Bis(4-carbamoylpiperidinium) biphenyl-4,4′-disulfonate

Abstract

In the title isonipecotamide salt 2C6H13N2O+·C12H8O6S22−, the asymmetric unit comprises one biphenyl-4,4′-disulfonate dianion which lies across a crystallographic inversion centre and another in a general position [dihedral angle between the two phenyl rings is 37.1 (1)°], together with three isonipecotamide cations. Two of these cations give a cyclic homomeric amide–amide dimer interaction [graph set R22(8)], the other giving a similar dimeric interaction but across an inversion centre, both dimers then forming lateral cyclic R42(8) pyrimidinium–amide N—H...O interactions. These units are linked both laterally and longitudinally to the sulfonate groups of the dianions through piperidinium N—H...O hydrogen bonds, giving a three-dimensional framework structure.