Highly stable ionic liquid-in-water emulsions as a new class of fluorescent sensors for metal ions: the case study of Fe<sup>3+</sup> sensing

Bettoschi, Alexandre; Bencini, Andrea; Berti, Debora; Caltagirone, Claudia; Conti, Luca; Demurtas, Davide; Giorgi, Claudia; Isaia, Francesco; Lippolis, Vito; Mamusa, Marianna; Murgia, Sergio

doi:10.1039/c5ra05055c

Cited by 21 publications

(12 citation statements)

References 39 publications

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“…Potentiometric measurements : Equilibrium constants for protonation and metal ion binding of L were determined by means of potentiometric measurements (pH=‐log [H + ]), carried out in degassed 0.1 m NaCl at 298.1±0.1 K, by using equipment and procedures which have been already described …”

Section: Methodsmentioning

confidence: 99%

“…After being cooled at room temperature, the solvent was removed by distillation at low pressure, and the residue was dissolved in the minimal amount of HCl 6 m. Potentiometric measurements:E quilibrium constants for protonation and metal ion binding of L were determined by means of potentiometric measurements (pH =-log [H + ]), carried out in degassed 0.1 m NaCl at 298.1 AE 0.1 K, by using equipment and procedures which have been already described. [56,57] The reference electrode was an Ag/AgCl electrode in saturated KCl solution. The glass electrode was calibrated as ah ydrogen concentration probe by titrating known amounts of HCl with CO 2 -free NaOH solutions and the equivalent point was determined by using the Gran'sm ethod.…”

Section: Experimental Section Synthesismentioning

confidence: 99%

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Highly Charged Ruthenium(II) Polypyridyl Complexes as Effective Photosensitizer in Photodynamic Therapy

Conti

Bencini

Ferrante

et al. 2019

Chemistry A European J

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A comparative study between two novel, highly water soluble, ruthenium(II) polypyridyl complexes, [Ru(phen)2L′] and [Ru(phen)2Cu(II)L′] (L and L‐CuII), containing the polyaazamacrocyclic unit 4,4′‐(2,5,8,11,14‐pentaaza[15])‐2,2′‐bipyridilophane (L′), is herein reported. L and L‐CuII interact with calf‐thymus DNA and efficiently cleave DNA plasmid when light‐activated. They also possess great penetration abilities and photo‐induced biological activities, evaluated on an A375 human melanoma cell line, with L‐CuII being the most effective. Our study highlights the key role of the Fenton active CuII center within the macrocycle framework, that would play a synergistic role with light activation in the formation of cytotoxic ROS species. Based on these results, an optimal design of RuII polypyridyl systems featuring specific CuII‐chelating polyamine units could represent a suitable strategy for the development of novel and effective photosensitizers in photodynamic therapy.

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Section: Methodsmentioning

confidence: 99%

Section: Experimental Section Synthesismentioning

confidence: 99%

Highly Charged Ruthenium(II) Polypyridyl Complexes as Effective Photosensitizer in Photodynamic Therapy

Conti

Bencini

Ferrante

et al. 2019

Chemistry A European J

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“…Ionic liquids (ILs), organic salts that are liquid below 100 °C, have diverse applications in energy storage, gas handling, and carbon capture. − ILs have garnered much attention for advanced applications due to their nearly negligible vapor pressure and high thermal stability (most decompose above 450 °C). − Some ILs have surfactant properties themselves; for example, those containing bis-2-ethylhexyl sulfosuccinate (AOT) anions can form micelles in water. , Further, IL-in-water and IL-in-oil (mini)emulsions stabilized by small molecule or polymeric surfactants have been reported and used in energy-related applications as well as in chemical sensing, drug delivery, lubrication, etc. Thus, IL-containing emulsions are attractive for a number of different applications; given the unique properties of Pickering emulsions, accessing IL-containing systems and understanding their formation will help establish advanced applications.…”

Section: Introductionmentioning

confidence: 99%

Ionic Liquid-Containing Pickering Emulsions Stabilized by Graphene Oxide-Based Surfactants

et al. 2018

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Emulsions stabilized by particles (i.e., Pickering emulsions) are complementary to those stabilized by small molecules or polymers and most commonly consist of oil droplets dispersed in a continuous water phase, with particles assembled at the fluid-fluid interface. New particle surfactants and different fluid-fluid interfaces are critical for developing next-generation systems for a number of advanced applications. Herein we report the preparation of IL-containing emulsions stabilized by graphene oxide (GO)-based nanoparticles using the IL [Bmim][PF]: GO nanosheets stabilize IL-in-water emulsions, and alkylated GO nanosheets (C-GO) stabilize IL-in-oil emulsions. The impact of particle concentration, fluid-fluid ratio, and addition of acid or base on emulsion formation and stability is studied, with distinct effects for the water and oil systems observed. We then illustrate the broad applicability of GO-based particle surfactants by preparing emulsions with different ILs and preparing inverted emulsions (water-in-IL and oil-in-IL emulsions). The latter systems were accessed by tuning the polarity of GO nanosheets by functionalization with a perfluorinated alkyl chain such that they were dispersible in IL. This work provides insight into the preparation of different IL-containing emulsions and lays a foundation for the architecture of dissimilar materials into composite systems.

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“…Potentiometric measurements : Protonation and metal ion coordination with L1 and L2 were studied, determining the corresponding equilibrium constants, in 0.1 M NaCl aqueous solution at 298±0.1 K with previously reported equipment and methods . The reference electrode was an Ag/AgCl electrode in saturated KCl solution, while the hydrogen concentration probe was a glass electrode, calibrated by titrating known amounts of HCl with CO 2 ‐free NaOH solutions.…”

Section: Methodsmentioning

confidence: 99%

Switching on the Fluorescence Emission of Polypyridine Ligands by Simultaneous Zinc(II) Binding and Protonation

et al. 2020

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The synthesis and characterization of the two new open-chain ligands 1,15-bis-[6-(2,2'-bipyridyl)]-2,5,8,11,14-pentaaza-octadecane (L1) and 1,15-bis-[2-(1,10-phenanthroline)-9-methyl]-2,5,8,11,14-pentaazaoctadecane (L2), both featuring a tetraethylenpentaamine chain linking via methylene bridges the 6 and 2 positions of two identical 2,2'-bipyridyl (bpy) and 9-methyl-1,10phenanthroline (9-methyl-phen) moieties respectively, are reported. Their protonation and binding ability for Cu 2 + , Zn 2 + , Cd 2 + and Pb 2 + have been studied by coupling potentiometric titrations with UV-vis absorption and fluorescence emission measurements in water. L1 and L2 afford stable mono-and dinuclear complexes, in which the metal ion is bound by a single bpy or 9-methyl-phen unit and the amine groups on the aliphatic chain. However, L1 displays a greater binding ability for Cu 2 + and Zn 2 + with respect to L2, the stability constants of the [ML1] 2 + complexes being 21.8 (Cu 2 + ) and 19.4 (Zn 2 + ) log units vs 20.34 and 16.8 log. units for the corresponding L2 species. Among all the metal ions tested, only the Zn 2 + complex with L2 features an enhanced fluorescence emission at neutral pH, thanks to the simultaneous binding of one Zn 2 + ion and H + ion(s), that inhibits any possible photoinduced electron transfer (PET) process from the amine donors to the excited phen moiety. Binding of a second metal switches off the emission again.[a] Dr.by the structural characteristics of the ligand and its Zn 2 + complexes, including the number and disposition of amine donors, the overall rigidity of the molecular backbone, and, in the case of macrocyclic ligands, the dimension of the cavity. In these complexes, the heteroaromatic nitrogens are unequivocally coordinated to the metal cations. However, the stiffening of the macrocyclic structure imposed by the heteroaromatic moieties may not allow the simultaneous coordination to the metal cations of all the nitrogen donors of the binding unit. Interestingly enough, the 'benzylic' amine groups, close to the heteroaromatic unit, are not coordinated, or weakly coordinated, to the metal cation. Therefore, their lone pairs are able to quench the fluorophore excited state thanks to a photoinduced electron transfer (PET) process. As a consequence, normally fluorescent Zn 2 + complexes result to be scarcely emissive. [8a,b,22-24] In this paper, we extend this study to two open-chain ligands, L1 and L2 in Scheme 1, containing a pentaamine aliphatic chain linked at its extremities to two equal 2,2'bipyridyl (bpy) or 9-methyl-1,10-phenanthroline (9-methylphen) moieties, respectively. Our purpose is the analysis of the effects on both metal binding and sensing of the presence of two fluorogenic units linked by a flexible chain.Therefore, complex stability and fluorescence emission in the presence of metal cations will be compared to those of the previously reported ligands L3 [24] and L4 [8a] (Scheme 1), which contain the same aliphatic pentaamine chain linking the 6,6' and 2,9 positions of a single...

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Highly stable ionic liquid-in-water emulsions as a new class of fluorescent sensors for metal ions: the case study of Fe³⁺ sensing

Cited by 21 publications

References 39 publications

Highly Charged Ruthenium(II) Polypyridyl Complexes as Effective Photosensitizer in Photodynamic Therapy

Highly Charged Ruthenium(II) Polypyridyl Complexes as Effective Photosensitizer in Photodynamic Therapy

Ionic Liquid-Containing Pickering Emulsions Stabilized by Graphene Oxide-Based Surfactants

Switching on the Fluorescence Emission of Polypyridine Ligands by Simultaneous Zinc(II) Binding and Protonation

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Highly stable ionic liquid-in-water emulsions as a new class of fluorescent sensors for metal ions: the case study of Fe3+ sensing

Cited by 21 publications

References 39 publications

Highly Charged Ruthenium(II) Polypyridyl Complexes as Effective Photosensitizer in Photodynamic Therapy

Highly Charged Ruthenium(II) Polypyridyl Complexes as Effective Photosensitizer in Photodynamic Therapy

Ionic Liquid-Containing Pickering Emulsions Stabilized by Graphene Oxide-Based Surfactants

Switching on the Fluorescence Emission of Polypyridine Ligands by Simultaneous Zinc(II) Binding and Protonation

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Highly stable ionic liquid-in-water emulsions as a new class of fluorescent sensors for metal ions: the case study of Fe³⁺ sensing