Low power threshold photochemical upconversion using a zirconium(<scp>iv</scp>) LMCT photosensitizer

Yang, Mo; Sheykhi, Sara; Zhang, Yu; Milsmann, Carsten; Castellano, Felix N.

doi:10.1039/d1sc01662h

Cited by 68 publications

(77 citation statements)

References 80 publications

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“…46 where I ( t ) is the upconverted emission intensity, β is a dimensionless parameter between 0 and 1 expressing the initial decay fraction resulting from second-order channels, t is time, and τ t is the triplet excited state lifetime. The analytical solution to the term β is known, 24,46,47 and to calculate k TTA requires only the initial concentration of triplet annihilators to be known (eqn (4)). We used the intensity of the T 1 –T n transition of perylene ( ε T 1 _485 nm = 13 400 M −1 cm −1 ) to calculate [ 3 A *] 0 in the upconversion solution.…”

Section: Resultsmentioning

confidence: 99%

Modulating TTA efficiency through control of high energy triplet states

Carrod

Cravcenco

et al. 2022

J. Mater. Chem. C

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Section: Resultsmentioning

confidence: 99%

Modulating TTA efficiency through control of high energy triplet states

Carrod

Cravcenco

et al. 2022

J. Mater. Chem. C

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“…With this in mind, researchers have leveraged PDP metal complexes in catalysis, 50 atom and group transfer, 56 , 57 , 61 and photochemistry. 64 − 68 Despite this expanding wealth of research, PDP compounds of either lanthanide or actinide elements have not been reported. 74 …”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Pyridine Dipyrrolide Uranyl Complexes

et al. 2022

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The first actinide complexes of the pyridine dipyrrolide (PDP) ligand class, ( Mes PDP Ph )UO 2 (THF) and ( Cl2Ph PDP Ph )UO 2 (THF), are reported as the U VI uranyl adducts of the bulky aryl substituted pincers ( Mes PDP Ph ) 2– and ( Cl2Ph PDP Ph ) 2– (derived from 2,6-bis(5-(2,4,6-trimethylphenyl)-3-phenyl-1 H -pyrrol-2-yl)pyridine (H 2 Mes PDP Ph , Mes = 2,4,6-trimethylphenyl), and 2,6-bis(5-(2,6-dichlorophenyl)-3-phenyl-1 H -pyrrol-2-yl)pyridine (H 2 Cl2Ph PDP Ph , Cl 2 Ph = 2,6-dichlorophenyl), respectively). Following the in situ deprotonation of the proligand with lithium hexamethyldisilazide to generate the corresponding dilithium salts (e.g., Li 2 Ar PDP Ph , Ar = Mes of Cl 2 Ph), salt metathesis with [UO 2 Cl 2 (THF) 2 ] 2 afforded both compounds in moderate yields. The characterization of each species has been undertaken by a combination of solid- and solution-state methods, including combustion analysis, infrared, electronic absorption, and NMR spectroscopies. In both complexes, single-crystal X-ray diffraction has revealed a distorted octahedral geometry in the solid state, enforced by the bite angle of the rigid meridional ( Ar PDP Ph ) 2– pincer ligand. The electrochemical analysis of both compounds by cyclic voltammetry in tetrahydrofuran (THF) reveals rich redox profiles, including events assigned as U VI /U V redox couples. A time-dependent density functional theory study has been performed on ( Mes PDP Ph )UO 2 (THF) and provides insight into the nature of the transitions that comprise its electronic absorption spectrum.

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“…The power density threshold value I th , which indicates the turning point from a biphotonic to a linear (monophotonic) process reflecting UC saturation, amounts to about 1.56 W cm −2 (Figure 4b). This value, which is relatively high compared to I th values of sTTA‐UC systems reported for systems utilizing Zn II , Zr IV , and Cu I sensitizers, [6d, 11d, 35] is ascribed to the very small absorption of [Cr(bpmp) 2 ] 3+ above 520 nm ( ϵ ≈30–45 M −1 cm −1 ) [14e] . This leaves room for improvement of the sTTA‐UC by further red shifting the absorption band the of the Cr III sensitizer and/or increasing its molar absorption coefficient for green light excitation.…”

Section: Resultsmentioning

confidence: 82%

“…This can reduce their excited state lifetimes. Notable exceptions are Cu I 3 MLCT and Zr IV 3 LMCT sensitizers with 3d 10 and 4d 0 electron configurations that lack detrimental MC excited states, [6d, 11] as well as Cr 0 , Mn I , and Mo 0 triplet sensitizers with a d 6 electron configuration in a strong ligand field [1l, 12] …”

Section: Introductionmentioning

confidence: 99%

Efficient Triplet‐Triplet Annihilation Upconversion Sensitized by a Chromium(III) Complex via an Underexplored Energy Transfer Mechanism

et al. 2022

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Sensitized triplet‐triplet annihilation upconversion (sTTA‐UC) mainly relies on precious metal complexes thanks to their high intersystem crossing (ISC) efficiencies, excited state energies, and lifetimes, while complexes of abundant first‐row transition metals are only rarely utilized and with often moderate UC quantum yields. [Cr(bpmp)2]3+ (bpmp=2,6‐bis(2‐pyridylmethyl)pyridine) containing earth‐abundant chromium possesses an absorption band suitable for green light excitation, a doublet excited state energy matching the triplet energy of 9,10‐diphenyl anthracene (DPA), a close to millisecond excited state lifetime, and high photostability. Combined ISC and doublet‐triplet energy transfer from excited [Cr(bpmp)2]3+ to DPA gives 3DPA with close‐to‐unity quantum yield. TTA of 3DPA furnishes green‐to‐blue UC with a quantum yield of 12.0 % (close to the theoretical maximum). Sterically less‐hindered anthracenes undergo a [4+4] cycloaddition with [Cr(bpmp)2]3+ and green light.

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Low power threshold photochemical upconversion using a zirconium(iv) LMCT photosensitizer

Abstract: The current investigation demonstrates highly efficient photochemical upconversion (UC) where a long-lived Zr(IV) ligand-to-metal charge transfer (LMCT) complex serves as a triplet photosensitizer in concert with well-estabilished 9,10-diphenylanthracene (DPA) along...

Cited by 68 publications

References 80 publications

Modulating TTA efficiency through control of high energy triplet states

Modulating TTA efficiency through control of high energy triplet states

Synthesis and Characterization of Pyridine Dipyrrolide Uranyl Complexes

Efficient Triplet‐Triplet Annihilation Upconversion Sensitized by a Chromium(III) Complex via an Underexplored Energy Transfer Mechanism

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