Supramolecular Self-Assembly of the Zwitterionic Sn(IV)-Porphyrin Complex

[Sn(OSO3)2(TPyHP)](HSO4)2∙8H2O (1), an ionic Sn(IV)-porphyrin complex, was prepared by reacting [Sn(OH2)2TPyP] with dilute sulfuric acid. X-ray structural analysis revealed that the zwitterionic [Sn(OSO3)2TPyHP]2+ species consists of two anionic axial Sn–O–SO3 units and four peripheral pyridinium moieties, with an overall dicationic charge balanced by two hydrogen sulfate (HSO4−) counter-anions. Ionic hydrogen bonding between the oxygen atoms of axial sulfato ligands and the peripheral pyridinium groups of adjacent Sn(IV)-porphyrin cations led to the formation of a 1D channel filled with counter-anions and water molecules. The supramolecular self-assembly of 1 was further characterized using various spectroscopic techniques, including 1H NMR spectroscopy, elemental analysis, ESI-mass spectrometry, UV-vis spectroscopy, fluorescence spectroscopy, FT-IR spectroscopy, thermogravimetric analysis (TGA), and powder X-ray diffractometry. The zwitterionic [Sn(OSO3)2TPyHP]2+ complex is a structurally well-defined complementary scaffold involved in supramolecular self-assembly. This novel class of ion-assembled metalloporphyrin is a potential functional porphyrin material used in ion exchange applications.