Role of Protons in and around Strongly Coupled Nitroxide Biradicals for Cross-Effect Dynamic Nuclear Polarization.

ABSTRACT: In magic angle spinning dynamic nuclear polarization (DNP), biradicals such as bis-nitroxides are used to hyperpolarize protons under microwave irradiation through the cross-effect mechanism. This mechanism relies on electron-electron spin interactions (dipolar coupling and exchange interaction) and electron-nuclear spin interactions (hyperfine coupling) to hyperpolarize the protons surrounding the biradical. This hyperpolarization is then transferred to the bulk sample via nuclear spin diffusion. However, the involvement of the protons in the biradical in the cross-effect DNP process has been under debate. In this work, we address this question by exploring the hyperpolarization pathways in and around bis-nitroxides. We demonstrate that for biradicals with strong electron-electron interac

SUBMITTER: Chatterjee S 

PROVIDER: S-EPMC11562033 | biostudies-literature | 2024 Feb

REPOSITORIES: biostudies-literature