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1.
A Nanoparticle Catalyst for Heterogeneous Phase Para‐Hydrogen‐Induced Polarization in Water 下载免费PDF全文
Dr. Stefan Glöggler Alexander M. Grunfeld M. Sc. Yavuz N. Ertas M. Sc. Jeffrey McCormick Prof. Shawn Wagner Dipl.‐Chem. P. Philipp M. Schleker Prof. Louis‐S. Bouchard 《Angewandte Chemie (International ed. in English)》2015,54(8):2452-2456
Para‐hydrogen‐induced polarization (PHIP) is a technique capable of producing spin polarization at a magnitude far greater than state‐of‐the‐art magnets. A significant application of PHIP is to generate contrast agents for biomedical imaging. Clinically viable and effective contrast agents not only require high levels of polarization but heterogeneous catalysts that can be used in water to eliminate the toxicity impact. Herein, we demonstrate the use of Pt nanoparticles capped with glutathione to induce heterogeneous PHIP in water. The ligand‐inhibited surface diffusion on the nanoparticles resulted in a 1H polarization of P=0.25 % for hydroxyethyl propionate, a known contrast agent for magnetic resonance angiography. Transferring the 1H polarization to a 13C nucleus using a para‐hydrogen polarizer yielded a polarization of 0.013 %. The nuclear‐spin polarizations achieved in these experiments are the first reported to date involving heterogeneous reactions in water. 相似文献
2.
Kirill V. Kovtunov Igor V. Koptyug Marianna Fekete Simon B. Duckett Thomas Theis Baptiste Joalland Eduard Y. Chekmenev 《Angewandte Chemie (International ed. in English)》2020,59(41):17788-17797
Imaging of gases is a major challenge for any modality including MRI. NMR and MRI signals are directly proportional to the nuclear spin density and the degree of alignment of nuclear spins with applied static magnetic field, which is called nuclear spin polarization. The level of nuclear spin polarization is typically very low, i.e., one hundred thousandth of the potential maximum at 1.5 T and a physiologically relevant temperature. As a result, MRI typically focusses on imaging highly concentrated tissue water. Hyperpolarization methods transiently increase nuclear spin polarizations up to unity, yielding corresponding gains in MRI signal level of several orders of magnitude that enable the 3D imaging of dilute biomolecules including gases. Parahydrogen‐induced polarization is a fast, highly scalable, and low‐cost hyperpolarization technique. The focus of this Minireview is to highlight selected advances in the field of parahydrogen‐induced polarization for the production of hyperpolarized compounds, which can be potentially employed as inhalable contrast agents. 相似文献
3.
Homogeneous hydrogenations of unsaturated substrates with parahydrogen yield strong NMR signal enhancements of the transferred 1H nuclei if the symmetry of H2 is broken in the resulting hydrogenated products. This chemically induced hyperpolarization known as Parahydrogen-induced polarization (PHIP) is also transferred to other protons and heteronuclei (2H, 13C, 29Si, 31P) when the hydrogenation is initiated at low magnetic fields. Hydrogenating various fluorinated styrenes and phenylacetylenes, we show that PHIP-derived hyperpolarization is transferred to 19F not only in the Earth's magnetic field (ALTADENA condition) but also in a strong magnetic field, e.g., when carrying out the reaction in the NMR spectrometer (PASADENA condition). Upon conducting a systematic analysis of the observed PHIP transfer to 1H, 13C, and 19F in the hydrogenation products to elucidate the mechanisms that govern this parahydrogen-aided resonance transfer (PART), we conclude that high- and low-field PHIP transfer mechanisms differ in detail depending on either through-bond or through-space interactions. Substrates with high hydrogenation rates and long spin-lattice relaxation times (T1) yield the highest degree of heteronuclear hyperpolarization. Possible medical applications for hyperpolarized 19F-containing molecules as "active" contrast agents for magnetic resonance imaging (MRI) are outlined. 相似文献
4.
Oleg G. Salnikov Dr. Danila A. Barskiy Dr. Aaron M. Coffey Dr. Kirill V. Kovtunov Prof. Igor V. Koptyug Prof. Eduard Y. Chekmenev 《Chemphyschem》2016,17(21):3395-3398
We report on a simple approach for efficient NMR proton hyperpolarization of propane using the parahydrogen‐induced polarization (PHIP) technique, which yielded ≈6.2 % proton polarization using ≈80 % parahydrogen, a record level achieved with any hyperpolarization technique for propane. Unlike in previously developed approaches designed for continuous‐flow operation, where reactants (propene and parahydrogen) are simultaneously loaded for homogeneous or heterogeneous pairwise addition of parahydrogen, here a batch‐mode method is applied: propene is first loaded into the catalyst‐containing solution, which is followed by homogeneous hydrogenation via parahydrogen bubbling delivered at ≈7.1 atm. The achieved nuclear spin polarization of this contrast agent potentially useful for pulmonary imaging is approximately two orders of magnitude greater than that achieved in the continuous‐flow homogeneous catalytic hydrogenation, and a factor of 3–10 more efficient compared to the typical results of heterogeneous continuous‐flow hydrogenations. 相似文献
5.
D.?B.?Burueva I.?V.?Skovpin V.?V.?Zhivonitko O.?G.?Salnikov A.?S.?Romanov K.?V.?Kovtunov I.?V.?Koptyug
Parahydrogen-induced polarization technique (PHIP), based on the pairwise addition of molecular hydrogen to a substrate, was successfully applied to obtain novel information on the mechanisms of heterogeneous catalytic hydrogenation, hydrodesulfurization, and oligomerization processes. In particular, the PHIP effects were observed upon hydrogenation with parahydrogen catalyzed by the immobilized neutral complexes of rhodium and iridium, which confirms the similarity in the mechanisms of homogeneous and heterogeneous hydrogenation for such systems. In the study of acetylene oligomerization, a significant NMR signal enhancement was revealed for a number of C4 oligomers, with the enhancement levels by far exceeding that observed in hydrogenation of carbon-carbon triple bonds. The mechanistic features of heterogeneous hydrogenation of a number of six-membered cyclic hydrocarbons over supported metal catalysts were investigated, and their hydrogenation scheme based on the pairwise addition of molecular hydrogen was proposed. Furthermore, the PHIP technique revealed that heterogeneous hydrodesulfurization of thiophene mainly proceeds via hydrogenation followed by a C—S bond cleavage. A significant enhancement of sensitivity in combination with characteristic line shapes of NMR signals make the PHIP method a unique and highly informative tool for the investigation of heterogeneous catalytic processes. 相似文献
6.
Zhenfeng Pang Hanxi Guan Lina Gao Weicheng Cao Jinglin Yin Xueqian Kong 《物理化学学报》2020,36(4):1906018-0
核磁共振(NMR)技术凭借其高空间分辨率,宽时间响应尺度和非侵入检测等特点,在化学分析和医疗诊断中发挥着重要的作用。但是原子核的低极化使现阶段NMR技术的灵敏度较低。超极化技术是一类可以有效提高NMR灵敏度的方法。其通过物理或化学过程把原子核自旋态推向一个偏离热力学平衡的状态,使NMR信号强度得到几个数量级的提升,极大地改善了灵敏度。多种超极化技术已经在各个领域崭露头角。本文用较为形象的描述对几种常见的超极化技术包括:动态核极化、光泵、光核极化、化学诱导动态核极化、仲氢诱导极化。从其精巧的原理和广泛的应用进行介绍,有助于人们对超极化技术的认知。 相似文献
7.
More Than 12 % Polarization and 20 Minute Lifetime of 15N in a Choline Derivative Utilizing Parahydrogen and a Rhodium Nanocatalyst in Water 下载免费PDF全文
Jeffrey McCormick Dr. Sergey Korchak Dr. Salvatore Mamone Dr. Yavuz N. Ertas Zhiyu Liu Luke Verlinsky Dr. Shawn Wagner Dr. Stefan Glöggler Prof. Louis‐S. Bouchard 《Angewandte Chemie (International ed. in English)》2018,57(33):10692-10696
Hyperpolarization techniques are key to extending the capabilities of MRI for the investigation of structural, functional and metabolic processes in vivo. Recent heterogeneous catalyst development has produced high polarization in water using parahydrogen with biologically relevant contrast agents. A heterogeneous ligand‐stabilized Rh catalyst is introduced that is capable of achieving 15N polarization of 12.2±2.7 % by hydrogenation of neurine into a choline derivative. This is the highest 15N polarization of any parahydrogen method in water to date. Notably, this was performed using a deuterated quaternary amine with an exceptionally long spin‐lattice relaxation time (T1) of 21.0±0.4 min. These results open the door to the possibility of 15N in vivo imaging using nontoxic similar model systems because of the biocompatibility of the production media and the stability of the heterogeneous catalyst using parahydrogen‐induced polarization (PHIP) as the hyperpolarization method. 相似文献
8.
Ekaterina V. Pokochueva Dr. Dudari B. Burueva Dr. Oleg G. Salnikov Prof. Igor V. Koptyug 《Chemphyschem》2021,22(14):1421-1440
Parahydrogen-induced polarization with heterogeneous catalysts (HET-PHIP) has been a subject of extensive research in the last decade since its first observation in 2007. While NMR signal enhancements obtained with such catalysts are currently below those achieved with transition metal complexes in homogeneous hydrogenations in solution, this relatively new field demonstrates major prospects for a broad range of advanced fundamental and practical applications, from providing catalyst-free hyperpolarized fluids for biomedical magnetic resonance imaging (MRI) to exploring mechanisms of industrially important heterogeneous catalytic processes. This review covers the evolution of the heterogeneous catalysts used for PHIP observation, from metal complexes immobilized on solid supports to bulk metals and single-atom catalysts and discusses the general visions for maximizing the obtained NMR signal enhancements using HET-PHIP. Various practical applications of HET-PHIP, both for catalytic studies and for potential production of hyperpolarized contrast agents for MRI, are described. 相似文献
9.
Arne Brahms Dr. Andrey N. Pravdivtsev Tim Stamp Frowin Ellermann Prof. Dr. Frank D. Sönnichsen Prof. Dr. Jan-Bernd Hövener Prof. Dr. Rainer Herges 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(55):e202201210
The hyperpolarization of nuclear spins has enabled unique applications in chemistry, biophysics, and particularly metabolic imaging. Parahydrogen-induced polarization (PHIP) offers a fast and cost-efficient way of hyperpolarization. Nevertheless, PHIP lags behind dynamic nuclear polarization (DNP), which is already being evaluated in clinical studies. This shortcoming is mainly due to problems in the synthesis of the corresponding PHIP precursor molecules. The most widely used DNP tracer in clinical studies, particularly for the detection of prostate cancer, is 1-13C-pyruvate. The ideal derivative for PHIP is the deuterated vinyl ester because the spin physics allows for 100 % polarization. Unfortunately, there is no efficient synthesis for vinyl esters of β-ketocarboxylic acids in general and pyruvate in particular. Here, we present an efficient new method for the preparation of vinyl esters, including 13C labeled, fully deuterated vinyl pyruvate using a palladium-catalyzed procedure. Using 50 % enriched parahydrogen and mild reaction conditions, a 13C polarization of 12 % was readily achieved; 36 % are expected with 100 % pH2. Higher polarization values can be potentially achieved with optimized reaction conditions. 相似文献
10.
Jonischkeit T Bommerich U Stadler J Woelk K Niessen HG Bargon J 《The Journal of chemical physics》2006,124(20):201109
Recently, Levitt and co-workers demonstrated that conserving the population of long-lasting nuclear singlet states in weak magnetic fields can lead to a preservation of nuclear spin information over times substantially longer than governed by the (high-field) spin-lattice relaxation time T1. Potential benefits of the prolonged spin information for magnetic resonance imaging and spectroscopy were pointed out, particularly when combined with the parahydrogen induced polarization (PHIP) methodology. In this contribution, we demonstrate that an increase of the effective relaxation time by a factor up to three is achieved experimentally, when molecules hyperpolarized by PHIP are kept in a weak magnetic field instead of the strong field of a typical NMR magnet. This increased lifetime of spin information makes the known PHIP phenomena more compatible with the time scales of biological processes and, thus, more attractive for future investigations. 相似文献
11.
Production of Pure Aqueous 13C‐Hyperpolarized Acetate by Heterogeneous Parahydrogen‐Induced Polarization 下载免费PDF全文
Dr. Kirill V. Kovtunov Dr. Danila A. Barskiy Dr. Roman V. Shchepin Oleg G. Salnikov Dr. Igor P. Prosvirin Dr. Andrey V. Bukhtiyarov Dr. Larisa M. Kovtunova Prof. Valerii I. Bukhtiyarov Prof. Igor V. Koptyug Prof. Eduard Y. Chekmenev 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(46):16446-16449
A supported metal catalyst was designed, characterized, and tested for aqueous phase heterogeneous hydrogenation of vinyl acetate with parahydrogen to produce 13C‐hyperpolarized ethyl acetate for potential biomedical applications. The Rh/TiO2 catalyst with a metal loading of 23.2 wt % produced strongly hyperpolarized 13C‐enriched ethyl acetate‐1‐13C detected at 9.4 T. An approximately 14‐fold 13C signal enhancement was detected using circa 50 % parahydrogen gas without taking into account relaxation losses before and after polarization transfer by magnetic field cycling from nascent parahydrogen‐derived protons to 13C nuclei. This first observation of 13C PHIP‐hyperpolarized products over a supported metal catalyst in an aqueous medium opens up new possibilities for production of catalyst‐free aqueous solutions of nontoxic hyperpolarized contrast agents for a wide range of biomolecules amenable to the parahydrogen induced polarization by side arm hydrogenation (PHIP‐SAH) approach. 相似文献
12.
Dariusz Gołowicz Dr. Krzysztof Kazimierczuk Dr. Mateusz Urbańczyk Dr. Tomasz Ratajczyk 《ChemistryOpen》2019,8(2):196-200
Low-field benchtop nuclear magnetic resonance (BT-NMR) spectrometers with Halbach magnets are being increasingly used in science and industry as cost-efficient tools for the monitoring of chemical reactions, including hydrogenation. However, their use of low-field magnets limits both resolution and sensitivity. In this paper, we show that it is possible to alleviate these two problems through the combination of parahydrogen-induced polarization (PHIP) and fast correlation spectroscopy with time-resolved non-uniform sampling (TR-NUS). PHIP can enhance NMR signals so that substrates are easily detectable on BT-NMR spectrometers. The interleaved acquisition of one- and two-dimensional spectra with TR-NUS provides unique insight into the consecutive moments of hydrogenation reactions, with a spectral resolution unachievable in a standard approach. We illustrate the potential of the technique with two examples: the hydrogenation of ethylphenyl propiolate and the hydrogenation of a mixture of two substrates – ethylphenyl propiolate and ethyl 2-butynoate. 相似文献
13.
Gong Q Klankermayer J Blümich B 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(49):13795-13799
para-Hydrogen induced polarization (PHIP) NMR spectroscopy emerges as an efficient and robust method for on-line monitoring of gas-phase hydrogenation reactions. Here we report detailed investigations of supported ionic liquid phase (SILP) catalysts in a continuous gas-phase hydrogenation of propene with PHIP NMR spectroscopy. A relocation of the rhodium complex in the thin layer of ionic liquid in the SILP catalyst at the initial stage of the propene hydrogenation is demonstrated. PHIP NMR spectroscopy can provide profound insight into the evolution of SILP catalysts during hydrogenation reactions. 相似文献
14.
Dr. Neil J. Stewart Hitomi Nakano Shuto Sugai Mitsushi Tomohiro Yuki Kase Yoshiki Uchio Dr. Toru Yamaguchi Yujirou Matsuo Dr. Tatsuya Naganuma Dr. Norihiko Takeda Dr. Ikuya Nishimura Dr. Hiroshi Hirata Dr. Takuya Hashimoto Dr. Shingo Matsumoto 《Chemphyschem》2021,22(10):915-923
Hyperpolarized [1-13C]fumarate is a promising magnetic resonance imaging (MRI) biomarker for cellular necrosis, which plays an important role in various disease and cancerous pathological processes. To demonstrate the feasibility of MRI of [1-13C]fumarate metabolism using parahydrogen-induced polarization (PHIP), a low-cost alternative to dissolution dynamic nuclear polarization (dDNP), a cost-effective and high-yield synthetic pathway of hydrogenation precursor [1-13C]acetylenedicarboxylate (ADC) was developed. The trans-selectivity of the hydrogenation reaction of ADC using a ruthenium-based catalyst was elucidated employing density functional theory (DFT) simulations. A simple PHIP set-up was used to generate hyperpolarized [1-13C]fumarate at sufficient 13C polarization for ex vivo detection of hyperpolarized 13C malate metabolized from fumarate in murine liver tissue homogenates, and in vivo 13C MR spectroscopy and imaging in a murine model of acetaminophen-induced hepatitis. 相似文献
15.
16.
Perry DA Razer TM Cordova JS Schiefer EM Chen T Primm KM Bonde AM Biris AS 《Journal of colloid and interface science》2012,372(1):239-244
Multimodal imaging technique is an alternative approach to improve sensitivity of early cancer diagnosis. In this study, highly fluorescent and strong X-ray absorption coefficient gold nanoclusters (Au NCs) are synthesized as dual-modality imaging contrast agents (CAs) for fluorescent and X-ray dual-modality imaging. The experimental results show that the as-prepared Au NCs are well constructed with ultrasmall sizes, reliable fluorescent emission, high computed tomography (CT) value and fine biocompatibility. In vivo imaging results indicate that the obtained Au NCs are capable of fluorescent and X-ray enhanced imaging. 相似文献
17.
Dr. Oleg G. Salnikov Dr. Dudari B. Burueva Dr. Larisa M. Kovtunova Prof. Valerii I. Bukhtiyarov Dr. Kirill V. Kovtunov Prof. Igor V. Koptyug 《Chemphyschem》2022,23(7):e202200072
In this work the mechanism of methylenecyclobutane hydrogenation over titania-supported Rh, Pt and Pd catalysts was investigated using parahydrogen-induced polarization (PHIP) technique. It was found that methylenecyclobutane hydrogenation leads to formation of a mixture of reaction products including cyclic (1-methylcyclobutene, methylcyclobutane), linear (1-pentene, cis-2-pentene, trans-2-pentene, pentane) and branched (isoprene, 2-methyl-1-butene, 2-methyl-2-butene, isopentane) compounds. Generally, at lower temperatures (150–350 °C) the major reaction product was methylcyclobutane while higher temperature of 450 °C favors the formation of branched products isoprene, 2-methyl-1-butene and 2-methyl-2-butene. PHIP effects were detected for all reaction products except methylenecyclobutane isomers 1-methylcyclobutene and isoprene implying that the corresponding compounds can incorporate two atoms from the same parahydrogen molecule in a pairwise manner in the course of the reaction in particular positions. The mechanisms were proposed for the formation of these products based on PHIP results. 相似文献
18.
A Hyperpolarizable 1H Magnetic Resonance Probe for Signal Detection 15 Minutes after Spin Polarization Storage 下载免费PDF全文
Dr. Soumya S. Roy Dr. Philip Norcott Dr. Peter J. Rayner Prof. Dr. Gary G. R. Green Prof. Dr. Simon B. Duckett 《Angewandte Chemie (International ed. in English)》2016,55(50):15642-15645
Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are two extremely important techniques with applications ranging from molecular structure determination to human imaging. However, in many cases the applicability of NMR and MRI are limited by inherently poor sensitivity and insufficient nuclear spin lifetime. Here we demonstrate a cost‐efficient and fast technique that tackles both issues simultaneously. We use the signal amplification by reversible exchange (SABRE) technique to hyperpolarize the target 1H nuclei and store this polarization in long‐lived singlet (LLS) form after suitable radiofrequency (rf) pulses. Compared to the normal scenario, we achieve three orders of signal enhancement and one order of lifetime extension, leading to 1H NMR signal detection 15 minutes after the creation of the detected states. The creation of such hyperpolarized long‐lived polarization reflects an important step forward in the pipeline to see such agents used as clinical probes of disease. 相似文献
19.
Dr. Mai T. Huynh Emily Buchanan Dr. Sara Chirayil Adeniyi M. Adebesin Dr. Zoltan Kovacs 《Angewandte Chemie (International ed. in English)》2023,62(46):e202311669
Parahydrogen-induced polarization (PHIP) followed by polarization transfer to 13C is a rapidly developing technique for the generation of 13C-hyperpolarized substrates. Chirality plays an essential role in living systems and differential metabolism of enantiomeric pairs of metabolic substrates is well documented. Inspired by asymmetric hydrogenation, here we report stereoPHIP, which involves the addition of parahydrogen to a prochiral substrate with a chiral catalyst followed by polarization transfer to 13C spins. We demonstrate that parahydrogen could be rapidly added to the prochiral precursor to both enantiomers of lactic acid (D and L), with both the (R,R) and (S,S) enantiomers of a chiral rhodium(I) catalyst to afford highly 13C-hyperpolarized (over 20 %) L- and D-lactate ester derivatives, respectively, with excellent stereoselectivity. We also show that the hyperpolarized 1H signal decays obtained with the (R,R) and (S,S) catalysts were markedly different. StereoPHIP expands the scope of conventional PHIP to the production of 13C hyperpolarized chiral substrates with high stereoselectivity. 相似文献
20.
Zacharias NM Chan HR Sailasuta N Ross BD Bhattacharya P 《Journal of the American Chemical Society》2012,134(2):934-943
The Krebs tricarboxylic acid cycle (TCA) is central to metabolic energy production and is known to be altered in many disease states. Real-time molecular imaging of the TCA cycle in vivo will be important in understanding the metabolic basis of several diseases. Positron emission tomography (PET) with FDG-glucose (2-[(18)F]fluoro-2-deoxy-d-glucose) is already being used as a metabolic imaging agent in clinics. However, FDG-glucose does not reveal anything past glucose uptake and phosphorylation. We have developed a new metabolic imaging agent, hyperpolarized diethyl succinate-1-(13)C-2,3-d(2) , that allows for real-time in vivo imaging and spectroscopy of the TCA cycle. Diethyl succinate can be hyperpolarized via parahydrogen-induced polarization (PHIP) in an aqueous solution with signal enhancement of 5000 compared to Boltzmann polarization. (13)C magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) were achieved in vivo seconds after injection of 10-20 μmol of hyperpolarized diethyl succinate into normal mice. The downstream metabolites of hyperpolarized diethyl succinate were identified in vivo as malate, succinate, fumarate, and aspartate. The metabolism of diethyl succinate was altered after exposing the animal to 3-nitropropionate, a known irreversible inhibitor of succinate dehydrogenase. On the basis of our results, hyperpolarized diethyl succinate allows for real-time in vivo MRI and MRS with a high signal-to-noise ratio and with visualization of multiple steps of the TCA cycle. Hyperpolarization of diethyl succinate and its in vivo applications may reveal an entirely new regime wherein the local status of TCA cycle metabolism is interrogated on the time scale of seconds to minutes with unprecedented chemical specificity and MR sensitivity. 相似文献