English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  “Proton sponges” and the geometry of hydrogen bonds: aromatic nitrogen bases with exceptional basicities

Staab, H. A., & Saupe, T. (1988). “Proton sponges” and the geometry of hydrogen bonds: aromatic nitrogen bases with exceptional basicities. Angewandte Chemie, International Edition in English, 27(7), 865-879. doi:10.1002/anie.198808653.

Item is

Files

show Files
hide Files
:
AngewChemIntEdEngl_27_1988_865.pdf (Any fulltext), 2MB
 
File Permalink:
-
Name:
AngewChemIntEdEngl_27_1988_865.pdf
Description:
-
OA-Status:
Visibility:
Restricted (Max Planck Institute for Medical Research, MHMF; )
MIME-Type / Checksum:
application/pdf
Technical Metadata:
Copyright Date:
-
Copyright Info:
-
License:
-

Locators

show
hide
Description:
-
OA-Status:
Description:
-
OA-Status:

Creators

show
hide
 Creators:
Staab, Heinz A.1, Author           
Saupe, Thomas1, Author           
Affiliations:
1Department of Organic Chemistry, Max Planck Institute for Medical Research, Max Planck Society, ou_1497706              

Content

show
hide
Free keywords: -
 Abstract: Certain aromatic diamines (the “proton sponges”) are found to have exceptionally high basicity constants: this is due to spatial interaction of the basic centers, which are in close proximity. The two factors which are most important in causing this effect are, on the one hand, the extreme steric strain in these systems and the destabilizing effect of the overlap of the nitrogen lone pairs of the neutral diamines and, on the other, the strong N . . H . . . N hydrogen bonds which are formed on monoprotonation and which lead to a considerable relaxation of the steric strain. By the systematic variation of the structures of such aromatic diamines we have been able to study these effects as a function of steric factors, in particular of the geometry and the bond length of the N- . .H. . -N hydrogen bonds, by means of X-ray structural analysis. The hydrophobic shielding of the basic centers and the N . . . H . . . N hydrogen bonds, which was characteristic of the “proton sponge” compounds studied previously, is indeed responsible for the extremely low rate of protonation and deprotonation of these compounds; however, it apparently has no influence on their high thermodynamic basicity. The recent synthesis and basicity determination of a new type of “proton sponge” with no hydrophobic shielding whatever show that not only very strong
but also kinetically active bases are accessible using the “proton sponge” concept. Their unusual properties, which are discussed here as the result of steric interactions between two basic centers, provide examples of the fact that cooperative steric interactions of reactive
structural elements can lead to properties which cannot be derived from an isolated consideration of the various functional groups. Such “proximity effects” are certainly of general importance in chemistry and biochemistry; the study of their structure-function relationships is worthy of closer consideration.

Details

show
hide
Language(s): eng - English
 Dates: 1988-02-101988-07-01
 Publication Status: Issued
 Pages: 15
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1002/anie.198808653
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Angewandte Chemie, International Edition in English
  Abbreviation : Angew. Chem., Int. Ed. Engl.
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Weinheim : Wiley-VCH
Pages: - Volume / Issue: 27 (7) Sequence Number: - Start / End Page: 865 - 879 Identifier: ISSN: 0570-0833
CoNE: https://pure.mpg.de/cone/journals/resource/0570-0833