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Raman, infrared and microwave spectra, $r_{0}$ structural parameters, and conformational stability of isopropylisocyanate

Tijdschriftbijdrage - Tijdschriftartikel

The microwave spectrum of isopropylisocyanate, (CH3)2CHNCO, has been investigated from 11,000 to 21,000 MHz and 18 transitions for the more stable trans conformer were assigned and A = 6693.23(15), B = 2263.10(3), C = 1960.05(2) MHz were obtained. By utilizing these rotational constants along with ab initio MP2(full)/6-311 + G(d,p) predicted structural values, adjusted r0 parameters have been obtained for the trans conformer along with estimated values for the gauche conformer. Variable temperature Raman and infrared spectra of xenon solutions have been recorded and a ΔH value of 115 ± 11 cm−1 (1.38 ± 0.13 kJ/mol) has been determined. The conformational stabilities have been predicted from ab initio calculations utilizing several different basis sets up to cc-PVQZ for MP2(full) and 6-311 + G(3df,3pd) for density functional theory calculations by the B3LYP method. From the MP2(full)/cc-PVQZ calculations an energy difference of 87 cm−1 (1.04 kJ/mol) is predicted between the trans and the gauche forms and 168 cm−1 (2.01 kJ/mol) for the cis form which is a transition state.
Tijdschrift: Journal of Molecular Structure
ISSN: 0022-2860
Volume: 109
Pagina's: 163 - 173
Jaar van publicatie:2015
Trefwoorden:Fysische scheikunde