Preparation of Long-Lived Nuclear Singlet States in Three-Spin Systems

Abstract

Long-lived nuclear singlet states are widely used in NMR because they have longer lifetime (TS) than conventional longitudinal relaxation time (T1). In this paper, we present a new method to calculate the parameters for preparing long-lived nuclear singlet states, which is applicable to weakly-coupled three-spin systems. It was found that in the same three-spin system, there existed a variety of combination of singlet states with different proportional coefficients. Herein, we prepared two singlet states in an acrylic acid sample. The lifetime of the two states was measured experimentally, which showed significant difference. In addition, the effects of temperature on the singlet state lifetimes of acrylic acid were investigated.

Keywords

• liquid-state NMR
• long-lived nuclear singlet states
• longitudinal relaxation time
• acrylic acid