The present contribution analyzes the special bonding situation of the [FAAF](-) anions (A = O, S, Se, Te), where the addition on an extra charge turns the covalent A-A bond of the neutral into a charge-shift (CS) bond. By means of theoretical calculations, we demonstrate that electrostatic interactions produced by negative point charges can transform the covalent A-A bond in the A2(+) cation i...

The Gd-doped Bi2Te3 compounds were prepared by solvothermal synthesis and spark plasma sintering. It was found that for the Bi2-xGdxTe3±y with x = 0.01; 0.05; 0.1; 0.15 0.2, Gd doping results in relevant changing Te content, y, i.e. y are inter-dependent. Governing Te-deficient Bi2-xGdxTe3-y compositions 0; 0.05 0.018; 0.011; 0.003, Te-rich Bi2-xGdxTe3+y 0.15; 0.2 0.013; 0.023; 0.04, successful...

This Highlight presents an overview of the rapidly growing field of dynamic covalent polymers. This class of polymers combines intrinsic reversibility with the robustness of covalent bonds, thus enabling formation of mechanically stable, polymer-based materials that are responsive to external stimuli. It will be discussed how the inherent dynamic nature of the dynamic covalent bonds on the mole...

The NMR spin-spin coupling constants (SSCCs) across the H-bond in proteins are sensitive to the electronic structure of the H-bonded system, i.e., the N-H‚‚‚OdC group in proteins. The spin-spin coupling mechanism across the H-bond involves a strong electric field effect, steric exchange interactions, and some weak covalent effects (transfer of electronic charge). The electric field effect is re...

The efficacy of a mechanism-based enzyme inhibitor depends not only on the rate of covalent modification of the target enzyme, but also on the affinity with which the enzyme binds the inhibitor before covalent bond formation. Since proteinases have binding regions that extend many residues beyond the scissile peptide bond, specific and potent mechanism-based inhibitors of this class of enzyme c...

We describe the development of Lewis’s ideas concerning the chemical bond and in particular the concept of the electron pair bond and the octet rule. We show that the concept of the electron pair bond has endured to the present day and is now understood to be a consequence of the Pauli principle. In contrast the octet rule is now regarded as much less important than was originally generally bel...

In a novel application, infrared spectroscopic ellipsometry is used to provide clear evidence for the formation of a covalent bond at a polymer/polymer interface. Specifically, there is evidence for the formation of a Si-O-C bond resulting from a reaction between the silyl (SiH) group of a poly(hydrogen methyl siloxane) crosslinker used in poly(dimethyl siloxane) and the carboxylic acid group o...

The dimeric, peroxisomal 3-ketoacyl-CoA thiolase catalyses the conversion of 3-ketoacyl-CoA into acyl-CoA, which is shorter by two carbon atoms. This reaction is the last step of the beta-oxidation pathway. The crystal structure of unliganded peroxisomal thiolase of the yeast Saccharomyces cerevisiae has been refined at 1.8 A resolution. An unusual feature of this structure is the presence of t...