Abstract
| - The synthesis, spectroscopic properties, and electrochemistry of six different alkyl- and aryl-substituted Co(III)corroles are presented. The investigated compounds contain methyl, ethyl, phenyl, or substituted phenyl groupsat the eight β-positions of the corrole macrocycle and four derivatives also contain a phenyl group at the 10-mesoposition of the macrocycle. Each cobalt corrole undergoes four reversible oxidations in CH2Cl2 containing 0.1 Mtetra-n-butylammonium perchlorate and exists as a dimer in its singly and doubly oxidized forms. The differencein potential between the first two oxidations is associated with the degree of interaction between the two corroleunits of the dimer and ranges from an upper value of 0.62 V, in the case of (Me6Et2Cor)Co, to a lower value ofabout 0.17 V, in the case of four compounds which have a phenyl group located at the 10-meso position of themacrocycle. These Co(III) corroles strongly coordinate two pyridine molecules or one carbon monoxide moleculein CH2Cl2 media, and ligand binding constants were evaluated using spectroscopic and electrochemical methods.The structure of (Me4Ph5Cor)Co(py)2 was also determined by X-ray diffraction. Crystal data: (Me4Ph5Cor)Co(py)2·3CH2Cl2·H2O, orthorhombic, a = 19.5690(4) Å, b = 17.1070(6) Å, c = 15.9160(6) Å, V = 5328.2(5) Å3,space group Pna21, Z = 2, 35 460 observations, R(F) = 0.069.
- Novel aryl substituted free base corroles and their respective cobalt(III) complexes have been prepared and characterized by UV−vis, 1H NMR, elemental analyses, mass spectrometry, and electrochemistry. The molecular structure of the bis-pyridine adduct of 15, (Me4Ph5Cor)Co(py)2, has been established by X-ray diffraction. The cobalt(III) metal atom is six-coordinated with two pyridine molecules as fifth and sixth ligands.
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