The Decomposition of Transition Metal Tetrafluoroborates by some strong Base Ligands

Abstract

Some transition metal complexes of triethylene-diamine (TED, I) and quinuclidine (Q, II) have been reported.^1–5 Recently we treated I and II with metal bistetrafluoroborates (M=Co²⁺, Ni²⁺, and Cu²⁺) which have not been studied yet, and postulated that pure coordination complexes might be obtained. However, evidence for the existence of 1:1 adducts such as C₆H₁₂N₂:BF₃ (III) and C₇H₁₃N:BF₂ (IV) in treatment of I and II with metal bistetrafluoroborates has now been found. We wish to describe our results concerning formation of these two new 1:1 adducts in this letter.     

N-PHOSPHORYL AMINO ACIDS AND PEPTIDES: PART I. THE CRYSTAL AND MOLECULAR STRUCTURE OF N-(O,O-DIISOPROPYL PHOSPHORYL)-TRANS-4-HYDROXY-D,L-PROLINE

Abstract

The crystal and molecular structure of N-(O,O-diisopropyl phosphoryl)-trans-4-hydroxy-D,L-proline has been determined by X-ray diffraction analysis and is compared with proline or hydroxyproline residue in a peptide chain described in the literature. The compound crystallized in orthorhombic system with space group P2₁2₁2₁, a=6.934(2), b=8.694(3), c=26.727(7) Å, V=1611.3(8) ų, Z=4, Dx=1.22 g/cm³. The structure was solved by direct method and refined by anisotropic least squares to a discrepancy index R=0.072. In the compound, the nitrogen atom is trigonal and its remaining 2p orbital is conjugated with the P?Oπ system; the conformation of the phosphorimidate function is favoured by the trans orientation of the P=O bond with respect to the N-C4 bond. In the pyrrolidine ring moeity, the C2-C1-N-C4 atoms are nearly copolnar and the C3 atom is out of the plane by about 0.47 Å.     

COPPER(II) COORDINATION COMPOUNDS: CLASSIFICATION AND ANALYSIS OF CRYSTALLOGRAPHIC AND STRUCTURAL DATA II. MONONUCLEAR-, HEXA-, HEPTA-AND OCTACOORDINATE COMPOUNDS

Abstract

This review summarizes the data for over five hundred and fifty six-, seven- and eight-coordinate Cu(II) coordination compounds. The six-coordinate derivatives are mostly distorted tetragonal (elongation along a single C ₄ axis). The seven-coordinate derivatives are only penta-gonal-bipyramidal with different degrees of distortion and the eight-coordinate complexes are dodecahedral. The most common ligands are O- and N-donors. There is a trend for the Cu-L distance to increase with covalent radius of the coordinated atom and also increasing coordination number. In general, Cu(II) compounds “prefer” a monoclinic class and are blue or green. Several relationships were found and discussed. The data are compared and discussed with those of four- and five-coordinate Cu(II) compounds.     

New Types of Functionally Substituted Methylphosphonites and Their Derivatives

Abstract

Organophosphorus compounds containing a functional group in the a-position of the alkyl radical are of great interest in both theoretical fundamental investigations and for practical applications. Functionally substituted methyl-phosphonites and their derivatives, belonging to this broad class of organophosphorus compounds, are convenient objects for investigating mutual effects of trivalent phosphorus and a heteroatom, or functional groups attached to it in the a-position. They have also become key substances in obtaining new organophosphorus compounds. Functionally sub-stituted compounds of tetracoordinated phosphorus have been intensively investigated in recent years; rather convenient methods of synthesis of these compounds have been proposed and their properties have been studied in detail¹. However, the corresponding compounds of tricoordinated phosphorus are not available or difficult to obtain. Recently we re-ported on the properties of halogen-substituted methylphos-phines and their derivatives². The present paper is devoted to the synthesis and investigation of the reactivity of alkoxy-, dialkylamino- and carbonyl substituted methylphos-phonites and their derivatives. In synthesis of alkoxymeth-ylphosphonites and their analogs we were the first to use labile alkoxymethylmagnesium chlorides in the reactions with tricoordinated phosphorus acid chlorides³. Previously unknown dialkoxymethylphosphonites and their analogs were obtained from hypophosphorous acid and trialkylorthofor-mates. The process of esterification and dialkoxymethylat-ion of hypophosphorous acid, being dependent on a catalyst, proceeds in different ways and results in the formation of dialkoxymethylphosphonite structures     

Determination of N-methylcarbamate insecticides in water samples using dispersive liquid–liquid microextraction and HPLC with the aid of experimental design and desirability function

A rapid and simple method for the extraction and preconcentration of N-methylcarbamates (NMCs) (carbofuran, carbaryl and promecarb) in water samples using dispersive liquid–liquid microextraction (DLLME) using chemometrics was developed. Influence variables such as volume of extracting (CHCl₃) and dispersing solvents (ACN), pH and ionic strength, extraction time and centrifugation time and speed were screened in a 2^7–4 Plackett–Burman design was investigated. The significant variables were optimized by using a central composite design (CCD) combined with desirability function (DF). At optimum conditions values of variables set as 126 μL chloroform, 1.5 mL acetonitrile, 1 min extraction time, 10 min centrifugation at 4000 rpm min⁻¹, natural pH, 4.7% (w/v) NaCl, the separation was reached in less than 14 min using a C₁₈ column and an isocratic binary mobile phase (acetonitrile: water (50:50, v/v)) with flow rate of 1.0 mL min⁻¹. At optimum conditions method has linear response over 0.001–10 μg mL⁻¹ with detection limit between 0.0001 and 0.0005 μg mL⁻¹ with relative standard deviations (RSDs) in the range 2.18–5.06% (n = 6).     

ACTION OF WITTIG‐HORNER REAGENTS ON o-QUINONES

Abstract

When 3,4,5,6-tetrachloro-1,2-benzoquinone (1) was reacted with two molar amounts of triethylphosphonoacetate (I), the corresponding 5,6,7,8-tetrachlorocoumarin-4-carbethoxy-3-diethylphosphonate (4) was obtained. Moreover, phenanthrene-9,10-quinone (2) was converted by reaction of Wittig-Horner reagent (I) into 2,3-dicarbethoxy-phenanthro[9,10-b]dihydrofuran (5) and the dimeric form (6). On the other hand, adducts (7) and (8) were isolated from the reaction of acenaphthenequinone (3) with triethylphosphonoacetate (I). Possible reaction mechanisms are considered and the structure of the new compounds (4), (5, 6) and (7, 8) was confirmed on the basis of the elemental analysis and spectral studies.     

Synthesis, structural characterization and antimicrobial activity evaluation of metal complexes of sparfloxacin

The synthesis and characterization of binary Cu(II)- (1), Co(II)- (2), Ni(II)- (3), Mn(II)- (4), Cr(III)- (5), Fe(III)- (6), La(III)- (7), UO₂(VI)- (8) complexes with sparfloxacin (HL₁) and ternary Cu(II)- (9), Co(II)- (10), Ni(II)- (11), Mn(II)- (12), Cr(III)- (13), Fe(III)- (14), La(III)- (15), UO₂(VI)- (16) complexes with sparfloxacin (HL₁) and dl-alanine (H₂L₂) complexes are reported using elemental analysis, molar conductance, magnetic susceptibility, IR, UV–Vis, thermal analysis and ¹H-NMR spectral studies.The molar conductance measurements of all the complexes in DMF solution correspond to non-electrolytic nature.All complexes were of the high-spin type and found to have six-coordinate octahedral geometry except the Cu(II) complexes which were four coordinate, square planar and U- and La-atoms in the uranyl and lanthanide have a pentagonal bipyramidal coordination sphere. The antimicrobial activity of these complexes has been screened against two Gram-positive and two Gram-negative bacteria. Antifungal activity against two different fungi has been evaluated and compared with reference drug sparfloxacin. All the binary and ternary complexes showed remarkable potential antimicrobial activity higher than the recommended standard agents. Ni(II)- and Mn(II) complexes exhibited higher potency as compared to the parent drug against Gram-negative bacteria.     

SYNTHESIS OF SYMMETRICAL AND UNSYMMETRICAL AMIDOPHOSPHITES

Abstract

A method is proposed for one-pot synthesis of either symmetrical or unsymmetrical diester amidophosphites, developed on the basis of tris-(N,N-dimethyl)-amide/or tris-(N,N-diethyl)-amide/of phosphorous acid, activated by iodine, as a new phosphorylating reagent.

Nine thiophosphate, phosphite and phosphite monoester and diester derivatives of 1-O-stearoyl-ethane-2-ol, cholesterol, β-sitosterol and R,S-α-tocopherol have been synthesized under mild conditions (20–75°C) and in high final yields (83--98%).     

Performance evaluation of a new nanocomposite polymer gel for water shutoff in petroleum reservoirs

Abstract

A new polymer gel nanocomposite is fabricated for excess water production control (water shut off) in petroleum reservoirs and its rheological behavior is evaluated in the presence of sea water and formation water at the temperature of 100?°C. It is shown that at a high salinity without using SiO₂ nanoparticles, the elastic modulus of synthesized polymer gel in the presence of sea water and formation water are 12.5?Pa and 9.8?Pa respectively. However by incorporation of SiO₂ nanoparticles in the polymer gel matrix, the elastic modulus of synthesized polymer gel in the presence of sea water and formation water can be improved to 13.56?Pa and 11.57?Pa respectively, which is quite interesting from reservoir engineering viewpoint. Equilibrium Swelling Ratio (ESR) of the nanocomposite polymer gel in sea water and formation water decreases as the concentration of the SiO₂ increases. Thermal stability of the polymer gel is investigated by differential scanning calorimetry (DSC) measurements. The inflexion temperature of the polymer gel is improved by incorporation of 2000?ppm SiO₂ nanoparticles. The fabricated polymer gel nanocomposite in this work can have potential application in reduction of excess water production during enhanced oil recovery (EOR) operations in petroleum industry.     

Indole-based distinctive chemosensors for ‘naked-eye’ detection of CN and HSO4−, associated with hydrogen-bonded complex and their DFT study

Colorimetric detection of anions (HSO₄^? and CN^?) was achieved via analyte triggered colour changing of the dipodal and tripodal sensors in CH₃CN–H₂O (1:1). The sensors exhibited very sharp visual colour changes and fluorescence quenching–enhancing effect upon addition of the HSO₄^? and CN^?. The large downfield shift of the NH proton signals in ¹H-NMR complexation studies and quantum chemical DFT calculations proved the formation of hydrogen-bonded complexes where no proton transfer mechanism was found.     

Protoberberine ausReissert-Verbindungen, 5. Mitt.: Synthese des (±)-Bharatamins

Summary Alkylation of theReissert compound1 by methyl 2-bromomethylbenzoate (2) followed by spontaneous intramolecular cyclization affords dibenzo [a,g]quinolizinone4 which in turn can be reduced to benzyl ether5 by LiAlH₄/NaBH₄. Debenzylation of5 by ethanolic HCl furnishes the title compound6 in improved total yield.

     

HYDROBORATION OF UNSATURATED AMINES X. HYDROBORATION-HALOGENATION OF ALLYL PHOSPHORAMIDATES ROUTE TO γ-HALOGENOPROPYL PHOSPHORAMIDATES AND γ-HALOGENATED AMINES

Abstract

This paper describes the synthesis of γ-halogenopropyl phosphoramidates I by hydroboration-halogenation reaction of N-phosphorylated allylamines II (phosphoramidates and phosphoramides). Only the use of allyl phosphoramidates leads to a good regioselectivity of the addition of boron atom on the terminal carbon atom of the allyl structure (compounds III).

The absence of N→B complex formation permits a good reactivity of the trialkylboranes III and IV. The breaking of the P[sbnd]N bond, in acidic medium of the compounds I gives corresponding γ-halogenated amines V.     

Pd-catalyzed asymmetric allylation of an o-carborane derivative

The asymmetric synthesis of methyl 2-phenyl-2-(2-phenyl-ortho-carboran-1-yl)pent-4-enoate was carried out by palladium-catalyzed allylation in the presence of amino phosphites of the type (RO)₂P—O—CH₂—CHR"—NR₂ as chiral ligands.     

FURTHER STUDIES ON THE KINETICS AND MECHANISM OF THE COPPER-IMIDAZOLE CATALYSED DECOMPOSITION OF HYDROGEN PEROXIDE

Abstract

The catalytic decomposition of hydrogen peroxide in the presence of the tetrakis(imidazole)copper(II) complex was investigated. The kinetics, based on the rates of oxygen evolution, indicated that a ternary copper(I1)-imidazole-peroxo complex is involved in the rate-determining step. The equilibrium constant for the coordination of hydrogen peroxide to the cupric ion, and the acid dissociation constant for the coordinated H202 ligand were calculated as 1.7 M¹ and 2.1 × 10⁹ M, respectively. The ternary complex undergoes intramolecular electron transfer, with k = 4 s¹, generating Cu(1) species which can react with hydrogen peroxide or dioxygen, returning to the catalytic cycle. A complete mechanism is proposed, based on the kinetics of oxygen and on the electrocatalytic behdviour observed for the copperimidazole complexes under a dioxygen atmosphere.     

Synthesis,characterization, and antitumor activities of two copper(II) complexes with pyrazole derivatives

Two mononuclear copper(II) complexes with pyrazole derivatives, 1,1′-(anthracen-9-ylmethylene)bis(1H-pyrazole) (L¹ ) and 9-(4-(di(1H-pyrazol-1-yl)methyl)phenyl)-9H-carbazole (L² ), of formulae [CuL¹(CH₃CN)₂](ClO₄)₂ (1) and [CuL²(CH₃CN)₂](ClO₄)₂ (2) were prepared. Both complexes were confirmed by IR, MS, ¹H NMR, and elemental analyses. Complex 1 was also characterized by X-ray crystallography, confirming that copper(II) is coordinated by four nitrogen atoms from two L¹ and two oxygen atoms from two perchlorates. Furthermore, all ligands and complexes were tested in vitro for their antitumor activities using mouse melanoma cell line B16-F10, HepG2 human hepatoma cell line, and A549 human lung adenocarcinoma cell line. Both complexes displayed potent cytotoxicity and are promising substrates for further investigations.     

Aminomethylation of hindered 2-propargyl-1,3-diketones

2-Propargyl-substituted methoxy-1,3-diketones react with alkoxymethylamines or paraform and secondary amines in the presence of CuCl at the acetylene group to afford Mannich bases.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1293–1295, May, 1996.     

双核Ni(II)配合物[C17H20N4Ni(H2O)Cl]2Cl2•(CH3OH)的晶体结构及其模板合成新配体

采用“一锅煮”方法, 在金属Ni(II)离子作用下, 以2-乙酰吡啶和1,2-丙二胺物质的量比为2∶1进行反应, 得到了一种新的闭环单Schiff碱N₄四齿配体的配合物[C₁₇H₂₀N₄Ni(H₂O)Cl]₂Cl₂•(CH₃OH). 配合物的晶体结构测定表明, 其配位单元为N桥连的双核配合物, 配位单元间再通过氢键连接成一维链状结构.     

Synthesis and properties of (−)-menthol-derived chiral liquid crystals by introducing adipoyloxy spacer between mesogenic core and chiral menthyl

A homologous series of new chiral liquid crystal compounds, M6BnB (n = 2, 4, 6, 8, 10, 12, 14, 16, 18), with varying length of n-alkoxy chains at one end, was formed by covalently linking a chiral (?)-menthyl with biphenyl-benzoate via adipoyloxy spacer group. A combination of analysis methods such as Fourier transform infrared, ¹H NMR spectra, differential scanning calorimetry, polarised optical microscopy and X-ray diffraction was carried out to systematically investigate their phase structures and phase transition behaviours. The length of the flexible terminal alkoxy group has a profound influence on the clearing points (T_iso) and T_iso decrease with the increase of alkoxy chain (n). In addition, increasing the length of the terminal alkoxy group tends to narrow the temperature range of the N* phase and favour the development of chiral smectic C phase.     

钙钛矿结构荧光材料MZrO3:Eu3+,A (M=Ca2+, Ba2+; A=Li+, Na+, K+)的制备及其发光性质

Calcium and barium zirconate powders based upon CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) were prepared by combustion synthesis method and heating to ~1000℃ to improve crystallinity.The structure and morphology of materials were examined by X-ray diffraction (XRD) and scanningelectron microscopy (SEM). XRD results showed that CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) perovskites possessed orthorhombic and cubic structures, respectively. The morphologies of all powderswere very similar consisting of small, coagulated, cubical particles with narrow size distributions andsmooth and regular surfaces. The characteristic luminescences of Eu³⁺ ions in CaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) lattices were present with strong emissions at 614 and 625 nm for ⁵D₀→⁷F₂ transitions with other weakeremissions observed at 575, 592, 655, and 701 nm corresponding to ⁵D₀→⁷F_n transitions (where n=0, 1, 3, 4 respectively). In BaZrO₃:Eu³⁺ both the ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transitions at 595 and 613 nm were strong.Photoluminescence intensities of CaZrO₃:Eu³⁺ samples were higher than those of BaZrO₃:Eu³⁺ lattices. Thisremarkable increase of photoluminescence intensity (corresponding to ⁵D₀→⁷F_n transitions) was observedin CaZrO₃:Eu³⁺ and BaZrO₃:Eu³⁺ if co-doped with Li⁺ ions. An additional broad band composed of manypeaks between 440 to 575 nm was observed in BaZrO₃:Eu³⁺,,A samples. The intensity of this band wasgreatest in Li⁺ co-doped samples and lowest for K⁺ doped samples.     

Triphenylethanediol-Derived 2-Chloro-1,3,2- dioxaphospholane: Synthesis,Structure, and Reaction with Chiral Alcohols

The reaction of (S)-1,1,2-triphenylethanediol (3) with phosphorus trichloride leads to the diastereoselective formation of (S _C,R _P)-2-chloro-1,3,2-dioxaphospholane (2). Its configuration has been determined by single crystal X-ray diffraction. When reacted with racemic secondary alcohols, diastereomeric phosphites are obtained, which display substantial shift differences in the ³¹P NMR spectra. Thus, chlorodioxaphospholane 2 can serve as derivatizing reagent for chiral secondary alcohols permitting to determine their enantiomeric excess.