Kinetically Stabilized Diarylpnictogenium Ions

The preparation and full characterization of the stibenium and bismuthenium ions completes the series of kinetically stabilized heavier pnictogenium ions [R_indMesE]⁺ (E=P, As Sb, Bi). The different colours of the species within this series were attributed to energy differences of the LUMOs. Comparison with the bis(m-terphenyl)-substituted stibenium and bismuthenium ions [(2,6-Mes₂C₆H₃)₂E]⁺ (E=Sb, Bi) reveals differences in the E−C bond lengths that are attributed to the repulsion of the bulky substituents.

Abstract

The newly prepared and fully characterized stibenium and bismuthenium ions [R_indMesE]⁺ (E=Sb, Bi; R_ind=dispiro[fluorene-9,3′-(1′,1′,7′,7′-tetramethyl-s-hydrindacen-4′-yl)-5′,9′′-fluorene) were rigorously compared to the previously communicated phosphenium and arsenium ions (E=P, As) as well as the bis(m-terphenyl) pnictogenium ions [(2,6-Mes₂C₆H₃)₂E]⁺ (E=Sb, Bi). It is demonstrated that the choice of the aryl substituents dramatically effects the molecular structures (e. g. the primary E−C bond lengths) and the electronic structures (e. g. the energy of the LUMOs).

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