Directed Gas-Phase Formation of Aminosilylene (HSiNH2; X1A'): The Simplest Silicon Analogue of an Aminocarbene, under Single-Collision Conditions

Zhenghai Yang; Chao He; Shane Goettl; Ralf I Kaiser; Valeriy N Azyazov; Alexander M Mebel

doi:10.1021/jacs.1c05510

Directed Gas-Phase Formation of Aminosilylene (HSiNH₂; X¹A'): The Simplest Silicon Analogue of an Aminocarbene, under Single-Collision Conditions

J Am Chem Soc. 2021 Sep 8;143(35):14227-14234. doi: 10.1021/jacs.1c05510. Epub 2021 Aug 25.

Authors

Zhenghai Yang¹, Chao He¹, Shane Goettl¹, Ralf I Kaiser¹, Valeriy N Azyazov², Alexander M Mebel³

Affiliations

¹ Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States.
² Lebedev Physical Institute, Samara 443011, Russian Federation.
³ Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States.

PMID: 34431671
DOI: 10.1021/jacs.1c05510

Abstract

The aminosilylene molecule (HSiNH₂, X¹A')-the simplest representative of an unsaturated nitrogen-silylene-has been formed under single collision conditions via the gas phase elementary reaction involving the silylidyne radical (SiH) and ammonia (NH₃). The reaction is initiated by the barrierless addition of the silylidyne radical to the nonbonding electron pair of nitrogen forming an HSiNH₃ collision complex, which then undergoes unimolecular decomposition to aminosilylene (HSiNH₂) via atomic hydrogen loss from the nitrogen atom. Compared to the isovalent aminomethylene carbene (HCNH₂, X¹A'), by replacing a single carbon atom with silicon, a profound effect on the stability and chemical bonding of the isovalent methanimine (H₂CNH)-aminomethylene (HNCH₂) and aminosilylene (HSiNH₂)-silanimine (H₂SiNH) isomer pairs is shown; i.e., thermodynamical stabilities of the carbene versus silylene are reversed by 220 kJ mol^-1. Hence, the isovalency of the main group XIV element silicon was found to exhibit little similarities with the atomic carbon revealing a remarkable effect not only on the reactivity but also on the thermochemistry and chemical bonding.