Synthesis and Study of Derivatives of the [B10H10]2– Anion with Heterofunctional Amines

Abstract

In the present work, the reaction between 1,4-dioxane and tetrahydropyran monosubstituted derivatives of the closo-decaborate anion ([2-B₁₀H₉O(CH₂)₄O]^– or [2-B₁₀H₉O(CH₂)₅]^–, respectively) and oxygen-containing heterofunctional amines (2-(methylamino)ethanol, 2-aminoethanol, 3-dimethylamino-1-propanol, bis(2-methoxyethyl)amine) was investigated. It was shown that these reactions are accompanied by the opening of the oxonium cyclic substituent and the addition of nucleophilic reagents to the boron cluster through the alkoxy spacer chain. The use of heterofunctional amines of different structures does not fundamentally affect the structure of the resulting products, and in all the reactions studied, the pendant group is bound exclusively through the nitrogen atom. Thus, the developed method is highly selective and enables the addition of ammonium fragments to the boron cluster via an alkoxy spacer, preserving the oxygen-containing functional groups unchanged. This approach holds considerable promise for further modification of the resulting compounds. Varying the structure of the amines used in combination with various types of oxonium exo-polyhedral substituents allows for the construction of closo-decaborate anion derivatives with a specified structure of both the pendant group and the spacer chain. The resulting compounds were studied using modern methods of physical and physicochemical analysis, including elemental analysis, IR, ¹¹B, ¹³C, and ¹H NMR spectroscopies, and ESI mass-spectrometry.