Forty years of progress in the study of the hydrogen bond

Abstract

The author looks back at developments over the last few decades concerning the H-bond. The list of atoms involved as proton donor and acceptor has broadened dramatically, including most electronegative atoms and even metals. The factors that control the transfer of the proton across the H-bond have been elucidated and show the importance of even minor changes in its geometry. Small stretches can shut down the transfer entirely and certain bends can force a proton to transfer against a pK gradient. Along with recognition that a CHꞏꞏO interaction can represent a true H-bond, and one with strength comparable to more traditional H-bonds, has come an understanding of its contributions to protein structure and function. The replacement of the bridging H by any of a litany of electronegative atoms leads to similarly strong interactions, with many features virtually indistinguishable from a true H-bond. These noncovalent interactions are typically referred to as halogen, chalcogen, pnicogen, and tetrel bonds, depending upon the identity of the substitute bridging atom.

Cooperativity in alkane‐1,2‐ and 1,3‐polyols: NMR, QTAIM, and IQA study of O─H…OH and C─H…OH bonding interactions

“…The interaction between an aromatic or aliphatic C─H hydrogen and an oxygen, very often a carbonyl oxygen, is one of the several weak but often numerous, non‐conventional hydrogen bonds (others are C─H … π, C─H … n , C─H … X, X─H … π, etc. ), which are very important in determining the conformations of organic compounds 91–94 . The C─H … O hydrogen bond is common in the solid state 95–98 and is implicated in the 3D structure and reactivity of proteins and other biomolecules 91–94, 99–103 …”

A perspective approach on the amine reactivity and the hydrogen bonds effect on epoxy-amine systems

“…N, O, F or Cl), 28 and the environment (steric hindrance, substituent, angle of H bonds, …) has also an impact on the H bond force. 29 For instance, the H bond linkage geometry is known to be flexible, but should approach linear profile to reach a minimum energy. Thus, the closer the D-H---A angle to 180°, the stronger the H bond and the shorter the H---A distance.…”

Chalcogen-bond driven molecular recognition at work

“…EBIs and XBIs are often seen as competitive interactions to hydrogen bonding interactions (HBIs), and the interested reader is addressed to the relevant papers in the field. [22][23][24][25][26][27] Since the first observation of an EBI at the solid state in the sixties, [28] and its conceptualisation in 2000, [1,3,[29][30][31][32][33] several chemical systems exploiting the chalcogen-bonding recognition in the solid state [3,[34][35][36][37] and in solution [38] have been reported in the literature. Compared to halogens, chalcogen atoms depict two -holes, and can allow the formation of two interactions (e.g., see the -holes depicted by the ESP maps of 1,2,5-telluradiazole 2Te and iodopentafluorobenzene 1, Figure 1).…”