Porphyrin-Coumarin Dyads: Investigation of Photophysical Properties and DNA Interactions
Abstract
Two new nonconjugated porphyrin-coumarin dyads with different orientations with respect to donor-acceptor entities and their zinc complexes were synthesized. Single-crystal structures of the free-base porphyrin-coumarin dyads were successfully resolved. The absorption spectra of the dyads were linear combinations of the spectra of their corresponding monomers, indicating a negligible electronic communication between the coumarin and porphyrin moieties. However, the fluorescence emission of the coumarin entity in all of the dyads was quenched significantly compared to that of pristine coumarin, and this effect was attributed to intramolecular energy transfer from the coumarin to the porphyrin. The energy transfer kinetics from the coumarin to the porphyrin was shown to be fast ( kFörster = 1.13 × 1013 s-1 for the ortho-isomer and 5.13 × 1011 s-1 for the para-isomer in DMF) and efficient (transfer efficiency ca. 96-97%). Transient absorption studies showed that the excited state decay process (S2 → S1*, S1* → S1, S1 → S0, and S1 → T1) of the para-isomer was faster than that of the ortho-isomer in DMF. All of the synthesized dyads were tested for their interactions with ct-DNA and photocleavage activity toward PBR322-DNA. The results revealed that all of the dyads interacted with ct-DNA via only an external groove-binding mode; the binding constants were calculated to be 3.24 × 105 (3a), 3.05 × 105 (3b), 3.04 × 105 (4a), and 4.88 × 105 (4b), and the photocleavage activity was…
How strong is the evidence?
Evidence Hub reads this as a experimental / empirical study, done in cell cultures (in vitro), not in people. Its evidence level is 5 of 5 (Very low · case / narrative / animal / in vitro / in silico). Case reports, narrative reviews, and animal, cell or computer-model studies give the weakest evidence for human health.
Read the paper
Related studies
- Chaos and quantum thermalization
- The Dalton quantum chemistry program system
- Quantum dots: synthesis, bioapplications, and toxicity
- Cord Blood Leptin and Adiponectin as Predictors of Adiposity in Children at 3 Years of Age: A Prospective Cohort Study
- A Guide to In Silico Drug Design
- Quantitative metabolomics by H-NMR and LC-MS/MS confirms altered metabolic pathways in diabetes
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.