Bis(porphyrin)–Anthraquinone Triads: Synthesis, Spectroscopy, and Photochemistry

Abstract

Molecular triads based on bis(porphyrin)-anthraquinone having azomethine bridge at the pyrrole-β position have been designed and synthesized. Both free-base AQ-(H2)2 and zinc AQ-(Zn)2 triads are characterized by elemental analysis, MALDI-MS, (1)H NMR, UV-visible, and fluorescence spectroscopy (steady-state and time-resolved) as well as electrochemical method. The absorption spectra of both Soret and Q-bands of the triads are red-shifted by 12-20 nm with respect to their monomer units. The study supported by theoretical calculations manifests that there exists a negligible electronic communication in the ground state between the donor porphyrin and acceptor anthraquinone of these triads. However, interestingly, both the triads exhibit significant fluorescence emission quenching (51-92%) of the porphyrin emission compared to their monomeric units. The emission quenching is attributed to the excited-state intramolecular photoinduced electron transfer from porphyrins to anthraquinone. The electron-transfer rates (kET) of these triads are found in the range 1.0 × 10(8) to 7.7 × 10(9) s(-1) and are found to be solvent dependent.

Triphenylamine-functionalized corrole sensitizers for solar-cell applications

“…The characterization of the investigated samples has been carried out as described elsewhere, in our previous works . Cyclic and differential pulse voltammetry techniques in dichloromethane solution have been employed for the determination of oxidation and reduction potential.…”

Ultrafast Photoinduced Charge Separation Leading to High‐Energy Radical Ion‐Pairs in Directly Linked Corrole–C60 and Triphenylamine–Corrole‐C60 Donor–Acceptor Conjugates

“…Owing to its resemblance to the natural photosynthetic chlorophyll pigment and relatively easy synthetic manipulations, porphyrin as the primary photoactive molecule has dominated this area of research . Its functions include panchromatic light harvesting through most of the visible part of the solar spectrum and electron transport.…”

β-Formyl- and β-Vinylporphyrins: Magic Building Blocks for Novel Porphyrin Derivatives

“…Giribabu and co-workers used the condensation between 1,2-diaminoanthraquinone and β-CHOTPP or its Zn(II) complex to prepare molecular bis(porphyrin)-anthraquinone triads having azomethine bridges [ 146 ]. The same approach was used to couple the cutaneous leishmaniasis agents aminotriazole 91a , isoniazid (pyridine-4-carbohydrazide, 91b ) and the aminothiadiazoles 91c and 91d with the β-formylporphyrins 3 and 3a (Ar = Ph and m -MeOC 6 H 4 ) as a strategy to obtain molecules with dual function potentialities ( Scheme 22 and Scheme 23 ) [ 147 ].…”