To What Extent Do Iodomethane and Bromomethane Undergo Analogous Reactions?

Haiming Wu; Yuhan Jia; Xiaoyun Zhao; Lijun Geng; Shiquan Lin; Si-Dian Li; Zhixun Luo

doi:10.1021/acs.jpca.3c08337

To What Extent Do Iodomethane and Bromomethane Undergo Analogous Reactions?

J Phys Chem A. 2024 Feb 22;128(7):1274-1279. doi: 10.1021/acs.jpca.3c08337. Epub 2024 Feb 9.

Authors

Haiming Wu^{1

2}, Yuhan Jia¹, Xiaoyun Zhao^{3

4}, Lijun Geng¹, Shiquan Lin¹, Si-Dian Li³, Zhixun Luo^{1

5}

Affiliations

¹ Beijing National Laboratory for Molecular Science (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
² Department of Chemistry, Tsinghua University, Beijing 100084, China.
³ Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.
⁴ Department of Applied Chemistry, Yuncheng University, Yuncheng 044000, China.
⁵ School of Chemistry, University of Chinese Academy of Sciences, Beijing 100049, China.

PMID: 38334079
DOI: 10.1021/acs.jpca.3c08337

Abstract

Iodomethane and bromomethane (CH₃I/CH₃Br) are common chemicals, but their chemistry on nanometals is not fully understood. Here, we analyze the reactivity of Rh_n⁺ (n = 3-30) clusters with halomethanes and unveil the spin effect and concentration dependence in the C-H and C-X bond activation. It is found that the reactions under halomethane-rich conditions differ from those under metal-rich conditions. Both CH₃I and CH₃Br undergo similar dehydrogenation on the Rh_n⁺ clusters in the presence of small quantity reactants; however, different reactions are observed in the presence of sufficient CH₃I/CH₃Br, showing dominant Rh(CH₃Br)_x⁺ (x = 1-4) products but a series of Rh_nC_xH_yI_z⁺ species (x = 1-4, y = 1-12, and z = 1-5) pertaining to H₂, HI, or CH₄ removal. Density functional theory calculations reveal that the dehydrogenation and demethanation of CH₃Br are relatively less exothermic and will be deactivated by sufficient gas collisions if helium cooling takes away energy immediately; instead, the successive adsorption of CH₃Br gives rise to a series of Rh(CH₃Br)_x⁺ species with accidental C-Br bond dissociation.