Crystal structure, vibrational spectra, optical properties and thermal behavior of the 1D perovskite (2-amino-4-methylpyridinium)trichlorocadmate(II) (C6H9N2)1∞[CdCl3]

The organic-inorganic hybrid compound (2-amino-4-methylpyridinium) trichlorocadmate(II), (C6H9N2)1∞[CdCl3] was prepared in crystalline form by solvent evaporation at room temperature. Infrared and Raman spectra allowed tracing the entities of the organic aromatic cation and the inorganic 1∞CdCln scaffold. X-ray diffraction showed that the compound crystallizes in the orthorhombic system in the centrosymmetric space group Pnma and has a one-dimensional (1 D) perovskite structure. Hirshfeld surface analyses (dnorm and shape index) of the studied structure, as well as its fingerprints, allowed us to identify and quantify the intermolecular interactions such as H bonds and π stacking. UV-visible absorption spectroscopy allowed us to estimate the direct band gap using the Tauc-extrapolation method. From this, we conclude a semiconducting character of the compound with a band gap of about 3.5 eV. Photoluminescence was observed with maxima at 351 and 388 nm when excited at 312 nm and can be traced to excited π–π* states in the organic cation. Thermogravimetric and differential thermal analysis showed that the compound is stable up to 200 °C and decomposes stepwise.