Precursors of Titanium Carbonitride

1986 ◽  
Vol 73 ◽  
Author(s):  
L. Maya
Keyword(s):  
Liquid Ammonia ◽  
Mixed Valence ◽  
Reaction Medium ◽  
Ceramic Materials ◽  
Titanium Content ◽  
Alkali Metal Halide ◽  
Ammonium Salts ◽  
Titanium Carbonitride ◽  
Ammonium Ion ◽  
Synthetic Approach

ABSTRACTA series of novel compounds was isolated in the course of exploratory work on the chemistry of titanium halides in liquid ammonia. This work was undertaken to study synthetic approaches to titanium-containing precursors of ceramic materials. Representative of these compounds is a mixed valence Ti(III)-Ti(IV) tetramer, [NH4+·NH3]2[Ti4Br4 (NH2)12]−2, which was produced by the reaction of potassium borohydride and titanium IV bromide in liquid ammonia at room temperature. Similar ammonium salts of either Ti(IV) or Ti(III) were also prepared. The reaction of the ammonium salts with sodium acetylide in liquid ammonia evolves acetylene in an amount equivalent to the ammonium ion present. This provided the charge of the complex and yielded novel titanium acetylide derivatives. The acetylides convert into titanium carbonitrides upon thermal treatment to 800°C.The reaction of titanium halides of their ammonolytic products with sodium acetylide in liquid ammonia to yield halogen-free acetylide precur-sors having a relatively high titanium content appears to be a convenient synthetic approach. This is made possible by the fact that the alkali metal halide by-products are soluble and easily separated in that reaction medium. This approach appears to be a generalized route applicable to a number of transition metal elements of interest.

scholarly journals Novel Unsymmetrical Ru(III) and Mixed-valence Ru(III)/Ru(II) Dinuclear Compounds Related to the Antimetastatic Ru(III) Drug NAMI-A

2001 ◽  
Vol 8 (1) ◽  
pp. 9-18 ◽  
Author(s):  
B. Serli ◽  
E. Iengo ◽  
T. Gianferrara ◽  
E. Zangrando ◽  
E. Alessio
Keyword(s):  
Ascorbic Acid ◽  
Mixed Valence ◽  
Physiological Solution ◽  
The Other ◽  
Synthetic Approach ◽  
Bulky Substituent ◽  
Chemical Behavior ◽  
Complete Reduction ◽  
Dinuclear Compounds

In this paper we report the stepwise preparation and the characterization of new unsymmetrical monoanionic Ru(III) dinuclear compounds, [NH4][{trans-RuCl4(Me2SO-S)}(μ-L){mer-RuCl3(Me2SO-S)(Me2SO-O)}] (L = pyz (1), pym (2)). By a similar synthetic approach we also prepared new mixed-valence Ru(III)/Ru(II) dinuclear compounds of formula [NH4][{trans-RuCl4(Me2SO-S)}(μ-pyz){cis,cis,cis-RuCl2(Me2SO-S)2(CO)}] (L = pyrazine (pyz, 3), pyrimidine (pym, 4)). Moreover, we describe the chemical behavior of compounds 1-4 in physiological solution, also after complete reduction (with ascorbic acid) to the corresponding Ru(II)/Ru(II) species. Overall, the chemical behavior of 1 and 2 after reduction resembles that of the corresponding dianionic and neutral dinuclear species, [{trans-RuCl3(Me2SO-S)}2(μ-L)]2− and [{mer-RuCl3(Me2SO-S)(Me2SO-O)}2 (μ-L)]. On the other hand, the mixed-valence dinuclear compounds 3 and 4, owing to the great inertness of the cis,cis,cis-RuCl2(Me2SO-S)2(CO)(1/2μ-L) fragment, behave substantially like the mononuclear species [trans-RuCl4(Me2SO-S)(L)]− in which the terminally bonded L ligand can be considered as bearing a bulky substituent on the other N atom.

Erstmalige Charakterisierung der Ammoniak-Proton-Komplexe [(NH3)3H]+ und [(NH3)4H]+ in den Kristallstrukturen von (NH4)3AsS4 · 5 NH3 und (NH4)3SbS4 · 8 NH3 / First Characterization of the Ammonia-Proton-Complexes [(NH3)3H]+ and [(NH3)4H]+ in the Crystal Structures of (NH4)3AsS4 · 5 NH3 and (NH4)3SbS4 · 8 NH3

2003 ◽  
Vol 58 (7) ◽  
pp. 672-677 ◽  
Author(s):  
Thomas Roßmeier ◽  
Nikolaus Korber
Keyword(s):  
Low Temperature ◽  
Ion Exchange ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Liquid Ammonia ◽  
Ammonium Ion ◽  
X Ray ◽  
Exchange Material ◽  
First Time

The compounds (NH4)3AsS4· 5 NH3 (1) and (NH4)3SbS4· 8 NH3 (2) were prepared by the reaction of Na3AsS4 and Na3SbS4 with a proton-charged ion exchange material in liquid ammonia and characterized by low temperature single crystal X-ray structure analysis. The ammonium-ammoniates show H3N-H···N-hydrogen bonds between the ammonium ion and ammonia molecules ranging from 1.86 to 2.55 Å (DHA-angles: 145 - 173°) and H3N-H···S-bonds to the thioanions between 2.36 and 2.97 Å (DHA-angles: 130 - 176°). The former of the interactions are responsible for the formation of [(NH3)2H]+, [(NH3)3H]+ and [(NH3)4H]+-complexes, the last two of which were characterized by X-ray analysis for the first time.

Effect of the Water Spectrum on the Determination of Dissolved Ammonia, Urea, and Chloride Concentrations by Raman Spectroscopy

1998 ◽  
Vol 52 (2) ◽  
pp. 240-249 ◽  
Author(s):  
Hsiaoling Wang ◽  
Chao Wang ◽  
Charles K. Mann ◽  
Thomas J. Vickers
Keyword(s):  
Least Squares ◽  
Partial Least Squares ◽  
The Other ◽  
Ammonium Salts ◽  
Ammonium Ion ◽  
Water Band ◽  
Chloride Concentrations ◽  
Better Than ◽  
Least Squares Approach

The effect of large, changing concentrations of electrolytes on the behavior of the OH stretching band of water have been investigated with the aim of developing methods for compensating for spectral interferences when solute NH bands are made the basis for mixture analyses. With the use of urea and ammonium salts as analytes, it was found that changing electrolyte concentrations affect the shape of the water band but do not appreciably affect the shapes of either the ammonium ion or urea Raman lines. Chlorides, nitrates, and mixtures of these were used as electrolytes. The identity of the anion had a significant effect on the shape of the OH band. Two methods of compensation were used. One involved factor analyzing the spectra of a set of solutions that contained chlorides and nitrates that are Raman inactive in the vicinity of the OH stretching band. The principal abstract factors were used in place of a water reference for a least-squares mixture analysis. The other method was application of partial least-squares. In addition to urea and ammonium ion, the concentration of KCl and the ionic strength of the system can be determined in the partial least-squares approach with limits of detection better than 0.1 M.

SALTING-IN BY QUATERNARY AMMONIUM SALTS

1965 ◽  
Vol 43 (12) ◽  
pp. 3232-3237 ◽  
Author(s):  
J. E. Desnoyers ◽  
G. E. Pelletier ◽  
C. Jolicoeur
Keyword(s):  
Quaternary Ammonium ◽  
Alkyl Group ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Smooth Transition ◽  
Ammonium Ion ◽  
Ammonium Bromide ◽  
Structure Of Water ◽  
Organic Ions ◽  
Bromide Solutions

The solubility of benzene in substituted quaternary ammonium bromide solutions has been measured by ultraviolet absorption. The solubility is found to increase in the presence of such salts as R4−nHnN+Br− where R is an alkyl group and n varies between 0 and 3; a smooth transition in behavior is observed when passing from simple salts to long-chained micellar salts. This salting-in can be explained in terms of an association between the nonelectrolyte and the quaternary ammonium ion, which is induced by the increase in the structure of water near large nonpolar groups of the organic ions.

scholarly journals The conductivities of tetraethylammonium and ammonium salts in methyl alcohol

1931 ◽  
Vol 132 (820) ◽  
pp. 427-441 ◽  
Keyword(s):  
Methyl Alcohol ◽  
Practical Importance ◽  
Ammonium Salts ◽  
Ammonium Ion ◽  
Transport Numbers ◽  
Average Value ◽  
Primary Object ◽  
Ionic Mobilities ◽  
Tetraethylammonium Salts ◽  
Chlorine Ion

If the motion of an electrolytic ion in an electric field obeys Stokes’s law and its effective radius remains unchanged in different solvents, then its velocity should be inversely proportional to the viscosity of the solvent, i. e ., l 0 X η = constant. The investigations of Walden have shown that this relationship, known as Walden’s rule, only holds good for certain large organic ions which therefore are presumed to be unsolvated. The NE t 4 + ion is of particular interest in this respect, since its salts have been studied by Walden in a number of solvents ; he has shown that the quantity A 0 X η is approximately constant for tetraethylammonium picrate both in different solvents and over a range of temperature in each. Owing to the lack of transport number data, the mobility of the NE t 4 + ion is only known directly in water, methyl alcohol and ethyl alcohol. Its value in these solvents is of considerable practical importance, since Ulich has used the average value of the product l 0 X η to calculate ionic mobilities in other solvents in which no transport numbers are at present available and in which they would be extremely difficult to measure in dilute solution. The value of the mobility of the tetraethylammonium ion in methyl alcohol is based solely on measurements with the picrate, apart from some early measurements with the iodide. The primary object of the present investigation was to measure the conductivity of a number of tetraethylammonium salts in methyl alcohol in order to obtain confirmatory evidence of its mobility. In addition, the conductivities of some ammonium salts have been determined in order to compare the mobilities of the simple and the tetra-substituted ammonium ion. It is remarkable that in spite of its complexity the NE t 4 + ion ( l 0 = 62) moves faster than the NH4 + ion ( l 0 = 58) and has a higher mobility in methyl alcohol than any cation except cæsium ( l 0 = 62·3 ) and hydrogen ( l 0 = 142), just as the symmetrical ClO 4 - ion is faster than the simple chlorine ion.

Structures ofN-acetyl-DL-isoleucine,N-acetyl-DL-alloisoleucine and their ammonium salts; role of ammonium ions in crystal structure formation

2016 ◽  
Vol 72 (4) ◽  
pp. 650-657
Author(s):  
Tatsuo Yajima ◽  
Makiko Kimura ◽  
Yoshihiro Hori ◽  
Tadashi Shiraiwa
Keyword(s):  
Hydrogen Bond ◽  
Room Temperature ◽  
Optically Active ◽  
Ammonium Salts ◽  
Ammonium Ion ◽  
Amino Group ◽  
Ammonium Ions ◽  
Screw Axis ◽  
Crystal Structure Formation

The crystal structures ofN-acetyl-DL-isoleucine,N-acetyl-DL-alloisoleucine and their ammonium salts show that these four compounds exist as racemic compounds around room temperature. The two ammonium salts are arranged around a 21screw axis, forming a helical column which consists of ammonium ions and single enantiomeric anions similar to the crystals of the ammonium salts of optically activeN-acetyl-L-isoleucine andN-acetyl-D-alloisoleucine. The ammonium ion and the carboxylate ion in the helix are connected by three hydrogen bonds, the fourth hydrogen bond being formed between the ammonium ion and an external acetyl amino group of the neighboring helical column. The fourth hydrogen bond is formed between the ammonium ion and an external acetyl amino group of the neighboring 21column. AmmoniumN-acetyl-DL-alloisoleucinate was revealed to exist as an unstable racemic compound due to conformational similarity between the racemic and optically active compounds in the solid state and was optically resolved by fractional crystallization at 293 K.

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