Fate of transient isomer of CH2I2: Mechanism and origin of ionic photoproducts formation unveiled by time-resolved x-ray liquidography

• DOI: 10.1063/1.5099002
• Publication Date: 2019-06-14T14:39:53Z
• Authors: Sungjun Park; Jungkweon Choi; Hosung Ki; Kyung Hwan Kim; Key Young Oang; Heegwang Roh; Joonghan Kim; Shunsuke Nozawa; Tokushi Sato; Shin-ichi Adachi; Jeongho Kim; Hyotcherl Ihee
• Keywords: Heterolysis; Homolysis; Diiodomethane; Solvolysis

Diiodomethane, CH2I2, in a polar solvent undergoes unique photoinduced reaction whereby I2- and I3- are produced from its photodissociation, unlike for other iodine-containing haloalkanes. While previous studies proposed that homolysis, heterolysis, or solvolysis of iso-CH2I-I, which is major intermediate the can account formation I3-, there has been no consensus on mechanism clue reason why those negative ionic species not observed photodissociation chemicals same solvent, example, CHI3, C2H4I2, C2F4I2, I2. Here, using time-resolved X-ray liquidography, we revisit CH2I2 methanol determine structures all transient photoproducts involved reveal formed via heterolysis iso-CH2I-I methanol. In addition, demonstrate high polarity responsible photochemistry CH2I2.