The Electronic Structure of Some Cyanohydrins—A Spectroscopically Under‐Investigated Family of Compounds

Abstract

Cyanohydrins are usually formed by addition of hydrogen cyanide to aldehydes or ketones while the elimination of HCN from cyanohydrins is easily observed upon heating. The low thermal stability of these highly boiling compounds leads to difficult studies in the gas phase where partial or complete decomposition is usually observed. Consequently, the reported physicochemical properties of such compounds in the gas phase are still scarce. Keeping with this, four simple cyanohydrins, the glycolonitrile and methyl, vinyl and ethynyl derivatives, have been selected. These are possible candidates for the Interstellar Medium, where the corresponding aldehydes and HCN have been detected, and could have played an important role in prebiotic chemistry, as already proposed for some of them. Three well-suited spectroscopic techniques, namely, UV photoelectron, infrared, and Raman spectroscopies, in tandem with quantum calculations, have been chosen for the structure analysis. Photoelectron spectroscopy, successfully performed with gaseous compounds, provides the first comparative study on cyanohydrins in the gas phase.

Spectroscopic Studies on Hydrazine–Boranes, Key Compounds for Chemical Hydrogen Storage

“…For the reliable assignment of PE bands, density functional theory [ΔSCF + TD-DFT (CAM-B3LYP)] − and ab initio [outer valence green function (OVGF), − P3 and symmetry adapted cluster/configuration interaction (SAC–CI) calculations of IEs using the 6-311G­(d,p) basis set on the ground state have been carried out on optimized geometrical structures of all studied compounds. The advantages of the most frequently employed ΔSCF–density functional theory (DFT) method of calculations of the first IEs have been demonstrated previously. ,, The time-dependent (TD)-DFT approach provides a first-principal method for the calculation of excitation energies within a density functional context taking into account the low-lying ion calculated by the ΔSCF method. The vertical IEs were also calculated at the ab initio level according to OVGF (in this case, the effects of electron correlation and reorganization are included beyond the Hartree–Fock approximation and the self-energy part was expanded up to third order) and SAC–CI (symmetry adapted cluster/configuration interaction methods of Nakatsuji which describes accurately and efficiently the electronic structures of the excited, ionized, and electron-attached states of molecules) methods.…”

Submillimeter spectra of 2-hydroxyacetonitrile (glycolonitrile; HOCH2CN) and its searches in GBT PRIMOS observations of Sgr B2(N)

“…The gas-phase, infrared spectrum of HOCH 2 CN has been recently reinvestigated (Chrostowska et al 2015), while the microwave spectrum of HOCH 2 CN has not been treated since it was first observed by Cazzoli et al (1973) from 8-40 GHz. The gauche rotamer has been observed.…”