A. Degtyarev, O. Ryabtsova, A. Pozharskii
Jun 30, 2008
Citations
0
Influential Citations
21
Citations
Journal
Tetrahedron
Abstract
Abstract Protonated 2,7-bis(trimethylsilyl)- and 2,7-di(hydroxymethyl)-1,8-bis(dimethylamino)naphthalenes have been prepared and studied by a combination of X-ray crystallography at room and low temperatures, IR and NMR spectroscopic techniques in conjunction with quantum-chemical calculations. It was demonstrated that the intramolecular [NHN] + hydrogen bond in the 2,7-bis(trimethylsilyl) system, being sterically compressed, is the shortest among all known aromatic diamine systems. Nevertheless, as it is evidenced by the primary 1 H/ 2 H isotope effect, IR spectra and MP2 calculations, a double minimum potential for the proton motion still exists with a very low barrier estimated to be about 0.7 kcal/mol. An influence of a counter-anion on the NH proton involving the spatially hindered H-bond is also considered.