Electrochemistry of Nitrated N‐Confused Free‐Base Tetraaryl‐Porphyrins in Nonaqueous Media. Issue 41 (26th August 2015)

• Record Type: Journal Article
• Authors: Ye, Lina; Ou, Zhongping; Fang, Yuanyuan; Xue, Songlin; Chen, Xueyan; Lu, Guifen; Jiang, Xiaoqin; Kadish, Karl M.
• Is Part Of: Chemistry. Volume 21:Issue 41(2015)
• Page Start: 14579
• Page End: 14588
• Publication Date: 2015-08-26
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201501720
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>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<sub>2</sub>(Ar)<sub>4</sub>NcpH<sub>2</sub>, where NO<sub>2</sub>(Ar)<sub>4</sub>Ncp is the dianion of a tetraaryl N‐confused porphyrin with an inner carbon bound NO<sub>2</sub> group and Ar is a <italic>p</italic>‐CH<sub>3</sub>OPh, <italic>p</italic>‐CH<sub>3</sub>Ph, Ph or <italic>p</italic>‐ClPh substituent on each <italic>meso</italic>‐position of the macrocycle. UV/Vis spectra and NMR spectroscopy data indicate that the same form of the porphyrin exists in CH<sub>2</sub>Cl<sub>2</sub> and DMF which is unlike the case of non‐NO<sub>2</sub> N‐confused porphyrins. The Soret band of NO<sub>2</sub>(Ar)<sub>4</sub>NcpH<sub>2</sub> exhibits a 30–36 nm red‐shift in CH<sub>2</sub>Cl<sub>2</sub> and DMF as compared to the spectrum of the non‐NO<sub>2</sub> N‐confused porphyrins. The first two reductions and first oxidation of NO<sub>2</sub>(Ar)<sub>4</sub>NcpH<sub>2</sub> are reversible in CH<sub>2</sub>Cl<sub>2</sub> containing 0.1 <sc>M</sc> TBAP. The measured HOMO–LUMO gap averages 1.65 V in CH<sub>2</sub>Cl<sub>2</sub> and 1.53 V in DMF, with both values being similar to those of the non‐NO<sub>2</sub> substituted compounds. The nitro group on the inverted pyrrole is itself not reduced within the negative potential limit of CH<sub>2</sub>Cl<sub>2</sub> or DMF, but its presence significantly affects both the UV/Vis spectra and redox potentials.</p> </abstract>