Synthesis, characterization, structural analysis and electrocatalytic performance of zinc(II) porphyrinates

• Published in: Journal of molecular structure 2023-05, Vol.1279, p.134973, Article 134973
• Main Authors: Soury, Raoudha, Oudi, Mabrouka El, Haque, Ashanul, Chaabene, Marwa, El-Moll, Hani, Alenezi, Khalaf M., Jabli, Mahjoub, Teka, Safa, Ghalla, Houcine, Philouze, Christian, Bchetnia, Amor
• Format: Article
• Language: English
• Subjects: Computational study; Hydrogen evolution reaction; Photophysical studies; X-ray diffraction; Zinc(ii) porphyrin
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2023.134973

•Penta-coordinated zinc(II) complex (4-cyanopyridine) (meso-tetrakis (ethyl-4 (4-butyryl) oxyphenyl) porphyrinato) zinc (II) [Zn (TEBOP)(4-CNpy)] (III) was prepared.•1HNMR, UV–visible, X-Ray, and fluorescence were measured.•HER study revealed higher activity of complex (III) than complex (II).•TD-DFT calculations were carried out. The design of new molecular electrocatalysts for Hydrogen Evolution Reaction (HER) is an active area of research. In the present work, we report the synthesis and structural characterization of tetra-coordinated [5,10,15,20-(tetraethyl-4(4-butyryl) oxyphenylporphyrinato)] zinc(II) [Zn(TEBOP)] (II) and penta-coordinated (4-cyanopyridine)(meso‑tetrakis (ethyl-4 (4-butyryl) oxyphenyl) porphyrinato) zinc(II) [Zn (TEBOP)(4-CNpy)] (III) complexes. All compounds, including the parent ligand 5,10,15,20-(tetraethyl-4(4-butyryl)oxyphenylporphyrin (H2TEBOP) (I), were fully characterized using multiple analytical, spectroscopic and electrochemical techniques. Single-crystal X-ray diffraction study revealed stabilization of the structure via multiple non-covalent C–H …Cg π inter-molecular interactions. Optical absorption and emission spectroscopy results indicated a noticeable effect of the axial ligands on the photophysical properties. HER study revealed higher activity of complex (III) than complex (II), possibly due to the presence of an axial ligand (4-cyanopyridine, 4-CNpy) in the former. Both experimental and computational modelling results suggested a ligand-centred HER process. [Display omitted]