English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

New proton sponges, 14. - Isomeric tetrakis(dimethylamino)naphthalenes: syntheses, structure-dependence of basicities, crystal structures, and physical properties

MPS-Authors
/persons/resource/persons95446

Staab,  Heinz A.
Department of Organic Chemistry, Max Planck Institute for Medical Research, Max Planck Society;

/persons/resource/persons93901

Krieger,  Claus
Department of Organic Chemistry, Max Planck Institute for Medical Research, Max Planck Society;

/persons/resource/persons94523

Neugebauer,  Franz A.
Department of Organic Chemistry, Max Planck Institute for Medical Research, Max Planck Society;

Fulltext (public)
There are no public fulltexts available
Supplementary Material (public)
There is no public supplementary material available
Citation

Staab, H. A., Kirsch, A., Barth, T., Krieger, C., & Neugebauer, F. A. (2000). New proton sponges, 14. - Isomeric tetrakis(dimethylamino)naphthalenes: syntheses, structure-dependence of basicities, crystal structures, and physical properties. European Journal of Organic Chemistry, 2000(8), 1617-1622. doi:10.1002/(SICI)1099-0690(200004)2000:8<1617:AID-EJOC1617>3.0.CO;2-C.


Cite as: http://hdl.handle.net/11858/00-001M-0000-0028-3733-5
Abstract
For comparison to the recently described 2,3,6,7-tetrakis(dimethylamino)naphthalene (1) the three isomers 2,3, and 4 were synthesized. The basicities of this group of isomers are strongly dependent upon the different mutual orientations of the pairs of dimethylamino substituents: only the isomers 3 and, partially, 4, both with dimethylamino groups in adjacent peri-positions of the naphthalene, are strong “proton sponges”. For the isomers 1 and 2 with the same number and kind of twofold dimethylamino substituents in neighbouring ortho-positions, however, no significant basicity increase is observed. To explain this difference between the two groups of isomers it is suggested that in the ortho-pairs of 1 and 2 the C-N bonds diverge considerably, leading to an increased N···N distance and consequently to less stable [N···H···N]+ hydrogen bonds in contrast to the parallel C-N bonds in the peri-substituted isomers 3 and 4. X-ray crystal structure analyses of the bases and of some of the salts derived therefrom were solved and are discussed. Cyclic voltammetry indicates that 1 to 4 are strong electron donors, reacting easily to radical cations or dications which with suitable acids have been obtained as salts.