From weak to strong interactions: structural and electron topology analysis of the continuum from the supramolecular chalcogen bonding to covalent bonds.

The relationship between covalent and supramolecular bonding, and the criteria of the assignments of different interactions were explored the review of selenium and tellurium containing structures in the Cambridge Structural Database and their computational analysis using Quantum Theory of Atoms in Molecules (QTAIM). This combined study revealed continuums of the interatomic Se⋯Br and Te⋯I distances, , in the series of associations from the sums of the van der Waals radii of these atoms ( + ) to their covalent bond lengths. The electron densities, (), at Bond Critical Points (BCPs) along the chalcogen bond paths increased gradually from about 0.

Examining a Transition from Supramolecular Halogen Bonding to Covalent Bonds: Topological Analysis of Electron Densities and Energies in the Complexes of Bromosubstituted Electrophiles.

The transition from weak (noncovalent) interactions to fully developed covalent bonds is examined using the quantum theory of atoms in molecules in a series of halogen-bonded (XB) complexes of bromosubstituted electrophiles, RBr, with 1,4-diazabicyclo[2.2.2]octane (DABCO) and Cl and Br anions.

The immunorecognition, subcellular compartmentalization, and physicochemical properties of nucleic acid nanoparticles can be controlled by composition modification.

Nucleic acid nanoparticles (NANPs) have become powerful new platforms as therapeutic and diagnostic tools due to the innate biological ability of nucleic acids to identify target molecules or silence genes involved in disease pathways. However, the clinical application of NANPs has been limited by factors such as chemical instability, inefficient intracellular delivery, and the triggering of detrimental inflammatory responses following innate immune recognition of nucleic acids. Here, we have studied the effects of altering the chemical composition of a circumscribed panel of NANPs that share the same connectivity, shape, size, charge and sequences.

Modulating Immune Response with Nucleic Acid Nanoparticles.

Nano-objects made of nucleic acids are becoming promising materials in the biomedical field. This is, in part, due to DNA and RNA self-assembly properties that can be accurately computed to fabricate various complex nanoarchitectures of 2D and 3D shapes. The nanoparticles can be assembled from DNA, RNA, and chemically modified oligonucleotide mixtures which, in turn, influence their chemical and biophysical properties.

Facile conversion of chromane-6-triflate to chromane-6-alanines under Palladium conditions.

Conversion of chromane-6-triflate to chromane-6-dehydroalanine or via its Bpin-derivative followed by Suzuki coupling with protected dehydroalanine bromides or were reported (86%). Alternatively, a palladium-catalyzed stannation of with BuSn afforded the tributyltin derivative , and iodination ( followed by coupling with gave chromane-6-alanine (75%). Either approach constitutes a conversion from chromane-6-triflate to the corresponding protected chromane-6-alanine or its dehydro analog.