Molecular structure and spectroscopic properties of [2,3,9,10,16,17,23,24-octakis(3-carboxyphenoxy)phthalocyaninato-κ⁴N](pyridine-κN)zinc(ii) pyridine octasolvate

The title complex, [2,3,9,10,16,17,23,24-octakis(3-carboxyphenoxy)-phthalocyaninato-k ⁴N](pyridine-kN)zinc(II)pyridine octasolvate abbreviated as [ZnPc(3-CO₂H)₈(Py)]'8(Py) (2), has been obtained by recrystallization of [ZnPc(3-CO₂H)₈] (1) from pyridine. Molecular structure of 2 determined by X-ray crystallography exhibits the anticipated N₅ square pyramidal coordination around zinc(II) ion, where the average Zn-N(Pc) and Zn-N(Py) bond lengths are 2.027(4) Å and 2.121(4) Å, respectively. The deviation of the zinc(II) ion from phthalocyanine N₄ plane is 0.417 Å. Eight pyridine molecules are involved in hydrogen bonding with the carboxylic acid moieties of phenoxy rings in a 1:1 Two discrete phthalocyanine molecules in a unit cell are stacked in a back-to-back fashion with an interplanar distance of 3.376 Å. Pyridine solutions of 1 exhibit well-resolved ¹H NMR, UV-Vis, and fluorescent spectra, suggesting that 1 exists pyridine ligated monomeric species.