Effects of deuteration on the structure of NH_4H_2PO_4 crystals characterized by neutron diffraction

A series of deuterated ammonium dihydrogen phosphate(DADP) crystals were grown and their structures were investigated by using powder neutron diffraction method. In the entire composition range, the deuterated level in the crystals is lower compared with the aqueous growth solution. The deuterium segregation coefficient in the crystals decreases with increasing deuterium content of the solution. The deuterium content in the NH_4^+ group is higher than that in H_2PO_4^- group.In addition, the variations of lattice parameters are shown here.

Electrical Conduction in Deuterated Ammonium Dihydrogen Phosphate Crystals with Different Degrees of Deuteration

Conductivity measurements of deuterated ammonium dihydrogen phosphate （DADP） crystals with different deuterated degrees are described. The conductivities increase with the deuterium content, and the value of the a-direction is larger than that of the e-direction. Compared with DKDP crystals, DADP crystals have larger conductivities, which is partly due to the existence of A defects. The ac conductivity over the temperature range 25-170℃has shown a knee in the curve ofln（σT） versus T-1. The conductivity activation energy calculated by the slope of the high temperature region decreases with the deuterium content. The previously reported phase transition is not seen.

Recent Advances in Deuteration Reactions

The deuteration of organic compounds has attracted more attentions in recent years for the potential applications in new drug discovery and synthetic chemistry.For this purpose,many efficient deuterium labeling methodologies have been developed,including hydrogen isotope exchange(HIE),reductive deuteration,and dehalogenative deuteration that allow for the synthesis of selectively deuterated compounds.In the last few years,great breakthroughs in selective isotope labeling have been achieved and the interest in new methodologies for the deuteration of organic molecules is rising.In this review,we summarized the recent developments in the selective deuteration of organic molecules since 2021.Several types of key processes in deuterium incorporation reactions,including H/D exchange,reductive deuteration and dehalogenative deuteration,are introduced and discussed.

A visible-light-photocatalytic water-splitting strategy for sustainable hydrogenation/deuteration of aryl chlorides

Hydrogenation/deuteration of carbon chloride(C–Cl)bonds is of high significance but remains a remarkable challenge in synthetic chemistry,especially using safe and inexpensive hydrogen donors.In this article,a visible-light-photocatalytic watersplitting hydrogenation technology(WSHT)is proposed to in-situ generate active H-species(i.e.,Had)for controllable hydrogenation of aryl chlorides instead of using flammable H2.When applying heavy water-splitting systems,we could selectively install deuterium at the C–Cl position of aryl chlorides under mild conditions for the sustainable synthesis of high-valued added deuterated chemicals.Sub-micrometer Pd nanosheets(Pd NSs)decorated crystallined polymeric carbon nitrides(CPCN)is developed as the bifunctional photocatalyst,whereas Pd NSs not only serve as a cocatalyst of CPCN to generate and stabilize H(D)-species but also play a significant role in the sequential activation and hydrogenation/deuteration of C–Cl bonds.This article highlights a photocatalytic-WSHT for controllable hydrogenation/deuteration of low-cost aryl chlorides,providing a promising way for the photosynthesis of high-valued added chemicals instead of the hydrogen evolution.

Facile and Economical Electrochemical Dehalogenative Deuteration of(Hetero)Aryl Halides

Deuterated compounds are valuable in synthetic,pharmaceutical,and analytical chemistry.The deuteration of halides is a widespread method for highly site-selective deuterium installation.However,the facile,efficient,and economical deuterium incorporation remains challenging.In this work,we introduced a practical deuteration of(hetero)aryl halides through an electrochemical reduction method.This transformation proceeded smoothly at room temperature without metal catalysts,external reductants,or toxic or dangerous reagents.Remarkably,low-cost and chemically equivalent D2O was the sole deuterium source in this reaction.Professional electrosynthesis equipment was not essential because we demonstrated common batteries and electrodes were enough for this reaction.

Visible Light Promoted Direct Deuteration of Alkenes via Co(III)–H Mediated H/D Exchange

We report herein a visible light-mediated direct deuteration of alkenes with D_(2)O or deuterated methanol(MeOD)using a cobaloxime as a hydrogen/deuterium(H/D)exchange catalyst.The synergistic photoredox/Co catalysis enabled facile deuterium(D)-incorporation of a variety of terminal and internal alkenes at either terminal or benzylic positions.We proposed that this process proceeded through a sequence of reversible addition-elimination reactions and fast proton exchange involving Co(III)–H,which was generated in situ by photoreduction.

Combining Neutron Scattering,Deuteration Technique,and Molecular Dynamics Simulations to Study Dynamics of Protein and Its Surface Water Molecules

Protein internal dynamics is essential for its function. Exploring the internal dynamics of protein molecules as well as its connection to protein structure and function is a central topic in biophysics. However, the atomic motions in protein molecules exhibit a great degree of complexities. These complexities arise from the complex chemical composition and superposition of different types of atomic motions on the similar time scales, and render it challenging to explicitly understand the microscopic mechanism governing protein motions, functions, and their connections. Here, we demonstrate that, by using neutron scattering, molecular dynamics simulation, and deuteration technique, one can address this challenge to a large extent.

Highly efficient electrocatalytic deuteration of acetylene to deuterated ethylene using deuterium oxide

Deuterated ethylene is an important building block for manufacturing various deuterated polyolefins and chemicals.However,low-cost and large-scale production of deuterated ethylene still remain a great challenge.Herein,with D_(2)O as the D source,we first propose an electrocatalytic deuteration strategy for continuous production of deuterated ethylene from acetylene under ambient conditions.Specially,Ag nanoparticles exhibit a very high deuterated ethylene Faradic efficiency of up to 99.3%at-0.6 V vs.reversible hydrogen electrode.Meanwhile,Ag nanoparticles achieve a deuterated ethylene production rate of 3.72×10^(3)mmol h^(-1)g^(-1)cat and an excellent long-term stability with deuterated ethylene Faradaic efficiencies of~95%in a two-electrode flow cell,which substantially outperform state-of-the-art values for previously reported deuterated alkenes.In-situ electrochemical Infrared absorption and Raman spectroscopies reveal superior acetylene absorption and formation of deuterated ethylene on Ag nanoparticles.This efficient electrocatalytic deuteration strategy opens a new window for continuous and economic production of deuterated alkenes.

Deuteration triggered downward shift of dielectric phase transition temperature in a hydrogen-bonded molecular crystal

Deuteration of hydrogen-bonded phase transition crystals can increase the transition temperatures due to the isotope effect. But rare examples show the opposite trend that originates from the structural changes of the hydrogen bond, known as the geometric H/D isotope effect. Herein, we report an organic crystal, diethylammonium hydrogen 1,4-terephthalate, exhibits a reversible structural phase transition and dielectric switching. Structural study shows the cations reside in channels formed by one-dimensional hydrogen-bonded anionic chains and undergo an order-disorder transition at around 206 K. The deuterated counterpart shows an elongation of the O…O hydrogen bond by about 0.005 A. This geometric isotope effect releases the internal pressure of the anionic host on the cation guests and results in a downward shift of the phase transition temperature by 10 K.

Transition metal-free photocatalytic reductive deuteration of ketone derivatives

Deuterium labelling techniques have shown widespread applications in organic synthesis,analytic chemistry,life science and material science.The design of practical deuteration reactions which is environmentally friendly is highly desired for pharmaceutical development and industrial processes while remaining underexplored.We herein report a convenient,transition metal-free strategy for reductive deuteration of ketone derivatives toα-deuterated alcohols by employing a conjugated aryl amine-based organophotocatalyst,a dipropyl disulfide cocatalyst and an inorganic reductant.Upon irradiation with visible light and under an air atmosphere,a variety of diaryl ketones,heteroaryl ketones,cyclic ketones,α-ketoesters,benzil derivatives,aliphatic ketones and drug-like molecules were converted into correspondingα-deuterated aryl alcohols in good to excellent yields and with high deuterium incorporation(up to 99%D-incorporation).Only low toxic side-products,such as sodium salts and carbon dioxide,were generated.Consequently,the synthetic utility of this method is highlighted by the preparation of several D-labeled drug-like molecules,including orphenadrine,carbinoxamine and modafinil.

Water-involving transfer hydrogenation and dehydrogenation of N-heterocycles over a bifunctional MoNi_(4)electrode

A room-temperature electrochemical strategy for hydrogenation(deuteration)and reverse dehydrogenation of N-heterocycles over a bifunctional MoNi_(4)electrode is developed,which includes the hydrogenation of quinoxaline using H2O as the hydrogen source with 80%Faradaic efficiency and the reverse dehydrogenation of hydrogen-rich 1,2,3,4-tetrahydroquinoxaline with up to 99%yield and selectivity.The in situ generated active hydrogen atom(H^(*))is plausibly involved in the hydrogenation of quinoxaline,where a consecutive hydrogen radical coupled electron transfer pathway is proposed.Notably,the MoNi_(4)alloy exhibits efficient quinoxaline hydrogenation at an overpotential of only 50 mV,owing to its superior water dissociation ability to provide H^(*)in alkaline media.In situ Raman tests indicate that the Ni^(Ⅱ)/Ni^(Ⅲ)redox couple can promote the dehydrogenation process,representing a promising anodic alternative to low-value oxygen evolution.Impressively,electrocatalytic deuteration is easily achieved with up to 99%deuteration ratios using D2O.This method is capable of producing a series of functionalized hydrogenated and deuterated quinoxalines.

Determination of the Coreactant Level in Crosslinked Polyurethane System by FTIR

Infrared spectrum is a general quantitation method which can be used to determine the concentration of a certain component in mixture.We proposed that it could also be used to determine the coreactant level of a reactive system.A two-part polyurethane film was used as a model system.The results showed that the height ratio of ring mode signal in urea and C—O signal in polyester polyol can be used to calculate the ratio of the two reactants.The assignments of the peaks were studied by in-situ reaction monitoring with moisture level changes and deuteration methods.The applicable conditions of this calibration curves were also discussed.

Synthesis and Pharmacokinetic Property Improvement of Deuterated Plinabulin 9

Plinabulin,a potent microtubule-targeting agent,is derived from marine natural diketopiperazine ‘phenylahistin'.To develop novel plinabulin analogue that could display better pharmacokinetic properties and less side effects,deuterated plinabulin 9 was synthesized and evaluated in vitro and in vivo.In comparison with plinabulin,in vivo pharmacokinetic studies indicated that the deuterated derivative 9 could alter blood circulation behavior obviously,which was proved by increased area under the plasma concentration-time curve(AUC_(0–∞)),reduced clearance(CL),and prolonged total body mean residence time(MRT).The derivative 9 also has higher inhibition rates against Bx PC-3,Jurkat and A-431 tumor cell lines as compared with its prototype plinabulin.Therefore,the deuterated compound 9 might be developed as a potential agent for different cancer treatments.

Isotopic Shifts of the infrared Spectra of Cholic Acid and Sodium Cholate

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Revealing the catalytic mechanism of an ionic liquid with an isotope exchange method

The alkylation mechanism catalyzed by an ionic liquid （as a Lewis acid） may be different from the traditional alkylation mechanism catalyzed by Br nsted acid,especially as their initiation steps are still not clear.In this paper,an isotope exchange method is used to investigate the catalytic mechanism of AlCl 3 /butyl-methyl-imidazolium chloride ionic liquid in the alkylation of benzene with 1-dodecene.The proposed catalytic mechanism was confirmed by analysis of ionic liquid before and after reaction and of the alkylation products of deuterated benzene （C 6 D 6） with 1-dodecene.The proposed mechanism consists of the equilibrium reaction between [Al 2 Cl 7 ] ＋H ＋ and [AlHCl 3 ] ＋ ＋[AlCl 4 ],in which the Br nsted acid [AlHCl 3 ] ＋ is supplied by the reaction of 2-H on the imidazolium ring and [Al 2 Cl 7 ].The alkylation reaction is initiated by the Br nsted acid [AlHCl 3 ] ＋ which reacts with 1-dodecene to form a carbonium ion,then the carbonium ion reacts with benzene to form an unstable σ complex,leading to the formation of 2-phenyldodecane.

Characteristics of Laser-Induced Surface and Bulk Damage of Large-Aperture Deuterated Potassium Dihydrogen Phosphate at 351 nm

Deuterated potassium dihydrogen phosphate damage performance at 351 nm is studied on a large-aperture laser system. Bulk and rear-surface damage are initiated under the 3ω fluences of 6.T J/cm2 and 33/cm2, and show different growth characteristics under multiple laser irradiations with the fluence of 6 J/cm2. The size and number of bulk damage keep unchanged once initiated. However, surface damage size also does not grow, while surface damage number increases linearly with laser shots. Different damage thresholds and growth behaviors suggest different formations of bulk and surface damage precursors. The cause of surface damage is supposed to be near-surface absorbing particles buried under the sol-gel coating.

Measurement of Raman scattering gain coefficient in large-aperture DKDP crystals irradiated by 351 nm pulses

Transverse stimulated Raman scattering （TSRS） gain coefficient in a large aperture 65% deu terated potassium dihydrogen phosphate （DKDP） is measured at 351 nm. The measurement involves the use of an optical fiber sensor system to detect Raman scattering light in the DKDP crystal. A Raman scattering gain coefficient of 0. 109 cm/GW is obtained and will be used to set upper limit of the DKDP crystals in our laser fa cility to avoid the TSRS induced energy loss and laser damage. The effect of bulk damage on growth behavior of TSRS is also examined and it is found that bulk damage has little impact on the TSRS growth. Thus the influ ence of bulk damage on the measurement of TSRS gain coefficient can be ignored.

Coulomb expansion of deuterated methane clusters irradiated by an ultrashort intense laser pulse

The simulations of three-dimensional particle dynamics show that when irradiated by an ultrashort intense laser pulse, the deuterated methane cluster expands and the majority of deuterons overrun the more slowly expanding carbon ions, resulting in the creation of two separated subelusters. The enhanced deuteron kinetic energy and a narrow peak around the energy maximum in the deuteron energy distribution make a considerable contribution to the efficiency of nuclear fusion compared with the ease of homonuelear deuterium clusters. With the intense laser irradiation, the nuclear fusion yield increases with the increase of the cluster size, so that deuterated heteronuelear clusters with larger sizes are required to achieve a greater neutron yield.

Overrun phenomenon and neutron yield in Coulomb explosion of deuterated alkane clusters driven by intense laser field

By using a simplified Coulomb explosion model, the laser-driven Coulomb explosion processes of three deuterated alkane clusters, i.e., deuterated methane（CD4）N, ethane（C2D6）N and propane（C3D8）N clusters are simulated numerically.The overrun phenomenon that the deuterons overtake the carbon ions inside the expanding clusters, as well as the dependence of the energetic deuterons and fusion neutron yield on cluster size, is discussed in detail. Researches show that the average kinetic energy of deuterons and neutron yield generated in the Coulomb explosion of（C2D6）N cluster are higher than those of（CD4）N cluster with the same size, in qualitative agreement with the reported conclusions from the experiments of（C2 H6）N and（CH4）N clusters. It is indicated that（C2D6）N clusters are superior to（CD4）N clusters as a target for the laser-induced nuclear fusion reaction to achieve a higher neutron yield. In addition, by comparing the relevant data of（C3D8）N cluster with those of（C2D6）N cluster with the same size, it is theoretically concluded that（C3D8）N clusters with a larger competitive parameter might be a potential candidate for improving neutron generation. This will provide a theoretical basis for target selection in developing experimental schemes on laser-driven nuclear fusion in the future.