Aurélie Perrier

The monitoring of glyphosate (GlyP), the most widely used herbicide in the world, and aminomethylphosphonic acid (AMPA), its primary degradation product, in surface water is a public health concern due to their association with various diseases and carcinogenicity. In this study, we describe a novel terpyridine derivative incorporating recognition moieties specific for carboxylate, phosphonic acid and amine functionalities present in glyphosate and AMPA. The fluorescent molecular probe was synthesised and then activated through the formation of a Zn(II) complex. The photophysical properties of the probe and its complexation abilities with target analytes in aqueous solution (MeOH/HEPES buffer mixture) were characterized using both experimental approaches and computational modelling based on (TD-)DFT. The fluorescent molecular probe displayed high selectivity and sensitivity for both analytes, with detection limits of 51 nM for glyphosate and 70 nM for AMPA. The two different mechanisms for glyphosate and AMPA, respectively, complexation, with a high log(β) of 6.8, and covalent binding, even allowed for sequential detection of both analytes from the same sample. Owing to its efficiency and robustness, the molecular probe was successfully integrated into an embedded sensor system, whose performance was validated by analyzing real water samples (e.g. river water) with high recovery rates.

Molecular dynamics simulations provide insight into the mutual interaction between a photochrome, azobenzene, during photoisomerization, and its surrounding polymer matrix. It is a first step in understanding photonastic materials.

Blinking efficiency at the plasma membrane is not only driven by the p K _a of photoswitchable spiroamide rhodamines.

Photomodulable fluorophores constitute advanced materials as they possess the ability to modify their photophysical properties upon photoirradiation. A new mechanism of photoconversion is recently established, called Directed Photooxidation Induced Conversion based on the coupling of fluorophores with Aromatic Singlet oxygen Reactive Moieties (ASORMs). In this work, The Directed Photooxidation Induced Conversion (DPIC) mechanism is intended to be applied to Perylene BisImide (PBI) due to its appealing photophysical properties. The experimental results showed that coupling two ASORMs to the PBI core, here furan and pyrrole, led to impressive photomodulable fluorophores. While PBI‐F exhibited a photoconversion of 100 nm shift, PBI‐P displayed an 80‐fold fluorescence intensity enhancement upon photoactivation. Analysis of the photoproducts showed that the conversion do not involve an addition of singlet oxygen on the ASORM. Instead, photoconversion occurred through efficient successive photocyclizations. Finally, intracellular vesicles are successfully photoconverted by means of endocytosed PLGA‐polymer nanoparticles loaded with PBI‐F. This study highlights the unique capability of furan‐ and pyrrole‐conjugated fluorophores to enable advanced optical materials with phototransformation properties.

The photophysical properties of an azacrown–iridium(iii) complex, designed to trap and photo-release Ca²⁺, are investigated with ultrafast spectroscopy and TDDFT calculations.

A new class of photoswitches and the corresponding elementary photoinduced reaction, the so-called Excited-State Cation Transfer (ESCT), are investigated. This reaction relies on an intramolecular photo-release/photo-complexation of cation: after irradiation, the cation is translocated from a complexation site 1 to a site 2 during the excited state lifetime. Our purpose is thus to develop a computational strategy based on Density Functional theory (DFT) and its time-dependent counterpart (TD-DFT) to improve the different properties of the ESCT photoswitches, namely (i) the ground state complexation constant K, (ii) the excited state complexation constant K*, (iii) the photoejection properties and (iv) the population of the triplet states from a singlet state via intersystem crossing to increase the lifetime of the excited state. In this work, we are interested in optimizing the ESCT properties of a betaine pyridinium chromophore substituted by a 15-aza-5-crown, that was previously shown to efficiently photoeject a Ca²⁺ cation from the site 1 but no photo-recapture was observed in the site 2 [Aloïse et al., Phys. Chem. Chem. Phys., 2016, 22, 15384]. To this purpose, we have investigated the impact of the modification of the site 1 on the ESCT properties by introducing different substituents (EDG groups, halogen atoms) at different positions. So far, promising systems have been identified but a simultaneous improvement of all the ESCT photoswitches properties has yet not been achieved.

Here, we report an approach to the synthesis of highly charged enantiopure cyclophanes by the insertion of axially chiral enantiomeric binaphthyl fluorophores into the constitutions of pyridinium‐based macrocycles. Remarkably, these fluorescent tetracationic cyclophanes exhibit a significant AIE compared to their neutral optically active binaphthyl precursors. A combination of theoretical calculations and time‐resolved spectroscopy reveal that the AIE originates from limited torsional vibrations associated with the axes of chirality present in the chiral enantiomeric binaphthyl units and the fine‐tuning of their electronic landscape when incorporated within the cyclophane structure. Furthermore, these highly charged enantiopure cyclophanes display CPL responses both in solution and in the aggregated state. This unique duality of AIE and CPL in these tetracationic cyclophanes is destined to be of major importance in future development of photonic devices and bio‐applications.

Here, we report an approach to the synthesis of highly charged enantiopure cyclophanes by the insertion of axially chiral enantiomeric binaphthyl fluorophores into the constitutions of pyridinium‐based macrocycles. Remarkably, these fluorescent tetracationic cyclophanes exhibit a significant AIE compared to their neutral optically active binaphthyl precursors. A combination of theoretical calculations and time‐resolved spectroscopy reveal that the AIE originates from limited torsional vibrations associated with the axes of chirality present in the chiral enantiomeric binaphthyl units and the fine‐tuning of their electronic landscape when incorporated within the cyclophane structure. Furthermore, these highly charged enantiopure cyclophanes display CPL responses both in solution and in the aggregated state. This unique duality of AIE and CPL in these tetracationic cyclophanes is destined to be of major importance in future development of photonic devices and bio‐applications.

A multi‐environment computational approach is proposed to study the modulation of the emission behavior of the triphenylamine (Z)‐4‐benzylidene‐2‐methyloxazol‐5(4H)‐one (TPA‐BMO) molecule [Tanget al., J. Phys. Chem. C119, 21875 (2015)]. We aim at (1) proposing a realistic description of the molecule in several environments (solution, aggregate, polymer matrix), (2) modelling its absorption and emission properties, and (3) providing a qualitative understanding of the experimental observations by highlighting the photophysical phenomena leading to the emission modulation. To this purpose, we rely on (TD‐)DFT calculations and classical Molecular Dynamics simulations, but also on the hybrid ONIOM QM/QM’ approach and thein situchemical polymerization methodology. In low‐polar solvents, the investigation of the potential energy surfaces and the modulation of the emission quantum yield can be attributed to possible photophysical energy dissipation caused by low‐frequency vibrational modes. In the aggregate and in the polymer matrix, the emission modulation can be qualitatively interpreted in terms of the possible restriction of the intramolecular vibrations. For these two systems, our study highlights that a careful modelling of the environment is far from trivial but is fundamental to model the optical properties of the fluorophore.

A multi-scale and multi-environment computational approach is proposed to study of the modulation of the emission behavior of the triphenylamine (Z)-4-benzylidene-2-methyloxazol-5(4H)-one (TPA-BMO) molecule [Tang et al., J. Phys. Chem. C,119, 21875 (2015)]. Going from (TD-)DFT calculations to classical Molecular Dynamics simulations through the hybrid ONIOM QM/QM’ approach and the in situ chemical polymerization methodology, we have rationalized distinct photophysical phenomena: (1) in low-polar solvents, a polarity-dependent solvatochromic effect as well as a modulation of the emission quantum yield, attributed to possible photophysical energy dissipation caused by low-frequency vibrational modes, (2) in the aggregate, a subtle competition between an excitonic coupling and a restriction of the intramolecular vibrations leading to an Aggregation-Induced Emission behavior, and (3) in the polymer matrix, an antagonist effect between the loss of global flexibility and the presence of vibrational modes similar to those observed in solution, explaining a similar emissive behavior within the polymer.