Matrix Infrared Spectroscopic and Theoretical Investigations of X2CX···MX and CX3-MX Provided in Reactions of Ag and Au with Tetrahalomethanes

Han-Gook Cho; Lester Andrews

doi:10.1021/acs.inorgchem.0c02436

Matrix Infrared Spectroscopic and Theoretical Investigations of X₂CX···MX and CX₃-MX Provided in Reactions of Ag and Au with Tetrahalomethanes

Inorg Chem. 2020 Oct 19;59(20):15438-15446. doi: 10.1021/acs.inorgchem.0c02436. Epub 2020 Oct 8.

Authors

Han-Gook Cho¹, Lester Andrews²

Affiliations

¹ Department of Chemistry, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, South Korea.
² Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, Virginia 22904-4319, United States.

PMID: 33028072
DOI: 10.1021/acs.inorgchem.0c02436

Abstract

Reactions of laser-ablated silver atoms with tetrahalomethanes have been carried out in excess argon, and the products were identified via examination of the matrix spectra and their variation on photolysis and annealing. While production of the insertion products (CX₃-AgX) was evident in all Ag reactions, different sets of product absorptions were also observed in the higher frequency region (1260-720 cm^-1). They increased on photolysis but decreased on annealing, opposite to the absorptions of the insertion products. They have been assigned to weakly bound complexes of CX₃ and AgX (X₂CX···AgX), which were generated in halogen abstraction by the metal atom from CX₄. These Cl-mediated Ag complexes are only slightly higher in energy than the insertion products due to the d¹⁰s¹ electron configuration of the group 11 metal. NBO analyses reveal that the CX₃ radical is coordinated to an ionic species (Ag⁺Cl^-) via electron-rich X. The product absorptions marked "m" in the previous Au + CX₄ study also most probably originated from the weakly bound product, which is more stable than the methylidene (X₂C-AuX₂).