Low-temperature single-crystal X-Ray diffraction, 1H and 13C solid-state NMR and 14N NQR studies of 1,8-bis(dimethyl-amino)naphthalene

Abstract

Low-temperature ¹³C and ¹H MAS NMR and ¹⁴N NQR spectra of solid 1,8-bis(dimethylamino)naphthalene (DMAN) have been measured. X-Ray diffraction shows that the molecule is more symmetric than at room temperature. The low-temperature geometry of DMAN is very similar to the ab initio optimized geometry. Solid-state NMR and nuclear quadrupole resonance (NQR) confirm the symmetry of the molecule at low temperature despite the asymmetry of intermolecular interactions in the crystal. Experimental values of the principal components of electric field gradients at ¹⁴N, which characterize the properties of the lone pair electrons of the nitrogen atoms, are in good agreement with the ab initio calculated values.