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91.
Vincenzo Barone Alessandro Bencini Federico Totti Myriam G. Uytterhoeven 《International journal of quantum chemistry》1997,61(3):361-367
A parallel MP2 and DFT study was performed for mercury dihalides and for representative organomercury compounds including a Hg(SINGLE BOND)C bond. From a methodological point of view, medium-size basis sets provide reliable general trends for a number of properties already at the HF level. However, quantitative results can only be obtained including correlation energy by post-Hartree-Fock (even at the MP2 level) or density functional models and adding f-polarization functions on Hg. At this level, geometrical parameters are sufficiently accurate for most purposes and reliable thermodynamic data can be obtained using isodesmic reactions. The advantage of the DF approach resides, besides the shorter computation times, in the lower dependence of the results on the basis set. From a more general point of view, all the computations indicate that Hg(SINGLE BOND)C bond breaking is favored, decreasing the electronegativity of further substituents. We have next investigated the reaction mechanism for cleavage of the Hg(SINGLE BOND)C bond by halogenic acids. Our results show that the reaction occurs through a one-step mechanism in which, however, bond forming and breaking are not completely synchronous. © 1997 John Wiley & Sons, Inc. 相似文献
92.
Dr. Irene Vassalini Dr. Laura Borgese Michele Mariz Prof. Stefano Polizzi Dr. Giuliana Aquilanti Prof. Paolo Ghigna Prof. Andrea Sartorel Prof. Vincenzo Amendola Prof. Ivano Alessandri 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(23):6689-6693
Oxygen evolution reaction (OER) is the most critical step in water splitting, still limiting the development of efficient alkaline water electrolyzers. Here we investigate the OER activity of Au–Fe nanoalloys obtained by laser-ablation synthesis in solution. This method allows a high amount of iron (up to 11 at %) to be incorporated into the gold lattice, which is not possible in Au–Fe alloys synthesized by other routes, due to thermodynamic constraints. The Au0.89Fe0.11 nanoalloys exhibit strongly enhanced OER in comparison to the individual pure metal nanoparticles, lowering the onset of OER and increasing up to 20 times the current density in alkaline aqueous solutions. Such a remarkable electrocatalytic activity is associated to nanoalloying, as demonstrated by comparative examples with physical mixtures of gold and iron nanoparticles. These results open attractive scenarios to the use of kinetically stable nanoalloys for catalysis and energy conversion. 相似文献
93.
Dr. Vincenzo Grande Dr. Filippo Doria Prof. Dr. Mauro Freccero Prof. Dr. Frank Würthner 《Angewandte Chemie (International ed. in English)》2017,56(26):7520-7524
G-quadruplexes (G4s) are peculiar DNA or RNA tertiary structures that are involved in the regulation of many biological events within mammalian cells, bacteria, and viruses. Although their role as versatile therapeutic targets has been emphasized for 35 years, G4 selectivity over ubiquitous double-stranded DNA/RNA, as well as G4 differentiation by small molecules, still remains challenging. Here, a new amphiphilic dicyanovinyl-substituted squaraine, SQgl , is reported to act as an NIR fluorescent light-up probe discriminating an extensive panel of parallel G4s while it is non-fluorescent in the aggregated state. The squaraine can form an unconventional sandwich π-complex binding two quadruplexes, which leads to a strongly fluorescent (ΦF=0.61) supramolecular architecture. SQgl is highly selective against non-quadruplex and non-parallel G4 sequences without altering their topology, as desired for applications in selective in vivo high-resolution imaging and theranostics. 相似文献
94.
Leopoldo Ceraulo Mirella Ferrugia Vincenzo Sprio 《Journal of mass spectrometry : JMS》1992,27(1):37-38
The positive-ion electron impact ionization mass spectra of eight substituted 3-nitropyrroles were examined. The major fragment ions arise by ortho interactions between the 3-nitro group and the 2-methyl or 2-aryl group. 相似文献
95.
Ana A. C. Pacheco Arnaldo F. da Silva Filho Kristoffer Kortsen Magnus W. D. Hanson-Heine Vincenzo Taresco Jonathan D. Hirst Muriel Lansalot Franck D'Agosto Steven M. Howdle 《Chemical science》2021,12(3):1016
Reversible addition–fragmentation chain transfer (RAFT) dispersion polymerisation of methyl methacrylate (MMA) is performed in supercritical carbon dioxide (scCO2) with 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (DDMAT) present as chain transfer agent (CTA) and surprisingly shows good control over PMMA molecular weight. Kinetic studies of the polymerisation in scCO2 also confirm these data. By contrast, only poor control of MMA polymerisation is obtained in toluene solution, as would be expected for this CTA which is better suited for acrylates. In this regard, we select a range of CTAs and use them to determine the parameters that must be considered for good control in dispersion polymerisation in scCO2. A thorough investigation of the nucleation stage during the dispersion polymerisation reveals an unexpected “in situ two-stage” mechanism that strongly determines how the CTA works. Finally, using a novel computational solvation model, we identify a correlation between polymerisation control and degree of solubility of the CTAs. All of this ultimately gives rise to a simple, elegant and counterintuitive guideline to select the best CTA for RAFT dispersion polymerisation in scCO2.RAFT dispersion polymerisation of methyl methacrylate is performed in scCO2 with 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (DDMAT) present as chain transfer agent (CTA) and surprisingly shows good control over PMMA molecular weight. 相似文献
96.
Gaetano Isola Alessandro Polizzi Vincenzo Ronsivalle Angela Alibrandi Giuseppe Palazzo Antonino Lo Giudice 《Molecules (Basel, Switzerland)》2021,26(6)
Matrix metalloproteinase-9 (MMP-9) has been shown to play a key role in endothelial function and perhaps pivotal in the correlation between periodontal disease and cardiovascular disease (CVD). For the study, the impact of MMP-9 of periodontitis and CVD on serum and saliva concentrations was analyzed. For the study patients with periodontitis (n = 31), CVD (n = 31), periodontitis + CVD (n = 31), and healthy patients (n = 31) were enrolled. Clinical and demographic characteristics as well as serum and salivary MMP-9 were evaluated. MMP-9 concentrations in serum and saliva were statistically elevated in patients with CVD (p < 0.01) and in patients with periodontitis plus CVD (p < 0.001) compared to patients with periodontitis and healthy subjects. Multivariate regression analysis showed that c-reactive protein (hs-CRP) was the only significant predictor for MMP-9 serum (p < 0.001), whereas hs-CRP (p < 0.001) and total cholesterol (p = 0.029) were the statistically significant salivary MMP-9 predictors. This study evidenced that patients with CVD and periodontitis + CVD presented elevated MMP-9 concentrations in serum and saliva compared to patients with periodontitis and healthy subjects. Furthermore, hs-CRP was a negative predictor of serum and salivary MMP-9. 相似文献
97.
Greta Petrella Camilla Montesano Sara Lentini Giorgia Ciufolini Domitilla Vanni Roberto Speziale Andrea Salonia Francesco Montorsi Vincenzo Summa Riccardo Vago Laura Orsatti Edith Monteagudo Daniel Oscar Cicero 《Molecules (Basel, Switzerland)》2021,26(14)
A new strategy that takes advantage of the synergism between NMR and UHPLC–HRMS yields accurate concentrations of a high number of compounds in biofluids to delineate a personalized metabolic profile (SYNHMET). Metabolite identification and quantification by this method result in a higher accuracy compared to the use of the two techniques separately, even in urine, one of the most challenging biofluids to characterize due to its complexity and variability. We quantified a total of 165 metabolites in the urine of healthy subjects, patients with chronic cystitis, and patients with bladder cancer, with a minimum number of missing values. This result was achieved without the use of analytical standards and calibration curves. A patient’s personalized profile can be mapped out from the final dataset’s concentrations by comparing them with known normal ranges. This detailed picture has potential applications in clinical practice to monitor a patient’s health status and disease progression. 相似文献
98.
Maria Fernanda Taviano Emilia Cav Vivienne Spadaro Francesco Maria Raimondo Vincenzo Musolino Francesco Cacciola Yassine Oulad El Majdoub Luigi Mondello Concetta Condurso Fabrizio Cincotta Antonella Verzera Natalizia Miceli 《Molecules (Basel, Switzerland)》2021,26(14)
In a project designed to investigate the specific and infraspecific taxa of Matthiola endemic to Sicily (Italy) as new potential sources of bioactive compounds in this work, the infraspecific taxa of Matthiola fruticulosa were studied, namely, subsp. fruticulosa and subsp. coronopifolia. HPLC–PDA/ESI–MS and SPME–GC/MS analyses of hydroalcoholic extracts obtained from the aerial parts of the two subspecies led to the detection of 51 phenolics and 61 volatile components, highlighting a quite different qualitative–quantitative profile. The antioxidant properties of the extracts were explored through in vitro methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH), reducing power and Fe2+ chelating activity assays. The results of the antioxidant tests showed that the extracts possess a different antioxidant ability: particularly, the extract of M. fruticulosa subsp. fruticulosa exhibited higher radical scavenging activity than that of subsp. coronopifolia (IC50 = 1.25 ± 0.02 mg/mL and 2.86 ± 0.05 mg/mL), which in turn displayed better chelating properties (IC50 = 1.49 ± 0.01 mg/mL and 0.63 ± 0.01 mg/mL). Lastly, Artemia salina lethality bioassay was performed for toxicity assessment. The results of the bioassay showed lack of toxicity against brine shrimp larvae for both extracts. The data presented indicate the infraspecific taxa of M. fruticulosa as new and safe sources of antioxidant compounds. 相似文献
99.
Conventional methods generally used to synthesize heterogeneous photocatalysts have some drawbacks, mainly the difficult control/preservation of catalysts’ morphology, size or structure, which strongly affect the photocatalytic activity. Supercritical carbon dioxide (scCO2)-assisted techniques have recently been shown to be a promising approach to overcome these limitations, which are still a challenge. In addition, compared to traditional methods, these innovative techniques permit the synthesis of high-performance photocatalysts by reducing the use of toxic and polluting solvents and, consequently, the environmental impact of long-term catalyst preparation. Specifically, the versatility of scCO2 allows to prepare catalysts with different structures (e.g., nanoparticles or metal-loaded supports) by several supercritical processes for the photocatalytic degradation of various compounds. This is the first updated review on the use of scCO2-assisted techniques for photocatalytic applications. We hope this review provides useful information on different approaches and future perspectives. 相似文献
100.
Li-Bo Huang Maria Di Vincenzo Dr. Yuhao Li Dr. Mihail Barboiu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(7):2224-2239
Natural Aquaporin (AQP) channels are efficient water translocating proteins, rejecting ions. Inspired by this masterpiece of nature, Artificial Water Channels (AWCs) with controlled functional structures, can be potentially used to mimic the AQPs to a certain extent, offering flexible avenues toward biomimetic membranes for water purification. The objective of this paper is to trace the historical development and significant advancements of current reported AWCs. Meanwhile, we attempt to reveal important structural insights and supramolecular self-assembly principles governing the selective water transport mechanisms, toward innovative AWC-based biomimetic membranes for desalination. 相似文献