Pyrazine bound, zinc 5,10,15,20-tetrakis(4-chlorophenyl)porphyrin: Synthesis, crystal structure and computational studies

This work describes the synthesis, characterization, crystal structure, and computational analyses of the zinc porphyrin [ZnT(4-Cl)PP], 1 and its pyrazine bound analogue, [ZnT(4-Cl)PP(pyz)], 2, (where T(4-Cl)PP stands for 5,10,15,20-tetrakis-(4-chlorophenyl)porphyrin and pyz represents pyrazine). Both compounds were structurally characterized by UV–visible spectroscopy, infrared spectroscopy, ¹HNMR spectroscopy, ¹³CNMR spectroscopy and single crystal XRD. The crystal structure of the 2 consists of a zinc porphyrin with an axial pyrazine ligand forming a penta-coordinated complex with Zn1-N5(pyz) distance 2.228(3) Å. To investigate the key insights into their photophysical properties, fluorescence emission spectral analysis of the synthesized compounds has been studied. Theoretical calculations like optimization of geometry, the energy of frontier orbitals, Hirshfeld surface analysis and simulation of electronic spectra were performed which supports the experimental results.