Vacuum ultraviolet photoionization mass spectrometric study of ethylenediamine

The photoionization and dissociative photoionizations of ethylenediamine have been studied both experimentally and theoretically. In experiments, photoionization efficiency spectra for ions NH(2)CHCH(3)(+), NH(2)CH=CH(2)(+), CH(2)NH(2)(+), NH(3)(+), NH(2)CH(2)CHNH(2)(+) and NH(2)CH(2)CH(2)NH(2)(+) have been obtained. In addition, the energetics of the dissociative photoionization is investigated with ab initio Gaussian-3 (G3) calculations. The computational results are useful in analyzing the dissociation channels near the ionization thresholds. With the help of the G3 results, the dissociation channels for the formation of the aforementioned fragment ions have been established.     

Structure of liquid ethylenediamine according to data on molecular scattering of light

M. V. Lomonosov Moscow State University. Institute of General and Inorganic Chemistry, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 4, pp. 175–177, July–August, 1989.     

Molecular-dynamic simulation of nanosized droplet spreading over a continual solid surface

Molecular dynamics methods are employed for a comparative study of the spread of nanosized simple fluid droplets and nanodroplets composed of model chains that reflect molecules of normal alkanes over a solid substrate. The effects of the droplet size, the energy of the molecule-substrate interactions, temperature, and degree of chain rigidity on the spreading kinetics are investigated. The substrate is described in terms of the continual Lennard-Jones model.     

On the structures of ethylene glycol,monoethanolamine, and ethylenediamine in the liquid phase

Characteristics of instant (I) and frozen (F) structures of ethylene glycol (EG), monoethanolamine (MEA), and ethylenediamine (ED) are determined by means of molecular dynamics in the temperature range of 268–443 K. Radial distribution functions are obtained and compared for the I- and F-structures of fluids. Coordination numbers of molecules are calculated and the energies of intermolecular hydrogen bonds are estimated for the studied compounds. The greatest difference between the I- and F-structures is observed in ED, and the least difference is observed in EG. The F-structures are compared to the crystal structures of the studied compounds.     

Extended ensemble molecular dynamics study of cellulose I–ethylenediamine complex crystal models: atomistic picture of desorption behaviors of ethylenediamine

Cellulose - Cellulose I crystals swell on exposure to ethylenediamine (EDA) molecules to form a cellulose I–EDA complex, and successive extraction of EDA molecules converts the complex...     

Kinetics of ammoniation of some halobis(ethylenediamine)-rhodium(III) perchlorates in liquid ammonia

Summary The ammoniation ofcis-[Rh(en)₂Cl₂] · (ClO₄) in liquid NH₃ was studied at constant ionic medium of 0.20 m perchlorate in the 0 to 35° range. The complex reacts in two distinct steps to givecis-[Rh(en)₂(NH₃)₂] · (ClO₄)₃, with the intermediate formation ofcis-[Rh(en)₂(NH₃)Cl] · (ClO₄)₂. Both steps follow a conjugate-base mechanism. Activation parameters were obtained for the acid-base preequilibrium and the rate-determining step. The entropies of activation for the rate-determining step are 0 and –42 JK^–1mol^–1 for the first and second ammoniations respectively. These values are considerably lower than those found for the cobalt(III) analogues. The entropy changes for the acid-base equilibria are –84 and –36 JK^–1mol^–1 respectively, which is less negative than those values found for the cobalt(III) analogues. Trans-[Rh(en)₂I₂] · (ClO₄) ammoniates totrans-[Rh(en)₂(NH₃)I] · (ClO₄)₂. The contribution of spontaneous ammoniation to the overall reaction oftrans-[Rh(en)₂I₂] · (ClO₄) is negligible, so the uniqueness oftrans-[Co(en)₂Cl₂] · (ClO₄) among cobalt(III) complexes in this respect is not reproduced for thetrans-dihalotetraamine structure in rhodium(III) complexes. A comparison of cobalt(III) and rhodium(III) amines with respect to activation parameters and the influence of formal charge of the metal complex on reactivity indicates a more associative type of activation for rhodium(III).     

Molecular-dynamic simulations of the thermophysical properties of hexanitrohexaazaisowurtzitane single crystal at high pressures and temperatures

Molecular dynamic simulations of isothermal compression parameters are performed for a hexanitrohexaazaisowurtzitane single crystal (C₆H₆O₁₂N₁₂) using a modified ReaxFF-log reactive force field. It is shown that the pressure–compression ratio curve for a single C₆H₆O₁₂N₁₂ crystal at constant temperature T = 300 K in pressure range P = 0.05–40 GPa is in satisfactory agreement with experimental compression isotherms obtained for a single C₆H₆O₁₂N₁₂ crystal. Hugoniot molecular-dynamic simulations of the shock-wave hydrostatic compression of a single C₆H₆O₁₂N₁₂ crystal are performed. Along with Hugoniot temperature–pressure curves, calculated shock-wave pressure–compression ratios for a single C₆H₆O₁₂N₁₂ crystal are obtained for a wide pressure range of P = 1–40 GPa. It is established that the percussive adiabat obtained for a single C₆H₆O₁₂N₁₂ crystal is in a good agreement with the experimental data. All calculations are performed using a LAMMPS molecular dynamics simulation software package that provides a ReaxFF-lg reactive force field to support the approach.     

Galvanodynamic study of the electrochemical switching effect in perfluorinated cation-exchange membranes modified by ethylenediamine

Perfluorinated sulfonyl-fluoride cation-exchange flat-sheet membranes were treated with ethylene diamine to investigate the influence of EDA-surface-treatment on the process of electrochemical “switching” in such membranes. The galvanodynamic method was used to obtain i–V cyclic curves of the membranes. Electroless chemical deposition of Pt particles on modified membranes was achieved using the Takenaka–Torikai method. Galvanodynamic i–V cyclic curves of the plain and platinum-containing aminated membranes were compared. Chemical modification of the membrane surface and membrane structure was investigated by means of electrical conductivity measurements and IR-spectroscopy. Experimental results indicated that the “switching” phenomenon is more likely to occur due to a pH change in the electrolyte resulting in the formation of additional fixed-charged groups in the aminated layers of the membranes rather than due to heterolytic dissociation of water according to the second Wien effect.     

Kinetics of ethylenediamine and piperazine ethoxylation

The ethoxylation of ethylenediamine and piperazine was studied in the temperature range 343 - 363 K in the presence of 0 - 10 % water. Kinetic parameters of all reactions occurring in the system and a factor describing the water effect on the rate of the reactions are given. No formation of quaternary bases was observed. This revised version was published online in August 2006 with corrections to the Cover Date.     

A polarographic study of the complexes formed in alkaline solution by the cadmium(II) ion with ethylenediamine,N-(2-hydroxyethyl)ethylenediamine,and N,N′-bis(2-hydroxyethyl)ethylenediamine

A multiple regression analysis of polarographic data has been used to determine the formulas and formation constants of complexes formed in alkaline solution by reaction of cadmium(II) ion and hydroxide ion with ethylenediamine (en), N-(2-hydroxyethyl)-ethylenediamine (hn) and N,N′-bis(2-hydroxyethyl)ethylenediamine (2hn). The complexes formed are designated by the general formula Cd(A)_p(OH)_p^2?q and the formation constants are given as log β_pq. The complexes found and their formation constants are: for en, 1 : 2 (10.3), 1 : 3 (12.3), and 1 : 2 : 1 (12.2); for hn, 1 : 2 (9.5), 1 : 2 : 1 (12.2), and 1 : 2 : 2 (12.6); and for 2hn, 1 : 2 (8.9), 1 : 1 : 2 (11.1), 1 : 2 : 1 (11.2), and 1 : 2 : 2 (12.6). It is concluded that in each case for which the hydroxide ion is reacted, a proton is removed from an alcoholic hydroxyl group which is coordinated to form a five-membered chelate ring linking a nitrogen atom and oxygen atom to the cadmium(II) ion.     

Synthesis of alpha-P-modified nucleoside diphosphates with ethylenediamine

This report describes a one-pot synthesis of alpha-P-borano-, alpha-P-thio-, and alpha-P-seleno-modified nucleoside diphosphate analogues that are otherwise difficult to obtain. The key step involves the intramolecular nucleophilic attack by an amino group in 5 to remove the gamma-phosphate. The absolute configurations of P-diastereomers were confirmed by analysis of their 1H NMR. Affinity studies revealed that the nucleoside boranodiphosphates are potentially useful in antiviral research.     

Calorimetric study of liquid gadolinium-based alloys

The enthalpies of mixing of liquid Gd-Si (1770±5 K) and Al-Gd (1760±5 K) alloys have been measured by high-temperature isoperibolic calorimetry. The calorimetric study of the gadolinium-based liquid alloys demonstrates the great negative enthalpies of mixing, which is associated with the contribution of GdSi and GdAl₂ intermetallides into the liquid-state thermodynamics. The comparison of obtained results with literature data has been performed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Template reactions of fluorine-containing 1,3-diketones with ethylenediamine

Depending on the nature of the dicarbonyl fragment, the reaction of fluorinated copper(II) bis(1,3-diketonates) with ethylenediamine and its monoprotonated salts under mild conditions gives N,N-ethylenebis(aminovinyl ketones) and/or 1,4-diazepines. In excess ethylenediamine, copper(II) and nickel(II) N,N-ethylenebis(aminovinyl ketonates) undergo cyclization to 1,4-diazepines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2088–2092, September, 1991.     

TRANS-1,4,5,8-tetraazodecalin crystals occurring in ethylenediamine

Composition and structure of crystals of unknown origin, crystallizing spontaneously from ethylenediamine on standing, has been determined by elemental analysis, FTIR, ¹H and ¹³C NMR spectroscopy and X-ray diffraction. The crystal with molecular formula C6H14N4 has been found to be a highly symmetric saturated imino compound with double-ring structure, and unambiguously identified as trans-1,4,5,8-tetraazodecalin by ¹H NMR and powder X-ray diffraction based on both its specific AA'BB' spin coupling system and simulated XRD pattern calculated from available data of previous single crystal structure determination, respectively. Simultaneous TG/DTA measurement shows one-step degradation of this compound. The volatile decomposition products have been followed by both TG/DTA-MS and TG-FTIR. Group of the largest fragments (m/z=80, 81 and 82) observed by TG/DTA-MS corresponds to an aromatic 1,4-diazine (pyrazine). In the EGA-FTIR spectrum of released gaseous species measured at the highest evolution rate by TG-FTIR, ethylenediamine can be identified as another decomposition product. This revised version was published online in July 2006 with corrections to the Cover Date.     

The thermal decomposition of metal ethylenediamine oxalate complexes

The thermal dehydration and deamination of some ethylenediamine complexes of Zn, Cd, Cu, Ni and Co oxalate were studied by TGA, DTA, DSC, reflectance spectroscopy, and by GE. The tris(amine) complexes deaminated to mono(amine) compounds which then decomposed directly to the metal oxide. The kinetics and heats of dehydration and deamination of several of the complexes were determined.