N-（氟甲酰基）亚硫酰二氯，FC（O）N=SCl2的结构与构象

Structure and conformations of N-(fluoroformyl)imidosulfurous dichloride, FC(O)N=SCl2.

作者信息

Leibold Christiane, Alvarez Rosa M S, Cutin Edgardo H, Della Vedova Carlos O, Oberhammer Heinz

机构信息

Institut für Physikalische und Theoretische Chemie, Universität Tübingen, 72076 Tübingen, Germany.

出版信息

Inorg Chem. 2003 Jun 30;42(13):4071-5. doi: 10.1021/ic030058p.

DOI:10.1021/ic030058p

PMID:12817963

Abstract

The IR (gas) and Raman (liquid) spectra of FC(O)NSCl(2) demonstrate the presence of a conformational mixture in both phases. According to a gas electron diffraction study, the main conformer (94(8)%) possesses a syn-syn structure (C(O)F group synperiplanar with respect to the SCl(2) bisector and the C=O bond synperiplanar to the N=S bond). Quantum chemical calculations (HF, B3LYP and MP2 with 6-31G basis set, and MP2/6-311(2df)) predict a syn-anti structure for the second conformer. Analysis of the IR (gas) spectrum results in a contribution of 5(1)% of the minor form, corresponding to a Gibbs free energy difference DeltaG degrees = G degrees (syn-anti) - G degrees (syn-syn) = 1.75(15) kcal/mol. This value is reproduced very well by quantum chemical calculations, which include electron correlation effects (DeltaG degrees = 1.28-1.56 kcal/mol). The HF approximation overestimates this energy difference (DeltaG degrees = 3.24 kcal/mol).

摘要

FC(O)NSCl₂的红外（气体）光谱和拉曼（液体）光谱表明，在两个相中均存在构象混合物。根据气体电子衍射研究，主要构象异构体（94(8)%）具有顺-顺结构（C(O)F基团相对于SCl₂平分线处于同面共平面，且C=O键与N=S键处于同面共平面）。量子化学计算（采用6-31G基组的HF、B3LYP和MP2方法，以及MP2/6-311(2df)方法）预测第二种构象异构体为顺-反结构。对红外（气体）光谱的分析得出次要形式的贡献为5(1)%，这对应于吉布斯自由能差ΔG° = G°(顺-反) - G°(顺-顺) = 1.75(15) kcal/mol。通过包括电子相关效应的量子化学计算（ΔG° = 1.28 - 1.56 kcal/mol），能很好地重现该值。HF近似高估了这个能量差（ΔG° = 3.24 kcal/mol）。