Publications by authors named "Federico Begato"

Photosynthetic hydrogen generation by cobalt(II) tris(2-pyridylmethyl)amine (TPMA) complexes is mainly limited by protonation kinetics and decomposition routes involving demetallation. In the present work we have explored the effects of both proton shuttles and improved rigidity on the catalytic ability of cobalt(II) TPMA complexes. Remarkably, we demonstrate that, while a small enhancement in the catalytic performance is attained in a rigid cage structure, the introduction of ammonium groups as proton transfer relays in close proximity to the cobalt center allows to reach a 4-fold increase in the quantum efficiency of H formation, and a surprising 22-fold gain in the maximum turnover number, at low catalyst concentration.

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Spatial organization using confinement has been of great interest since the early ages of supramolecular chemistry. Application such as sensing, catalysis and delivery are continuously emerging. This minireview highlights the evolution of chiral supramolecular cages (CSC) applications in the fields of catalysis, sensing and chiroptical properties.

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Taking inspiration from Nature, where (bio)molecular geometry variations are exploited to tune a large variety of functions, supramolecular chemistry has continuously developed novel systems in which, as a consequence of a specific stimulus, structural changes occur. Among the different architectures, supramolecular cages have been continuously investigated for their capability to act as functional hosts where guests can be released in a controlled fashion. In this paper, a novel methodology based on the use of phenanthrenequinone is applied to selectively change the binding properties of a tris(2-pyridylmethyl)amine TPMA-based cage.

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The use of chiroptical techniques in combination with stereodynamic probes is becoming one of the leading strategies for chiral sensing. While in most of the reported studies circular dichroism (CD) is the adopted spectroscopic technique, examples regarding the use of vibrational CD (VCD), circularly polarized luminescence (CPL), and Raman optical activity (ROA) are emerging as innovative tools. In this communication, an anthracene-decorated tris(2-pyridylmethyl)amine zinc complex (TPMA) is reported for its capability to act as a chiral sensor using either CD or fluorescence detected circular dichroism (FDCD).

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Dynamic covalent chemistry (DCC) has, in recent years, provided valuable tools to synthesize molecular architectures of increasing complexity. We have also taken advantage of imine DCC chemistry to prepare TPMA-based supramolecular cages for molecular recognition applications. However, the versatility of this approach has as a major drawback the intrinsic hydrolytic lability of imines, which hampers some applications.

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The fundamental implications that chirality has in science and technology require continuous efforts for the development of fast, economic, and reliable quantitative methods for enantiopurity assessment. Among the different analytical approaches, chiroptical techniques in combination with supramolecular methodologies have shown promising results in terms of both costs and time analysis. In this article, a tris(2-pyridylmethyl)amines ()-based supramolecular cage is able to amplify the circular dichroism (CD) signal of a series of chiral dicarboxylic acids also in the presence of a complex mixture.

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Two imine based supramolecular cages are able to self-assemble in the presence of a complex mixture like wine or fruit juices. Taking advantage of templating agents present in these mixtures the systems are able to form and to selectively encapsulate dicarboxylic systems present in the mixtures. This capability has been exploited to develop molecular systems able to report the enantiomeric excess and composition of (a)chiral dicarboxylic acids in fruit juices and wines using H-NMR.

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