1,721,105 research outputs found
Celebrating 150 years from Mendeleev: The Periodic Table of Chemical Interactions
No full textYear 2019 marked the sesquicentennial anniversary of Mendeleev’s paper and many events were organized to celebrate this milestone in science. We considered that linking to Periodic Table of Chemical Elements the repeating trends observed in the chemical interactions formed by various elements was a particularly timely and remarkable tribute to that milestone and his inventor. A collection of reviews acknowledging and framing this link was the most convenient tool to pursue our objective and we are grateful to Prof. P. A. Gale for accepting to publish in Coordination Chemistry Reviews the Article Collection entitled “Celebrating 150 Years from Mendeleev: The Periodic Table of Chemical Interactions”
Photoluminescent nanocluster-based probes for bioimaging applications
Full text linkIn the continuous search for versatile and better performing probes for optical bioimaging and biosensing applications, many research efforts have focused on the design and optimization of photoluminescent metal nanoclusters. They consist of a metal core composed by a small number of atoms (diameter < 2–3 nm), usually coated by a shell of stabilizing ligands of different nature, and are characterized by molecule-like quantization of electronic states, resulting in discrete and tunable optical transitions in the UV–Vis and NIR spectral regions. Recent advances in their size-selective synthesis and tailored surface functionalization have allowed the effective combination of nanoclusters and biologically relevant molecules into hybrid platforms, that hold a large potential for bioimaging purposes, as well as for the detection and tracking of specific markers of biological processes or diseases. Here, we will present an overview of the latest combined imaging or sensing nanocluster-based systems reported in the literature, classified according to the different families of coating ligands (namely, peptides, proteins, nucleic acids, and biocompatible polymers), highlighting for each of them the possible applications in the biomedical field. Graphical abstract: [Figure not available: see fulltext.
Chalcogen Bonds Involving Selenium in Protein Structures
Full text linkChalcogen bonds are the specific interactions involving group 16 elements as electrophilic sites. The role of chalcogen atoms as sticky sites in biomolecules is underappreciated, and the few available studies have mostly focused on S. Here, we carried out a statistical analysis over 3562 protein structures in the Protein Data Bank (PDB) containing 18 »266 selenomethionines and found that Se···O chalcogen bonds are commonplace. These findings may help the future design of functional peptides and contribute to understanding the role of Se in nature
Halogen bonding in hypervalent iodine compounds
No full textHalogen bonds occur when electrophilic halogens (Lewis acids) attractively interact with donors of electron density (Lewis bases). This term is commonly used for interactions undertaken by monovalent halogen derivatives. The aim of this chapter is to show that the geometric features of the bonding pattern around iodine in its hypervalent derivatives justify the understanding of some of the longer bonds as halogen bonds. We suggest that interactions directionality in ionic and neutral λ3-iodane derivatives is evidence that the electron density distribution around iodine atoms is anisotropic, a region of most positive electrostatic potential exists on the extensions of the covalent bonds formed by iodine, and these positive caps affect, or even determine, the crystal packing of these derivatives. For instance, the short cation–anion contacts in ionic λ3-iodane and λ5-iodane derivatives fully match the halogen bond definition and geometrical prerequisites. The same holds for the short contacts the cation of ionic λ3-iodanes forms with lone-pair donors or the short contacts given by neutral λ3-iodanes with incoming nucleophiles. The longer and weaker bonds formed by iodine in hypervalent compounds are usually called secondary bondings and we propose that the term halogen bond can also be used. Compared to the term secondary bond, halogen bond may possibly be more descriptive of some bonding features, e.g., its directionality and the relationships between structure of interacting groups and interaction strength
Confined space design by nanoparticle self-assembly
Full text linkNanoparticle (NP) self-assembly has led to the fabrication of an array of functional nanoscale systems, having diverse architectures and functionalities. In this perspective, we discuss the design and application of NP suprastructures (SPs) characterized by nanoconfined compartments in their self-assembled framework, providing an overview about SP synthetic strategies reported to date and the role of their confined nanocavities in applications in several high-end fields. We also set to give our contribution towards the formation of more advanced nanocompartmentalized SPs able to work in dynamic manners, discussing the opportunities of further advances in NP self-assembly and SP research
Halogen bonding at the wet interfaces of an amyloid peptide structure
No full textAmyloid peptide hydrogels are a class of materials of great interest due to their structural simplicity, good performances and easy tuning of their properties by chemical modification. Among the possible modifications, halogenation has not yet been exploited extensively. Here, we report the single-crystal X-ray structure of two dihalogenated derivatives of the amyloidogenic sequence DFNKF. The obtained results show how halogenation is a promising tool to stabilize-through halogen bonds-the wet interface of amyloid structures, to determine an increase in the water uptake, hence the hydrogelation properties of the peptide sequence
Halogen Bonding in Perovskite Solar Cells: A New Tool for Improving Solar Energy Conversion
Full text linkHybrid organic–inorganic halide perovskites (HOIHPs) have recently emerged as a flourishing area of research. Their easy and low-cost production and their unique optoelectronic properties make them promising materials for many applications. In particular, HOIHPs hold great potential for next-generation solar cells. However, their practical implementation is still hindered by their poor stability in air and moisture, which is responsible for their short lifetime. Optimizing the chemical composition of materials and exploiting non-covalent interactions for interfacial and defects engineering, as well as defect passivation, are efficient routes towards enhancing the overall efficiency and stability of perovskite solar cells (PSCs). Due to the rich halogen chemistry of HOIHPs, exploiting halogen bonding, in particular, may pave the way towards the development of highly stable PSCs. Improved crystallization and stability, reduction of the surface trap states, and the possibility of forming ordered structures have already been preliminarily demonstrated
Halogen-bonded photoresponsive materials
No full textThe aim of the present review is to illustrate to the reader the state of the art on the construction of supramolecular azobenzene-containing materials formed by halogen bonding. These materials include several examples of polymeric, liquid crystalline or crystalline species whose performances are either superior to the corresponding performances of their hydrogen-bonded analogues or simply distinctive of the halogen-bonded specie
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