Cyclopalladation of N,N,N′,N′-tetramethylisophthalthioamide

Summary N,N,N,N-Tetramethylisophthalthioamide (Hmpt) was cyclopalladated with PdCl₂ in hot dimethylsulphoxide to give [PdCl(mpt)]. The structure was determined by X-ray analysis. The thioamide is metallated at C(2) to act as an S528-01C528-02S tridentate anionic ligand. There is appreciable steric repulsion between the benzene ring H(4, 6) and the dimethylamino groups. The hydrogens and the methyl groups mutually deviate from the coordination plane in opposite directions. The stability of the fused 5,5-membered chelate ring formed by the S528-03C528-04S ligand seems to overcome the steric hindrance. Derivatives were prepared by replacement of the chloride ion with iodide, diethyldithiocarbamate, 4-tert-butylpyridine, or tri-n-butylphosphine, and characterized spectroscopically. The S528-05C528-06S-fused chelate ring was maintained in these derivatives.     

The structure effect of N,N,N′,N′-alkylamide in the extraction of uranium and thorium

In this paper, nine N,N,N,N-tetraalkyldiamides have been synthesized and the extracting ability for uranium and thorium under different conditions has been studied. All results were compared with those obtained by using tributyl phosphate (TBP) under exactly the same conditions. The extracting ability of thorium and uranium for different N,N,N,N-tetraalkyldiamides is discussed.     

Thermodynamic characteristics of protolytic equilibria of hexamethylenediamine-N,N,N′,N′-tetraacetic acid

The heats of dissociation of betaine groups of hexamethylenediamine-N,N,N′,N′-tetraacetic acid (H₄L) at 298.15 K and the ionic strengths of 0.1, 0.5, and 1.0 (KNO₃) were determined by direct calorimetry. The standard thermodynamic characteristics of the ptotolytic equilidria of H₄L were calculated using the results from thermochemical and potentiometric measurements made under identical test conditions.     

Sensitive Spectrophotometric Determination of Benzoylperoxide with N,N,N′,N′-Tetramethyl-p-phenylenediamine

Abstract

A highly sensitive spectrophotometric determination of benzoylperoxide (BPO) based on the color developing reaction between N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) and BPO in the presence of cerium(IV) in weakly acidic media is proposed. The calibration graph is linear in the range 0–6000 ng BPO per 10 ml with an apparent molar absorptivity of 4.73 × 10⁵ 1 mol^?1 cm-1 at 612 nm. The proposed method is about 50-fold more sensitive than N-ethyl-2-naphthylamine (NENA), and application to assays of flour is described.     

Vibrational spectra of N,N-dimethyl/diethylaniline,N,N,N′,N′-tetramethyl/tetraethyl-p-phenylenediamine and N,N,N′,N′-tetramethyl/tetraethylbenzidine derivatives

The ground state and protonated state (quaternized salt) vibrational spectra (200–1800 cm⁻¹) of the title amines are reported for various ring and/or methyl deuterated derivatives. Complete assignments are proposed and compared to those established for the parent hydrocarbons, benzene and biphenyl, and for the parent primary amines, aniline, p-phenylenediamine and benzidine. The electronic distribution, N(n)→ring(π) charge-transfer character and inductive effects are characterized from a vibrational point of view. Finally changes in the vibrational and electronic conformation upon protonation of the nitrogen atom are discussed. These results provide a fundamental basis for the vibrational investigation of excited states and reactive transients of aromatic amines.     

Thermodynamic characteristics of the protolytic equilibria of tetramethylenediamine-N,N,N′,N′-tetraacetic acid

The stepwise dissociation constants of tetramethylenediamine-N,N,N′,N′-tetraacetic acid (H₄L) are determined by means of potentiometry at 298.15 K and ionic strength values of 0.1, 0.5, and 1.0 (KNO₃). The heat effects of the dissociation of the betaine groups of the complexone are measured by direct calorimetry. The standard thermodynamic characteristics of the protolytic equilibria of H₄L are calculated via combined use of the results from thermochemical and potentiometric studies performed under identical experimental conditions. Our results are compared with the corresponding data on relative compounds.     

PVT properties of N,N,N′,N′-Tetraoctyl-3-oxapentanediamide (TODGA)

N,N,N??,N??-Tetraoctyl-3-oxapentanediamide (TODGA) is a versatile extractant for partitioning of fission products from highly active raffinate wastes. Its PVT properties are not available in literature. In this work, PVT properties of TODGA, estimated using group contribution method, are reported. A corresponding-states based equation as well as Wagner constants were also reported in the range of 273.15?K to critical temperature.     

Calorimetric study of the solubilization of ethylenediamine,N,N-dimethylaminoethylamine and N,N,N′,N′-tetramethylethylenediamine by reversed AOT micelles

Distribution constants and standard enthalpies of transfer of ethylenediamine (en), N,N-dimethylaminoethylamine (dmen) and N,N,N,N-tetramethylethylenediamine (tmen) partitioned between n-heptane and water containing reversed sodium bis(2-ethylhexyl) sulfosuccinate (AOT) micelles as a function of the molar concentration ratio R (R=[water]/[AOT]) were evaluated by a calorimetric method. The results show that en, dmen and tmen molecules, solubilized in the reversed micelles, are distributed between the micellar aqueous core and the micellar palisade layer. An analysis of the thermodynamic parameters of the partition process demonstrates the peculiar solvent properties of the water containing reversed AOT micelles.     

Solvent extraction of uranyl by N,N,N′,N′-tetraoctylsuccinylamide from nitric acid solution

Synthesis and characterization of N,N,N′,N′-tetraoctylsuccinylamide (TOSA) was carried out and used for extraction of U(VI) from nitric acid solutions. The effect of different factors affecting the extraction distribution ratio (TOSA concentration, concentrations of nitric acid, salting-out agent LiNO₃ concentration, equilibration time, temperature and effect of diluents) have been investigated. The results obtained indicated that TOSA have a great capability to extract uranyl with kerosene-1,3,5-trimethylbenzene than other diluents, it have a high extraction distribution ratios when the concentration of TOSA is lower and not found the third matter. It was found that the main extracted species is UO₂(NO₃)₂·TOSA. The apparent equilibrium constant of extraction determined is (2.32 ± 0.31) L³/mol³ at (298 ± 1) K. The enthalpy of extraction is ?35.20 ± 0.352 kJ/mol.     

Enantioselectivity switch controlled by N,N′-di- or N,N,N′,N′-tetra-substituted chiral thiophosphorodiamide ligands,structural relatives of thioureas,in catalytic additions of diethylzinc to aldehydes

We have developed a series of new chiral thiophosphorodiamide ligands derived from (1R,2R)-(+)-1,2-diphenylethylenediamine, which are the structural relatives of thioureas. An investigation into their catalytic properties in asymmetric additions of diethylzinc to aldehydes has shown that N,N,N′,N′-tetra-substituted chiral thiophosphorodiamides can give (R)-secondary alcohols with up to 98% yield and 98% ee, while N,N′-di-substituted chiral thiophosphorodiamides give (S)-secondary alcohols with up to 99% yield and 97% ee values. The enantioselectivity switch is highly efficient with a broad substrate scope. We have also proposed hypothetical reaction pathways, which result in an enantioselectivity switch.     

Efficient reduction of acyl chlorides with zinc borohydride/N,N,N′,N′-tetramethylethylenediamine

Various acyl chlorides are efficiently reduced to the corresponding alcohols under mild conditions by treatment with zinc borohydride in the presence of N,N,N′,N′-tetramethylethylenediamine.     

Electronic Spectroscopic Studies of the Charge Transfer Complex of N,N , N ′, N ′-Tetramethyl-4-4′-Diamino-Benzophenone with Iodine in Methanol

The UV-visible absorption bands of the charge transfer (CT) complex of N, N, N', N'-tetramethyl-4,4'-diamino-benzophenone with iodine in methanol at 30°C have been studied. The value of K^AD , ?^AD and E _CT were calculated for this complex. The value of the equilibrium constant, K^AD , for the above complex reaction was calculated as 28.85m³·mol^?1. The value of the molar extinction coefficient of the CT complex, ?^AD , was also calculated as 1171m²·mol^?1 for λ_max = 602 nm and the absorption band energy E _CT of the complex was found to be 2.06 e.v. The ionization potential of the electron donor was also obtained spectroscopically and found to be 6.284 e.v. The rate constant obtained for the forward reaction is 3.624 x 10^?5M^1/2s^?1 and for the reverse reaction is 1.256 x 10^?6s^?1. Finally, the half-life value for the above reaction was graphically calculated and shown to be 1.549 day. The kinetics of the above reaction were studied showing the reaction to be a half-order reaction. The values of rate constants and half-life were calculated.     

Binuclear complexes of chromium,manganese and rhodium withN-hydroxyethyl-N,N′,N′-tribenzimidazolylmethylethylenediamine

Summary Three novel binuclear complexes, Cr₂Cl₆L·EtOH, Mn₂OAc₄L·EtOH, Rh₂Cl₆L.2H₂O, where L =N-hydroxyethyl-N,N,N-tribenzimidazolylmethylethylenediamine, have been prepared and characterized by elemental analyses, i.r., u.v.-vis. and e.s.r. spectra, and by magnetic susceptibility measurements. A weak antiferromagnetic spin exchange interaction exists between the metal ions in a binuclear unit for the dimanganese complex. Preliminary bioassays show that the manganese complex possesses antitumour activityin vitro.     

2,7-Dibromonaphthalene and 4,4′-dibromobiphenyl in the synthesis of oxadiamine N,N, N′, N′-tetraaryl derivatives and studies of formation of bismacrocyclic compounds from them

Russian Chemical Bulletin - The Pd-catalyzed tetraarylation of diamines and oxadiamines with 2,7-dibromonaphthalenes and 4,4′-dibromobiphenyl was studied. These reactions gave the...     

Extraction behavior of strontium from nitric acid solution with N,N,N′,N′-Tetraisobutyl diglycolamide

The extraction behaviors of strontium from nitric acid solution were investigated with N,N,N′,N′-tetraisobutyl diglycolamide (TiBDGA). Effects of acidity, diluents, concentration of extractant and temperature on the distribution ratio of strontium (D _Sr) were examined. The stoichiometry of the extracted molecule was Sr²⁺:TiBDGA of 1:3. The apparent extraction equilibrium concentration constant logK _ex was 3.25. The enthalpy change ΔH and entropy change ΔS were ?55.6 kJ mol^-1 and ?124 J mol^-1 K^-1, respectively. The extraction is an exothermic process. Through two strip stages, strontium could be stripped effectively by 0.01 M nitric acid solution.     

Catalase activity of cobalt(II) complexes with N,N,N′,N′-tetrasubstituted thiocarbamoylsulfenamides

On the base of the kinetic and activation parameters of the hydrogen peroxide decomposition in the presence of chelates of CoX₂ salts (X = Cl, Br, I, NCS) with N,N,N′,N′-tetrasubstituted thiocarbamoylsulfenamides containing exocyclic (out-of-chelate) fragments of dimethylamine (I), piperidine (II), and piperazine (III) the nature of acido-ligands influence on catalase activity of complexes I–III was revealed, depending on the structure and composition of the chelating ligand. Mononuclear complexes I(Br) and II(Br) can transform into 10-membered binuclear macrochelate intermediates.     

N,N,N′,N′-tetrabutylmalonamide as a new extractant for extraction of nitric acid and uranium(VI) in toluene

N,N,N,N-tetrabutylmalonamide (TBMA) was synthesized and used for extraction of uranyl(II) ion from nitric acid media in toluene. The effects of nitric acid concentration, extractant concentration, temperature and salting-out agent (LiNO₃) on distribution coefficients of uranyl(II) ion have been studied. The extraction of nitric acid is also studied. The main adduct of TBMA and HNO₃ is HNO₃. TBMA in 1.0 mol/l nitric acid solution. The 1:2:3 complex of uranyl(II) ion, nitrate ion and TBMA as extracted species is further confirmed by IR spectra of the extraction of uranyl(II) ion with TBMA, and found that the NO ₃ ^– in the extraction species UO₂(NO₃)₂·3TBMA did not participate in coordination of uranyl(II) ion. The values of thermodynamic parameters have also been calculated.