Facemask-derived C-dots were used to prepare luminescent solar concentrators exhibiting a remarkable solar-to-energy conversion of 6.1%.

Carbon dots (CDs) have been prepared from olive solid wastes and employed as capping agents in photo-activated gold-nanoparticles synthesis, thus creating CD–Au nanohybrids which act as an efficient material for electrochemical sensing hydroquinone.

As a development of our research on biocompatible glycoconjugate probes and specifically multi-chromophoric systems, herein, we report the synthesis and early bactericidal tests of two luminescent glycoconjugates whose basic structure is characterized by two boron dipyrromethene difluoride (BODIPY) moieties and three galactoside rings mounted on an oligophenylene ethynylene (OPE) skeleton. BODIPY fluorophores have found widespread application in many branches of biology in the last few decades. In particular, molecular platforms showing two different BODIPY groups have unique photophysical behavior useful in fluorescence imaging. Construction of the complex architecture of the new probes is accomplished through a convergent route that exploits a series of copper-free Heck–Cassar–Sonogashira cross-couplings. The great emergency due to the proliferation of bacterial infections, in conjunction with growing antibiotic resistance, requires the production of new multifunctional drugs and efficient methods for their targeted delivery to control bacteria-associated diseases. Preliminary studies of the glycoconjugate properties as antibacterial agents against representatives of Gram-negative (P. aeruginosa) and Gram-positive (S. aureus) pathogens, which are associated with chronic infections, indicated significant bactericidal activity ascribable to their structural features.

Two new supramolecular photocatalysts made of covalently linked Ru(II) polypyridine chromophore subunits ([Ru(bpy)3]2+-type species; bpy = 2,2′-bipyridine) and [RuL(pic)2] (L = 2,2′-bipyridine-6,6′-dicarboxylic acid; pic = 4-picoline) water oxidation catalyst subunits have been prepared. The new species, 1 and 2, contain chromophore and catalyst subunits in the molecular ratios 1:1 and 1:2, respectively. The model chromophore species [Ru(bpy)2(L1)]2+ (RuP1; L1=4-[2-(4-pyridyl)-2-hydroxyethyl]-4-methyl-2,2′-bipyridine) and [Ru(bpy)2(L2)]2+ (RuP2; L2 = 4,4′-bis[2-(4-pyridyl)-2-hydroxyethyl]-2,2′-bipyridine) have also been prepared. The absorption spectra, oxidation behavior, and luminescent properties of 1 and 2 have been studied, and the results indicate that each subunit largely maintains its own properties in the supramolecular species. However, the luminescence of the chromophore subunits is significantly quenched in 1 and 2 in comparison with the luminescence of the respective model species. Both 1 and 2 exhibit catalytic water oxidation in the presence of cerium ammonium nitrate, exhibiting an I2M mechanism, with a better efficiency than the known catalyst [RuL(pic)2] under the same experimental conditions. Upon light irradiation, in the presence of persulfate as a sacrificial acceptor agent, 1 and 2 are more efficient photocatalysts than a system made of separated [Ru(bpy)3]2+ and [RuL(pic)2] species, highlighting the advantage of using multicomponent, supramolecular species with respect to isolated species. The O–O bond formation step is I2M, even in the photo-driven process. The photocatalytic process of 2 is more efficient than that of 1, with the turnover frequency reaching a value of 1.2 s−1. A possible reason could be an increased local concentration of catalytic subunits in the needed bimolecular assembly required for the I2M mechanism in 2 with respect to 1, a consequence of the presence of two catalytic subunits in each multicomponent species 2.

Schematic representation of light-induced processes in artificial photosinthetic systems composed by multinuclear metal complexes.

Luminescent solar concentrators (LSCs) appear as an attractive solution to extend the application of photovoltaic panels by installing them “invisibly” in urban architectures. Many researchers are working on boosting the photovoltaic performances of LSCs, and an appealing strategy is to involve a multichromophoric system where Förster resonance energy transfer (FRET) occurs. To investigate the role of the energy donor, which is crucial in FRET processes inside LSCs, we designed a light-harvesting antenna composed of a highly emissive donor, such as pyrene, covalently connected to a BODIPY unit as an energy acceptor. Such an antenna was used as the chromophore to fabricate a LSC and the photovoltaic performance of the device was compared with that of the LSC based on a physical mixture of BODIPY and pyrene not covalently bonded. The results indicate that the LSC based on the antenna system has a lower optical efficiency than the LSC containing the physical mixture. Such a conclusion highlights that designing an antenna system composed of a highly luminescent species as the energy donor (e.g. pyrene, in this case) could not improve the LSC photovoltaic performances compared to the LSC based on the physical mixture of the separated chromophores.