Insights into the new cadmium(II) metalloporphyrin Synthesis, X-ray crystal structure, Hirshfeld surface analysis, photophysical and cyclic voltammetry characterization of the (morpholine){(meso-tetra(para-chloro-phenyl)porphyrinato}cadmium(II)

C. Mchiri (1) , S. Dhifaoui (1) , K. Ezzayani (1) , M. Guergueb (1) , Thierry Roisnel (2) , F. Loiseau (3) , H. Nasri (1)

1 FSM - Faculté des Sciences de Monastir
2 ISCR - Institut des Sciences Chimiques de Rennes
3 DCM - CIRE - Département de Chimie Moléculaire - Chimie Inorganique Redox

Absract In this work we report the synthesis of the cadmium(II)-meso-tetra(para-chloro-phenyl)porphyrin with the morpholine O-donor axial ligand with formula [Cd(TClPP)(morph)] (I). This coordination compound adopts a distorted five-coordinate square pyramidal geometry indicated by a major doming, a moderate ruffling and saddle distortions of the porphyrinato core. The supramolecular architecture is dominated by intermolecular N−H···Cl and C−H···Cl interactions formed between the morpholine and the chlorine atom of the adjacent meso-phenylporphyrin of complex (I). Hirshfeld surface analysis was carried out to understand the nature of intermolecular contacts, where the fingerprint plot provides the information about the percentage contribution. UV-visible spectroscopy study highlighted the red-shift of the absorption bands after the insertion of Cd(II) metal ion into TClPP moiety and after coordination of the morpholine axial ligand. Fluorescence emission spectroscopy study showed a remarkable blue-shift effect of the Q bands followed by a dramatical diminution of the fluorescence intensity, quantum yield (φ f) and lifetime (τ f) as consequence of the high quenching effect of the cadmium heavy metal and the distortion of the porphyrin core, which promotes the loss of the "motion energy" by other non-radiative energy dissipation processes than light emission. An increase of the singlet oxygen quantum yield ( ) is also observed due to the heavy atom effect of cadmium(II) cation. The cyclic voltammetry investigation of the free base H 2 TClPP, the starting material [Cd(TClPP)] and the Cd(II)-morpholine porphyrin species (I) is also reported.

Keywords: X-ray crystal structure; Cadmium(II) porphyrin coordination compound; Hirshfeld surfaces; Fluorescence; Singlet Oxygen

Domains: Chemical Sciences

C. Mchiri, S. Dhifaoui, K. Ezzayani, M. Guergueb, Thierry Roisnel, et al.. Insights into the new cadmium(II) metalloporphyrin Synthesis, X-ray crystal structure, Hirshfeld surface analysis, photophysical and cyclic voltammetry characterization of the (morpholine){(meso-tetra(para-chloro-phenyl)porphyrinato}cadmium(II). Polyhedron, 2019, 171, pp.10-19. ⟨10.1016/j.poly.2019.06.055⟩. ⟨hal-02281772⟩