Cerium bis(tetradiazepinoporphyrazinate): synthesis and peculiarities of spectral and electrochemical behavior. (4th June 2015)

• Record Type: Journal Article
• Authors: Tarakanova, Ekaterina N.; Levitskiy, Oleg A.; Magdesieva, Tatiana V.; Tarakanov, Pavel A.; Pushkarev, Victor E.; Tomilova, Larisa G.
• Is Part Of: New journal of chemistry. Volume 39:Number 7(2015:Jul.)
• Page Start: 5797
• Page End: 5804
• Publication Date: 2015-06-04
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c5nj00884k
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : A cerium sandwich double-decker complex of tetradiazepinoporphyrazine was synthesized for the first time, which exhibited specific spectral and electrochemical properties. Abstract : Bis{tetrakis(5, 7-bis(4- tert -butylphenyl)-6 H -1, 4-diazepino)[2, 3- b, g, l, q ]porphyrazinato} cerium has been prepared for the first time via two alternative synthetic pathways: template macrocyclization of 5, 7-bis(4- tert -butylphenyl)-6 H -1, 4-diazepine-2, 3-dicarbonitrile and direct complexation employing its cyclic tetramer, a free-base porphyrazine ligand. A combination of HRMS, UV-Vis, FT-IR and NMR spectroscopic methods allowed the identification of the tetravalent oxidation state of cerium ion in the double-decker obtained. Unlike Pc2 Ce IV (Pc 2− = phthalocyaninate anion), the compound revealed a complicated UV-Vis spectrum that demonstrated a strong solvent dependence. A comparative electrochemical study of the cerium complex and the corresponding free-base ligand was carried out. Ligand-centered processes are diffusion controlled, whereas Ce 4+/3+ transformation is characterized by slow electron transfer kinetics. This is as a result of poor accessibility of the metal center to an electrode surface due to the presence of bulky ligands, as well as a considerable structural rearrangement of the sandwich molecule.