Document Type

Article

Journal/Book Title

Molecules

Publication Date

9-11-2017

Publisher

MDPI

Volume

22

Issue

9

First Page

1521

Last Page

1521

DOI

10.3390/molecules22091521

Abstract

Even after more than a century of study [1–6], scrutiny, and detailed examination, the H-bond continues [7–12] to evoke a level of fascination that surpasses many other phenomena. Perhaps it is the ability of the simple H atom, with but a single electron, to act as a glue that maintains contact between much more complicated species. Or it might be its geometry, which prefers to hold the bridging proton on a direct line between the two heavy atoms. Not to be ignored are the spectral features of the H-bond: the large red shift of the stretching frequency of the covalent A–H bond, coupled with its intensification, or the downfield shift of the proton’s NMR signal. Yet study of this bond is far from complete, with one surprise after another continuing to emerge. As it turns out, the aforementioned red shift, for example, long considered as the trademark of this bond, is not so characteristic after all. H-bonds that shift in the opposite direction, to the blue, have been observed [13–16] in a variety of systems. The long held belief that only very electronegative atoms like F, O, and N can participate in these bonds has been shattered, as one atom after another, S and Cl and even metals to name just a few, have been added [17–20] to the rapidly growing list.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.