A possible target: triple-bonded indiumantimony molecules with high stability

Abstract

We have considered as a theoretical possibility the development of triple-bonded RInSbR molecules bearing suitable substituents (R). Calculations have demonstrated that the RInSbR molecules possessing smaller substituents (such as R = F, OH, CH₃, H, and SiH₃) cannot be stabilized. Only the triple-bonded R′InSbR′ molecules featuring sterically bulky groups (R′ = SiMe(SitBu₃)₂, SiiPrDis₂, Tbt (= C₆H₂-2,4,6-{CH(SiMe₃)₂}₃), and Ar* (= C₆H₃-2,6-(C₆H₂-2,4,6-i-Pr₃)₂)) are found to locate on the global minimum of the singlet potential energy surface and are thermodynamically stable. The valence-electron bonding model reveals that the bonding nature of R′InSbR′ can be represented as . Our computational investigations based on several theoretical methods (i.e., the charge decomposition analysis, the natural bond orbital analysis and the natural resonance theory) reveal that both the electronic and steric effects of bulkier substituent groups play important roles in making triple-bonded R′InSbR′ species synthetically accessible and isolable in a stable form.