Related Experiment Video
Updated: Feb 1, 2026

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
Chloro- and Dichloro-methylsulfonyl Nitrenes: Spectroscopic Characterization, Photoisomerization, and Thermal
Yang Yang1, Xianxu Chu2, Yan Lu3
1College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China. 20174209103@stu.suda.edu.cn.
Abstract:
Chloro- and dichloro-methylsulfonyl nitrenes, CH₂ClS(O)₂N and CHCl₂S(O)₂N, have been generated from UV laser photolysis (193 and 266 nm) of the corresponding sulfonyl azides CH₂ClS(O)₂N₃ and CHCl₂S(O)₂N₃, respectively. Both nitrenes have been characterized with matrix-isolation IR and EPR spectroscopy in solid N₂ (10 K) and glassy toluene (5 K) matrices. Triplet ground-state multiplicity of CH₂ClS(O)₂N (|D/hc| = 1.57 cm-1 and |E/hc| = 0.0026 cm-1) and CHCl₂S(O)₂N (|D/hc| = 1.56 cm-1 and |E/hc| = 0.0042 cm-1) has been confirmed. In addition, dichloromethylnitrene CHCl₂N (|D/hc| = 1.57 cm-1 and |E/hc| = 0 cm-1), formed from SO₂-elimination in CHCl₂S(O)₂N, has also been identified for the first time. Upon UV light irradiation (365 nm), the two sulfonyl nitrenes R⁻S(O)₂N (R = CH₂Cl and CHCl₂) undergo concomitant 1,2-R shift to N-sulfonlyamines R⁻NSO₂ and 1,2-oxygen shift to S-nitroso compounds R⁻S(O)NO, respectively. The identification of these new species with IR spectroscopy is supported by 15N labeling experiments and quantum chemical calculations at the B3LYP/6-311++G(3df,3pd) level. In contrast, the thermally-generated sulfonyl nitrenes CH₂ClS(O)₂N (600 K) and CHCl₂S(O)₂N (700 K) dissociate completely in the gas phase, and in both cases, HCN, SO₂, HCl, HNSO, and CO form. Additionally, ClCN, OCCl₂, HNSO₂, •NSO₂, and the atmospherically relevant radical •CHCl₂ are also identified among the fragmentation products of CHCl₂S(O)₂N. The underlying mechanisms for the rearrangement and decomposition of CH₂ClS(O)₂N and CHCl₂S(O)₂N are discussed based on the experimentally-observed products and the calculated potential energy profile.
More Related Videos
11:25Identification and Quantification of Decomposition Mechanisms in Lithium-Ion Batteries; Input to Heat Flow Simulation for Modeling Thermal Runaway
Published on: March 7, 2022
09:02Manganese Oxide Nanoparticle Synthesis by Thermal Decomposition of ManganeseII Acetylacetonate
Published on: June 18, 2020
Related Concept Videos
Synthesis and Decomposition Reactions
Thermal expansion and Thermal stress: Problem Solving
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
Thermal Strain
Thermal Expansion
Thermal Stress
Temperature and Thermal Equilibrium
The concept of temperature has evolved from the common concepts of hot and cold. The scientific definition of temperature explains more than just our sense of hot and cold. Temperature is operationally defined as the quantity measured with a thermometer. Furthermore, temperature is...