Artículo
Chlorodifluoroacetyl Isothiocyanate, ClF2CC(O)NCS: Preparation and Structural and Spectroscopic Studies
Ramos, Luis A.; Ulic, Sonia Elizabeth
; Romano, Rosana M.; Vishnevskiy, Yury V.; Mitzel, Norbert W.; Beckers, Helmut; Willner, Helge; Tong, Shengrui; Ge, Maofa; Della Védova, Carlos Omar
Fecha de publicación:
06/2013
Editorial:
American Chemical Society
Revista:
Journal of Physical Chemistry A
ISSN:
1089-5639
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Chlorodifluoroacetyl isothiocyanate, ClF2CC(O)NCS, was synthesized by the reaction of ClF2CC(O)Cl with an excess of AgNCS. The colorless product melts at −85 °C, and its vapor pressure follows the equation ln p = −4471.1 (1/T) + 11.35 (p [atm], T [K]) in the range −38 to 22 °C. The compound has been characterized by IR (gas phase, Ar matrix, and matrix photochemistry), by liquid Raman, by 19F and 13C NMR, gas UV−vis, and photoelectron spectroscopy (PES), by photoionization mass spectrometry (PIMS), and by gas electron diffraction (GED). The conformational properties of ClF2CC(O)NCS have been analyzed by joint application of vibrational spectroscopy, GED and quantum chemical calculations. The existence of two conformers has been detected in the gas and liquid phases, in which the C−Cl bond adopts a gauche orientation with respect to the CO group; the CO group is in syn- or anti-position with respect to the NC double bond of the NCS group. The computed ΔG° difference between these two gauche−syn and gauche−anti forms is ΔG° = 0.63 kcal mol−1 in the B3LYP/6-31G(d) approximation. The most significant gas-phase structural parameters for gauche−syn ClF2CC(O)NCS are re(NCS) 1.559(2) Å, re(NCS) 1.213(2) Å, re(NC) 1.399(7) Å, re(CO) 1.199(2) Å, and ∠e(CNC) 134.7(13)°. Photolysis of ClF2CC(O)NCS using an ArF excimer laser (193 nm) mainly yields ClF2CNCS, CO, and ClC(O)CF2NCS. The valence electronic properties of the title compound were studied using PES and PIMS. The experimental first vertical ionization energy of 10.43 eV corresponds to the ejection primarily of the sulfur lone-pair electrons of the in-plane nonbonding orbital on the NCS group.
Palabras clave:
Chlorodifluoroacetyl Isothiocyanate
,
Spectroscopic
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Articulos(CEQUINOR)
Articulos de CENTRO DE QUIMICA INORGANICA "DR. PEDRO J. AYMONINO"
Articulos de CENTRO DE QUIMICA INORGANICA "DR. PEDRO J. AYMONINO"
Citación
Ramos, Luis A.; Ulic, Sonia Elizabeth; Romano, Rosana M.; Vishnevskiy, Yury V.; Mitzel, Norbert W.; et al.; Chlorodifluoroacetyl Isothiocyanate, ClF2CC(O)NCS: Preparation and Structural and Spectroscopic Studies; American Chemical Society; Journal of Physical Chemistry A; 117; 27; 6-2013; 5597-5606
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