Some reactions of nitrogen bases with cobalt(II) complexes of the bidentate chelate Di(2-pyridyl) sulphide

1970 ◽  
Vol 23 (6) ◽  
pp. 1191 ◽  
Author(s):  
ME Bridson ◽  
WR Walker
Keyword(s):  
Room Temperature ◽  
Equilibrium Constants ◽  
Spectrophotometric Investigation ◽  
Nitrogen Bases ◽  
Bidentate Chelate ◽  
Temperature Equilibrium

Cobalt(11) compounds containing the chelate di(2-pyridyl) sulphide (dps) of the types Co(dps)X2 (X = Cl, Br, and I) and Co(dps)2X2 (X = Cl, Br, and NCS) have been prepared and investigated. An attempt to prepare cobalt(11) complexes containing mixed chelates such as Co(dps)(4-mepy)2X2 (4-mepy = 4-methylpyridine) was unsuccessful. However, a spectrophotometric investigation of the following replacement reactions Co(dps)Cl2 + 2(N-base) ↔ Co (N-base)2Cl2 + dps was carried out in chloroform and room-temperature equilibrium constants were determined. For N-base = 4-mepy, pyridine, 4-ethylpyridine, isoquinoline, 4-benzoylpyridine, quinoline, and 4-cyanopyridine K values were evaluated as 113, 73, 56, 43, 10, 0.7, and 0.03 respectively. For the tetrahedral-octahedral configurational equilibrium Co(4-mepy)2X2 + 2(4-mepy) ↔ Co(4-mepy)4X2(X = Cl, Br, and I) equilibrium constants have been determined at room temperature in chloroform as 13.2, 12.9, and 8.7 respectively.

Using of Sukary and Khlass Date Pits as a Bio-adsorbents for Adsorption of Lead and Copper Ions from Waste Water

2021 ◽  
Vol 37 (2) ◽  
pp. 302-307
Author(s):  
Abdulrahman G. Alhamzan
Keyword(s):  
Adsorption Capacity ◽  
Room Temperature ◽  
Copper Ions ◽  
Phoenix Dactylifera ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Palm Trees ◽  
Phoenix Dactylifera L ◽  
Temperature Equilibrium ◽  
Date Pits

In this study date pits of two types of date-palm trees (Phoenix Dactylifera L.), in Saudi Arabia were used as bio-sorbents for heavy metals (e.g. lead and copper) from aqueous solutions. Investigation of equilibrium time and the effect of different concentrations of metals were performed. Adsorption capacity of bio-sorbents increased when increasing concentration of metal ions. Maximum adsorption capacity at room temperature of Sukary date pits was 17.53 mg g-1 and 9.86 mg g-1 for lead and copper ions, respectively. Whereas, Khlass date pits showed maximum adsorption capacity at 14.1 mg g-1 and 7.91 mg g-1 for lead and copper ions, respectively at room temperature. Equilibrium isotherm models, (Langmuir and Freundlich models), were used for analysis of equilibrium experimental results. these models describe the experimental data well.

Infrared Study of Acetic Acid Solutions in CCl4

1995 ◽  
Vol 60 (7) ◽  
pp. 1094-1100 ◽  
Author(s):  
Ivona Malijevská ◽  
Martin Polášek
Keyword(s):  
Acetic Acid ◽  
Regression Analysis ◽  
Carbon Tetrachloride ◽  
Room Temperature ◽  
Equilibrium Constants ◽  
Acid Solutions ◽  
Standard State ◽  
Infrared Study ◽  
Mean Values ◽  
Linear Dimer

Spectra of acetic acid solutions in carbon tetrachloride were taken at room temperature over the concentration range 0.025-0.00125 mol dm-3. Solutions of acetic acid were modelled as an ideal mixture of monomers, and cyclic and linear dimers. Regression analysis effected separation of the experimental envelope into its component bands. Band shapes were approximated by a Lorenzian function with the resolved band peak frequencies 1 712 cm-1 for the cyclic dimer, 1 724 cm-1 for the linear dimer and 1 765 cm-1 for the acetic acid monomer. Mean values of equilibrium constants for the standard state of unit concentration are 2 700 for the cyclic and 393 for the linear dimer, respectively.

Ligand Redistribution Equilibria in Aqueous Fluoroberyllate Solutions

1998 ◽  
Vol 53 (11) ◽  
pp. 1294-1300 ◽  
Author(s):  
Michael Schmidt ◽  
Hubert Schmidbaur
Keyword(s):  
Experimental Data ◽  
Ligand Exchange ◽  
Room Temperature ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Individual Species ◽  
Ph Values ◽  
Exchange Processes ◽  
The Individual ◽  
Good Agreement

The composition of aqueous fluoroberyllate solutions has been studied by 9Be and 19F NMR spectroscopy for various ratios of the beryllium and fluorine concentrations, and at different pH values. The equilibrium constants have been determined for the ligand exchange processes, which involve the species [Be(OH2)4]2+, [BeF(OH2)3]+, [BeF2(OH2)2], [BeF3(OH2)]- , and [BeF4]2-. These equilibria are shifted towards [BeF4]2- at high pH. No polynuclear fluoroberyllates have been detected. The fluoride exchange between the individual species is slow on the NMR time scale at room temperature, and separate sharp signals with the expected multiplicity are therefore recorded. Calculated 9Be chemical shifts are in good agreement with experimental data.

STUDIES OF RATES OF CONVERSION AND POPULATIONS OF VARIOUS CONFORMATIONS OF SATURATED RING COMPOUNDS BY N.M.R.: I. CHLOROCYCLOHEXANE AND BROMOCYCLOHEXANE

1960 ◽  
Vol 38 (8) ◽  
pp. 1241-1248 ◽  
Author(s):  
L. W. Reeves ◽  
K. O. Strømme
Keyword(s):  
Energy Barrier ◽  
Room Temperature ◽  
Carbon Disulphide ◽  
Equilibrium Constants ◽  
Jones Potential ◽  
Lennard Jones ◽  
Ring Compounds ◽  
Saturated Ring ◽  
Van Der Waals Radii ◽  
Bromo Compound

The populations of equatorial and axial halogen forms of chloro- and bromo-cyclohexane have been studied by proton magnetic resonance between 25° and −104 °C in carbon disulphide solution. From the equilibrium constants obtained the free energy change between the two conformations is obtained. The bromo compound has 82% of the equatorial halogen form and the chloro compound 77%. Estimates of the populations are also available for room temperature from the chemical shift measurements. The energy barrier for conversion between the two forms is approximately 10,850 calories. A simple Lennard-Jones potential with the available estimates of van der Waals radii is used to calculate the differences in energy of the two forms.

Nanosized Thallium Inclusions in Aluminium

1993 ◽  
Vol 316 ◽  
Author(s):  
E. Johnson ◽  
A. Johansen ◽  
K.K. Bourdelle ◽  
H.H. Andersen ◽  
L. Sarholt-Kristensen
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Orientation Relationship ◽  
Room Temperature ◽  
Equilibrium Phase ◽  
Lattice Parameter ◽  
Metastable Equilibrium ◽  
Stable Phase ◽  
Pure Aluminium ◽  
Temperature Equilibrium

ABSTRACTIon implantation of pure aluminium with thallium induces formation of nanosized crystalline thallium inclusions with either fee or bee structure. The size of the inclusions depends on the implantation conditions and subsequent annealing treatments. Inclusions less than 10-15 nm in size are generally fee while larger inclusions are bee. The fee inclusions are aligned topotactically with the aluminium matrix with a cube/cube orientation relationship, and they have a truncated octahedral shape bounded by {111} and {001} planes. The lattice parameter of the fee thallium inclusions is 0.484 nm ± 0.002 nm, which is slightly but significantly larger than for the high pressure fee thallium phase known to be stable above 3.8 GPa. The lattice parameter of the bec inclusions is close to the equilibrium value of 0.387 nm and the orientation relationship is given by the Kurdjumov-Sachs rule (011)bcc ║ (111)fcc and [111]bcc ║ [101]fcc The bec inclusions,, representing the high temperature equilibrium phase but existing in metastable equilibrium at lower temperatures, have curved and less well-defined facets. Inclusions with hep structure, the stable phase at room temperature, have not been observed.

scholarly journals Investigation of Charge Transfer Complexes Formed between Mirtazapine and Someπ-Acceptors

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Hulya Demirhan ◽  
Mustafa Arslan ◽  
Mustafa Zengin ◽  
Mustafa Kucukislamoglu
Keyword(s):  
Charge Transfer ◽  
Dosage Form ◽  
Room Temperature ◽  
Equilibrium Constants ◽  
Formation Constants ◽  
Electron Acceptors ◽  
Spectral Studies ◽  
Charge Transfer Complexes ◽  
Ir And Nmr Spectroscopy ◽  
Ft Ir

Charge transfer complexes (CTC) of mirtazapine with tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), and tetracyanoquinodimethane (TCNQ) have been studied spectrophotometrically in dichloromethane at room temperature. The stoichiometries of the complexes were found to be 1 : 1 ratio by the Job Method between mirtazapine and the acceptors. The equilibrium constants and thermodynamic parameters of the complexes were determined by the Benesi-Hildebrand and Van't Hoff equations. Mirtazapine in pure and dosage form was applied in this study. The results indicate that the formation constants for the complexes depend on the nature of electron acceptors and donor. And also the spectral studies of the complexes were determined by FT-IR and NMR spectroscopy.

Relative methylmercury cation affinities in the gas phase determined by high pressure mass spectrometry

1981 ◽  
Vol 59 (12) ◽  
pp. 1779-1786 ◽  
Author(s):  
John A. Stone ◽  
Dena E. Splinter
Keyword(s):  
High Pressure ◽  
Gas Phase ◽  
External Rotation ◽  
Equilibrium Constants ◽  
Partition Functions ◽  
Pulsed Electron Beam ◽  
Nitrogen Bases ◽  
Relative Affinity ◽  
The Difference ◽  
Soft Acid

A pulsed electron beam, high pressure mass spectrometer has been used to determine equilibrium constants for the exchange of CH3Hg+ between bases; [Formula: see text] A series of aromatic, hydrocarbon bases has been studied at 417 K and several nitrogen bases have been studied at 580 K. There is a good linear correlation between differences in CH3Hg+ affinity (ΔG0) and H+ affinity for bases in each series. The single sulfur base examined ((C3H7)2S) shows anomalously high relative affinity for CH3Hg+ compared with H+ while two oxygen bases (CH3COOCH3 and C6H5NO2) show lesser relative affinity. These results are in qualitative agreement with the hard–soft acid base theory. ΔH0 and ΔS0 values have been obtained from Arrhenius plots. For a pair of aromatic bases (toluene–ethylbenzene) ΔH0 is of the same magnitude as that for H+ and ΔS0 may be calculated using partition functions for translation and external rotation. For toluene/methylacetate the difference in binding energy is much greater for H+ than for CH3Hg+ and a similar calculation of ΔS0 gives a result not consistent with the experimental value.

An acidity scale of phosphonium tetraphenylborate salts and ruthenium dihydrogen complexes in dichloromethane

2006 ◽  
Vol 84 (2) ◽  
pp. 164-175 ◽  
Author(s):  
Tianshu Li ◽  
Alan J Lough ◽  
Cristiano Zuccaccia ◽  
Alceo Macchioni ◽  
Robert H Morris
Keyword(s):  
Room Temperature ◽  
Equilibrium Constants ◽  
Ion Pairs ◽  
H Nmr ◽  
Protonation Reaction ◽  
Dihydrogen Complexes ◽  
Continuous Scale ◽  
Nmr Techniques ◽  
Acidic Compounds ◽  
Acidity Scale

Equilibrium constants (KDM) for reactions between acids and bases of the title compounds in CD2Cl2 (DM) have been determined by 31P and 1H NMR spectroscopy at room temperature. [HPCy3]BPh4 and [HPCy3]BF4, with pKDM assigned by literature convention to 9.7, have been used as the anchor compounds for the pKDM determinations. A continuous scale of pKDM values covering the range 9.7 to 5.7 is created with the acidic compounds [HPR3]BPh4. Those acids with pKDM greater than 6 are stable, while those with more acidic cations HPR3+ protonate BPh4– to produce R3PBPh3 and benzene. The literature pKTHF values reported for [HPBu2Ph]BPh4, [HPMePh2]BPh4, and [HPEtPh2]BPh4 are questionable because of this protonation reaction. NOE and PGSE 1H NMR techniques are used to show that [HPCy2Ph]BPh4 in DM exists as ion pairs and higher aggregates up to quadrupoles at the concentrations used in the acid–base studies. The new dihydrogen complexes [Ru(H2)Cl(PPh3)2(dach)]BF4 (dach = (1R,2R)-(–)-diaminocyclohexane) and [Ru(H2)Cl{tmeP2(NH)2}]BF4 (tmeP2(NH)2 = PPh2C6H4CH2NHCMe2CMe2NHCH2C6H4PPh2) were prepared by reaction of RuHCl(PPh3)2(dach) and RuHCl{tmeP2(NH)2} with HBF4. Their crystal structures are reported, and the pKDM values of their BPh4– salts were determined to be 8.6 and 6.9, respectively.Key words: acidity, dihydrogen complex, hydride, phosphonium, dichloromethane.

Studies of fluoroberyllate complexes in aqueous solution by I9F nuclear magnetic resonance

1970 ◽  
Vol 48 (19) ◽  
pp. 2960-2964 ◽  
Author(s):  
M. G. Hogben ◽  
K. Radley ◽  
L. W. Reeves
Keyword(s):  
Aqueous Solution ◽  
Nuclear Magnetic Resonance ◽  
Melting Point ◽  
Magnetic Resonance ◽  
Room Temperature ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Coupling Constants ◽  
Intensity Measurements ◽  
Nuclear Magnetic

Studies of aqueous solutions containing fluoride and beryllium ion in ratios between 5 and 0.5 were made by 19F nuclear magnetic resonance at temperatures between the melting point of solutions and room temperature. Signals clearly identifiable as arising from BeF42−, BeF3−, BeF2, and BeF+ were assigned. Chemical shifts and coupling constants JBe–F are reported for all species and approximate equilibrium constants are determined from intensity measurements for the reactions [Formula: see text] [Formula: see text] and [Formula: see text]

Phase Transformations in β- Phase Cuzn Single Crystals Induced By Ion Irradiation

2001 ◽  
Vol 7 (S2) ◽  
pp. 1254-1255
Author(s):  
Alfredo J. Tolley ◽  
Esteban A. Sanchez
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Vibrational Entropy ◽  
Β Phase ◽  
Transmission Electron ◽  
Close Packed Structure ◽  
Bcc Structure ◽  
Packed Structure ◽  
Temperature Equilibrium

The high temperature equilibrium β phase in Cu-based alloys has a disordexed bcc structure. Its stability at high temperatures is due to the large amplitude ﹛0 ζ ζ)﹜ <0 ζ ζ> soft mode which provides a large vibrational entropy. This stability decreases with temperature as the entropy term in the Gibbs free energy becomes smaller. However, by quenching it is possible to retain the β phase avoiding decomposition by diffusion controlled transformations. in ternary β phase Cu-Zn- Al alloys, ion irradiation at room temperature has been reported to induce a phase transformation to a close packed structure or to produce γ phase precipitates. in order to further study the tendency of the β phase to decompose into other phases at room temperature, ion irradiation experiments in binary Cu-Zn single crystals were carried out using a beam of 30 keV Ar ions. The changes in the microstructure were examined using transmission electron microscopy.

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