Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Mar 2;59(5):3193-3199.
doi: 10.1021/acs.inorgchem.9b03561. Epub 2020 Feb 13.

Luminescent Carbazole-Based EuIII and YbIII Complexes with a High Two-Photon Absorption Cross-Section Enable Viscosity Sensing in the Visible and Near IR with One- and Two-Photon Excitation

Jorge H S K Monteiro, Natalie R Fetto  1 , Matthew J Tucker  1 , Ana de Bettencourt-Dias  1
Affiliations

Luminescent Carbazole-Based EuIII and YbIII Complexes with a High Two-Photon Absorption Cross-Section Enable Viscosity Sensing in the Visible and Near IR with One- and Two-Photon Excitation

Jorge H S K Monteiro et al. Inorg Chem. .

Abstract

The newly synthesized EuIII and YbIII complexes with the new carbazole-based ligands CPAD2- and CPAP4- display the characteristic long-lived metal-centered emission upon one- and two-photon excitation. The EuIII complexes show the expected narrow emission bands in the red region, with emission lifetimes between 0.382 and 1.464 ms and quantum yields between 2.7% and 35.8%, while the YbIII complexes show the expected emission in the NIR region, with emission lifetimes between 0.52 and 37.86 μs and quantum yields between 0.028% and 1.12%. Two-photon absorption cross sections (σ2PA) as high as 857 GM were measured for the two ligands. The complexes showed a strong dependence of the one- and two-photon sensitized emission intensity on solvent viscosity in the range of 0.5-200 cP in the visible and NIR region.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
A) Energy level diagram illustrating the antenna effect for LnIII. 2PA and 1PA are the two- and one-photon absorption, F fluorescence, P phosphorescence, ISC intersystem crossing, ET energy transfer, BT back-transfer, L luminescence, NR non-radiative pathways, S states with singlet and T states with triplet multiplicity. B) Molecules studied in this work.
Figure 2.
Figure 2.
A) 1PA excitation (black lines, left) and emission spectra (red lines, right) of EuIII complexes (λexc = 380 nm). B) 2PA emission spectra of EuIII complexes. C) Plot of the log of the emission intensity I at 615 nm upon 2PA excitation as a function of the log of the laser power P. From top to bottom in each figure (a) K3[Eu(CPAD)3] in DMSO, (b) K[Eu(CPAP)(DMSO)2] in DMSO, and (c) K[Eu(CPAP)(H2O)2] in TRIS/HCl buffered aqueous system (pH ~7.4, 10% DMSO); λexc = 720 nm; [complex] = 1x10−4 M.
Figure 2.
Figure 2.
A) 1PA excitation (black lines, left) and emission spectra (red lines, right) of EuIII complexes (λexc = 380 nm). B) 2PA emission spectra of EuIII complexes. C) Plot of the log of the emission intensity I at 615 nm upon 2PA excitation as a function of the log of the laser power P. From top to bottom in each figure (a) K3[Eu(CPAD)3] in DMSO, (b) K[Eu(CPAP)(DMSO)2] in DMSO, and (c) K[Eu(CPAP)(H2O)2] in TRIS/HCl buffered aqueous system (pH ~7.4, 10% DMSO); λexc = 720 nm; [complex] = 1x10−4 M.
Figure 3.
Figure 3.
Excitation (black lines, left) and emission spectra (pink lines, right) of YbIII complexes. a) K3[Yb(CPAD)3] in DMSO (λexc = 370 nm), b) K[Yb(CPAP)(DMSO)2] in DMSO (λexc = 350 nm), and c) K[Yb(CPAP)(H2O)2] in TRIS/HCl buffered aqueous system (pH ~7.4, 10% DMSO) (λexc = 350 nm) in TRIS/HCl buffered aqueous system (pH ~7.4, 4% DMSO);. [complex] = 1x10−4 M.
Figure 4.
Figure 4.
A) Emission spectra of K3[Eu(CPAD)3] (λexc = 400 nm) upon one-photon excitation with varying viscosities. B) Emission spectra of K3[Eu(CPAD)3] (λexc = 720 nm) upon two-photon excitation with varying viscosities. The insets show the plot of the emission intensity at 615.5 nm upon one-photon or two-photon excitation as a function of viscosity. [complex] = 1x10−4 M.
Figure 5.
Figure 5.
Emission spectra of K3[Yb(CPAD)3] (λexc = 400 nm) upon one-photon excitation with varying viscosities. The inset shows the plot of the emission intensity ratios at 976 and 1020 nm upon one-photon excitation as a function of viscosity. MeOH:glycerol with various ratios were used as solvents with variable viscosity. [complex] = 1x10−4 M.
See this image and copyright information in PMC

References

    1. Bünzli J-CG, Lanthanide luminescence for biomedical analyses and imaging. Chem. Rev 2010, 110 (5), 2729–55. - PubMed
    1. Zhao J; Gao J; Xue W; Di Z; Xing H; Lu Y; Li L, Upconversion Luminescence-Activated DNA Nanodevice for ATP Sensing in Living Cells. J. Am. Chem. Soc 2018, 140 (2), 578–581. - PubMed
    1. Hai J; Li T; Su J; Liu W; Ju Y; Wang B; Hou Y, Anions Reversibly Responsive Luminescent Tb(III) Nanocellulose Complex Hydrogels for Latent Fingerprint Detection and Encryption. Angew. Chem. Int. Ed 2018, 57 (23), 6786–6790. - PubMed
    1. Mathieu E; Sipos A; Demeyre E; Phipps D; Sakaveli D; Borbas KE, Lanthanide-based tools for the investigation of cellular environments. Chem. Commun 2018, 54, 10021–10035. - PubMed
    1. Kaczmarek MT; Zabiszak M; Nowak M; Jastrzab R, Lanthanides: Schiff base complexes, applications in cancer diagnosis, therapy, and antibacterial activity. Coord. Chem. Rev 2018, 370, 42–54.