Synergism of primary and secondary interactions in a crystalline hydrogen peroxide complex with tin.

Despite the significance of HO-metal adducts in catalysis, materials science and biotechnology, the nature of the interactions between HO and metal cations remains elusive and debatable. This is primarily due to the extremely weak coordinating ability of HO, which poses challenges in characterizing and understanding the specific nature of these interactions. Herein, we present an approach to obtain HO-metal complexes that employs neat HO as both solvent and ligand. SnCl effectively binds HO, forming a SnCl(HO) complex, as confirmed by Sn and O NMR spectroscopy. Crystalline adducts, SnCl(HO)·HO·18-crown-6 and 2[SnCl(HO)(HO)]·18-crown-6, are isolated and characterized by X-ray diffraction, providing the complete characterization of the hydrogen bonding of HO ligands including geometric parameters and energy values. DFT analysis reveals the synergy between a coordinative bond of HO with metal cation and its hydrogen bonding with a second coordination sphere. This synergism of primary and secondary interactions might be a key to understanding HO reactivity in biological systems.