1,721,016 research outputs found
A Haigh-Mallion-Based Approch for the Evaluation of the Intensity Factors of Aromatic Rings
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Palladium Catalysed Cyclotrimerisation Reactions of Polycyclic Alkenes under the Stille and Grigg Coupling Conditions
No full textStereochemistry of the Cyclotrimerisation of Enantiopure Polycyclic Bromostannylalkenes: Mechanistic Considerations on the Coupling of Alkenyl Stannanes by Copper(II) Nitrate
No full textGoing 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
A Diastereodynamic Probe Transducing Molecular Length into Chiroptical Readout
No full textNature takes advantage of molecular conformational changes to express functions such as signaling across cellular membranes or allosteric protein activation. At the synthetic level, molecular recognition events have been used to induce conformational changes able to trigger functions such as catalysis or sensing. In this context, transduction of stereochemical information has been the leading strategy. In particular, stereodynamic elements have been extensively employed to amplify and/or transduce chiral information. In this article, we report a chiral supramolecular cage with two stereodynamic units, which invert their helicities according to the length of the molecular guest confined within the system. Interestingly, achiral information is transduced by the supramolecular system to different diastereomeric states that have opposite chiroptical absorptions. This is the first example in which it is possible to produce a continuous modulation of the chiroptical output of a system by varying a physical achiral molecular property (viz. molecular dimension). This phenomenon can be exploited for the establishment of novel methods to program conformational control, for the development of innovative sensors and/or for transduction of molecular properties into chiroptical information
Hetero-Coencapsulation within a Supramolecular Cage: Moving away from the Statistical Distribution of Different Guests
No full textBeside sensing and delivery, another peculiar property arising from confinement in discrete molecular hosts comes from the possibility to have in close proximity, and in defined position, two different molecules (hetero-coencapsulation). This phenomenon can be tuned considering steric and electronic properties of the guests. In this work, a study on the parameters affecting homo- and hetero-coencapsulation processes within a supramolecular cage is reported. In particular, different benzoate guests were bound within a supramolecular cage containing two metal-binding sites and the experimental binding thermodynamics measured. Unexpectedly, from competition experiments it was observed that the maximum concentration of hetero-coencapsulation is achieved if a weakly binding guest is used to partially displace a strongly binding guest
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