p-Block Element Catecholates: Lewis Superacidic, Constitutionally Dynamic, and Redox Active

Abstract

Numerous strategies for enhancing the reactivity and properties of p-block elements have been devised in the past decades. The present Account article discusses our approaches by a distinct ligand control on p-block elements in their normal (group) oxidation states. Catecholato ligands at silicon, germanium, and phosphorous enable a range of rewarding properties. Substantial electron withdrawal paired with structural constraint effects (influence of deformation energy) impart Lewis superacidity to these abundant elements. The ease of synthesis of such species facilitates screening in catalysis, promising a range of applications by powerful bond activation. Low barrier Si-O/Si-O bond metathesis imposes the most abundant bond in our Earth’s crust with adaptive features under mild conditions and establishes a new branch of constitutional dynamic chemistry. The redox-active character of catecholates grants access to novel compounds with tunable open-shell features. Overall, p-block catecholates offer unique opportunities due to the versatile features that will enrich the chemistry of the main group elements.

Predicting Lewis Acidity: Machine Learning the Fluoride Ion Affinity of p‐Block‐Atom‐Based Molecules

“…For that, the perfluoro‐ ( F cat ) and perchlorocatecholato ( Cl cat ) ligand were chosen as they have been applied in multiple studies to prepare strong neutral p ‐block atom‐based Lewis acids (Figure 9). [8a,c,d,f,28] In all cases, the maximum number of catecholato ligands was placed at the central atom, while free valences in molecules with an odd central atom oxidation state (e.g., in B(III)‐based molecules) were saturated with methyl groups. FIA values were successfully calculated for 31 of the 42 different combinations (FIA31‐cat dataset, see Chapter S12 in the Supporting Information).…”