Synthesis, photophysical, electrochemical and electrochemiluminescence properties of A2B2 zinc porphyrins: the effect of π-extended conjugation. Issue 22 (19th May 2016)

• Record Type: Journal Article
• Authors: Galván-Miranda, Elizabeth K.; Castro-Cruz, Hiram M.; Arturo Arias-Orea, J.; Iurlo, Matteo; Valenti, Giovanni; Marcaccio, Massimo; Macías-Ruvalcaba, Norma A.
• Is Part Of: Physical chemistry chemical physics. Volume 18:Issue 22(2016)
• Page Start: 15025
• Page End: 15038
• Publication Date: 2016-05-19
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c6cp01926a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Electrogenerated chemiluminescence of A2 B2 porphyrins: the effect of extended conjugation. Abstract : The synthesis of two A2 B2 porphyrins, {5, 15-bis-[4-(octyloxy)phenyl]-porphyrinato}zinc(ii ) (4 ) and {5, 15-bis-(carbazol-3-yl-ethynyl)-10, 20-bis-[4-(octyloxy)phenyl]-porphinato}-zinc(ii ) (9 ), is reported. Their photophysical properties were studied by steady-state absorption and emission. Substituting the carbazolylethynyl moieties at two of the meso positions results in a large bathochromic shift of all the absorption bands, a notable increase in the absorption coefficient of the Q(0, 0) band, and higher fluorescence quantum yield compared to porphyrin4, with two unsubstituted meso positions. Cyclic voltammetry and digital simulation show that electrogenerated radical ions of9 are more stable than those of4 . The lack of substituents at the meso positions of4 leads to dimerization reactions of the radical cation. Despite this, the annihilation reaction of4 and9 produces very similar electrogenerated chemiluminescence (ECL) intensity. Spectroelectrochemical experiments demonstrate that the electroreduction of9 leads to a strong absorption band that might quench the ECL.