Investigation of Bis(α-Phenylethylamido)Methylphosphonates by NMR Spectroscopy

Abstract

The influence of the relative location of chiral carbon and phosphorus atoms and the position of the aryl-group on diastereomeric anisochronity in non-racemic mixtures of enantiomers has been examined. The optical isomers of methanephosphonic acid bis(α-phenylethylamide) (I), which contain pro-chiral phosphorus atom, were synthesized by the reaction of methanephosphonic acid dichloride(II) with (+)- or (-) -α-phenylethylamine (III). The extent of chemical shift nonequivalence in ³¹P and ¹H NMR spectra of non-racemic mixtures of RR- and SS-I was negligible. It can be explained by the absence of aryl-amino group, favouring intermolecular association, effect of SCADA¹, and the long distance between the chiral center and pro-chiral phosphorus. Phosphonylation of non-racemic mixtures of (+)- and (-)-III by II proceeds stereospecifically giving mixture of RR-, SS-I, and two meso-compounds analyzed by ³¹P ¹H NMR.     

Absorption Spectra and Resonance Rayleigh Scattering Spectra of Cu(Ⅱ)-Fluoroquinolone Chelates with Tetrachlorotetraiodo-fluoresceindisodium Salt System and Their Analytical Applications

在pH 4.2～4.8的B-R缓冲介质中,莫西沙星(MXFX)和加替沙星(GTF)等氟喹诺酮类抗生素(FLQs)能与铜(Ⅱ)形成螯合阳离子,进一步与虎红(Tf)阴离子通过静电引力和疏水作用形成FLQs∶Cu(Ⅱ)∶Tf为1∶1∶1的离子缔合物,体系反应导致共振瑞利散射(RRS)显著增强并出现新的RRS光谱.两种药物的反应产物具有相似的光谱特征,最大RRS峰位于373 nm处,并在590 nm处有1个较小的散射峰.在373 nm处一定浓度的抗生素与散射增强(△I)成正比,MXFX和GTF的线性范围分别为0.031 ～7.8 mg/L和0.029～9.0 mg/L.据此建立了测定氟喹诺酮类药物的新方法,方法用于胶囊和人尿液中FLQs的测定并取得满意结果.同时对反应机理及RRS增强原因进行了讨论.     

Synthesis,Crystal Structure,Thermal Stability and Solid UV-Vis Absorption Spectra of One New Copper(Ⅱ) Coordination Polymer

A new coordination polymer [Cu2(OH)(nbta)(tib)(H2 O)2]n(1, H3 nbta = 5-nitro-1,2,3-benzenetricarboxylic acid, tib = 1-(4 H-1,2,4-triazol-4-yl)-4-(imidazol-1-yl)benzene) constructed from dimeric Cu(Ⅱ) units has been synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction analysis. The compound crystallizes in monoclinic system, space group I2/c, with a = 17.8474(9), b = 11.7588(6), c = 21.9221(11) ?, β = 104.419(5)°, V = 4455.7(4) ?3 and Z = 8. Compound 1 is a three-dimensional structure constructed from dimeric Cu(Ⅱ) units and presents a 2-nodal(3,5)-connected net. Moreover, the thermal stability and solid UV-Vis absorption spectra have been investigated.     

Synthesis and Crystal Structure of Bis(dicyanamide) (5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane) Nickel(Ⅱ)

1 INTRODUCTION Crystal engineering is becoming an increase- ingly interest field by means of coordinated co- valent bonding or supramolecular contacts (such as hydrogen bonds, p-p interaction etc.)[1～7]. The ligand [N(CN)2]- is a remarkably versatile building block for constructing supramolecular architectures since it may act in uni-, biand tridentate manner. Additional ligands, such as coordinating amines (Lewis bases), in combination with dicyan- amide have been shown to produce n…     

Synthesis of Novel Bis(mesocyclic) polyamines

介绍了带羟基桥连双－（中环多胺）的合成。首先利用Ｎ－对甲苯磺酰基－３－羟基－１，５－二氮杂环庚烷与５种双官能基化合物在Ｎ２气氛下于无水乙腈中反应，得到５种带对甲苯磺酰基的中环多胺，然后利用ＨＢｒ／ＨＯＡｃ脱去保护基团，得到桥连双－（中环多胺）的氢溴酸盐。所有新化合物的结构均经ＩＲ、１ＨＮＭＲ、ＭＳ或元素分析证实。     

Studies on the Absorption Spectra of Aqueous L-Tyrosine and Its Application

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Synthesis and Crystal Structure of Bis(S-methyl-β-N- (4-dimethylaminophenyl)methlenedithiocarbazate) Nickel (Ⅱ)

11NTRoDUCT1ONRecently,transitionmetalorganometallicandcoordinationcomplexeshavee-mergedaspotentialbuildingblocksfornonlinearoptical(NLO)materials(l-5i.Com-paredwlthorganlcmolecu1es,metalcomplexesofferalargervarietyofstructures,comparabIeor,insomecases,higherenvironmenta1stabilityandamuchgreaterdi-versityoftunableelectronicpropertiesbythevirtueofthecoordinatedmetalcen-tert6i.Thethio-Schiffbaseligandderivedfromdithiocarbazatesandthiosemicar-bazidescancoordinatereadilywithtransitionmetalstog…     

Synthesis and Crystal Structures of the α and β Forms of Bis(salicylaldoxime)copper(Ⅱ) Complexes

Modified α and β bis(salicylaldoxime)copper(Ⅱ) have been obtained by recrystallization from ethyl acetate(CCDC Nos. 212157 & 212158). The X-ray analysis reveals that the two modificated forms have the same structure with different geometric parameters. The α form crystallizes in the P2(1)/c space group and the β form in the P1 space group. Both the crystal structures consist of centrosymmetric monomeric molecules of Cu(OC6H4CNOH)2. The IR spectra are in agreement with the structural data.     

Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato)Cu（Ⅱ） and Zn(Ⅱ） Complexes

The structures of [Cu (S₂CN (CH₂)₄)₂] (1) and [Zn₂(S₂CN‐(CH₂)₄)₄] (2) have been determined by X‐ray crystallography analysis. They are all isomorphous and triclinic, space group of P1^?, with Z = 1. The lattice parameters of compound 1 is: a = 0.63483(2) nm, b = 0.74972(3) nm, c=0.78390(1) mn, α = 75.912(2)°, β = 78.634(2)° and γ = 86.845(2)°; compound 2: a = 0.78707(6) nm, b=0.79823(6) nm, c = 1.23246(9) nm, α = 74.813(2)°, β = 73.048(2)° and γ = 88.036(2)°. The copper atom is located on a crystallographic inversion center and zinc atom lies across centers of symmetry. The Cu(II) ion has a square‐planar geometry while Zn(II) has a distorted tetrahedral geometry. The thermal gravity (TG) data indicate that no structural transitions in the two compounds were abserved and the decomposition products can adsorb gas. Also they all have a high thermal stability.     

Modeling of the Electronic Absorption Spectra and Photoionization of Scandium and Titanium Tris(acetylacetonates) by the DV-XαMethod

In order to interpret the electronic absorption spectra of titanium tris(-diketonates) and to establish the correlation between the ionization and excitation energies, the oscillator strengths and energies and the ionization energies for the model complexes M(Mal)₃(Mal is deprotonated malonodialdehyde, M = Sc, Ti) were calculated in the transition state approximation of the DV-Xmethod. The good agreement between the calculated photoelectron spectra and the experimental data and the correlation found between two types of excitation justified the assignment of the experimental absorption bands to the electronic states of Ti(Acac)₃.     

Synthesis,Structure and Property of One Bis (benzimidazolin-2-ylidene) Arene-mercury(Ⅱ) Complex

Reaction of a N-heterocycliccarbene(NHC) containing an anthracene unit and two N-picolyl moieties with Hg(OAc)2 yielded a novel mercury(Ⅱ) complex(1). X-ray studies, UV-vis and fluorescence spectroscopy confirmed that a strong interaction exists between the mercury atom and anthracene unit.     

Investigation of Geometrical and Conformational Isomers of Cobalt(II) Bis(diphenylacetato)-bis(γ-picolinate) by Dynamic NMR Spectroscopy and Molecular Mechanics

Cobalt(II) bis(diphenylacetato)-bis(-picolinate) is synthesized and its geometrical and conformational isomers are investigated using dynamic NMR and molecular mechanics methods. The complex in the solution is shown to exist as cis and trans isomers, which are detected at 263 K in the course of a slow intermolecular ligand exchange. At T < 223 K, the intramolecular rotation of the phenyl radicals about the ^–O₂C–CH(Ph)₂ and ^–O₂CCH(Ph)–Ph bonds slows, which results in the formation of different conformers. The energies of the retarded intermolecular exchange and of the retarded rotation of the phenyl radicals were calculated from ¹H NMR and molecular mechanics data.     

The Investigation of Oxygen Absorption over LaOF by Means of Raman Spectroscopy

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Synthesis and Crystal Structure of Bis(dicyanamide)(5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane) Nickel(Ⅱ)

The nickel ( Ⅱ ) complex [Ni(teta) { N(CN)2 } 2] (teta = 5,7,7,12, 1 4, 1 4-hexamehyl- 1,4,8,1 1-tetraazacyclotetradecane) was synthesized and its structure has been determined by singlecrystal X-ray diffraction. Crystal data: C20H36N10Ni, monoclinic, space group P21/c, a = 9.632(2), b = 11.833(2), c = 10.613(2) A, β= 93.46(3)°, V= 1207.4(4) A3, Mr = 475.30, Z= 2, Dc= 1.307 g/cm3,F(000) = 508,μ(MoKα) = 0.831 mm-1, R = 0.0446 and wR = 0.1274 for 2423 observed reflections with I ＞ 2σ(I). The center nickel ion is coordinated by six nitrogen atoms, four from the macrocyclic ligand teta and the other two from two dicyanamides. The dicyanamide is coordinated to the metal atoms as uni-dentate manner via nitrile nitrogen atom.     

A One-dimensional Coordination Polymer of Copper(Ⅱ) and Bis(4,6-dimethyl-2-pyrimidinethiolato)methane

Reaction of bis(4,6-dimethyl-2-pyrimidinethiolato)methane(bpytm) with CuCl2·4H2O in a mixed methanol/dichloromethane solution gave a one-dimensional coordina-tion polymer [CuCl2(μ-bpytm)]n which was characterized by single-crystal X-ray diffraction.It crystallizes in monoclinic,space group P21/c with a=16.9433(5),b=13.6986(4),c=7.8434(2),β=100.371(2)°,V=1790.71(9)3,Z=4,Mr=426.86,Dc=1.583 g/cm3,μ(MoKα)=1.751mm-1,F(000)=868,S=1.025,the final R=0.0399 and wR=0.0924 for 2538 observed reflections with Ⅰ2σ(Ⅰ) and 206 variables.The neutral coordination polymer is constructed by the bidentate thioether ligands to link adjacent copper atoms.Each copper atom is bridged by two adjacent nitrogen atoms of bpytm ligands and terminally bonded by two chloride atoms to form a squareplanar coordination geometry.The average Cu-N and Cu-Cl bond lengths are 2.025(2) and 2.234(1),respectively.     

Synthesis and Thermal Rearrangement of Tetramethyldisilane-bridged Bis(cyclopentadienyl) Diiron Complexes with Bis(phosphine)Substitution

Photolysis of [Me2SiSiMe2)[C5H4Fe(CO2)]2with a series of bis(phosphine)ligands Ph2P(CH2)n PPh2(n=1-4) leads to the formation of the corresponding diiron complexes with intramolecular and intermolecular bis(phosphine) substitution.When these complexes were heated in refluxing xylene.only in the complexes with intermolecular bis(phosphine )substitution the thermal rearrangement reaction occurred.     

Kinetic Investigation of the Electrochemical Oxidation of Bis(benzene)chromium(0) in Diethyl ketone/N,N-Dimethylformamide

The cyclic voltametric technique utilizing a platinum working electrode was applied for the investigation of the electrochemical oxidation of bis(benzene)chromium(0), (C₆H₆)₂Cr to bis(benzene)chromium(I), (C₆H₆)₂Cr⁺ in diethyl ketone (DEK), N,N-dimethylformamide (DMF), and DEK/DMF binary mixtures containing n-tetrabutylammonium hexafluorophosphate (TBAPF₆) as the supporting electrolyte at T=298.15 K. The half-wave potentials (E _1/2) of the (C₆H₆)₂Cr^+/0 redox couple in DEK, DMF and DEK/DMF binary mixtures, were determined. The variation of E _1/2 with the solvent composition was found to be almost linear. The E _1/2 results were analyzed in terms of the electron-donating power of the solvent medium. The diffusion coefficients, D, were calculated using the Randles-Sevcik equation. The kinetics of the electrode reaction were investigated through the determination of the heterogeneous electron-transfer rate constants, k _s, according to the electrochemical rate equation proposed by Nicholson. Furthermore, the activation Gibbs energies for the electron-transfer process (ΔG ^≠) were also calculated. The results indicate that the redox couple (C₆H₆)₂Cr^+/0 exhibits an electrochemically reversible and diffusion-controlled process in all the investigated solvent media.     

Synthesis and Crystal Structure of a New Complex [Bis(dien)zinc(Ⅱ)] Zinc(Ⅱ) Tetrachloride (dien = Diethylenetriamine)

The title complex [bis(dien)zinc(Ⅱ)] zinc(Ⅱ) tetrachloride was synthesized and characterized by X-ray single-crystal diffraction, elemental analysis, electric conductivity, IR and electronic spectra. The compound crystallizes in the tetragonal system, space group I(4) with a = 10.250(3), b = 10.250(3), c = 9.054(2)(A), V= 951.2(5) (A)3, Mr= 486.95, Z= 2, F(000) = 504, Dc = 1.700 g/cm3,,μ = 3.083 mm-1, ,λ= 0.71073(A), the final R = 0.0226 and wR = 0.0642. The symmetric crystal smucture consists of a zinc complex cation [Zn(dien)2]2 and a zinc tetrachloride anion [ZnCl4]2-, forming a three-dimensional framework through intramolecular and intermolecular hydrogen bonds.     

Synthesis and Crystal Structure of a Novel Bis(chlorido)-bridged One-dimensional Chain-like Copper(Ⅱ) Polymer

A copper(Ⅱ) complex [LCu_2Cl_4]n was synthesized by a new bis-Schiff base ligand containing quinoline unit, 1,4-bis[2-(4-fluorophenyl)iminomethyl-8-quinolinoxy]butane(L). X-ray crystal structure shows that it is a binuclear complex, and the crystal belongs to the triclinic system, space group P1, with a = 9.387(2), b = 9.968(2), c = 10.291(2) ?, α = 87.532(3), β = 63.762(2), γ = 86.628(3)o, V = 862.1(3) ?~3, Z = 1, Dc = 1.640 Mg/m~3, F(000) = 428, R = 0.0416 and wR = 0.1141. Each Cu(Ⅱ) metal ion coordinates with a quinoline N atom, an imine N atom, an ether oxygen atom and three chlorides, forming a distorted six-coordinated octahedronal structure. Each copper(Ⅱ) complexation unit links with one of the adjacent ligand copper complexation units through the chlorido bridging groups, thus generating an infinite one-dimensional chain structure. Such 1D chains further construct a 2D network structure by π-π stacking interactions.     

Synthesis and Crystal Structure of Bis(nitrate)- bis(N,N''''-dimethyl-N,N''''-dibenzenyl-urea)uranyl(Ⅱ)

1 INTRODUCTION Tri-butyl phosphate (TBP) has been widely used as the extraction reagent in U-Th fuel to separate uranium from thorium. But di-butyl phos- phate (DBP) and butyl phosphate (MBP), the radio- lytic products of TBP, exhibit some coordinated ability to the fission elements, such as Zr and Nb. The substitutes for TBP have being studied for several decades[1～4]. The physical and chemical properties of amides are similar to those of TBP and they selectively extract U(Ⅵ…