60154-30-5Relevant academic research and scientific papers
DETERMINATION OF THE SIGN OF A ONE-BOND (15)N-(15)N SPIN-SPIN COUPLING CONSTANT FOR A TRANS-DIAZENE BY SELECTIVE (15)N DECOUPLING EXPERIMENTS IN (13)C NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY
Kuroda, Yoshihiro,Fujiwara, Yasuhiro,Kuwae, Akio,Matsushita, Kazuhiro
, p. 675 - 680 (2007/10/02)
The sign of the one-bond (15)N-(15)N spin-spin coupling constant, 1J(N-N), of a trans-diazene (4-acetyl-aminoazobenzene) has been determined to test the theoretical prediction that 1)(N-N) would be positive in sign when nitrogens have s-hybridized lone pairs and take a trans conformation.The sign was first determined relative to those of (13)C-(15)N spin-spin coupling constants, nJ(C-N), by selective (15)N decoupling experiments and then finally referenced to that of 1J(C-H) in the benzene ring, which undoubtedly bears a positive sign, by selective (15)N and (1)H decoupling experiments.It was found that the sign of 1J(N-N) of the trans-diazene is negative in contrast to the theoretical prediction.This discrepancy is attributed to the large negative contribution from the orbital-dipole term which was not correctly evaluated in previous calculations for the 1J(N-N) coupling of the N=N bond.
