G0900785 and by the Royal Society through the Paul Instrument Fun

G0900785 and by the Royal Society through the Paul Instrument Fund. The authors would

like to express appreciation to Clive Dixon, Mike Olsen, Ian Taylor, and Ian Thexton for fabrication of specialized glassware and equipment used in this work. The authors would like to also thank Prof. Ian Hall, and Prof. Peter Morris for useful discussions. A special thanks goes to Clémentine Lesbats for her assistance during the experiments. “
“By producing nuclear spin polarization far beyond that available at thermal equilibrium, hyperpolarization can provide improved sensitivity for NMR, enabling the detection of less concentrated molecules. In the area of molecular imaging, MRI has recently been used to study the distribution [1] and metabolism [2], selleck chemicals llc [3] and [4] of hyperpolarized substrates. For instance, multiple studies have reported on the conversion of hyperpolarized 13C-labeled pyruvate to its metabolic

products, alanine, lactate and carbonate in vivo [2], [3], [4], [5] and [6], in which higher lactate production is an important indicator of cancer. This technique is already being translated to the clinic and a first trial is ongoing [7]. Major hyperpolarization techniques include dynamic nuclear polarization (DNP) [8] and [9], spin exchange optical pumping polarization of noble gases [10] and parahydrogen induced polarization (PHIP) [11], [12], [13], [14], [15] and [16]. Parahydrogen is a spin isomer of hydrogen with an antisymmetric singlet spin state. By incorporating this pure spin state into a molecule through a hydrogenation reaction, STI571 in vitro large signal enhancements have been observed in a variety of situations as first conceived by Bowers

and Weitekamp [12] and Pravica and Weitekamp [14]. In 2009, Duckett’s group developed a parahydrogen polarization technique that works without the need for the chemical modification of the substrate [17]. In this approach, Etomidate the substrate and the parahydrogen bind to a catalyzing metal complex simultaneously, thus enabling polarization to be transferred to the substrate through the scalar coupling network. The polarized substrate is subsequently released, and replaced by new substrate which is polarized in turn. Such Signal Amplification By Reversible Exchange (SABRE) has already been applied to detect trace amounts of chemicals [18], [19] and [20] and used in conjunction with zero-field NMR spectroscopy [21]. According to a theoretical description of SABRE, the signal enhancement level depends on the binding kinetics and the magnetic field in which polarization transfer occurs [22]. In order to achieve better enhancement, new catalyst precursors have been developed to tune the binding kinetics. Enhancements can be boosted by using the bulky electron-donating phosphines of the Crabtree catalyst [23].

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