Molecular structure, IR, Raman and UV-VIS spectra of 2-cyanothiophene and 3-cyanothiophene: A comparative quantum chemical investigation

Chemical constituents, pharmacological activities and quality evaluation methods of genus Hippocampus: A comprehensive review

The genus Hippocampus is a multi-origin animal species with high medicinal and healthcare values. About 57 species of Hippocampus spread worldwide, of which about 14 species can be used as medicine, showing anti-oxidation, anti-inflammation, anti-depressant, anti-hypertension, anti-prostatic hyperplasia, antivirus, anti-apoptotic, antifatigue, and so on. And those pharmacological effects are mainly related to their active ingredients, including amino acids, abundant proteins (peptides and oligopeptides), fatty acids, nucleosides, steroids, and other small molecular compounds. The main means of authentication of Hippocampus species are morphological identification, microscopic identification, thin layer chromatography method, fingerprint method and genomics method. This review will provide useful insight for exploration, further study and precise medication of Hippocampus in the future.

On the formation of 2- and 3-cyanofurans and their protonated forms in interstellar medium conditions: quantum chemical evidence

The literature is still poor in theoretical and experimental, including both spectroscopic and thermodynamic data for protonated furan and protonated 2-cyanofuran and 3-cyanofuran (FH⁺, 2CFH⁺ and 3CFH⁺). These data are, however, crucial for astrophysicists and astrochemists in the detection of new species in interstellar medium (ISM), the discovery of these molecular species being not yet reported. It is in this perspective that a computational study based on quantum chemistry on FH⁺, 2CFH⁺ and 3CFH⁺ was undertaken. A series of properties including the proton affinity (PA) of furan and the two cyanofurans, the variations of enthalpy (Δ_rH), entropy (Δ_rS), and Gibbs free energy (Δ_rG) for the reactions yielding cyanofurans (neutral and protonated forms), were studied at different temperatures (5 K, 10 K, 150 K and 298 K) and pressures (P = 1 atm and P = 10⁻⁵ atm) based on modern computational models (G2MP2, G3, G4MP2 and G4). While confirming that the protonation favors the α-position for furan, the PA values show that the protonation favors the nitrogen atom in cases of 2CFH⁺ and 3CFH⁺. The Δ_rH, Δ_rS and Δ_rG values revealed spontaneous reactions producing these species under ISM conditions of temperature and pressure. In addition quadrupole hyperfine structures and vibrational spectra which are essential tools for the characterization and the identification of interstellar molecular species are predicted, while the region where brightest lines fall for different temperatures is discussed. The results reported in this work are expected to assist astrophysicists and astrochemists, in the search for new chemical species in interstellar environments.

The literature is still poor in theoretical and experimental, including both spectroscopic and thermodynamic, data for protonated furan and protonated 2-cyanofuran and 3-cyanofuran (FH⁺, 2CFH⁺ and 3CFH⁺).

Theoretical investigation of protonated thiophene and two of its nitrile substituted derivatives (2-cyanothiophene and 3-cyanothiophene)

Theoretical and experimental spectroscopic data for protonated cyano-thiophenes (R-CNH⁺ with R = C₄H₃S), which are needed for their interstellar search and/or detection, are still lacking in the literature. Considering the high abundance and reactivity of H₃⁺ in the interstellar medium (ISM), a quantum chemical investigation on protonated thiophene and two of its nitrile-substituted derivatives (2-cyanothiophene and 3-cyanothiophene) is undertaken for their characterization. The geometrical structures for the title species are calculated at the M06-2X/6-31G(d,p) level of theory, followed by an empirical correction for systematic errors. At the same level of theory, IR and Raman spectra are explored and the rotational parameters are calculated. The proton affinity (PA) of R-CN and the enthalpy, entropy and Gibbs free energy changes (Δ_rH, Δ_rS and Δ_rG) of the reactions producing R-CNH⁺ are computed at the G2(MP2) and G3B3 levels of theory and at different temperatures. The PA calculations show that the protonation favors the nitrogen atom, while Δ_rH, Δ_rS, and Δ_rG reveal the spontaneous reactions producing R-CNH⁺ and their neutral forms. In addition, quadrupole hyperfine structures are predicted, while the region where the brightest lines fall at different temperatures is discussed. These results are expected to assist astrophysicists and astrochemists in the search for new species in the ISM.