Coordination flexibility and function in tris(pyrazolyl)methanesulfonate coordination chemistry

Tris(pyrazolyl)methanesulfonate (Tpms) ligands constitute water-compatible scorpionate platforms that combine the facial N,N,N donor set of classical tris(pyrazolyl)borates (Tp) or tris(pyrazolyl)methane (Tpm) with an appended sulfonate functionality that enhances hydrolytic robustness, solubility in polar media and coordination flexibility. Over the last two decades, Tpms chemistry has evolved from simple alkali-metal salts into structurally diverse complexes spanning much of the periodic table, in which the sulfonate group may remain non-coordinating or engage as an auxiliary, often hemilabile, donor. This donor complementarity enables κ³/κ² coordination switching, modulation of nuclearity, access to multinuclear and polymeric architectures, and fine control over metal-centre environments. In this Perspective, we critically analyse the emerging structure-property relationships that govern Tpms coordination modes, stability and dimensionality and assess how these features translate into enabling functions in oxidation and carbonylation catalysis, Lewis-acid-mediated C-C bond formation, biologically active silver and copper systems, and coordination polymer design. Finally, we outline key challenges and opportunities for the field, including rational ligand-design strategies to control sulfonate engagement, the need for mechanistic benchmarking under aqueous and green conditions, and the potential of Tpms ligands as general scaffolds for sustainable and functional inorganic chemistry.