From layered architecture to red light: Structural and photophysical characterization of a new porphyrin framework

A new two-dimensional coordination polymer based on manganese(II) and 5,10,15,20-tetra-3-pyridinyl-21H,23H-porphine, formulated as [Mn(TPyP)][Formula: see text] (1; TpyP [Formula: see text] 5,10,15,20-tetra-3-pyridinyl-21H,23H-porphine), was successfully synthesized under solvothermal conditions. Single-crystal X-ray diffraction revealed that the Mn[Formula: see text] center adopts an octahedral geometry, coordinated by four equatorial pyrrolic nitrogen atoms from one porphyrin ligand and two axial pyridyl nitrogens from adjacent molecules, resulting in extended 2D layered frameworks. These layers are further assembled into a three-dimensional supramolecular architecture via [Formula: see text]-[Formula: see text] stacking interactions between planar porphyrin units. Solid-state UV-vis diffuse reflectance spectroscopy indicates a wide-bandgap semiconductor with an energy gap of 5.3 eV. In ethanol solution, complex 1 exhibits red luminescence, with CIE chromaticity coordinates of (0.7231, 0.2769) and a correlated color temperature of 7982 K. Time-dependent density functional theory (TD-DFT) simulations suggest that the observed emission arises from a [Formula: see text]* transition process.