Derivatives of azacalix[3](2,6)pyridine are strong neutral organic superbases: a DFT study

I Despotović; B Kovacević; Z B Maksić

doi:10.1021/ol0700299

Derivatives of azacalix[3](2,6)pyridine are strong neutral organic superbases: a DFT study

Org Lett. 2007 Mar 15;9(6):1101-4. doi: 10.1021/ol0700299. Epub 2007 Feb 21.

Authors

I Despotović¹, B Kovacević, Z B Maksić

Affiliation

¹ Quantum Organic Chemistry Group, Department of Organic Chemistry and Biochemistry, The Ruer Bosković Institute, P.O. Box 180, 10002 Zagreb, Croatia.

PMID: 17311392
DOI: 10.1021/ol0700299

Abstract

The gas phase basicities and pKa values in acetonitrile of azacalix[3](2,6)pyridine and its derivatives are determined by the B3LYP DFT method. It is found that all compounds of this series are neutral organic superbases. The proton attacks the inner pyridine N(sp2) atom, thus forming a bifurcated intramolecular hydrogen bond. The most powerful superbase is provided by the hexakis(dimethylamino) derivative of the title compound. Its gas phase proton affinity is 296.6 kcal mol-1, its basicity is 291.3 kcal mol-1, and its pKa(MeCN) is 30.9 units. [structure: see text]