Ana G. Iriarte

2-Chloro-2,2-difluoracetamide (ClF2CC(O)NH2). Thermal Decomposition, Vapour Infrared, Mass Spectrometry, Low-temperature NMR, and Theoretical Studies. Solvent Effects on Conformational Preferences

Gas-phase thermal decomposition of 2-chloro-2,2-difluoracetamide (CDFA) was studied at temperatures between 270 and 290°C. The rate constant for the decomposition follows the Arrhenius equation. Mass spectrometry was used to analyze the decomposition pattern of the title compound. The FT-IR spectrum of the vapour phase and the infrared spectra of CDFA in protic and aprotic solvents were recorded. Potential energy surfaces were studied by theoretical calculations performed at the density functional theory level (PBEPBE and B3LYP methods) using the 6-31G*, 6-31+G*, 6-311+G**, aug-cc-pVDZ, and aug-cc-pVTZ basis sets.

Synthesis, spectroscopic characterization and theoretical calculations of ClF2CC(O)NPCl3 ([chloro(difluor)acetyl]phosphorimidic trichloride).

The synthesis of [chloro(difluor)acetyl]phosphorimidic trichloride (ClF2CC(O)NPCl3), together with a tentative assignment of the vibrational, NMR and mass spectra, are reported. Quantum chemical calculations (MP2 and B3LYP methods with 6-311+G(d) and 6-311+G(2df,p) basis sets) predict three stable conformers in the gas phase (syn, gauche and anti, defined according to the rotation around both the ClCCN and the CCNP dihedral angles). However, only a single C1 symmetry conformer is observed in the liquid phase, possessing the CO double bond in synperiplanar orientation with respect to the PN double bond, and the ClC bond distorted from the plane defined by the CC(O)NP entity. A Natural Bond Orbital (NBO) analysis was carried out for the title compound and related molecules in order to provide an explanation about the electronic properties.

Vibrational spectra of solid cis- and trans-2- thioxohexahydroquinazolin-4(1H)-one and theoretical calculations towards the interpretation of its thermal reactivity†

FT-Raman and FT-IR spectra of solid cis- and trans-2-thioxohexahydroquinazolin-4(1H)-one are reported from 4000 to 200 cm−1. The molecular geometry, Wiberg Index, NBO analysis and vibrational wavenumbers in the ground state have been calculated using a density functional method (B3LYP) with 6-31+G** and 6-311+G** basis set. Both compounds are stable as dimers in the solid phase, possessing C2 symmetry. The scaled theoretical wavenumbers showed very good agreement with the experimental values. This work contributes to the knowledge of important data which are rather scarce for quinazolinones.