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1.
The reaction between salicylic acid and dialkyl phosphite was traced by electrospray ionization mass spectrometry and ^31P NMR. All reactants, unstable intermediates and products were detected. The mechanism was proposed based on ESI-MS results and ^31P NMR profiles.  相似文献   

2.
The reaction of diethyl α-oxoethylphosphonate and diethyl oxobenzylphosphonate with diethyl phosphite, dimethyl phosphite, and diphenylphosphine oxide affords, depending on the substrates and conditions (nature and quantity of the amine catalyst, temperature, and solvent), the Pudovik adduct and/or the corresponding >P(O)–CH–O–P(O)< product formed by rearrangement. The nature of the substituent on the central carbon atom (a methyl or phenyl group) influences the inclination for the rearrangement. The asymmetric products (either adducts or rearranged species) with different P(O)Y functions (Y = RO or Ph) exhibit interesting NMR features.  相似文献   

3.
1H, 13C, 17O and 31P NMR parameters, including chemical shift tensors and quadrupolar parameters for 17O, were calculated for phenylphosphonic acid, C6H5PO(OH)2, under periodic boundary conditions. The results are in very good agreement with experimental data and permit the unambiguous assignment of all the sites present in the structure. In particular, the 17O NMR parameters of the P=O and P-OH environments were precisely determined, which should help in the characterization of the bonding mode of phosphonate molecules in hybrid solids. Moreover, the effect of intermolecular interactions on the NMR parameters were investigated by comparing the results of the calculations in the crystal and in an isolated molecule of phenylphosphonic acid.  相似文献   

4.
Cinchonine was employed as backbone for the synthesis of novel phosphite compounds with diol substituents.These monophosphinites were provided in one pot with the yields ranged from 63%to 75%.Their structures were confirmed by NMR spectroscopy and HRMS.  相似文献   

5.
The reactions ofo-carboran-l-ylethyl mesylates with triethyl phosphite and sodium diethyl phosphite were studied. Carborane-containing phosphonates were synthesized. The reaction ofo-carboranylacetyl chloride with triethyl phosphite affordedO,O-diethyl (E)-2-(o-carboran-l-yl)-1-(o-carboran-1-ylacetoxy) vinylphosphonate rather than oxo phosphonate. Dedicated to the memory of Academician M. I. Kabachnik on his 90th birthday. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2041–2044, October, 1998.  相似文献   

6.
The organometallic compound [Cp*Rh(bpy)(H2O)]2+ is a versatile catalyst for the in situ regeneration of reduced nicotinamides and flavins by catalyzing the electron transfer between the cathode or formate to the oxidized cofactors and prosthetic groups. In the present contribution we demonstrate the feasibility of phosphite as an alternative source of reducing equivalents. Thus, [Cp*Rh(bpy)(H2O)]2+ combines the catalytic activities of hydrogenases, formate and phosphite dehydrogenases in one catalyst. The catalytic properties of this novel regeneration approach are investigated, demonstrating that the general catalytic properties of [Cp*Rh(bpy)(H2O)]2+ are preserved. The principal applicability to promote alcoholdehydrogenase‐catalyzed reduction reactions is demonstrated. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

7.
In NMR spectroscopy, situations may arise where sample concentrations are below the threshold for FT NMR detection, or sample lability constrains allowable acquisition times. In 31P NMR, for example, observation of 13C satellites may not be practical under given conditions. For 17O NMR, which is useful to characterize 17O-labeled phosphate derivatives, similar considerations may apply, and added factors are the cost of isotopically enriched samples and the requirement to obtain spectra at relatively high temperatures if narrow spectral peak line widths are desired. We report here application of a new signal processing method [S.D. Kunikeev, H.S. Taylor, J. Phys. Chem. A 108, 2004 743] to observation of weak 31P and 17O NMR peaks.  相似文献   

8.
31P nuclear magnetic resonance (NMR) spectroscopy was used to determine the structure of the intermediate species of sol derived from triethyl phosphite, calcium diethoxide and acetic acid. NMR spectral data revealed that the reaction proceeds via a dialkyl phosphite intermediate. The use of a dialkyl phosphite precursor (diethyl phosphite) with calcium diethoxide eliminated the aging time required in triethylphosphite method and offered an effective sol-gel procedure for monophasic hydroxyapatite.  相似文献   

9.
31P NMR Study on Some Phosphorus-Containing Compounds   总被引:1,自引:0,他引:1  
In view of the facts that the phenomena of aggregation are inseparably related to life processes and that phosphorus-containing compounds are one of the essential building blocks of life, we have studied the aggregation behavior of some phosphonates and phosphinates1. The application of NMR to the problems in chemistry has become rather popular. In phosphorus-containing compounds, phosphorus is a central or backbone atom in molecular structures. 31P NMR is of importance and special value in …  相似文献   

10.
本文合成了一系列短链、长链和大分子的亚磷酸酯,用Timken试验机和扫描电镜研究了它们对新型冷冻机油抗磨性能的改进作用。  相似文献   

11.
In this review, some of the latest research developments on the characterization of the structure and properties of oxide materials by applying solid-state nuclear magnetic resonance spectroscopy (NMR), including the use of dynamic nuclear polarization (DNP) NMR, 17O NMR combined with surface selective labeling and 31P NMR coupled with phosphorous-containing probe molecules, are discussed.  相似文献   

12.
A convenient method has been developed to synthesize diaryl arylphosphonates from triaryl phosphites, triethyl phosphite, and aromatic halides. The new method relies on the triethyl phosphite assisted nickel catalyzed Arbuzov reaction and can be applied to synthesize certain diaryl alkylphosphonates without catalysts.  相似文献   

13.
A new 3D vanadium hydrogen phosphite, (C5N2H14)[VO(H2O)]3(HPO3)4·H2O, has been prepared by hydrothermal reactions and characterized by single crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and magnetic techniques. It crystallizes in the triclinic space group P-1 (no. 2) with , , , α=76.124(3)°, β=83.726(4)o, γ=75.222(4)o, Z=2. The structure is built up from sharing equatorial oxygen atoms of VO5(H2O) octahedra with HPO3 tetrahedra, which can be viewed as a (3,4) connected net. The framework is mainly constructed by two types of four-ring related chains. Intrachain and interchain hydrogen bonds play an important role on supporting the framework structure. The 14-ring tunnels in the structure are filled with 1-methypiperazinium and water molecules, which also contribute the hydrogen bonding with the vanadium phosphite framework.  相似文献   

14.
17O‐enriched acetic acid (2.5% in 17O) was synthesized by hydrolysis of acetic anhydride with 17O‐enriched water. The reaction was monitored by 17O and 1H NMR spectroscopy. Acetic anhydride, 17O‐enriched in both the ether and the carbonyl oxygens, was observed as an intermediate. This can be ascribed to competition between acetic acid and water for nucleophilic attack on acetic anhydride. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

15.
In order to investigate the possibility of salt formation in the L‐Arg–H3PO3–H2O system, single crystals of L‐argininium phosphite, C6H15N4O2+·H2PO3, were prepared by evaporation of an aqueous solution containing equimolar quantities of L‐arginine and phosphorous acid. The asymmetric unit contains one L‐argininium(+) cation and one phosphite [HPO2(OH)] anion. The phosphite anions form chains parallel to [010] by O—H...O hydrogen bonding, with an O...O distance of 2.630 (3) Å. The protonated amine and guanidyl groups of the L‐argininium(+) cations form N—H...O hydrogen bonds with the carboxylate groups and anions. The IR and Raman spectra are discussed in relation to the crystal structure. The salt displays nonlinear optical (NLO) properties. Another salt was obtained from a solution with a 1:2 molar ratio of components, but was characterized by vibrational spectra only.  相似文献   

16.
17O NMR data for some 3-arylidenechromanones and -flavanones are discussed in terms of mesomeric and steric substituent interactions. The transmission of long-range substituent effects was studied. 17O NMR chemical shifts were correlated with Hammett σp+ values for 4′-substituted derivatives. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

17.
A closer look: Solid-state (7) Li and (17) O?NMR spectroscopy is a valuable tool in the characterization of products formed in the lithium-oxygen battery, a necessary step in the development of a viable cell. Since lithium peroxide, the desired discharge product, has a unique (17) O?NMR signature, it can be clearly identified.  相似文献   

18.
The addition of dimethyl phosphite to N,N'-terephthalylidene-alkyl- (or aryl-) amines resulted in new tetramethyl 1,4-phenylene-bis-(N-alkylaminomethyl)-phosphonates in moderate yields. The stereochemical behavior of these reactions was studied by NMR, demonstrating that the reactions lead to the formation of both possible diastereomeric forms from 1:1 to 1:2 ratios. This was unexpected considering that previously investigated additions of diethyl, dibenzyl, and diphenyl phosphites to terephthalaldimines were diastereoselective up to 100%. Attempts were made to find reasonable explanation for the phenomenon using semi-empirical and DFT calculations.  相似文献   

19.
The 17O NMR spectra of 17O isotope‐enriched tributyltin(IV) acetate (1) and dibutyltin(IV) diacetate (2) were recorded in various solvents over wide temperature ranges. Only a single 17O signal was observed for both oxygen atoms of the —COOSn—groups under these experimental conditions, in both non‐coordinating and coordinating solvents. The 17O NMR spectra of tert‐butyl acetate (3) were obtained for comparison. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

20.
在具有开放骨架结构的过渡金属磷酸盐微孔材料的合成中,钒磷酸盐因在催化和磁学方面具有潜在的性质和特殊结构特征而引起人们的广泛兴趣.近年来,人们正在尝试用假四面体结构的[HPO3]^2-替代四面体结构的[PO4]^3-,因为{HPO3}结构基元同钒原子的连接方式与{PO4}结构基元和钒原子的连接方式具有明显的差别,  相似文献   

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