1,720,983 research outputs found
Highly dynamic 1D coordination polymers for adsorption and separation applications
No full textOne-dimensional (1D) coordination polymers (CPs) are a class of materials with intriguing specific properties which however have been significantly overlooked, partially due to the monumental growth of research activities on their three-dimensional analogues, considered more robust and useful for applications. Here, we highlight the main advances on the use of 1D CPs for adsorption and separation purposes, focusing on larger guest molecules rather than common gaseous species (such as N2, CO2, etc...), also including CP systems capable to adsorb charged dyes or ions from aqueous solutions. Overall, in most cases, the adsorption processes here described induce quite significant structural changes in the CPs framework, which we were able to play up given the extensive X-ray characterization available. We aim to show how the dynamic properties of this class of compounds, in terms on their aptitude to respond to external chemical stimuli, is inherent with their structural features, for they are composed by robust chain-like arrays hold together by weak inter-chain interactions
Design and Synthesis of Multipurpose Derivatives for N-Hydroxyimide and NHPI-based Catalysis Applications**
No full textBi- and tricyclic derivatives 1 a and 2 a (Scheme 2) combining the catalytic N-hydroxyimide NO−H unit with the imidazole moiety were designed as multipurpose derivatives and proposed as chemical tools for achieving improved homogeneous and heterogeneous aerobic oxidation catalysis. BDE tunability, formation of a ZIF and of imidazolium ionic-liquid-like materials were obtained for N-hydroxyphthalimide (NHPI)-based 2 a and here described
Entrapment of a linear water pentamer into a uranyl-salophen dimer in the solid state
No full textIn the solid state, uranyl-salophen complex 1, decorated with bipyridyl sidearms, self-assembles from moist acetonitrile into dimeric species displaying a confined water pentamer, as observed by X-ray diffraction on single crystals. The linear water cluster is incarcerated within the dimeric cavity by coordination to the Lewis acidic uranyl centres and by a network of hydrogen bonds established with the pyridinic nitrogen atoms on the sidearms
Valutazione della capacità filtrante la componente UVA e UVB biologicamente attiva dello spettro solare di alcuni prototipi di vetro
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ON/OFF Control of the Flipping Motion of Diuranyl Bis(Salophen) Macrocycle by Extremely Strong Binding with Fluoride Ion
No full textDiuranyl bis(salophen) complex 1 features a relatively slow conformational motion, induced by an intramolecular O═U═O···UO2 binding motif, which interconverts the two nonsymmetric halves of the ligand. This flipping motion, which constitutes one of the fundamental molecular motions, can be completely halted by addition of fluoride anion, which is bound to 1, reaching one of the highest affinities reported to date. This system represents a model to study flipping dynamics in light of the possibility of developing novel types of molecular machines based on it
Determinazione "outdoor" in alta quota del fattore di protezione solare di una crema ad alta protezione
No full textSelective Cu(ii) sensing by a versatile AIE cyanostilbene-based gel system
No full textCyanostilbene-based derivatives 1-3 were designed, synthesized and fully characterized. By screening their gelating abilities, we observed that the subtle difference in the position of the pyridine nitrogen greatly affected the resulting fluorescence and gelation properties. Notably, 1 was found to be a versatile ambidextrous gelator capable of forming organo-, hydro-, and Cu(ii) specific metallogels. Furthermore, a rare organogel-to-metallogel transformation at room temperature was also observed upon exposure of the 1-DMSO/H2O gel to aqueous Cu(ii). This process, accompanied by colour and fluorescence changes, provides an effective strategy for the preparation of novel sensing soft materials
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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