Significant emission red-shift of BODIPY derivatives with strong electron-acceptor attached

Li, Xiaochuan; Sun, Saisai; Kim, Ick Jin; Son, Young-Α

doi:10.1080/15421406.2017.1358018

Cited by 6 publications

(1 citation statement)

References 32 publications

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“…When the room temperature emission spectra were normalized at their maxima, a redshift was also observed from ∼538 nm of the free BODIPY to ∼552 nm of the complex with a 500 nm excitation. The redshift is due to the coordination of the BODIPY to the metal center further lowering the energy of the π → π* BODIPY transition due to the rhodium center pulling electron density away from the ligand. − For the intermediate compound, [Rh(bpy-2BODIPY)(DMF)Cl 3 ], the fluorescence was completely quenched when excited at 500 nm where a large decrease in fluorescence intensity was observed (Figure ). At the emission maximum of the [Rh(bpy-2BODIPY)(DMF)Cl 3 ] complex (λ em = 535 nm), the emission intensity was at ∼2700 a.u., while the emission intensity of the [Rh(bpy-2BODIPY)(phen)Cl 2 ][PF 6 ] (λ em = 552 nm) was ∼40,000 a.u.…”

Section: Resultsmentioning

confidence: 99%

Visible Light-Assisted Coordination of a Rh(III)-BODIPY Complex to Guanine

et al. 2023

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Most photodynamic therapeutics (PDTs) used in cancer treatment require oxygen to work efficiently to terminate cancer cells. These PDTs do not efficiently treat tumors in hypoxic conditions. Rh(III) polypyridyl complexes have been reported to have a photodynamic therapeutic effect in hypoxic conditions when exposed to UV light. UV light can damage tissue and cannot penetrate deep to reach cancer cells. This work proposes the coordination of a BODIPY fluorophore to a rhodium metal center to form a Rh(III)-BODIPY complex that enhances the reactivity of the rhodium under visible light. This complex formation is facilitated with the BODIPY as the highest occupied molecular orbital (HOMO), while the lowest unoccupied molecular orbital (LUMO) is localized on the Rh(III) metal center. Irradiation of the BODIPY transition at ∼524 nm can cause an indirect electron transfer from the orbital of the BODIPY-centered HOMO to the Rh(III)-centered LUMO, populating the dσ* orbital. In addition, photo binding of the Rh complex covalently coordinated to the N (7) position of guanine in an aqueous solution was also observed by mass spectrometry after chloride dissociation upon irradiation with green visible light (532 nm LED). Calculated thermochemistry values of the Rh complex reaction in methanol, acetonitrile, water, and guanine were determined using DFT calculations. All enthalpic reactions and Gibbs free energies were identified as endothermic and nonspontaneous, respectively. This observation supports the chloride dissociation using 532 nm light. This Rh(III)-BODIPY complex expands the class of visible lightactivated Rh(III) photocisplatin analogs that may have potential photodynamic therapeutic activity for the treatment of cancers in hypoxic conditions.

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Section: Resultsmentioning

confidence: 99%