It is shown that the dissociation energy D e for the process B⋯A = B + A for 250 complexes B⋯A composed of 11 Lewis bases B (N₂, CO, HC≡CH, CH₂=CH₂, C₃H₆, PH₃, H₂S, HCN, H₂O, H₂CO and NH₃) and 23 Lewis acids (HF, HCl, HBr, HC≡CH, HCN, H₂O, F₂, Cl₂, Br₂, ClF, BrCl, H₃SiF, H₃GeF, F₂CO, CO₂, N₂O, NO₂F, PH₂F, AsH₂F, SO₂, SeO₂, SF₂, and SeF₂) can be represented to good approximation by means of the ...

Although it is known that most of the plasma proteinase inhibitors form complexes with proteinases that are not dissociated by SDS (sodium dodecyl sulphate), there has been disagreement as to whether this is true for a2M ( a2-macroglobulin). We have examined the stability to SDS with reduction of complexes between a2M and several 125I-labelled proteinases (trypsin, plasmin, leucocyte elastase, ...

Self-consistent generalized valence bond (GVB) and configuration-interaction calculations have been performed for a cluster model of the neutral vacancy in silicon. Three low-lying states ('E, 'T„sA2) are found to possess one electron in dangling-bond orbitals on each of the four silicon atoms around the defect. Of these three covalent states, the 'E is found to be the ground state with the exc...

Hydrogen bond (H-bond) covalency has recently been observed in ice and liquid water, while the penetrating molecular orbitals (MOs) in the H-bond region of most typical water dimer system, (H2O)2, have also been discovered. However, obtaining the quantitative contribution of these MOs to the H-bond interaction is still problematic. In this work, we introduced the orbital-resolved electron densi...

The study aimed to cast light on the structure and internal energetics of guanine- and xanthine-based model DNA quadruplexes and the physico-chemical nature of the non-covalent interactions involved. Several independent approaches were used for this purpose: DFT-D3 calculations, Quantum Theory of Atoms in Molecules, Natural Bond Orbital Analysis, Energy Decomposition Analysis, Compliance Consta...

We present an approach for the determination of covalent bond orders from the experimental electron density and its derivatives at the bond critical points. An application of this method to a series of organic compounds has shown that it provides a bonding quantification that is in reasonable agreement with that obtained by orbital theory. The 'experimental' atomic valence indices are also defi...

The covalent linkage of graphene acid (GA) with amine-functionalized UiO-66-NH 2 via an amide bond. resultant hybrid GA@UiO-66-NH acts as a chemiresistive CO sensor wth significant efficiency owing to its unique structural features.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a class of fluorinated organic chemicals containing at least one fully fluorinated carbon atom. The C-F bond is one of the strongest known covalent bonds, and the multiple C-F bonds in PFASs impart their chemical and thermal stability. The strength of the C-F bond arises, in part, from the electronegativity of the fluorine atom and from ...

Hydrogen bond donor catalysis represents a rapidly growing subfield of organocatalysis. While traditional hydrogen bond donors containing N-H and O-H moieties have been effectively used for electrophile activation, activation based on other types of non-covalent interactions is less common. This mini review highlights recent progress in developing and exploring new organic catalysts for electro...