Cobalt(III)-containing penta-dentate "helmet"-type phthalogens: synthesis, solid-state structures and their thermal and electrochemical characterization

Treatment of unsubstituted and substituted phthalonitrile (1a-d) with appropriate equivalents of sodium methoxide and ammonia afforded the corresponding 1,3-diiminoisoindolines (2a-d), which were converted to cobalt(III)-containing penta-dentate "helmet"-type phthalogens (3a-d) by the reaction with CoCl2·6H2O as templating agent in the inert solvent 1,2,4-trichlorobenzene. The identities of 2a-d and 3a-d were established by elemental analysis, infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and electrospray ionization mass spectrometry (ESI-MS). A computational study was performed to determine the most stable tautomeric form of 2a-c in the gas phase. The solid-state structures of 2b and 2c were determined by single crystal X-ray diffraction (SC-XRD) studies to confirm their existence in the stereoisomeric anti-form, which is aligned with quantum chemical computations. SC-XRD studies of 3a and 3b revealed a slightly distorted octahedral geometry around the CoIII ions which are coordinated by five N-donor atoms and one extra co-ligand, resulting in a coordination environment of CoN5Cl (3a) and CoN5O (3b), respectively. The thermal stabilities of 2a-d and 3a-d were investigated by thermogravimetric analysis (TGA) in the temperature range of 40-500 °C and 40-800 °C, respectively, revealing that 3a-d were converted to the parent cobalt(II)-containing phthalocyanines (4a-d), which was verified independently by furnace heating experiments. Moreover, the electrochemical behavior of 3a was studied exemplarily for the phthalogens by cyclic voltammetry and square wave voltammetry. This study showed that 4a (CoPc) is formed irreversibly by reducing 3a electrochemically.

Chlorosubstituted Copper Phthalocyanines: Spectral Study and Structure of Thin Films

In this work, the tetra-, octa- and hexadecachloro-substituted copper phthalocyanines CuPcCl_x (where x can equal 4, 8 or 16) were investigated by the methods of vibrational (IR and Raman) spectroscopy and X-ray diffraction. The assignment of the most intense bands, both in IR and Raman spectra, was carried out on the basis of DFT calculations. The structure of a CuPcCl₄ single crystal grown by sublimation in vacuum was refined for the first time. The effect of chloro-substitution on the structure of CuPcCl_x thin films deposited in a vacuum onto a glass substrate at 50 and 200 °C was studied. It was shown that CuPcCl₄ formed polycrystalline films with the preferential orientation of the (100) crystallographic plane of crystallites parallel to the substrate surface when deposited on a substrate at 50 °C. Introduction of more Cl-substituents into the phthalocyanine macrocycle leads to the formation of amorphous films on the substrates at 50 °C. At the elevated substrate temperature, the growth of polycrystalline disordered films was observed for all three copper phthalocyanines.

Recent advances in chemistry of phthalocyanines bearing electron-withdrawing halogen, nitro and N-substituted imide functional groups and prospects for their practical application

Herein, we present an overview of the approaches for the synthesis of phthalocyanines bearing electron-withdrawing halogen-, nitro- and N-substituted imide functional groups in different positions of the phthalocyanine macrocycle.