(1)H Hyperpolarization of Solutions by Overhauser Dynamic Nuclear Polarization with (13)C–(1)H Polarization Transfer

[Image: see text] Dynamic nuclear polarization (DNP) is a method that can significantly increase the sensitivity of nuclear magnetic resonance. The only effective DNP mechanism for in situ hyperpolarization in solution is Overhauser DNP, which is inefficient for (1)H at high magnetic fields. Here we demonstrate the possibility of generating significant (1)H hyperpolarization in solution at room temperature. To counter the poor direct (1)H Overhauser DNP, we implement steady-state (13)C Overhauser DNP in solutions and then transfer the (13)C hyperpolarization to (1)H via a reverse insensitive nuclei enhanced by polarization transfer scheme. We demonstrate this approach using a 400 MHz gyrotron-equipped 3.2 mm magic angle spinning DNP system to obtain (1)H DNP enhancement factors of 48, 8, and 6 for chloroform, tetrachloroethane, and phenylacetylene, respectively, at room temperature.