The rates and mechanism of coreactant electrogenerated chemiluminescence (ECL) from tris(2,2‘-bipyridyl)ruthenium(II) (Ru(bpy)3 2+) and the tertiary amines, tripropylamine (TPrA) and trimethylamine (TMeA), in aqueous solution were investigated. Transient (0.5 ms) potential steps were used with microelectrodes to investigate the emission time course under a variety of solution conditions. With amine concentrations that are low with respect to Ru(bpy)3 2+, the emission rises continually during the transient potential step and decays slowly after its termination. In contrast, the emission approaches a plateau during the potential step and is rapidly extinguished afterward with concentrations of Ru(bpy)3 2+ that are much lower than the amine concentration. At intermediate pH values, the emission intensity increases approximately linearly with pH. The emission after the potential step is unaffected by the rest potential. To simulate these temporal characteristics by finite difference methods, a mechanism employing 15 discrete chemical and electrochemical steps was employed, using literature-based thermodynamic values and electron-transfer rate constants evaluated from Marcus theory. The rate-limiting step was found to be the deprotonation of the amine radical cation. In addition, the simulations required a rate constant for the homogeneous oxidation of the tertiary amine by electrogenerated Ru(bpy)3 3+ value much below its Marcusian-calculated value to match the experimental data.

Several examples of nanosized therapeutic and imaging agents have been proposed to date, yet for most of them there is a low chance of clinical translation due to long-term in vivo retention and toxicity risks. The realization of nanoagents that can be removed from the body after use remains thus a great challenge. Here, we demonstrate that nonequilibrium gold–iron alloys behave as shape-morphing nanocrystals with the properties of self-degradable multifunctional nanomedicines. DFT calculations combined with mixing enthalpy-weighted alloying simulations predict that Au–Fe solid solutions can exhibit self-degradation in an aqueous environment if the Fe content exceeds a threshold that depends upon element topology in the nanocrystals. Exploiting a laser-assisted synthesis route, we experimentally confirm that nonequilibrium Au–Fe nanoalloys have a 4D behavior, that is, the ability to change shape, size, and structure over time, becoming ultrasmall Au-rich nanocrystals. In vivo tests show the potential of these transformable Au–Fe nanoalloys as efficient multimodal contrast agents for magnetic resonance imaging and computed X-ray absorption tomography and further demonstrate their self-degradation over time, with a significant reduction of long-term accumulation in the body, when compared to benchmark gold or iron oxide contrast agents. Hence, Au–Fe alloy nanoparticles exhibiting 4D behavior can respond to the need for safe and degradable inorganic multifunctional nanomedicines required in clinical translation.

Three polyazamacrocyclic ligands, i.e. 1,5,9-tris[2-(methylsulfanyl)ethyl]-1,5,9-triazacyclododecane (TACD3S), 1,4,7,10-tetrakis[2-(methylsulfanyl)ethyl]-1,4,7,10-tetrazacyclotridecane (TRI4S) and 1,4,8,11-tetrakis[2-(methylsulfanyl)ethyl]-1,4,8,11-tetrazacyclotetradecane (TE4S), were considered as potential chelators for the medically relevant copper radioisotopes. The ligands have been synthesized through facile, single-step...

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In this paper, we report the synthesis and characterization of nanoparticles of a PtxY alloy supported on a commercial mesoporous carbon with high mass and specific activity.

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Thirteen sulfur compounds (boiling points from 35 to 231 degrees C), usually considered as possible off-flavoring volatiles, were quantified by a concurrent headspace-solid phase microextraction method coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS) on 80 not off-flavoring wines of four varieties (Merlot, Marzemino, and Teroldego as red wines and Chardonnay as a white one) and of five vintages produced in the North Italian Trentino region. The results of the research, the first Italian data-bank per variety on such volatiles, allow us to make a comparison with the data of other winegrowing areas, to investigate the aging effect on the considered volatiles, and, finally, to try a variety discrimination using statistical procedures. Dimethyl sulfide, 3-(methylthio)-1-propanol, diethyl sulfide, and diethyl disulfide were found to increase with time whereas 2-mercaptoethanol and ethylmercaptan showed a decreasing trend. Furthermore, the concentration of several compounds was found to be dependent on the variety. For instance, sulfide, disulfides, benzothiazole, and thioalcohols are at higher levels in Merlot wines, whereas thiols and thioacetates are more abundant in Marzemino and Teroldego wines. Chardonnay products, well apart from the other wines, are the poorest in 3-(methylthio)-1-propanol and rather rich in dimethyl disulfide and in diethyl disulfide, mostly in the aged wines. Applying the principal component analysis to the data, it was possible to demonstrate that Chardonnay and Merlot wines are well-discriminated from the Italian native varietal wines, which on their turn are only partially distinguishable among them. A contribution of these compounds to the variety characteristics of wine is reasonable.