Vibrational Mode-Dependent Circular Dichroism of Jet-Cooled Styrene Oxide.

Vibrational mode-dependent circular dichroism (CD) effects in vibrational CD spectra are often used to determine the handedness of molecules with multiple chiral centers. Here, we investigate vibrational mode-dependent CD effects in the electronic CD spectra of jet-cooled ()-(+)- and ()-(-)-styrene oxide obtained by using resonant two-photon ionization CD (R2PICD) spectroscopy. Although most fundamental vibronic bands demonstrated CD signatures consistent with that of the origin band, the overtone and combination bands exhibited opposite CD signatures.

Electrochemically Active MoO/TiN Sulfur Host Inducing Dynamically Reinforced Built-in Electric Field for Advanced Lithium-Sulfur Batteries.

Although various electrocatalysts have been developed to ameliorate the shuttle effect and sluggish Li-S conversion kinetics, their electrochemical inertness limits the sufficient performance improvement of lithium-sulfur batteries (LSBs). In this work, an electrochemically active MoO/TiN-based heterostructure (MOTN) is designed as an efficient sulfur host that can improve the overall electrochemical properties of LSBs via prominent lithiation behaviors. By accommodating Li ions into MoO nanoplates, the MOTN host can contribute its own capacity.

A dual spin-controlled chiral two-/three-dimensional perovskite artificial leaf for efficient overall photoelectrochemical water splitting.

The oxygen evolution reaction, which involves high overpotential and slow charge-transport kinetics, plays a critical role in determining the efficiency of solar-driven water splitting. The chiral-induced spin selectivity phenomenon has been utilized to reduce by-product production and hinder charge recombination. To fully exploit the spin polarization effect, we herein propose a dual spin-controlled perovskite photoelectrode.

Anisotropic circular dichroism of jet-cooled chiral molecules.

Anisotropic circular dichroism (CD) refers to the CD of oriented molecules, which varies with the direction of light propagation toward the molecules. Thus, anisotropic CD spectroscopy has been used to investigate the orientations of molecules in anisotropic media such as liquid crystals and thin films. However, it is unclear whether anisotropic CD results from isolated chromophores or their intermolecular interactions with other atoms or molecules that form anisotropically aligned structures.

Hybrid Perovskite-Based Wireless Integrated Device Exceeding a Solar to Hydrogen Conversion Efficiency of 11.

A wireless solar water splitting device provides a means to achieve an inexpensive and highly distributed solar-to-fuel system owing to its portability, flexible scale, and simple design. Here, a highly efficient hydrogen-generating artificial leaf is introduced, which is a wireless configuration for converting solar energy into chemical energy, by integrating a hybrid perovskite (PSK) as the light absorber with catalysts for electrochemical reaction. First, a single integrated photoelectrochemical photocathode, and a spatially decoupled hydrogen evolution reaction catalyst, are fabricated.

Dual-Beam Circular Dichroism Spectroscopy of Jet-Cooled Chiral Molecules.

Circular dichroism (CD) spectroscopy of jet-cooled molecules provides conformation-specific CD spectra. However, its widespread utilization has been limited by the weak CD effects and the low density of gas-phase molecules. Here, we developed a dual-beam method to improve the sensitivity and accuracy of gas-phase CD measurements.

Induced Circular Dichroism of Jet-Cooled Phenol Complexes with ()-(-)-2-Butanol.

The induced circular dichroism (ICD) of phenol complexed with ()-(-)-2-butanol [PhOH-(-)BOH] in a supersonic jet is investigated using resonant two-photon ionization circular dichroism (R2PICD) spectroscopy. The R2PICD spectrum of PhOH-(-)BOH exhibits nonzero ICD bands near the absorption region of bare PhOH, where (-)BOH is transparent. Two different conformers containing a single hydrogen bond between PhOH and (-)BOH are identified using ultraviolet-ultraviolet hole-burning and infrared ion-dip spectroscopy combined with quantum theoretical calculations.

Electronic Circular Dichroism Spectroscopy of Jet-Cooled Phenylalanine and Its Hydrated Clusters.

We obtained resonant two-photon ionization circular dichroism (R2PICD) spectra of jet-cooled phenylalanine (Phe) and its hydrated clusters (Phe(HO), n = 1-2) near the origin band of the S-S transition. The R2PICD spectra of Phe exhibit well-resolved CD bands of six different conformers present in the jet, which vary in sign and magnitude depending on their conformations. We revised the previous structural assignments of the Phe conformers based on the comparison between the experimental and theoretical CD signs, infrared spectra, and rotational band contours.

Fluorescence-detected circular dichroism spectroscopy of jet-cooled ephedrine.

The resonant two-photon ionization circular dichroism (R2PICD) spectrum represents the cumulative circular dichroism (CD) of one-photon excitation and the subsequent one-photon ionization, whereas the fluorescence-detected circular dichroism (FDCD) spectra exhibit only the CD of one-photon excitation, similar to conventional CD spectra. We obtained the FDCD spectra of jet-cooled ephedrine (EPD) near the origin band of the S0-S1 transition to measure the CD of one-photon absorption and thus the CD of the ionization process in R2PI in comparison with the R2PICD spectra. The CD effects of the ionization following excitation of the A (0-0) and C (930 cm(-1)) bands in the spectrum are small, whereas those of the B band (530 cm(-1)) are anomalously large, leading to opposite CD signs for the FDCD and R2PICD spectra.

Conformation-specific circular dichroism spectroscopy of cold, isolated chiral molecules.

The CD spectroscopy of a chiral compound in solution yields an average CD value derived from all of the conformations of a chiral molecule. By contrast, CD spectroscopy of cold chiral molecules in the gas phase distinguishes specific conformers of a chiral molecule, but the weak CD effect has limited the practical application of this technique. Reported herein is the first resonant two-photon ionization CD spectra of ephedrines in a supersonic jet using circularly polarized laser pulses, which were generated by synchronizing the oscillation of the photoelastic modulator with the laser firing.