Four awl-substituted tripyrrinone copper（II） complexes were synthesized and characterized as to their electro- chemical and spectroelectrochemical properties. The examined compounds are represented as （YPh）3TPO2Cu, where TPO2 is a dianion of the tripyrrinone and Y is a CH3O, CH3, H or CI substituent on the para-position of each phenyl ring of the compound. The neutral compounds are ESR active and show a typical d9 Cu（II） signal in frozen CH2C12 solution. Each Cu（II） compound undergoes three reductions between -0.61 and -1.90 V and two oxidations between 1.00 and 1.24 V in CH2Cl2 containing 0.1 mol/L tetra-n-butylammonium perchlorate. The potentials for oxidation are similar to those of copper tetraarylporphyrins but the reduction potentials are positively shifted as compared to the corresponding tetraarylporphyrins. Thus, the potential difference between the first one-electron oxidation and first one-electron reduction （the HOMO-LUMO gap） of （YPh）3TPO2Cu, which ranges from 1.68 to 1.75 V, is similar to that of copper corroles （1.73-1.85 V）, but smaller than the separation of 2.30-2.37 V for the copper tetraarylporphyrins under the same solution conditions.
Wenda WangZhongping OuLina YeYuanyuan FangSonglin XueYang SongKarl M. Kadish
Three new cobalt triarylcorroles with sterically hindered haloginated phenyl rings were synthesized and characterized by UV-vis, ^1H NMR spectroscopy, mass spectrometry and electrochemistry. The compounds are represented as （Ar）3CorCo（PPh3）, where Cor is a trianion of the corrole macrocycle and Ar is a 2-ClPh （1）, 2,6-diClPh （2） or 2,6-diFPh （3） group on each of the three meso-positions. The structures of 1 and 3 were characterized in the solid state by single-crystal X-ray analysis. Rotating-disk electrode was utilized to examine the electrocatalytic activity of the corroles for reduction of O2 in 1.0 M HClO4. Effect of the sterically hindered meso-substituents on UV-vis spectra and redox potentials as well as the electrocatalytic activity for reduction of dioxygen was discussed.
