Development of new methods in modern selective organic synthesis: preparation of functionalized molecules with atomic precision

Parahydrogen‐Based Hyperpolarization for Biomedicine

“…HET-PHIP effects were also successfully observed using heterogeneous catalysts comprising Pt and Pd nanoparticles supported on γ-Al 2 O 3 , [79] and later for many other supported metals (e.g., Rh, Ir, Co, Ni, Au, Cu) catalysts in gas, liquid and aqueous phase hydrogenations. [11–12, 25, 27, 78f, 78g, 80] Variation of the type of metal, metal particle size [80a, 80d, 81] and shape, [80e, 80h] type of support [80a, 80d, 80g, 80i] and reaction conditions were all shown to influence the magnitude of the PHIP effect. Polarization transfer from 1 H to heteronuclei ( 13 C, 15 N) during heterogeneous hydrogenation [9b, 62a, 62b] helps to increase the hyperpolarization lifetime significantly, and is particularly important for potential biomedical applications along with the use of aqueous media.…”

“…Capping of metal nanoparticles with organic ligands may hinder surface mobility, as shown for PHIP in the gas phase, [83] organic solvents [84] and water, [4b, 7, 85] with the latter yielding ~1 mM of HP product with up to 1.2% polarization ( 1 H and 13 C) in 10 s. Reduced surface mobility of H atoms is also expected on metal oxides. Indeed, PHIP effects were observed using many such materials [80j, 86] (e.g., CeO 2 , Cr 2 O 3 , CaO, ZrO 2 ).…”

“…Nowadays significant efforts are underway to develop hyperpolarization techniques for gases other than costly noble gases, [119] such as 3 He and 129 Xe, [80l, 120] with gaseous hydrocarbons hyperpolarized via PHIP [2b] being one of the promising alternatives. [77, 121] The first successful utilization of PHIP to produce HP propane gas used immobilized catalysts.…”

“…[77] The resulting significant 1 H NMR signal enhancement facilitated the MR imaging of various model objects, [122] and was later used to image production of hyperpolarized propane in an operating heterogeneous catalytic reactor using both conventional [122b] and remote-detection MRI. [123] Efforts to increase the efficiency of pairwise hydrogen addition to unsaturated hydrocarbons by modifying the heterogeneous catalyst structure [80g] and varying the nature of catalytically active sites [80k, 86b] helped identify Rh/TiO 2 as an efficient hydrogenation catalyst for the production of HP propane for 3D MRI with micro-scale spatial resolution (625×625×625 μm 3 ). [81] …”

Photoactivity of TiO2/CdS and SiO2/CdS hybrid nanostructured systems in the partial oxidation of ethanol under irradiation with visible light

“…Fine particle, spatially struc tured materials with a core (cadmium sulfide)-shell (titanium dioxide) structure are considered to be espe cially promising [6][7][8]. In these systems, visible light passes through a thin film of titanium dioxide and is absorbed by a cadmium sulfide particle.…”