Efficient Förster Resonance Energy Transfer in 1,2,3-Triazole Linked BODIPY-Zn(II) Meso-tetraphenylporphyrin Donor–Acceptor Arrays

Abstract

Cu(I) catalyzed azide-alkyne cycloaddition (CuAAC) reactivity was successfully employed to synthesize three donor-acceptor energy transfer (EnT) arrays that contain one (Dyad), three (Tetrad) and four (Pentad) 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) donors connected to a Zn-tetraphenylporphyrin acceptor via 1,2,3-triazole linkages. The photophysical properties of the three arrays, along with individual donor and acceptor chromophores, were investigated by UV-vis absorption and emission spectroscopy, fluorescence lifetimes, and density functional theory (DFT) electronic structure modeling. Comparison of the UV-vis absorption spectra and frontier molecular orbitals from DFT calculations of the three arrays with ZnTPP, ZnTTrzlP, and Trzl-BODIPY shows that the electronic structure of the chromophores is essentially unperturbed by the 1,2,3-triazole linkage. Time-dependent DFT (TDDFT) calculations on the Dyad reproduce the absorption spectra in THF and show no evidence of excited state mixing of the donor and acceptor. The BODIPY singlet excited state emission is significantly quenched in all three arrays, consistent with EnT to the porphyrin core, with efficiencies of 95.8, 97.5, and 97.2% for the Dyad, Tetrad, and Pentad, respectively. Fluorescence excitation spectra of the three arrays, measured at the porphyrin emission, mirror the absorption profile of both the porphyrin and BODIPY chromophores and are consistent with the Förster resonance energy transfer (FRET) mechanism. Applying Förster theory to the spectroscopic data of the chromophores gives EnT efficiency estimates that are in close agreement with experimental values, suggesting that the through-space mechanism plays a dominant role in the three arrays.

A Hetero‐Bifunctional Spacer for the Smart Engineering of Carbon‐Based Nanostructures

“…Pristine SWCNTs (90 % C) were purchased from NanoAmor and used without further purification. Phenylazido‐decorated SWCNTs ( 13 ),11 amino‐ ( 17 )32 and azidophenyl BODIPy ( 6 )33 compounds were prepared according to literature procedures. Unless otherwise stated, all other chemicals/solvents were purchased from commercial suppliers and used as received without further purification.…”

Supramolecular BODIPY Dye Architectures for Advanced Light Harvesting and Energy Transfer Applications

“…[120][121][122][123][124] The efficiency of the intramolecular energy transfer in antennae assemblies depends on the extent of electronic coupling between the chromophores which could be modulated either by the bridge or the special orientation of the units. 125,126 Triazole bridged BODIPY-Zn or BODIPY-Ni porphyrin conjugates containing one BODIPY and one porphyrin (dyad, 1.20 127 and 1.21 128 ), three BODIPYs and one porphyrin (tetrad, 1.22 128 ) and four BODIPYs and one porphyrin (pentad, 1.23 128 ) were studied. The absorption spectra shows increase of roughly three and four times in the BODIPY (donor) π−π* transition.…”

Azo-triazolide bis-cyclometalated Ir(iii) complexes via cyclization of 3-cyanodiarylformazanate ligands

“…The ease of synthesis of a wide range of 1,2,3-triazole-based compounds, as well as the ability to include a variety of functional groups into the triazole core [13][14][15][16][17] have led to a rich metal coordination chemistry for triazoles. [18][19][20][21] The nitrogen-rich heterocycle can coordinate to metals in a variety of ways, and chelating ligands can be accessed by appending another donor group as a substituent. Deprotonation or C-H activation at the 5position may allow access to anionic triazolides, 22,23 while alkylation at the N-3 position, followed by deprotonation of the relatively acidic C-H bond, leads to the formation of abnormal mesoionic carbenes.…”