IINS, MIR, and DFT Investigations of Vibrational Spectra of 3, 3-Dimethyl-1-Butanol and 3, 3-Dimethyl-2-Butanol

Abstract

Molecularvibrational spectra in 3,3-dimethyl-1-butanol, (CH 3 ) 3 CCH 2 CH 2 OH, and 3,3-dimethyl-2-butanol, (CH 3 ) 3 CCHOHCH 3 , were measured by the inelastic incoherent neutron scattering and mid infrared spectroscopy and for 3,3-dimethyl-2-butanol additionally by the far infrared absorption method. Experimental results were discussed and compared with the results of the quantum chemical calculations performed by the density functional theory (DFT/B3LYP/6-311G * * ) and semi-empirical PM3 calculation methods assuming the isolated molecule approximation.

Dynamics of Dimethylbutanols in Plastic Crystalline Phases by Field Cycling 1H NMR Relaxometry

“…2,2-DM-1-B was available from previous studies. , 3,3-DM-1-B and 3,3-DM-2-B were purchased from Aldrich and used without further treatment.…”

“…These alcohols differ from each other by the positions of the OH and CH 3 groups, which influence both the tendency to form H-bonds and the number of conformational isomers, but all have a nearly globular shape, which promotes the formation of plastic crystals. The different molecular architecture and motional degrees of freedom give rise to a different solid-state polymorphism of 2,2-DM-1-B, 3,3-DM-1-B, and 3,3-DM-2-B, which was investigated by differential scanning calorimetry (DSC), adiabatic calorimetry, and inelastic incoherent neutron scattering in previous studies. − In particular, 2,2-DM-1-B was found to form a fully ordered crystalline phase, an ODIC phase, a conformational disordered (CONDIS) phase, and a glassy crystal of the CONDIS phase. 3,3-DM-2-B forms four ODIC phases, with the lower-temperature ODIC phase forming a glassy crystal on further cooling.…”