Molecular Chirality and Its Monitoring by Ultrafast X-ray Pulses

Abstract

Major advances in X-ray sources including the development of circularly polarized and orbital angular momentum pulses make it possible to probe matter chirality at unprecedented energy regimes and with Ångström and femtosecond spatiotemporal resolutions. We survey the theory of stationary and time-resolved nonlinear chiral measurements that can be carried out in the X-ray regime using tabletop X-ray sources or large scale (XFEL, synchrotron) facilities. A variety of possible signals and their information content are surveyed.

Basicity‐Controlled [3+2] Cyclization of 3‐Hydroxyquinolin‐ones and β‐Chlorinated Nitrostyrenes

“…Generally, s substituents both on 3-hydroxyquinolin-ones Recently, the enantioselective construction of optical active molecules was one of the most important tasks in organic chemistry, as the significance of chirality in medicinal chemistry and other related areas. [42][43][44] In this context, the preliminary attempt to develop the enantioselective version of this (3 + 2) cyclization process was essential. Firstly, the well-defined cinchona alkaloid derived bifunctional catalysts C1 and C2 were used to catalyze the reaction in the presence of stoichiometric K 2 HPO 4 • 3H 2 O in CHCl 3 (entries 1 and 2, Table 3).…”

FLASH and the FLASH2020+ project—current status and upgrades for the free-electron laser in Hamburg at DESY

“…In molecules, this allows addressing the molecular chirality with a combination of femtosecond time resolution and the X-ray typical site sensitivity. This leads to a novel understanding of molecular dynamics and interesting phenomena like molecular ring currents [49]. A method prone to be used is photoelectron circular dichroism, which has been established with ultrafast X-ray pulses recently [50].…”

Ultrafast chirality: the road to efficient chiral measurements

“…The possibility of structuring the local properties of light in space, 40,158 including both its intensity and phase, 159 creates unique opportunities for imaging 160 and manipulating 161 properties of matter. Likewise, structuring light's chirality 119,162–165 could open new efficient routes for enantio-sensitive imaging and control of chiral matter.…”

“…While standard CD signal relying on interaction with the magnetic field can be improved e.g . by using broadband ultrafast circular dichroism spectroscopy in the deep ultraviolet in combination with transient absorption measurements, 39 or using short-wavelength light, 31–33,40,41 developing ultrafast and highly enantio-sensitive approaches, which track electronic/vibronic dynamics without relying on magnetic interactions, is an important challenge. This challenge has been taken on by the electric–dipole revolution in chiral measurements.…”

“…It has the same unfavourable scaling, 29,30 especially in the IR-UV range and for small and medium-size molecules. This makes time-resolved measurements very challenging, especially in optically thin media, unless one uses X-ray light to match the pitch of the helix to the molecular size 40,41,112,113 or very intense fields 36,114–118 to generate and record high harmonic spectra. Both routes can enhance the chiral dichroism from 0.01% to a few percent level.…”