Relaxation Processes in the N-Methyl Group of 1,2,2,6,6-Pentamethylpiperidine

Abstract

Relaxation times (T₁) and methyl-methyl nuclear Overhauser effects were measured for ¹H, ¹³C and ²H nuclei in 1,2,2,6,6-pentamethylpiperidine and its N-CHD₂ analogue which was synthesized by LiAlD₄ reduction of the N-CHO compound. The relaxation pathways for hydrogens of the N-CH₃ group were estimated to be as follows: spin-rotation 0.046 s^-1, dipole-dipole within N-methyl 0.069 s^-1, and dipole-dipole with the hydrogens of the C- methyls 0.027 s^-1. The ¹H{¹H) Overhauser effect at the N-CH₃ was 7.6%.