Electrochemically Induced Release of a Luminescent Probe from a Rhenium‐Containing Metallopolymer

Valenti, G.; O’Reilly, Emmet J.; McNally, Andrea; Keyes, Tia E.; Marcaccio, Massimo; Paolucci, Francesco; Forster, Robert J.

doi:10.1002/cplu.201200193

Cited by 4 publications

(1 citation statement)

References 49 publications

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“…The photoluminescence quantum yield ϕ in THF was determined relative to [Re(CO) 3 (bpy)(py)]PF 6 (py = pyridine) in DCE according to eq from ref , with the known quantum yield ϕ of the reference standard [Re(CO) 3 (bpy)(Etpy)]PF 6 (Etpy = 4-ethylpyridine) in DCE of 13.5%, the integrated emission intensity I , the absorbance at excitation wavelength A , and the refractive indices for THF ( n = 1.405) and DCE ( n = 1.4422) ϕ = ϕ std true( I I normalstd A normalstd A true) true( n n normalstd true) 2 …”

Section: Experimental Section/methodsmentioning

confidence: 99%

Bifurcation of Excited-State Population Leads to Anti-Kasha Luminescence in a Disulfide-Decorated Organometallic Rhenium Photosensitizer

Franz,

Oelschlegel,

Zobel

et al. 2024

J. Am. Chem. Soc.

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We report a rhenium diimine photosensitizer equipped with a peripheral disulfide unit on one of the bipyridine ligands, [Re(CO) 3 (bpy)( S−S bpy 4,4 )] + (1 + , bpy = 2,2′-bipyridine, S−S bpy 4,4 = [1,2]dithiino[3,4-c:6,5-c′]dipyridine), showing anti-Kasha luminescence. Steady-state and ultrafast time-resolved spectroscopies complemented by nonadiabatic dynamics simulations are used to disclose its excited-state dynamics. The calculations show that after intersystem crossing the complex evolves to two different triplet minima: a ( S−S bpy 4,4 )-ligandcentered excited state ( 3 LC) lying at lower energy and a metal-to-(bpy)-ligand charge transfer ( 3 MLCT) state at higher energy, with relative yields of 90% and 10%, respectively. The 3 LC state involves local excitation of the disulfide group into the antibonding σ* orbital, leading to significant elongation of the S−S bond. Intriguingly, it is the higher-lying 3 MLCT state, which is assigned to display luminescence with a lifetime of 270 ns: a signature of anti-Kasha behavior. This assignment is consistent with an energy barrier ≥ 0.6 eV or negligible electronic coupling, preventing reaction toward the 3 LC state after the population is trapped in the 3 MLCT state. This study represents a striking example on how elusive excited-state dynamics of transition-metal photosensitizers can be deciphered by synergistic experiments and state-of-the-art calculations. Disulfide functionalization lays the foundation of a new design strategy toward harnessing excess energy in a system for possible bimolecular electron or energy transfer reactivity.

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Section: Experimental Section/methodsmentioning

confidence: 99%

Bifurcation of Excited-State Population Leads to Anti-Kasha Luminescence in a Disulfide-Decorated Organometallic Rhenium Photosensitizer

Franz,

Oelschlegel,

Zobel

et al. 2024

J. Am. Chem. Soc.

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Molecular Size and Electronic Structure Combined Effects on the Electrogenerated Chemiluminescence of Sulfurated Pyrene‐Cored Dendrimers

Valenti

Fiorani

Motta

et al. 2014

Chemistry A European J

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The electrochemistry, photophysics, and electrochemically generated chemiluminescence (ECL) of a family of polysulfurated dendrimers with a pyrene core have been thoroughly investigated and complemented by theoretical calculations. The redox and luminescence properties of dendrimers are dependent on the generation number. From low to higher generation it is both easier to reduce and oxidize them and the emission efficiency increases along the family, with respect to the polysulfurated pyrene core. The analysis of such data evidences that the formation of the singlet excited state by cation-anion annihilation is an energy-deficient process and, thus, the ECL has been justified through the triplet-triplet annihilation pathway. The study of the dynamics of the ECL emission was achieved both experimentally and theoretically by molecular mechanics and quantum chemical calculations. It has allowed rationalization of a possible mechanism and the experimental dependence of the transient ECL on the dendrimer generation. The theoretically calculated Marcus electron-transfer rate constant compares very well with that obtained by the finite element simulation of the whole ECL mechanism. This highlights the role played by the thioether dendrons in modulating the redox and photophysical properties, responsible for the occurrence and dynamics of the electron transfer involved in the ECL. Thus, the combination of experimental and computational results allows understanding of the dendrimer size dependence of the ECL transient signal as a result of factors affecting the annihilation electron transfer.

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Diazine bridged dinuclear rhenium complex: New molecular material for the CO2 conversion

Valenti

Panigati

D’Alfonso

et al. 2014

Inorganica Chimica Acta

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Electrochemically Induced Release of a Luminescent Probe from a Rhenium‐Containing Metallopolymer

Cited by 4 publications

References 49 publications

Bifurcation of Excited-State Population Leads to Anti-Kasha Luminescence in a Disulfide-Decorated Organometallic Rhenium Photosensitizer

Bifurcation of Excited-State Population Leads to Anti-Kasha Luminescence in a Disulfide-Decorated Organometallic Rhenium Photosensitizer

Molecular Size and Electronic Structure Combined Effects on the Electrogenerated Chemiluminescence of Sulfurated Pyrene‐Cored Dendrimers

Diazine bridged dinuclear rhenium complex: New molecular material for the CO2 conversion

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