Brucinium toluene‐4‐sulfonate trihydrate at 130 K

The low‐temperature (130 K) structure of the 1:1 proton‐transfer compound of brucine with toluene‐4‐sulfonic acid (systematic name: 2,3‐dimeth­oxy‐10‐oxostrychnidinium toluene‐4‐sulfonate trihydrate), C23H27N2O4+·C7H7O3S−·3H2O, has been determined. The asymmetric unit contains two cations, two anions and six molecules of water. Brucinium cations form the familiar undulating head‐to‐tail ribbon structures, which associate with the toluene‐4‐sulfonate anions and the water mol­ecules in the inter­stitial cavities through hydrogen‐bonding associations involving all available donor and acceptor atoms on all species. The result is a framework polymer structure.