Sebastiano Campagna | University of Messina (original) (raw)

Papers by Sebastiano Campagna

Dalton Transactions, 2014

Chemical Communications, 2014

Chemical Science, Aug 22, 2014

Journal of the American Chemical Society, Aug 1, 2007

Ru(II) polypyridine species have been assembled about dirhodium(II, II) tetracarboxylate cores. T... more Ru(II) polypyridine species have been assembled about dirhodium(II, II) tetracarboxylate cores. The complexes prepared have general formulas [{(terpy)Ru(La)}n{Rh2(CH3COO)4-n(CH3CN)2}]2n+ (a-type compounds: terpy = 2,2&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;:6&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;,2&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-terpyridine; La = 4&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-(p-carboxyphenyl)-2,2&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;:6&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;,2&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-terpyridine; n = 1, 1a; n = 2, cis-2a and trans-2a-cis and trans refer to the arrangement of the Ru(II) species around the dirhodium core; n = 3, 3a), [{(Lb)Ru(La)}n{Rh2(CH3COO)4-n(CH3CN)2}]2n+ (b-type compounds: Lb = 6-phenyl-2,4-di(2-pyridyl)-s-triazine; n = 1, 1b; n = 2, an inseparable mixture of cis-2b and trans-2b; n = 3, 3b; n = 4, 4b), and [{(terpy)Ru(Lc)}{Rh2(CH3COO)3(CH3CN)2}]2+ (1c; Lc = 6-(p-carboxyphenyl)-2,4-di(2-pyridyl)-s-triazine). As model species, also the mononuclear [(terpy)Ru(La)]2+ (5a), [(La)Ru(Lb)]2+ (5b), and [(terpy)Ru(Lc)]2+ (5c) have been prepared. All of the complexes have been characterized by several techniques, including NMR and mass spectra, and the stability of the various species is discussed. The absorption spectra of all of the compounds are dominated by the Ru(II) polypyridine moieties, showing intense ligand-centered (LC) bands in the UV region and intense metal-to-ligand charge-transfer (MLCT) bands in the visible. The compounds exhibit several metal-centered oxidation and ligand-centered reduction processes, which have been assigned to specific subunits. Both absorption and redox data indicate a supramolecular nature of the assembled systems. Efficient energy transfer from the MLCT triplet state of the Ru-based components to the lowest-energy excited state of the dirhodium core takes place for the a-type compounds at 298 K in acetonitrile solution, whereas such a process is inefficient for the b-type and c-type species, which exhibit the typical MLCT emission. At 77 K in butyronitrile matrix, Ru-to-Rh2 energy transfer is partly efficient for both the a-type and the b-type compounds and is inefficient for 1c. The reasons for such behavior are discussed by taking into account arguments concerning the driving force and reorganization energy of the complexes.

Inorganic Chemistry Communications, Jun 1, 2005

... Acknowledgments. We thank the Natural Sciences and Engineering Research Council of Canada, th... more ... Acknowledgments. We thank the Natural Sciences and Engineering Research Council of Canada, the Université de Montréal, and MIUR (PRIN and FIRB projects) for financial support. References. [1] K. Kalyanasundaram and M. Grätzel, Coord. Chem. Rev. 77 (1998), p. 347. ...

Inorganic Chemistry, Mar 1, 1995

We have synthesized a number of dinuclear species containing both identical or different metal-ba... more We have synthesized a number of dinuclear species containing both identical or different metal-based components by employing new bridging ligands having either atiphatic or aromatic spacers and taking advantage of the "'complexes as metals and complexes as ligands'" synthetic strategy. The bridging ligands are dpt-S-dpt (S is 1,4-cyclohexyt, 1,4-phenyl, 4,4'-biphenyl; dpt is 4-amino-3,5-bis(2-pyridyl)-1,2,4-triazole; the connections between S and dpt are provided by amide links). The complexes synthesized are: [(bpy):Ru(dpt-Sdpt)Ru(bpy).~](PF6)4 (bpy-2,2'-bipyridine; biq=2,2'-biquinoline; S=l,4-cyclohexyl (1), 1,4.-phenyl (4), 4,4'-biphenyl (7)); [(biq)2Ru(dpt-S-dpt)Ru(biq)2](PF6)4 (S=l,4-cyclohexyl (2), i,4-phenyl (5), 4,4'-biphenyl (8)); [(bpy._Ru(dpt-S-dpt)-Ru(biq)-, ] (PF6)4 (S = 1,4-cyclohexyl (3), 1,4-phenyl (6), 4,4'-biphenyl (9)). The absorption spectra, luminescence properties and redox behavior of all the compounds have been studied, in the complexes containing different metal-based components, photoinduced energy transfer occurs from the higher-lying Ru-~ bpy CT level, centered on a metal subunit, to the lower-lying Ru ~ biq CT excited state, centered on the other metal component. In fluid solution at room temperature, the energy transfer is suggested to be mediated by a two-step electron transfer mechanism, whereas direct energy transfer between the chromophores most likely occurs at 77 K in rigid matrix. At the momenl we are not able to say if the energy transfer at 77 K takes place via electron exchange or coulombic mechanisms. The results obtained indicate that the efficiency of the processes depends on the donor-aeceptor distance, as expected, and that occasional rr bonds which are present within the bridging ligands cannot be used for speeding up electron transfer in multicomponent systems if the main skeleton of the bridge is made by o" bonds.

Reference Module in Chemistry, Molecular Sciences and Chemical Engineering

International Journal of Molecular Sciences

In this paper we describe the synthesis of a novel bichromophoric system in which an efficient ph... more In this paper we describe the synthesis of a novel bichromophoric system in which an efficient photoinduced intercomponent energy transfer process is active. The dyad consists of one subunit of curcumin and one of BODIPY and is able to emit in the far-red region, offering a large Stokes shift, capable of limiting light scattering processes for applications in microscopy. The system has been encapsulated in MCM-41 nanoparticles with dimensions between 50 and 80 nm. Both the molecular dyad and individual subunits were tested with different cell lines to study their effective applicability in bioimaging. MCM-41 nanoparticles showed no reduction in cell viability, indicating their biocompatibility and bio-inertness and making them capable of delivering organic molecules even in aqueous-based formulations, avoiding the toxicity of organic solvents. Encapsulation in the porous silica structure directed the location of the bichromophoric system within cytoplasm, while the dyad alone stains...

Photochemical & Photobiological Sciences

A luminescent bipyridinium fused species acts as sensitizer for photoinduced electron transfer in... more A luminescent bipyridinium fused species acts as sensitizer for photoinduced electron transfer involving adenine or guanine moieties in polynucleotides.

Current Opinion in Green and Sustainable Chemistry

Dalton Transactions, 2021

Nano- and micrometric chloroform aggregates formed because of the dynamic behavior of the carrier... more Nano- and micrometric chloroform aggregates formed because of the dynamic behavior of the carrier Pt in the presence of HCl are responsible for the fast transport of HCl across a hydrophobic layer over macroscopic distances.

Advanced Optical Materials, 2020

The realization of low‐cost silicon (Si) light harvesting antennas, made with industrially compat... more The realization of low‐cost silicon (Si) light harvesting antennas, made with industrially compatible technology and implementable in current devices, represents a goal with a tremendous impact for several commercial applications. For the first time, the use of Si nanowires (NWs) as energy donor in a light harvesting antenna is demonstrated. Through a detailed study of the optical properties, an energy transfer process from the NWs to the dyes is reported here. In this paper, the realization of this novel hybrid material based on the luminescence of ultra‐thin Si NWs and dyes demonstrates the potential of these systems for the transfer of light, opening the route to several strategic applications from photonics to photovoltaics, sensors, and bio‐imaging.

Dyes and Pigments, 2021

Abstract The synthesis of a new biocompatible bichromophoric system (CURBO) was developed, by con... more Abstract The synthesis of a new biocompatible bichromophoric system (CURBO) was developed, by connecting the skeleton of the naturally occurring curcumin to a BODIPY derivative. The system exhibited an intense fluorescence band with maximum at about 510 nm in organic solvent, while its emission spectra in aqueous solution were more complicated and slightly red-shifted, due to the effect of aggregation for the poor solubility of the dyad. To overcome these problems, the bichomophoric system has been loaded into the halloysite nanotubes (HNT). The HNT/CURBO nanocomposite, suspended in aqueous solution, showed an intensity of emission in the red region of the spectrum higher than the one exhibited by the pristine CURBO. The biocompatibility and photophysical behavior of HNT/CURBO nanocomposite were studied using ASC52Telo, h-TERT immortalized adipose-derived mesenchymal stem cells. To investigate the localization of the CURBO alone and in HNT/CURBO, fluorescence epimicroscopy was performed. The HNT/CURBO nanocomposite showed a high propensity to cross cell membranes, resulting in a massive cell uptake around the cell nucleus. Moreover, it lighted up ASC52Telo cells both with intense green and red fluorescence while excited in the blue portion of the electromagnetic spectrum, a phenomenon that could not be observed for the free CURBO. Dual-channel emissions dyes and, in particular, materials, such as the HNT/CURBO nanocomposite, emitting in the red portion of the spectrum have become, in recent decades, particularly fascinating since they can minimize the autofluorescence detection of the cell medium and allow interesting microscopy applications.

Chemical Science, 2020

We have designed and synthesized a new tris-chelating polypyridine ligand (bpy3Ph) suitable to be... more We have designed and synthesized a new tris-chelating polypyridine ligand (bpy3Ph) suitable to be used as a bridging ligand (BL) for constructing various supramolecular photocatalysts.

Dyes and Pigments, 2018

Twelve new polycyclic aromatic chromophores whose structures recall 9,10-substituted anthracene h... more Twelve new polycyclic aromatic chromophores whose structures recall 9,10-substituted anthracene have been prepared and their absorption spectra, and luminescence properties (both in ethanol and dichloromethane solution at room temperature and in MeOH/EtOH (4:1 v/v) rigid matrix at 77 K) have been analyzed as well as pump-probe transient absorption spectroscopy and computational studies have been performed. The compounds have variously decorated pyrimidyl groups as substituents of the anthracene framework. The compounds are conveniently grouped in two series: 1-4 and 11, in which the pyrimidine nitrogen atoms are on the external side with respect to the anthracene framework (Ext-type compounds), and 5-10, where the pyrimidine nitrogen atoms are pointing towards the anthracene platform (Int-type compounds). Compound 12 contains both a pyrimidine substituent with "inner" nitrogen atoms ("Int") and a pyrimidine with "outer" nitrogen atoms ("Ext"). All the new species are quite efficient luminophores (spectral range of emission maxima: 400-450 nm at 77 K; 415-520 nm at room temperature; emission lifetimes: 0.25-8.7 ns range; emission quantum yields ranging between 0.08 to 0.99, with a single exception), with their photophysical properties depending on the connection scheme of the pyrimidyl groups to the anthryl platform (i.e., Int-type vs Exttype compounds). Luminescence originating from locally excited π−π* anthracene-based singlet states, delocalized states largely involving the pyrimidyl moieties, and charge transfer states has been identified. For the Int-type series, the initially-prepared excited state can deactivate via interconversion to a saddle-shaped conformation, opening the way to fast nonradiative decays.

Organic and Biomolecular Chemistry, 2017

The synthesis of an efficient energy donor–acceptor system is reported, together with its photoph... more The synthesis of an efficient energy donor–acceptor system is reported, together with its photophysical properties.

Inorganica Chimica Acta, 2017

Light driven water oxidation is a key step in artificial photosynthesis, aimed at splitting water... more Light driven water oxidation is a key step in artificial photosynthesis, aimed at splitting water into hydrogen and oxygen with sunlight. In such process, the interactions between a photosensitizer (PS) and a water oxidation catalyst (WOC) play a crucial role in the rates of photoinduced electron transfers, determining the overall quantum efficiency of the system. In this work, by means of Small Angle X-ray Scattering (SAXS) we investigate the nature of the aggregates between ruthenium polypyridine photosensitizers (Rubpy and Ru 4 dend) and a tetraruthenium polyoxometalate (Ru 4 POM) water oxidation catalyst. Aggregate scattering is confirmed by the strong intensity-increase in the low-q regime, whereas the power law-fit of this region show slopes between �3 and �4, suggesting globular and porous aggregates. Intermolecular PS/WOC distances lower than 3 nm support the observed fast photoinduced electron transfers (<120 ps), however the proximity of the two components in the hybrids is also responsible for fast charge recombination. Approaches for inhibiting such undesired process are discussed.

Org. Biomol. Chem., 2015

A Bodipy has been rationally designed and synthesized as a fluorescent ligand of GPER for diagnos... more A Bodipy has been rationally designed and synthesized as a fluorescent ligand of GPER for diagnostic purposes and prospective therapeutic implications.

Chem, 2017

Aggregation of metal dendrimers made of Ru(II) and Os(II) polypyridine photoactive subunits occur... more Aggregation of metal dendrimers made of Ru(II) and Os(II) polypyridine photoactive subunits occurs in solution, as shown by SAXS experiments. Aggregation-induced energy transfer takes place, suggesting inter-dendrimer energy migration, a process resembling an important property of the natural systems and one that can inspire interesting developments for artificial photosynthesis.