نتایج جستجو برای: parahydrogen
تعداد نتایج: 287 فیلتر نتایج به سال:
Symmetry breaking of parahydrogen using iridium catalysts converts singlet spin order into observable hyperpolarization. In this contribution, are designed to exhibit asymmetry in their hydrides, regulated by situ generation deuterated ammonia governed ammonium buffers. The concentrations (N) and pyridine (P) provide a handle generate variety stereo-chemically asymmetric N-heterocyclic carbene ...
Abstract Parahydrogen-induced polarization is a hyperpolarization method for enhancing nuclear magnetic resonance signals by chemical reactions/interactions involving the para spin isomer of hydrogen gas. This has allowed biomolecules to be hyperpolarized such level that they can used real time in vivo metabolic imaging. One particularly promising example fumarate, which rapidly and efficiently...
(1)H NMR signal amplification by reversible exchange (SABRE) was observed for pyridine and pyridine-d5 at 9.4 T, a field that is orders of magnitude higher than what is typically utilized to achieve the conventional low-field SABRE effect. In addition to emissive peaks for the hydrogen spins at the ortho positions of the pyridine substrate (both free and bound to the metal center), absorptive s...
We report an inelastic neutron scattering investigation of the quantum dynamics of hydrogen molecules trapped inside anisotropic fullerene cages. Transitions among the manifold of quantized rotational and translational states are directly observed. The spectra recorded as a function of energy and momentum transfer are interpreted in terms of the rotational potential and the cage dimensions. The...
Table S2. The results obtained in 1-butyne hydrogenation with parahydrogen over Cy3P-Cu/SiO2-700 catalyst: 1-butyne conversion (X), selectivity to 1-butene (S1-butene), signal enhancements (SE) calculated for vinyl CH and CH2 protons of 1-butene, and lower estimates of percentages of pairwise hydrogen addition calculated using SE values. Temperature, °C Flow rate, mL/s X, % S1-butene, % SE (CH)...
Substantial (31)P NMR signal enhancement of more than two orders of magnitude at 7 T for free and bound PPh3 species was observed under reversible interaction of (PPh3)3Ir(H2)Cl with parahydrogen. The large improvement in sensitivity made single-shot (31)P NMR imaging of a model object possible. The observed effects are temperature and magnetic field dependent as shown experimentally and theore...
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