherence to drug-likeness criteria, and easily controllable synthesis process were evaluated through ADME analysis, establishing it as an up-and-coming candidate for subsequent drug development. Ultimately, to determine the biological activity and the ability of the title compound to inhibit aldose reductase, a series of computational techniques are employed, including molecular docking study, molecular dynamic (MD) simulation, and MM-PBSA binding energy calculations. −7.86 kcal/mol was reported as the docking score. Hydrophobic interactions play an essential role in the efficiency of protein-ligand binding. The remarkable energetic contribution of DSOIP-Cl to the MM-PBSA binding dynamics highlights its unique association with the AR protein, with a binding energy of −79.81 kJ/mol.

Magnetic-free chiral eigenmode spectroscopy for simultaneous sensitive measurement of optical rotary dispersion and circular dichroism

Chirality, defined by Lord Kelvin, refers to the geometric symmetry property of an object that cannot be superposed onto its mirror image using rotations and translations. The material’s chirality can be probed with light as the optical activity: optical rotary dispersion (ORD) and circular dichroism (CD). It is still challenging to yield extremely sensitive ORD and CD for very weak chirality and measure both simultaneously. Cavity ringdown polarimetry has been reported to improve ORD detection sensitivity with the absence of equally important CD signature, at the price of high cavity finesse near 400, frequency-locking sophistication, and large magnetic field. Here, we report a unique recipe to demonstrate the simultaneous measurement of ORD and the CD by separately observing the chiral eigenmode spectra from a bowtie optical cavity with a finesse about 30, without resorting to frequency locking or magnetic field. We obtain a sensitivity of ∼2.7×10-3deg/Hz\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim 2.7\ imes 10^{-3} \ ext {deg}/\\sqrt{\ ext {Hz}}$$\\end{document} for ORD, ∼8.1×10-6/Hz\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim 8.1 \ imes 10^{-6} /\\sqrt{\ ext {Hz}}$$\\end{document} for CD, and a spectral resolution of 0.04pm\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0.04~\ ext {pm}$$\\end{document} within a millisecond-scale measurement. We present a cost-effective yet ultrasensitive account for chiral chromatography, the conformational dynamics and chiroptical analysis of biological samples which particularly exhibit weak and narrow spectral signals.

Synthesis, structure and red-light emission of a manganese halide directed by a methyldiphenylphosphine oxide complex.

Controlling the optical activity of halide perovskite materials through modulation of the coordination configurations of the metal ions is important. Herein, a novel manganese-based halide, specifically diaquatetrakis(methyldiphenylphosphine oxide)manganese(II) tetrachloridomanganate(II), [Mn(C13H13OP)4(H2O)2][MnCl4] or [Mn(MDPPO)4(H2O)2][MnCl4] (MDPPO is methyldiphenylphosphine oxide), was synthesized through the solvothermal reaction of MnCl2 with the neutral molecule MDPPO. In this compound, [Mn(MDPPO)4(H2O)2]2+ acts as the cation, while [MnCl4]2- serves as the anion, enabling the co-existence of tetrahedral and octahedral structures within the same system. Remarkably, the compound exhibits efficient red-light emission at 662 nm, distinct from the green-light emission typically observed in MnX4-based halides. Theoretical calculations show that the red emission comes from the charge transfer from the MDPPO to the Mn2+ of [MnCl4]2-. This work provides a new perspective for the design and synthesis of red-light-emitting manganese-based halides with unique structures.