The Structure and Conformational Properties of Diacetyl Sulfide, CH3C(O)SC(O)CH3, in the Gaseous and Condensed Phases Explored by Gas Electron Diffraction, Single-crystal X-ray Diffraction, Vibrational Spectroscopy, and Quantum Chemical Calculations

ROSANA M. ROMANO; CARLOS O. DELLA VÉDOVA; ANTHONY J. DOWNS; HEINS OBERHAMMER; SIMON PARSONS

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

Año: 2001 vol. 123 p. 12623 - 12631

0002-7863

On the evidence of the electron diffraction pattern of the vapor, of the IR spectrum of the matrixisolated molecule, and of quantum chemical calculations, the diacetyl sulfide molecule, CH3C(O)SC(O)CH3, adopts a planar heavy-atom skeleton with the [sp,ap] conformation. Other conformations contribute little (<1%) to the population of the gaseous molecules at normal temperatures. Salient structural parameters (ra structure, distances (in Å), angles (in deg), and 3ó uncertainties in parentheses) were as follows: r(CdO) 1.198(2)/ 1.196(2), r(C-S) 1.787(3)/1.808(3), r(C-C) 1.483(4)/1.472(4), ÐC-S-C 108.8(9), ÐS-CdO 125.7(6)/ 115.1(6), and ÐS-C-C 121.1(7)/111.2(7). The structure of a single crystal at 150 K [monoclinic, P21/n, a )3C(O)SC(O)CH3, adopts a planar heavy-atom skeleton with the [sp,ap] conformation. Other conformations contribute little (<1%) to the population of the gaseous molecules at normal temperatures. Salient structural parameters (ra structure, distances (in Å), angles (in deg), and 3ó uncertainties in parentheses) were as follows: r(CdO) 1.198(2)/ 1.196(2), r(C-S) 1.787(3)/1.808(3), r(C-C) 1.483(4)/1.472(4), ÐC-S-C 108.8(9), ÐS-CdO 125.7(6)/ 115.1(6), and ÐS-C-C 121.1(7)/111.2(7). The structure of a single crystal at 150 K [monoclinic, P21/n, a )<1%) to the population of the gaseous molecules at normal temperatures. Salient structural parameters (ra structure, distances (in Å), angles (in deg), and 3ó uncertainties in parentheses) were as follows: r(CdO) 1.198(2)/ 1.196(2), r(C-S) 1.787(3)/1.808(3), r(C-C) 1.483(4)/1.472(4), ÐC-S-C 108.8(9), ÐS-CdO 125.7(6)/ 115.1(6), and ÐS-C-C 121.1(7)/111.2(7). The structure of a single crystal at 150 K [monoclinic, P21/n, a )ra structure, distances (in Å), angles (in deg), and 3ó uncertainties in parentheses) were as follows: r(CdO) 1.198(2)/ 1.196(2), r(C-S) 1.787(3)/1.808(3), r(C-C) 1.483(4)/1.472(4), ÐC-S-C 108.8(9), ÐS-CdO 125.7(6)/ 115.1(6), and ÐS-C-C 121.1(7)/111.2(7). The structure of a single crystal at 150 K [monoclinic, P21/n, a )ó uncertainties in parentheses) were as follows: r(CdO) 1.198(2)/ 1.196(2), r(C-S) 1.787(3)/1.808(3), r(C-C) 1.483(4)/1.472(4), ÐC-S-C 108.8(9), ÐS-CdO 125.7(6)/ 115.1(6), and ÐS-C-C 121.1(7)/111.2(7). The structure of a single crystal at 150 K [monoclinic, P21/n, a )r(C-S) 1.787(3)/1.808(3), r(C-C) 1.483(4)/1.472(4), ÐC-S-C 108.8(9), ÐS-CdO 125.7(6)/ 115.1(6), and ÐS-C-C 121.1(7)/111.2(7). The structure of a single crystal at 150 K [monoclinic, P21/n, a )ÐS-C-C 121.1(7)/111.2(7). The structure of a single crystal at 150 K [monoclinic, P21/n, a ) 4.2230(7) Å, b ) 11.2105(17) Å, c ) 12.332(2) Å, â ) 94.544(16)°] also reveals planar molecules with the same conformation and dimensions close to those of the gaseous molecule. Changes in the vibrational spectra of the compound accompanying the transition from the vapor to the condensed phases are attributed not to the presence of more than one conformer but to differences in the local environment of the two carbonyl groups. The properties deduced are compared with those of other compounds of the type CH3C(O)XC(O)CH3 (X )b ) 11.2105(17) Å, c ) 12.332(2) Å, â ) 94.544(16)°] also reveals planar molecules with the same conformation and dimensions close to those of the gaseous molecule. Changes in the vibrational spectra of the compound accompanying the transition from the vapor to the condensed phases are attributed not to the presence of more than one conformer but to differences in the local environment of the two carbonyl groups. The properties deduced are compared with those of other compounds of the type CH3C(O)XC(O)CH3 (X )3C(O)XC(O)CH3 (X ) CH2, NH, or O).2, NH, or O).