DNA molecules containing a 1D silver array may be applied for nanotechnology applications, but first their conducting and photoluminescence behavior must be enhanced. Here we have synthesized and characterized three new helical compounds based on stacked silver–mediated cytosine base pairs [Ag(mC)₂]X (mC = N1-methylcytosine; X = NO₃ (1), BF₄ (2) and ClO₄ (3)), that contain uninterrupted polymeric Ag^I chains that run through the center of the helixes, comparable to related silver-DNA structures. The exposure of nanostructures of [Ag(mC)₂]BF₄ (2) to cold hydrogen plasma stimulates the reduction of the prearranged Ag^I polymeric chains to metallic silver along the material. This solvent-free reduction strategy leads to the compound [Ag^I(mC)₂]X@Ag⁰ (2H) that contains uniformly well-distributed silver metallic nanostructures that are responsible for the new conducting and photoluminescence properties of the material. The presence of silver nanostructures alongside compound 2H has been evaluated by means of X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, and X-ray powder diffraction (XRPD). The conducting and photoactive properties of 2H were studied by electrostatic force microscopy (EFM) and conducting-AFM (c-AFM), and photoluminescence microscopy (PL), respectively. The results demonstrate that the presence of well-organized metallic silver nanoentities on the material is responsible for the novel conductivity and photoactive properties of the material. This methodology can be employed for the generation of multifunctional silver-DNA related materials with tailored properties.

8-Methoxy-4,5-dihydrocyclopenta[de]quinolin-2(1H)-one and quinolin-2(1H)-one phosphonate and carboxylate derivatives are selective antennas exhibiting Eu³⁺ and Tb³⁺ luminescence, and highly sensitive water sensors.

A very active branch of organic chemistry is putting great effort into tailoring fluorescent dyes for a myriad of applications, from technological to bioanalytical and biomedical applications. Among the major families of fluorophores, those derived from 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY dyes) are undergoing a recent boost thanks to the simplicity and robustness of the chemistry involved. The BODIPY core can be modified with numerous side groups, the 8-position being a modification place with important effects on the spectroscopic and photophysical properties of the resulting dyes. Likewise, previous work has shown that the addition of groups attached at the 3- and 2-positions can result in dyes with very different properties. Herein, we generalize the effect of the substituent side groups by studying nine BODIPY dyes substituted with a phenyl, styryl or phenylethynyl moiety at the 2-, 3- or 8-position of the BODIPY scaffold. Within the class of phenyl- or phenylethynyl-substituted dyes, substitution at the 2-position always leads to dyes with the broadest bandwidths and the largest Stokes shifts. We investigate the solvent effect on the spectroscopic properties of the dyes, using four empirical solvent scales (dipolarity, polarizability, acidity and basicity: Catalán, J. Phys. Chem., 2009, 113, 5951). These analyses identify solvent dipolarity and polarizability as critical parameters accounting for the observed solvent-dependent shifts of the absorption and emission maxima. Finally, time-dependent density functional theory calculations provide insights into the structural and energetic issues concerning the spectroscopic properties of these fluorophores.

A new time-gated fluorescence-based imaging method to analyse microRNAs directly from human serum using dynamic chemistry labelling.