OUT-OF-PLANE COORDINATED ZIRCONIUM(IV) AND HAFNIUM(IV) PHTHALOCYANINATES

Abstract

The article is devoted to methods of synthesis, the structure, and spectral characteristics of zirconium and hafnium phthalocyaninates with out-of-plane coordinated ligands. The gene­ral scheme for the synthesis of out-of-plane coordinated Zr and Hf phthalocyanines includes obtaining initial dichloride or dihydroxo complexes, which then undergo substitution reactions with -dicarbonyl compounds, hydroxybenzoic, sulfo- and aliphatic carboxylic acids, etc. In the case of polyphenols, which are bidentate ligands, one ligand is coordinated to the central atom of the macrocycle. If -dicarbonyl compounds or carboxylic acids are introduced into the reaction, two ligands are coordinated. The reactivity of the out-of-plane coordinated ligands of Zr and Hf phthalocyanines was also investigated. In all obtained out-of-plane coordinated Zr and Hf phthalocyanines, the ligands are located in the cis position relative to the plane of the phthalocyanine macrocycle. X-ray diffraction, NMR, and UV-Vis spectroscopy have proved this arrangement of ligands. According to the X-ray diffraction data of Zr and Hf dibenzoylmethanato phthalocyanines, the metal atom is out of the plane of the phthalocyanine macrocycle, which itself is not planar. The central atoms are located almost in the middle between the N4 planes of the phthalocyanine macrocycle and the O4 of the extraplanar li­gands. The UV-Vis spectra of out-of-plane coordinated Zr and Hf phthalocyanines in organic solvents have a typical appearance for most metal phthalocyanines, characterized by a B-band of absorption in the region of 335–350 nm, a Q-band at 680-690 nm, and its satellite in the region of 615–620 nm. If the extraplanar ligand is a chromophore (e.g., curcumin or condensed derivatives of dehydroacetic acid), there are additional absorption bands in  UV-Vis spectra located between the B- and Q-bands. The influence of the nature of the central metal atoms, ligands and solvents on the fluorescent properties of the out-of-plane coordinated Zr and Hf phthalocyanines was also discussed.