Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001, Ta-Hsueh Road, Hsinchu 30010, Taiwan.
J Chem Phys. 2018 Feb 14;148(6):064301. doi: 10.1063/1.5019205.
We recorded time-resolved infrared absorption spectra of transient species produced on irradiation at 308 nm of a flowing mixture of CHI/O/N/SO at 298 K. Bands of CHOO were observed initially upon irradiation; their decrease in intensity was accompanied by the appearance of an intense band at 1391.5 cm that is associated with the degenerate SO-stretching mode of SO, two major bands of HCHO at 1502 and 1745 cm, and five new bands near >1340, 1225, 1100, 940, and 880 cm. The band near 1340 cm was interfered by absorption of SO and SO, so its band maximum might be greater than 1340 cm. SO in its internally excited states was produced initially and became thermalized at a later period. The rotational contour of the band of thermalized SO agrees satisfactorily with the reported spectrum of SO. These five new bands are tentatively assigned to an intermediate 1,3,2-dioxathietane-2,2-dioxide [cyc-(CH)O(SO)O] according to comparison with anharmonic vibrational wavenumbers and relative IR intensities predicted for this intermediate. Observation of a small amount of cyc-(CH)O(SO)O is consistent with the expected reaction according to the potential energy scheme predicted previously. SO+HCHO are the major products of the title reaction. The other predicted product channel HCOOH+SO was unobserved and its branching ratio was estimated to be <5%.
我们记录了在 298 K 时，用 308nm 光辐照 CHI/O/N/SO 流动混合物时产生的瞬态物种的时间分辨红外吸收光谱。辐照初始时观察到 CHOO 的带；随着其强度的降低，出现了一个强度为 1391.5cm 的强烈带，该带与 SO 的简并 SO 伸缩模式、HCHO 的两个主要带 1502 和 1745cm 以及五个新带（在 >1340、1225、1100、940 和 880cm 附近）有关。1340cm 附近的带受到 SO 和 SO 的吸收干扰，因此其带的最大值可能大于 1340cm。最初产生处于内部激发态的 SO，并在后期热化。热化 SO 带的旋转轮廓与报道的 SO 谱非常吻合。根据与该中间体预测的非谐振动波数和相对 IR 强度的比较，这些五个新带被暂时分配给中间体 1,3,2-二恶噻烷-2,2-二氧化物[环-（CH）O（SO）O]。观察到少量环-（CH）O（SO）O 与根据先前预测的势能方案预期的反应一致。SO+HCHO 是标题反应的主要产物。其他预测的产物通道 HCOOH+SO 未被观察到，其分支比估计小于 5%。
