Deuterium isotope effects on nuclear shielding constants and spin–spin coupling constants in the ammonium ion, ammonia, and water

Deuterium isotope effects on 15 N chemical shifts have been investigated for the ammonium ion, ammonia, and aniline; 1 Δ 15 N( 2/1 H) equals −293.3, −622.9, and −714.6 ppb respectively. Deviations from additivity are noted for NH 4−n D n + and NH 3−n D n ; these deviations follow the predictions of Jameson and Osten. For ammonia, examination of the proton nuclear magnetic resonance spectrum yields 1 Δ 1 H( 15/14 N) = −2.0 ± 0.4 ppb and [Formula: see text]. An accurate value of −1545 ± 5 ppb was obtained for 1 Δ 17 O( 2/1 H) in water. Derivatives of the heavy atom shielding constants with respect to extensions in the equilibrium bond length have been estimated for NH 4 + , NH 3 , and H 2 O; these derivatives are compared with the recent calculations of Chesnut. Deuterium isotope effects on 1 J ( 15 N,H) in ammonia and aniline have been measured for the first time. For the ammonium ion, deuterium isotope effects on 1 J ( 15 N,H) are in good agreement with the less accurate values we previously observed on 1 J ( 14 N,H). In the case of water, both primary and secondary deuterium isotope effects on 1 J ( 17 O,H) are less than 2%. The isotope effects on the spin–spin coupling constants observed here are compared with those previously reported for other hydrides in the literature.