Extreme magnetic separation of geminal protons in protonated N,N,N'-trimethyl-1,8-diaminonaphthalene. A puzzle of the fourth methyl group

Valery A Ozeryanskii; Alexander F Pozharskii; Alexander Filarowski; Gennady S Borodkin

doi:10.1021/ol400746u

Extreme magnetic separation of geminal protons in protonated N,N,N'-trimethyl-1,8-diaminonaphthalene. A puzzle of the fourth methyl group

Org Lett. 2013 May 3;15(9):2194-7. doi: 10.1021/ol400746u. Epub 2013 Apr 16.

Authors

Valery A Ozeryanskii¹, Alexander F Pozharskii, Alexander Filarowski, Gennady S Borodkin

Affiliation

¹ Department of Organic Chemistry, Southern Federal University, Zorge 7, 344090 Rostov-on-Don, Russian Federation.

PMID: 23590329
DOI: 10.1021/ol400746u

Abstract

Monoprotonated N,N,N'-trimethyl-1,8-diaminonaphthalene demonstrates fast exchange of H(in) and H(out) protons, in which a counterion (BF4(-) and Br(-) were tested) participates. The process can be frozen below 185 K revealing a tremendous magnetic separation (up to Δδ = 11.6 ppm) of these otherwise equal NH protons with the enzyme-like proton transfer and a ∼7 kcal mol(-1) energetic barrier.