Exploring Non-covalent Interactions by Jet-Cooled Electronic and Vibrational Spectroscopy

Sequence dependent folding motifs of the secondary structures of Gly-Pro and Pro-Gly containing oligopeptides

“…Conformation-specific electronic and IR spectra of the peptides were measured using various gas phase laser spectroscopic techniques in a home-built jet-cooled laser desorption Time of Flight (TOF) mass spectrometer, which has been described in detail, previously and also in the supporting information. 61–66 In brief, a pellet consisting of the peptide sample and graphite powder was mounted in a rotating sample holder placed in the vacuum chamber. A laser beam of 532 nm (Nd:YAG laser, Continuum, Minilite-I, 10 Hz, 10 nanoseconds) was mildly focused on the rotating pellet to desorb the peptide molecules, which were seeded into the supersonic expansion of the Ar (∼5 bar) carrier gas.…”

Understanding the n → π* non-covalent interaction using different experimental and theoretical approaches

“…96 Das and co-workers measured mass-selected electronic spectra of these complexes using one-color resonant two-photon ionization spectroscopy (1C-R2PI). 10 In this technique, the first photon of a tunable laser excites the molecules from the ground state (S 0 ) to the excited state (S 1 ). Subsequently, another photon ionizes the molecules to the ionization continuum (D 0 ), and the ionized molecules are detected as a function of the wavelength of the laser.…”

“…Subsequently, another photon ionizes the molecules to the ionization continuum (D 0 ), and the ionized molecules are detected as a function of the wavelength of the laser. 10 Conformation-specific IR spectra of the complexes were measured using resonant ion-dip infrared spectroscopy (RIDIR) by fixing the UV laser at a particular transition of the electronic spectrum and scanning the IR laser throughout the N–H stretching region. 10…”

“…10 Conformation-specific IR spectra of the complexes were measured using resonant ion-dip infrared spectroscopy (RIDIR) by fixing the UV laser at a particular transition of the electronic spectrum and scanning the IR laser throughout the N–H stretching region. 10…”

“…Non-covalent interactions play a crucial role in determining the specific structures and functions of biomolecules, drugs, supramolecular assemblies, materials, and molecular complexes. 1–12 Various non-covalent interactions such as hydrogen bonding, 1–20 halogen bonding, 21–25 chalcogen bonding, 25–29 π–π stacking, 30–33 cation–π, 34–37 and anion–π 38–41 interactions have been extensively studied in the literature. Hydrogen bonding is ubiquitous and well-established among all the non-covalent interactions reported in the literature.…”