14 N quadrupole resonance in carbonatotetramminecobalt(III) bromide

Abstract

The 14N quadrupole interactions in a single crystal of carbonatotetramminecobalt(III) bromide have been studied by 1 H 14 N double resonance in the rotating frame. In accordance with the existence of three kinds of nonequivalent nitrogen atom N(1), N(2), and N(3) in the cation, the following three sets of nuclear quadrupole coupling constants and asymmetry parameters have been observed: N(1) 1678 ± 2 kHz, 0.006 ± 0.003; N(2)1248 ± 3 kHz, 0.326 ± 0.006, and N(3)1506 ± 4 kHz, 0.050 ± 0.005. The lower quadrupole coupling constant and high asymmetry parameter of N(2) are attributable to intermolecular N(2)H---O hydrogen bonding and are interpreted by the Townes and Dailey method. Double-resonance lines of 79Br were detected near the frequency minima of their rotation patterns. The 79Br quadrupole coupling constant and asymmetry parameter have been determined as 16.769 ± 0.006 MHz and 0.322 ± 0.002 with the aid of pure quadrupole resonance experiments.