Premium
Electrochemistry of Nitrated N‐Confused Free‐Base Tetraaryl‐Porphyrins in Nonaqueous Media
Author(s) -
Ye Lina,
Ou Zhongping,
Fang Yuanyuan,
Xue Songlin,
Chen Xueyan,
Lu Guifen,
Jiang Xiaoqin,
Kadish Karl M.
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201501720
Subject(s) - porphyrin , chemistry , substituent , free base , pyrrole , electrochemistry , nitro , redox , homo/lumo , photochemistry , medicinal chemistry , ultraviolet visible spectroscopy , inorganic chemistry , organic chemistry , molecule , electrode , salt (chemistry) , alkyl
Four nitrated N‐confused free‐base tetraarylporphyrins were synthesized and characterized by electrochemistry and spectroelectrochemistry in nonaqueous media. The examined compounds are represented as NO 2 (Ar) 4 NcpH 2 , where NO 2 (Ar) 4 Ncp is the dianion of a tetraaryl N‐confused porphyrin with an inner carbon bound NO 2 group and Ar is a p ‐CH 3 OPh, p ‐CH 3 Ph, Ph or p ‐ClPh substituent on each meso ‐position of the macrocycle. UV/Vis spectra and NMR spectroscopy data indicate that the same form of the porphyrin exists in CH 2 Cl 2 and DMF which is unlike the case of non‐NO 2 N‐confused porphyrins. The Soret band of NO 2 (Ar) 4 NcpH 2 exhibits a 30–36 nm red‐shift in CH 2 Cl 2 and DMF as compared to the spectrum of the non‐NO 2 N‐confused porphyrins. The first two reductions and first oxidation of NO 2 (Ar) 4 NcpH 2 are reversible in CH 2 Cl 2 containing 0.1 M TBAP. The measured HOMO–LUMO gap averages 1.65 V in CH 2 Cl 2 and 1.53 V in DMF, with both values being similar to those of the non‐NO 2 substituted compounds. The nitro group on the inverted pyrrole is itself not reduced within the negative potential limit of CH 2 Cl 2 or DMF, but its presence significantly affects both the UV/Vis spectra and redox potentials.