Efficiency and Aging Comparison Between N,N′-Bis (3-methylphenyl)-N,N′-diphenylbenzidine (TPD) and N,N′-Di-[(1-naphthalenyl)-N,N′-diphenyl]-1,1′-biphenyl-4,4′-diamine (NPD) Based OLED Devices

In this paper we present and discuss experimental results to evaluate performances and aging behaviour of two Hole Transporting Material (HTM), TPD and NPD, in Organic Light Emitting Device (OLED) with structure: ITO/HTM/Alq3/Al. For each of these HTMs, devices with several thicknesses have been built, to measure and emphasize behaviours of material-geometry combinations. Electro-optical properties have been measured to estimate and compare brightness, power efficiency and aging decays.     

CIRCULAR DICHROISM AND ELECTRONIC ABSORPTION OF RHODIUM(III) EDTA-TYPE COMPLEXES: Ethylenediamine-N,N′-diacetato-N,N′-di-3-propionatorhodate(III) and (S,S)-Ethylenediamine-N,N′-disuccinatorhodate(III) Ions

Abstract

Electronic absorption and CD spectra are reported for the sexidentate complexes, trans(O₅)-Rh(EDDDA)^?, trans(O₅ O₆)-Rh(EDDDA)^?, and trans(O₅)-Rh(S,S-EDDS)^? (EDDDA)=ethylenediamine-N,N′-di-3-propionate; S,S-EDDS=(S,S)-ethylenediamine-N,N′-disuccinate). Because of the sterospecific coordination of the S,S-EDDS ligand the absolute configuration of (+)_D-trans(O₅)-Rh(S,S-EDDS)^? is known to be Λ. By comparison of their CD spectra to that of the (+)_D isomer of trans(O₅)-Rh(S,S-EDDS)^?, the absolute configurations of the (?)_DEDDDA complexes are assigned tentatively.     

Extraction of americium(III) and europium(III) using a gamma pre-irradiated solution of N,N′-dimethyl-N,N′-dibutyltetradecyl malonamide in n-dodecane modified with N,N′-dihexyloctanamide

The extraction of Am(III) and Eu(III) using a γ-pre-irradiated N,N′-dimethyl-N,N′-dibutyltetradecyl malonamide (DMDBTDMA) modified with N,N′-dihexyloctanamide (DHOA) in n-dodecane (NDD) at 4.5M HNO₃ has been studied as a function of the absorbed dose up to 2×10⁶ Gray. The distribution ratios of Am(III) and Eu(III) were almost constant until a dose of 1×10⁵ Gray and then they decreased gradually up to a dose of 2×10⁶ Gray. The decrease of the distribution ratios of Am(III) and Eu(III) are due to the decreasing concentration of the DMDBTDMA by a γ-pre-irradiation and these results were supported by a determination of the DMDBTDMA concentration with a gas chromatography method. The distribution ratios of Am(III), Eu(III), Ce, Nd and Y with γ-pre-irradiated (DMDBTDMA-DHOA)/NDD have also been studied as a function of the nitric acid concentration and the extraction temperature.     

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.     

Syntheses,crystal structures,and properties of optically active Lu(III) and Yb(III) complexes of N,N′-bis(2-hydroxybenzyl)-N,N′-bis(2-pyridylmethyl)-R-1,2-propanediamine with chloride or thiocyanate

The reaction of N,N′-bis(2-hydroxybenzyl)-N,N′-bis(2-pyridylmethyl)-R-1,2-propanediamine (R-bbppnH₂) with LnCl₃?6H₂O (Ln: Lu, Yb) stereoselectively gave an optically active complex, [LnCl(R-bbppn)], which crystallizes in the acentric space group of P2₁2₁2₁. The central lutetium(III) is coordinated by two oxygens from two phenolates, four nitrogens from two pyridines, and one bidentate propanediamine of R-bbppn^2?, one chloride to form a seven-coordinate distorted pentagonal bipyramidal geometry. Although two optical isomers, ΔΛΔ and ΛΔΛ, are possible for such a structure, the absolute configuration of the complex is stereoselectively unified to ΔΛΔ. The coordinated chloride of the complex is readily replaced by other ligands, and hence the reaction with thiocyanate results in formation of another seven-coordinate complex, [Ln(NCS)(R-bbppn)].     

Spin crossover studies in tris(N,N′-dialkyldithiocarbamato)iron(III) complexes

A series of fifteen complexes of the type [Fe(RRNCS₂)₃] with symmetric (R=R=n- C₆H₁₃, n-C₈H₁₇, CH₂–CH=;CH₂, C₆H₅, C₆H₁₁ and C₆H₅CH₂), unsymmetric (R = CH₃; R = n-C₄H₉, C₆H₁₁, C₆H₅ and R = C₂H₅; R = n-C₄H₉, C₆H₁₁, C₆H₅ and i-C₃H₇) and ring substituents (RNR=pyrrolidyl and piperidyl) have been synthesized and their magnetic moments and Mössbauer spectra recorded from room temperature (RT) to liquid nitrogen temperature (LNT). Room temperature Mössbauer spectra of all the complexes exhibit an asymmetric doublet, which could be resolved into two doublets, each corresponding to low and high spin states in equilibrium. The crystal structure of tris(N, N-diallyldithiocarbamato)iron(III) shows it to be monoclinic with trigonally distorted octahedral geometry and space group C2/c. Fe–S stretching vibrations in the far i.r. region also show equilibria, HS LS. Depending on the nature of the alkyl group substituent, variable temperature magnetic moment and Mössbauer spectral studies, all the complexes may be divided into three groups; high spin complexes exhibiting spin-crossover (⁶A_1g ²T_2g), high spin complexes exhibiting spin transition (⁶A_1g ⁴T_1g) and intermediate spin complexes showing spin transition (⁴A_1g ²T_2g). On the basis of areas of the two doublets corresponding to high and low spin states, their percent contributions were calculated. Furthermore, magnetic moments of the equilibrium mixture calculated on the basis of respective areas compare well with the experimentally determined _eff values. E_Q values for both high and low spin states show linear decrease with increasing temperature.     

Synthesis,Structure, and Biological Activity of N-p-(Dimethylamino)-N′-(p-dimethylaminobenzylidene)-N,N′′-diphenylbenzohydrazonohydrazide

Russian Journal of General Chemistry - A three-component reaction of 3,5-diacetyl-2,6-dimethylpyridine, p-N-dimethylaminobenzaldehyde and phenylhydrazine in the presence of KOH in ethanol gave the...     

Synthesis,crystal structures and characterization of iron(III) and cobalt(III) complexes bearing 2,2′-bipyridylcarboxylate ligands

Transition Metal Chemistry - The Fe(III) complex [FeIII(bpdc)(Hbpdc)] (1) (bpdc?=?2,2′-bipyridyl-6,6′-dicarboxylate and...     

Kinetics of solvolysis of the trans-dichlorobis(R-ethylenediamine)cobalt(III) ion (R = N-methyl or N,N′-dimethyl) in urea–water mixtures

First order solvolysis rates of the trans-dichlorobis(R-ethylenediamine)cobalt(III) ion (R=N-Me or N,N-Me₂) complex have been investigated in mixtures formed by adding urea to H₂O, which enhances the dielectric constant and decreases solvent structure. Differential effects of the changes in solvent structure on the initial and transition states are found to be important factors controlling changes in the rate constant with solvent composition. The variation of the enthalpy and the entropy of activation with solvent composition are contrasted with their variations found for the solvolysis of the complexes in mixtures where solvent structure is enhanced by additions of a co-solvent to water. The application of a free energy cycle to the process of the initial state going to the transition state suggests that the cationic cobalt(III) complexes in the transition state are more stable than the cationic cobalt complexes the initial state in the water+urea mixtures.     

Kinetics of aquation of trans-dichlorobis(N,N′-dimethylethylenediamine)cobalt(III) ion in water–methanol in water–propan-2-ol media

The complex trans-[Co(dmen)2Cl2]Cl (dmen=N,N-dimethylethylenediamine) has been prepared and characterized by elemental analysis, u.v.-vis. and i.r. spectra. The kinetics of the primary aquation of trans-[Co(dmen)2Cl2] in H2O, H2O–MeOH and H2O–i-PrOH have been examined over a wide range of solvent compositions and temperatures (40–55°C). Plots of rate constants (log k) versus the reciprocal of the dielectric constant of the medium (Ds–1) and Grunwald–Winstein values of the solvent (Y) were found to be non-linear. The variation of enthalpies (H) and entropies (S) of activation with solvent composition has been determined. Plots of H or S versus the mole fraction of each solvent exhibit extrema at x2=ca. 0.16 and 0.27 for MeOH and at x2=ca. 0.03 and 0.14 for i-PrOH. Furthermore, the cycle relating the free energy of activation in H2O to that in H2O–co-solvent shows that the stabilizing influence of the changes in the solvent structure is greater on the emergent five-coordinate cation in the transition state than that on the complex ion in the initial state, with the difference becoming greater as the mole fraction of the co-solvent increases.     

Electrochemical investigation of N,N′-Propylene-bis-(salicylideneiminato) Mn(III) in phosphate buffer solutions

Summary An electrochemical study on N,N-Propylene-bis-(salicylideneiminato) Mn(III) was performed using cyclic voltammetry with convolution-deconvolution and digital simulation in phosphate buffer solutions ofpH values ranging from 5–9.5 at a hanging mercury drop electrode (HMDE). The reduction pathway of the investigated complex shows that a moderately fast transfer of one electron is followed by a very fast chemical reaction (E _q C _irr scheme). The electrochemical parameters have been determined experimentally andvia digital simulation experiments.

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Elektrochemische Untersuchung von N,N-Propylen-bis-(salicylideniminato)-Mn(III) in Phosphatpufferlösungen

Zusammenfassung N,N-Propylen-bis-(salicylideniminato)-Mn(III) wurde in Phosphatpufferlösungen mitpH-Werten im Bereich von 5–9.5 an einer Quecksilbertrofelektrode (HMDE) mittels cyclischer Voltammetrie (Konvolution-Dekonvolution, digitale Simulation) elektrochemisch untersucht. Ein mäßig schneller Transfer eines Elektrons wird von einer sehr schnellen chemischen Reaktion gefolgt (E _q C _irr-Schema). Die elektrochemischen Parameter wurden experimentell und durch Simulations-experimente bestimmt.

     

Synthesis,crystal structure and reactivity of trans-diaquo N,N′-ethylenebis-(3-methoxysalicylideneiminato)chromium(III)

A new chromium(III) Schiff base complex, [Cr(3-methoxysalen)(H₂O)₂]ClO₄, where salen=N,N-ethylenebis- (salicylideneimine), has been synthesized and characterized by spectroscopic techniques. Single crystal X-ray data reveals that the complex assumes a trans-diaquo structure with formulation [Cr(C₁₈H₂₂N₂O₆)]ClO₄ but, unlike in Cr (salen)(H₂O)₂ ⁺, the two trans-water molecules are equidistant from Cr^III. The effect of the substituent on the phenyl ring in respect of redox reactivity has been investigated. The kinetics of the oxidation of [Cr(Schiff base)- (H₂O)₂]ClO₄, where Schiff base=salen, (1) and 3-OMe-salen, (2) by PhOI has been studied. The bimolecular rate constant for the formation of the O=Cr^v Schiff base in case of (2) was four times faster than that of (1). The introduction of the OMe group substituent on the phenyl ring influences not only the structure and crystal packing, but also the reactivity of the complex and the electronic environment around the metal ion.     

POLAROGRAPHIC INVESTIGATION OF THE SYSTEMS ARSENIC(III)-TARTARIC ACID AND ARSENIC(III)-1,2-DIAMINO-CYCLOHEXANE-N,N,N′,N′-TETRAACETIC ACID (DCTA)

Abstract

The reactions between As(III), tartaric acid (H₂T)and DCTA were investigated polarographically. The conditional stability constants of As(III)-complexes at a given pH-value and variable ligand concentration were calculated from the change of the limiting currents. The optimum conditions for calculating stability constants from the current were also discussed. It was found that DCTA (H₄L)formed the complex [As(OH)₂HL]^2- whose overall formation constant was lgβ111=(20.67 ±0.09)atμ=0.1 and t°- (25.0±0.2)°C, whereas the complex between As(III) and H₂T was [As(OH)₂T]^? with an overall stability constant 1gβ 101= 6.62 ±0.14 at μ=0.1 and t°= (25 ± 0.2)°C.     

N,N′-二乙(甲)基-N,N′-二苯基脲对铀(VI)和钍(IV)萃取行为的研究

目前国际上一般采用磷酸三丁酯(TBP)作为铀的萃取剂。TBP对铀有较强的萃取能力,但其耐辐照能力较差。酰胺的理化性质类似于TBP,与TBP相比降解产物易除去,“可完全燃烧”等优点而被认为是一种能取代应用于核燃料后处理的有前途的萃取剂。本文以二甲苯或三氯甲烷     

Dinuclear complexes of cobalt(II) with N,N′-substituted dithioxamides derived from α-aminoacids

Summary The coordination behaviour of N,N-bis(1-carboxymethyl)dithioxamide (GLYDTO), N,N-bis(1-carboxyethyl)dithioxamide (ALADTO), N,N-bis(1-carboxy-2-methylpropyl) dithioxamide (VALDTO) and N,N-bis(1-carboxy-3-methylbutyl)dithioxamide (LEUDTO) has been investigated by isolating and characterizing the dinuclear, neutral cobalt(II) complexes, [Co₂(L-4H)(H₂O)₂] (L = GLYDTO, ALADTO, VALDTO or LEUDTO) and [Co₂(L-4H)(H₂O)₆] (L = ALADTO or VALDTO). All ligands were characterized by mass, i.r., and ¹H- and ¹³C-n.m.r. spectroscopy. The complexes possess distorted octahedral structures as revealed by the magnetic and electronic (diffuse reflectance) spectral data. The i.r. data indicate that the ligands are bis-tridentate, bis-dianions coordinated to each metal ion through the carboxylate oxygen, deprotonated thioamide nitrogen and thiocarbonyl sulphur atoms.     

N,N′-Bis(silylmethyl)azodicarboxamides

Russian Journal of General Chemistry - The first representatives of silicon-containing azocarboxamides, N,N′-bis(silylmethyl) azodicarboxamides, were synthesized by the reaction of...     

N,N′-Bis(trimethylsilyl)dicyandiamide

N,N-Bis(trimethylsilyl)dicyandiamide was prepared for the first time by the reaction of dicyandiamide with hexamethyldisilazane in boiling tetrahydrofuran. Thermal transformations of this compound were studied by DTA. The novel compound may be used in the synthesis of bis(trimethylsilyl)carbodiimide.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 498–500, March, 1994.     

Synthesis and X-ray crystal structures of N,N,N′,N′-tetraalkylpyridine-2,6-dithiocarboxamides (S-dapt) complexes of cobalt(II) and nickel(II)

Reactions of anhydrous CoX₂ (X?=?Br^?, SCN^?) and Ni(ClO₄)₂ with N,N,N′,N′-tetraisobutylpyridine-2,6-dithiocarboxamides (S-dbpt), N,N,N′,N′-tetraisopropyl pyridine-2,6-dithiocarboxamides (S-dppt), and N,N,N′,N′-tetraethylpyridine-2,6-dithiocarboxamides (S-dept) lead to the formation of [Co(S-dbpt)Br₂] (1), [Co(S-dppt)(SCN)₂] (2), and [Ni(S-dept)₂]·(ClO₄)₂·H₂O (3), respectively. The X-ray crystal structures of the three S-dapt ligands and three complexes along with spectroscopic analyzes are presented. The molecular structure investigations of the S-dapt ligands show that the thiamide planes are twisted with respect to the pyridine ring, which is more in the case of phenyl groups. The structures of the Co(II) complexes reveal that an increase in steric crowding on the amide side arms of the ligands has no substantial effect on the geometry adopted by the corresponding complexes. The Co(II) gives only 1?:?1 five-coordinate, ion-paired complexes with a distorted square pyramidal geometry. Ni(II), on the other hand, prefers an octahedral geometry with 1?:?2 metal–ligand ratio. The coordination behavior of S-dapt has been compared to the analogous oxo(O-daap) ligands. Lesser propensity of S atom to get involved in H-bonding interactions ensures an S-N-S type of tridentate coordination by S-dapt.     

Radiolysis of cerium(III) 1,2-bis(β-aminoethoxy)ethane N,N,N′,N′-sodium sulfonate triacetic acid chelate

The publication describes chelation studies of cerium(III) with 1,2-bis(-aminoethoxy)-ethane N,N,N,N-sodium sulfonate triacetic acid (ASTA). The results showed the effectiveness of ASTA as a chelating agent by molar ratio, continuous variation and slope ratio methods. Stable 11 complex was formed at pH from 4 to 8. Aqueous solutions of the chelate of different mole ratios at pH and 7.5 were irradiated by -radiation with different doses. The results show that a decrease of absorbance with increasing absorbed dose was obtained in the dose range studied. A proposed radiolytic mechanism is discussed. The degradation of ligand was due to OH radical.     

Tris(Trifluoroacetylacetonato)(4,4′-bipyridyl-N,N′-dioxido)Lanthanum(III)∶ A One-dimensional Polynuclear Complex

A novel one-dimensional polynuclear complex, tris(trifluoroacetylacetonato)(4,4'-bipyridyl- N , N '-dioxido)lathanum(III), was synthesized and characterized by elemental analysis and IR spectroscopy. X-ray structure analysis revealed that the complex has an infinite one-dimensional polynuclear structure with the 4,4'-bipyridyl- N , N '-dioxide as a bridge. La(III) is coordinated to eight oxygen atoms, six from three trifluoroacetylacetonate anions and two from two 4,4'-bipyridyl- N , N '-dioxide molecules to form a slightly distorted square antiprismatic coordination polyhedron. The coordination moiety was linked through 4,4'-bipyridyl- N , N '-dioxide forming a one-dimensional chain.