The application of novel Ir-NHC polarization transfer complexes by SABRE.

In recent years, the hyperpolarization method Signal Amplification By Reversible Exchange (SABRE) has developed into a powerful technique to enhance Nuclear Magnetic Resonance (NMR) signals of organic substrates in solution (mostly via binding to the nitrogen lone pair of N-heterocyclic compounds) by several orders of magnitude. In order to establish the application and development of SABRE as a hyperpolarization method for medical imaging, the separation of the Ir-N-Heterocyclic Carbene (Ir-NHC) complex, which facilitates the hyperpolarization of the substrates in solution, is indispensable. Here, we report for the first time the use of novel Ir-NHC complexes with a polymer unit substitution in the backbone of N-Heterocyclic Carbenes (NHC) for SABRE hyperpolarization, which permits the removal of the complexes from solution after the hyperpolarization of a target substrate has been generated.

Ultrafast Single-Scan 2D NMR Spectroscopic Detection of a PHIP-Hyperpolarized Protease Inhibitor.

Two-dimensional NMR spectroscopy is one of the most important spectroscopic tools for the investigation of biological macromolecules. However, due to the low sensitivity of NMR spectroscopy, it takes usually from several minutes to many hours to record such spectra. Here, the possibility of detecting a bioactive derivative of the sunflower trypsin inhibitor-1 (SFTI-1), a tetradecapeptide, by combining parahydrogen-induced polarization (PHIP) and ultrafast 2D NMR spectroscopy is shown.

A highly versatile automatized setup for quantitative measurements of PHIP enhancements.

The design and application of a versatile and inexpensive experimental extension to NMR spectrometers is described that allows to carry out highly reproducible PHIP experiments directly in the NMR sample tube, i.e. under PASADENA condition, followed by the detection of the NMR spectra of hyperpolarized products with high spectral resolution.

Effective PHIP labeling of bioactive peptides boosts the intensity of the NMR signal.

A series of novel bioactive derivatives of the sunflower trypsin inhibitor-1 (SFTI-1) suitable for hyperpolarization by parahydrogen-induced polarization (PHIP) was developed. The PHIP activity was achieved by labeling with L-propargylglycine, O-propargyl-L-tyrosine, or 4-pentynoic acid. (1) H NMR signal enhancements (SE) of up to a factor of 70 were achieved in aqueous solution.

Parahydrogen-induced polarization of carboxylic acids: a pilot study of valproic acid and related structures.

Parahydrogen-induced polarization (PHIP) is a promising new tool for medical applications of MR, including MRI. The PHIP technique can be used to transfer high non-Boltzmann polarization, derived from parahydrogen, to isotopes with a low natural abundance or low gyromagnetic ratio (e.g.

PHIP-label: parahydrogen-induced polarization in propargylglycine-containing synthetic oligopeptides.

The unsaturated side chain of l-propargylglycine (Pra) was used to study parahydrogen-induced polarization (PHIP) in synthetic oligopeptides. For the first time PHIP-induced NMR signal enhancement was demonstrated using model peptides bearing various functional side chains.

Parahydrogen-induced polarization transfer to 19F in perfluorocarbons for 19F NMR spectroscopy and MRI.

Fluorinated substances are important in chemistry, industry, and the life sciences. In a new approach, parahydrogen-induced polarization (PHIP) is applied to enhance (19)F MR signals of (perfluoro-n-hexyl)ethene and (perfluoro-n-hexyl)ethane. Unexpectedly, the end-standing CF3 group exhibits the highest amount of polarization despite the negligible coupling to the added protons.