Synthesis of Lewis Acid‐Base Adducts Between PCO − and Group 13 Lewis Acids

Lewis acid–base adducts between [Na(diox)PCO] (diox = 1,4-dioxane) and trimethyltriels EMe$_3$ (E = B-In) were synthesized and crystallized using 18-crown-6 (18c6) as ligand for the sodium ions. In the course of these investigations, we were able to characterize the compounds [Na(18c6)][PCO(EMe$_3$)$_2$] (1: E = B; 2: E = Al) and [Na(18c6)][PCO(EMe$_3$)] (3: E = Ga; 4: E = In). All compounds were examined by NMR spectroscopy, IR spectroscopy, and elemental analysis. X-ray structure analysis was performed for compounds 1, 3, and 4. The obtained adducts of negatively charged PCO− anions with Lewis acids illustrate the HSAB concept, as the soft Lewis acids GaMe$_3$ and InMe$_3$ always coordinated at the soft phosphorus atom.