CENTRO DE QUIMICA INORGANICA "DR. PEDRO J. AYMONINO"
Unidad Ejecutora - UE
Dimers of Perhaloacetyl Cyanides: CClF2C(O)OC(CN)2CClF2 and CF3C(O)OC(CN) 2CF3. Preparation, Properties, and Spectroscopy.
LUIS A. RAMOS; SONIA E. ULIC; ROSANA M. ROMANO; HELMUT BECKERS; HELGE WILLNER; MAOFA GE; SHENGRUI TONG; CARLOS O. DELLA VEDOVA
JOURNAL OF PHYSICAL CHEMISTRY A
AMER CHEMICAL SOC
Lugar: Washington; Año: 2014 vol. 118 p. 1721 - 1721
ABSTRACT: The vapor of the new compound 1,1-dicyano-2-chloro-2,2-diﬂuoroethyl chlorodi-ﬂuoroacetate, CClF2C(O)OC(CN)2CClF2 and of the known 1,1-dicyano-2,2,2-triﬂuoroethyltriﬂuoroacetate, CF3C(O)OC(CN)2CF3, were investigated using vibrational spectroscopy tools.The existence of rotational isomerism was conﬁrmed for CClF2C(O)OC(CN)2CClF2 when the matrix isolated compound was examined in combination with the computational results applying quantum chemical models. From the four conformers gauche-syn-gauche, gauche-syn-anti, syn-synanti, syn-syn-gauche (the used nomenclature is with respect to the ϕ(ClC−C(O)), ϕ((O)C-OC), and ϕ(OC−CCl) torsion angles, respectively) predicted for CClF2C(O)OC(CN)2CClF2 the ﬁrst two forms can be evidenced using Ar-matrix IR spectroscopy, with the ﬁrst one being the most abundant at room temperature. On the other side, the results obtained for CF3C(O)OC(CN)2CF3 reveals the existence of only one syn-syn-anti form. CClF2C(O)OC(CN)2CClF2 melts at −40 °C and its vapor pressure was ﬁtted by the equation ln p = −4732.6 (1/T) + 10.75 (p [Atm], T [K]) in the range −20 to 20 °C. Its extrapolated boiling point is 167 °C. The ﬁrst ionization potentials occur for CClF2C(O)OC(CN)2CClF2 and CF3C(O)OC(CN)2CF3 at 12.13 and 12.43 eV, respectively, and were attributed to the ejection of electrons formally located at the carbonylic oxygen lone-pair electrons (nO). The proposed interpretation of the photoelectron spectrum is consistent with related molecules reported previously, and also with the prediction of Outer Valence Green?s Functions (OVGF).