The first molecular borophosphonate cage: synthesis, spectroscopy, and single-crystal X-ray structure

Abstract

The synthesis of the first molecular borophosphonate, [t-BuPO₃BEt]₄ (1), has been achieved from the reaction of tert-butylphosphonic acid and triethylboron in refluxing toluene/1,4-dioxane. The inorganic B₄O₁₂P₄ cubic framework in 1 is enveloped by butyl and ethyl groups, making the compound highly soluble in common organic solvents. The reactive B-C bonds present in the four corners of 1 might offer the possibility of the use of this compound as a starting material for building supramoleclar borophosphonate/phosphate structures.