Synthesis and X-ray Crystal Structure of the Novel Organotin Dication [n-Bu₂Sn(H₂O)₄]²⁺:  A Lamellar Layered Structure Assisted by Intermolecular Hydrogen Bonding

The reaction of n -Bu 2 SnO with 2,5-dimethylbenzenesulfonic acid affords the stable monomeric tin complex [ n -Bu 2 Sn(H 2 O) 4 ] 2+ [2,5-Me 2 -C 6 H 3 SO 3 ] - 2 . The solid-state structure of the molecule reveals that the hydrogen-bonding interaction between the coordinated water and the sulfonate anion moieties leads to an unprecedented two-dimensional layered structure with a planar array of tin atoms. Further, the Lewis acidic dication complex is an extremely good catalyst for acylation of alcohols and phenols.