bluuebunny/crossref_metadata_2025_split huggingface dataset:
The application of Raman spectroscopy in the determination of structures of some complex compounds
Authors: Gerding H. 
Published: September 2010

AbstractResults are discussed which have been obtained in the last few years by the application of Raman spectroscopy to the unravelling of structures of complex compounds, e.g. addition compounds of aluminium chloride with nitrosyl chloride, selenium tetrachloride, and tellurium tetrachloride.Arguments are brought forward for considering NOCl. AlCl3 as a compound intermediate in structure between NO+AlCl4− and NOCl…. AlCl3. Compounds such as SeCl4. AlCl3 and TeCl4. AlCl3 clearly show features of the ionic structures SeCl3+AlCl4− and TeCl3+AlCl4− respectively.In Cl3Al. NH3, on the contrary, a covalent bond between Al and N is present. Preliminary results for compounds SeCl4. SO3 and TeCl4. SO3 argue the presence in these compounds of SeCl3+ and TeCl3+ ions respectively as well.
The nature of some nitrosylchloride addition complexes
Authors: Lewis J. , Sowerby D. B. 
Published: September 2010

AbstractThe nature of the nitrosyl chloride addition compounds of some metallic and non‐metallic chlorides has been investigated. Weak compound formation with metallic chlorides (e.g. ZnCl2) leads to a slow heterogeneous exchange of labelled chloride with liquid nitrosyl chloride and to rapid exchange with the combined nitrosyl chloride. Rapid exchange of chloride occurs when the added chloride even forms a weak compound with nitrosyl chloride e.g. AsCl3. 2 NOCl. The stability of the addition complexes are investigated also in liquid nitrosyl chloride and other solvents by conductometric and spectroscopic methods.
Zur Frage der Bindung in den Cyclopentadienylmetallkomplexen mit Übergangsmetallen: Theoretisches
Authors: Ruch Ernst 
Published: September 2010

AbstractDie Bindungsverhältnisse in den Cyclopentadienylverbindungen werden auf der Grundlage der molecular orbitals und äquivalenten orbitals auseinandergesetzt. Ein Energieschema auf der Basis berechneter Überlappungsintegrale wird im Vergleich mit einem oktaedrischen Durchdringungskomplex besprochen.Die Möglichkeiten einer Bindung von aromatischen Systemen an Übergangsmetalle ohne wesentliche Beeinträchtigung der Bindungen innerhalb dieser Systeme wird diskutiert.
Crystal field stabilization and tendency towards complex formation of first transition group elements
Authors: Bjerrum Jannik , Jørgensen Chr. Klixbüll 
Published: September 2010

AbstractThe increased affinity towards complex formation exhibited by metal ions with an unfilled d‐shell is related to the crystal field stabilization of such compounds and furnishes an explanation of what is the basis of the so‐called Irving‐Williams rule. The orbital degeneracy of the ground term determines the symmetry of the configuration and is thus responsible for irregularities in the complexity constants.If the total spin quantum number changes during a set of consecutive complex formation steps, a sudden change of activation energies and formation constants is to be expected, as recently has been verified. The activation energies are then expected and found high only when the crystal field stabilization is large and the orbital degeneracy one. High reaction rates on the other hand are to be expected for complete or half‐complete d‐shells without crystal field stabilization, and for nearly complete d‐shells if the orbital degeneracy is higher than one.
Interpretation of spectra of transition‐group complexes by means of the crystal field theory
Authors: Ballhausen C. J. 
Published: September 2010

AbstractThe crystal field theory, when applied to complexes of the first transition group, is able to describe the “visible” absorption bands of a cubic MA4 complex in terms of a single parameter. A special consequence of the theory is that the splitting of the first band of trans complexes of the Co(III)A4X2 type should be twice the splitting for the corresponding cis complexes, as has been observed.By means of the crystal field theory it is further possible to account for the existence of magnetically normal (“ionic”) as well as magnetically anomalous (“covalent”) complexes. It is shown that a change in the magnetism does not a priori mean a change of the bond type.
Some new stereochemical arrangements of uni‐ and ter‐valent gold
Authors: Harris C. M. , Nyholm R. S. , Stephenson N. A. 
Published: September 2010

AbstractThe complex compounds formed by uni‐ and ter‐valent gold with a chelating ditertiary arsine group are described. Gold (I) co‐ordinates with two molecules of the chelate group to give four‐covalent, presumably tetrahedral, complex cations. Gold (III) gives rise to a four‐covalent cation with two molecules of the chelate group but on the addition of halide ions one can prepare cations of the formulae [Au(Diarsine)2]X++ and [Au(Diarsine)2X2]+ in which X is a halogen atom. The assigned five‐ and six‐covalency, in nitrobenzene solutions at least, are supported by various physical measurements. The structures of the compounds are discussed in terms of modern valency theory. Preliminary results of an X‐ray crystallographic study of AuI and the [Au(Diarsine)2]+ cation are reported. In each case a tetrahedrally co‐ordinated Au(I) atom is indicated.
The hydrolysis of some tripositive ions
Authors: Biedermann George 
Published: September 2010

AbstractA review of experimental methods for investigating hydrolysis equilibria by emf measurements is given. Liquid‐junction potentials and the activity factors of the reacting species can be estimated by a suitable combination of cells. An emf method is mentioned for the accurate determination of the analytical hydrogen ion concentration of a solution containing metal ions of appreciable acidity constant.Of the tripositive ions investigated only TI(III) forms exclusively mononuclear ions, TIOH2+, and TI(OH)2+ (pka1 = 1.14, pka2 = 1.49). The main products of hydrolysis of In(III) are ions of the formula In[(OH)2In]n3+n (for the first step pK = 5.21, for all following steps pK = 4.70).At low [In(III)]total, InOH2+ and In(OH)2+ become appreciable (pka1 = 4.4, pka2 = 3.9). Similar results were found by Kilpatrick and Pokras for Sc(III) and by Hedström for Fe(III), the main hydrolysis products being Sc[(OH)2Sc]n3+n and Fe[(OH)2Fe]4+; at low metal ion concentration. ScOH2+ and FeOH2+, Fe(OH)2+ are predominant species. Al(III) seems to be an exception; Brosset's emf studies and other available data are consistent with the assumption that Al6(OH)153+ is formed in acid solutions.
The incomplete dissociation of thallous hydroxide
Authors: Bell R. P. , Panckhurst M. H. 
Published: September 2010

AbstractThe thallous ion and silver ions are unique among univalent cations in forming fairly strong complexes with univalent anions. A review of previous evidence (involving measurements of solubilities, conductivities and reaction kinetics) indicates that thallous hydroxide is incompletely dissociated, having a thermodynamic dissociation constant of about 0.15. New data are reported on the effect of thallous ions on the velocity of the fast reaction between nitroethane and hydroxyl ions. These lead to a similar value for the dissociation constant if it is assumed that the species TIOH does not react.Measurements have also been made of the ultra‐violet absorption of solutions containing thallous and hydroxide ions. The results show clearly the presence of two distinct absorbing species, and although it is not possible to derive unambiguously a dissociation constant for TIOH, the data are consistent with the value given above.The nature of the binding in TIOH is discussed in the light of the above findings.
The influence of the structure of chelating agents on the complexity and distribution constants of thorium complexes
Authors: Dyrssen David 
Published: September 2010

AbstractThis paper deals with results obtained by the distribution method described in the preceding paperMargareta Dyrssen, The application of solvent extraction to the study of chelate complexes of thorium, p. 748.
. This work still being in progress and new data may considerably change the present picture. For those interested in the chemistry of coordination compounds the value of the acid dissociation constants pka and the mean complexity constants a of ThA4 are of the greatest interest. For those interested in metal extraction log K is very importantDefinitions of the complexity constants ka, a, and K: cf. M. Dyrssen, p. 750, eqs (8), (2), (11) respectively.
.It has been generally recognised that when comparing the reaction of a series of chelate ligand ions A− with hydrogen ion and with a metal ion MN+ the respective equilibrium constants ka and k1 show the same trend; i.e. there appears to be a correlation between acid strength and chelate stabilityH. Rossotti, this volume page 763.
. Furthermore it has been observed that 5‐membered chelate rings are more stable than 6‐ or 4‐membered ones. Such generalisations are however not sufficient to explain the behaviour of so different chelating agents as e.g. oxine, cupferron and acetylacetone. Some properties which at the present time seem relevant to the stability of the chelate‐complexes of H+ and Th4+ will be discussed here.
On the partial molal entropies of complex ions and their conjugate acids in aqueous solution
Authors: George P. , Hanania G. I. H. , Irvine D. H. 
Published: September 2010

AbstractThe partial molal entropies of HFeCN6−3 and HFedipyCN4−1, the conjugate acids of FeCN6−4 and FedipyCN4−2, have been determined relative to FeCN6−3 and FedipyCN4−1 respectively, and are found to be even more negative than the corresponding S° differences for pairs of oxy‐anions where the charge is also the same, e.g. XO2−1 and HXO2−1, etc. The values are examined in relation to an empirical equation for S°, and the possibility that the two conjugate acids have some special structure feature is discussed.
Some relationships among the stabilities of metal complexes
Authors: Rossotti Hazel 
Published: September 2010

AbstractThe stability constant, KML, of the first metal‐ligand complex, ML, can be related to the stability constant, KHL, of the corresponding proton‐ligand complex, and to the partial molar free energies of the various species in solution. The relationship has been modified for application to mixtures of aqueous and organic solvents. For closely related ligands, log KML, will be an approximately linear function of log KHL. Moreover, log KML, is often a linear function of the molar fraction of the organic component of the mixed solvent.The relationships between the stabilities of very closely related complexes are also discussed, and illustrated with reference to metal complexes of some derivatives of oxine, and to other metal chelates. Steric hindrance to complex formation may cause large deviations from predicted behaviour.
The influence of the composition and the properties of the solvent on complex formation between silver and chloride, bromide, iodide, and thiocyanate ions
Authors: Kratohvil J. , Težak B. 
Published: September 2010

AbstractIn order to obtain some insight into the effect of the dielectric constant of the medium on complex formation, the complex solubilities of silver chloride, silver bromide, silver iodide, and silver thiocyanate in halide or thiocyanate solutions in isodielectric mixtures of water and methanol, ethanol, iso‐propanol, glycerol, dioxane, and acetone have been determined. The complex solubility of the precipitates increased, relative to that in water, with increasing concentration of the organic component in solutions. The lowering of the dielectric constant of the medium caused an increase in the stability of the complex ions present.
Einschlussverbindungen der Cyclodextrine unter Besonderer Berücksichtigung der Blauen Jodverbindungen
Authors: Cramer Friedrich 
Published: September 2010

AbstractZunächst wird ein kurzer Überblick über die bisher bekannten Einschlussverbindungen der Cyclodextrine gegeben. Cyclodextrine werden aus Stärke erhalten, sie sind Ringmoleküle, bestehend aus 6, 7 und 8 Glucoseeinheiten. Die freien Durchmesser in der Mitte der Ringe betragen 6, 8 und 10 Å. Die Dextrine bilden unter anderem mit Chlor, Brom und Jod Einschlussverbindungen. Die blaue Jodverbindung ist der Schlüssel zum Verständnis des Jodstärke‐Komplexes. Auf verschieden Weise lässt sich zeigen, dass Jod in Einschlussröhren Ketten der folgenden Struktur ausbilden kann:magnified imageDie Ausbildung der Struktur In ist jedoch nur in ganz bestimmten Fällen möglich, nähmlich wenn das umgebende Gitter
Kanäle bildet
Elektronen zur obigen Resonanzstruktur beiträgt.
Es wurden eine grosse Zahl von blauen Jodadditionsverbindungen untersucht. Zahlreiche Cumarine und Flavonderivate bilden mit Jod kristallisierte, blaue Komplexe. Bei manchen von ihnen lassen sich unabhängige Jodketten röntgenographisch nachweisen, bei anderen wiederum bildet Jod und Wirtsmolekül eine kristallographische Einheit. Eine interessante Zwischenstellung nimmt das Benzonitril‐Jod‐Addukt ein. Die eindimensionalen Jodketten zeigen Anzeichen einer dreidimensionalen Ordnung. Die energetische Wechselwirkung zwischen Jod und Einschlussgitter ähnelt dem Benzol‐Jod‐Komplex von Mulliken. Das Einschlussgitter tritt als Lewis‐Base auf.Die Jod‐Einschlussverbindungen sind daher nicht reine Einschlussverbindungen im Sinne eines einfachen räumlichen Festhaltens, sondern bilden einen Übergang zu den charge‐transfer‐Komplexen.Es wird gezeigt, dass Einschlussverbindungen auch anderweitig als Lewis‐Basen wirken können. An den Cyclodextrinen kann man auch das Verhalten von Einschlussverbindungen in Lösung studieren, in einem Experiment wird dies gezeigt. Auf diese Weise kann man einen Einblick in die energetischen Verhältnisse in derartigen Hohlräumen gewinnen.
Investigations in the vitamin A series. III. Rearrangement of theretro‐system to thenormalsystem of conjugated double bonds in the vitamin A series
Authors: Huisman H. O. , Smit A. , van Leeuwen P. H. , van Rij J. H. 
Published: September 2010

AbstractA new synthesis of vitamin A essentially based on the almost quantitative rearrangement of theretro‐system to thenormalsystem of conjugated double bonds is described.This rearrangement is carried out by converting theretroC15acid and theretroC20‐acid respectively, by means of phosphorus trichloride in suitable solvents, into the correspondingretro‐acid chlorides, which thereupon rearrange smoothly to the acid chlorides with thenormalsystem of conjugated double bonds, β‐ionylidene acetic acid chloride and vitamin A acid chloride respectively.The acid chlorides are reduced with LiAlH4to the corresponding alcohols β‐ionylidene ethanol and vitamin A.The physical and chemical properties of the intermediates and geometric isomers obtained in the various reaction steps are described.
Complex coacervation. V Experiments on the distribution of salts. Comparison of theory and experiment
Authors: Voorn M. J. 
Published: September 2010

AbstractThe ratio of the salt concentrations (KCl) in the coacervate and the equilibrium liquid has been determined experimentally, for the system gelatinpotassium arabinate. The concentration of KCl was found to be higher in the coacervate.The theory, developed in previous papers, is compared with existing experimental data.
Application of paper chromatography to the identification of accelerators and antioxidants: II. Detection of some heterocyclic compounds
Authors: Zijp J. W. H. 
Published: September 2010

AbstractIn this paper a detailed procedure is given for the paper‐chromatographic separation and identification of some mercapto‐substituted heterocyclic compounds. The detection of these accelerators in rubber mixes and vulcanisates is also described.
Phenate ion and the Fe3+PhO− ion‐pair complex
Authors: Hush N. S. 
Published: September 2010

AbstractA value of 120 kcal/mole−1 is derived from available data for the electron affinity (E) of phenoxyl radical plus the solvation energy (S) of phenate ion (). Employing this value of E + S, it is shown that the location of the visible absorption maximum of the Fe3+PhO− ion pairJ. Babko, J. Gen. Chem. U.S.S.R. 33, 963 (1946).
is in good agreement with the interpretation of the spectra of Fe3+X− complexes of this type as charge‐transfer bands. The OH bond strength in phenol employed in this calculation is that recently proposed by HushN. S. Hush, J. Chem. Soc. London 1953, 2375.
, and its consistency with the light absorption measurements provides evidence in favour of the value 84 ± 5 kcal/mole−1 for this quantity.An estimate of S shows the EphO is ca. 1.2 e.v. mole−1; the electron affinity of phenoxyl radical is thus ∼ 1 e.v. mole−1 lower than that of OH radical.
Studies in polarography: Part II reduction of telluric acid at the dropping mercury electrode
Authors: Issa I. M. , Khalafalla S. E. , Issa R. M. 
Published: September 2010

AbstractThe reduction of telluric acid at the dropping mercury electrode is studied in buffer solutions of pH 1‐12, in 0.1 M KCl, and in 0.01‐1 M NaOH. It is found that telluric acid is reduced under all conditions to elementary tellurium. The relation between the diffusion current and the concentration is excellent in 0.1 M KCl and 0.1 M NaOH within the concentration range of 1 × 10−4 −1 × 10−3 M and in ammoniacal buffer of pH 10 within the range of 2 × 10−4 −3 × 10−3 M. Maxima, except in 1 M NaOH, are occasionally met with, which could be suppressed by gelatin.
Breaking of a single CC bond upon reduction with sodium and alcohol in ammonia
Authors: van der Zanden J. M. , ter Borg A. P. 
Published: September 2010

AbstractThe action of sodium and ethyl alcohol in liquid ammonia on allyl and benzyl alcohols in general leads to replacement of the OH group by HA. J. Birch, Quart. Revs. London 4, 64 (1950).
, i.e. breaking of the COH bond.With p‐isopropyl benzyl alcohol and p‐tert. butyl benzyl alcohol, however, we found breaking of the CC bond at the OH‐bearing carbon atom.As appears from the table below, all sorts of structural variations in the above‐mentioned molecule, which do not seem to be very essential to the occurrence or non‐occurrence of the breaking of the CC bond, result in the appearance of the “normal” OH reduction.We are of opinion that we cannot make any attempt at theoretical interpretation until a larger body of experimental data is available to us.
The action of hydrazine on 1:4‐dianisoylbutane and the reduction of 3,8‐di‐p‐methoxyphenyl‐4,5,6,7‐tetrahydro‐1,2‐diazocine
Authors: Zanden J. M. V. D. , de Vries G. 
Published: September 2010

AbstractThe interaction of hydrazine and 1,4‐dianisoylbutane furnished two cyclic products (I and II). The structures of these compounds were investigated and one of them (I) was treated as usual for a Wolff‐Kishner reduction. The substance was also hydrogenated. The hydrogenated product (VI) when oxidised with mercuric oxide gave VII, which when heated afforded a compound (VIII) synthesised previously.
Determination of the individual cyclic oligomers in equilibrium systems from ϵ‐caprolactam and water
Authors: Heikens D. 
Published: September 2010

AbstractThe content of cyclic dimer, trimer, tetramer in equilibrium polymerisates of ϵ‐caprolactam and water is determined by fractional sublimation of a methanolic extract, freed from the cyclic monomer and linear oligomers.The proportion of the cyclic dimer, trimer and tetramer in these products is 2/1/2 at 221.5° C and 5/2/7 at 253.5° C.The stability of the tetramer is tentatively explained on the basis of its molecular structure.
1,2‐Dehydroderivatives of Reichstein's substances U and E
Authors: Szpilfogel S. A. , van Hemert P. A. , de Winter M. S. 
Published: September 2010

AbstractAerobic fermentation of cortisone (I) using Fusarium and Calonectria strains gave rise to 17α,20β,21‐trihydroxy‐3,11‐diketopregna‐1,4‐diene (IV) (1,2‐dehydro‐U). IV is also formed by fermentation of prednisone (III) and Substance U (II).Selenium dioxide dehydrogenation of II and sodium borohydride reduction of III lead also to IV. The last reaction applied to prednisolone (VI) yielded the 1,2‐dehydroderivative of Reichstein's Substance E (VII).
Synthesis of (‐)‐β‐homocystine. A contribution to the problem of the high rotatory power of cystine
Authors: Balenović K. , Jambrešić I. , Gašpert B. , Cerar D. 
Published: September 2010

AbstractA new cystine homologue IV showing [α]D −260° has been prepared by applying the Arndt‐Eistert reaction to S‐benzyl‐N‐phthaloyl‐l‐cysteine (I). The high [α]D of this compound supports Fredga's explanation of the high rotatory power of cystine.
Paperchromatography of 2,4‐dinitrophenylhydrazones of aliphatic carbonyl compounds
Authors: Klein F. , de Jong K. 
Published: September 2010

AbstractThe separation of 2,4‐dinitrophenylhydrazones of aliphatic carbonyl compounds having 7 or more carbon atoms is possible by means of paper chromatography, employing paraffin oil as immobile phase and dioxan/water (4:1) as mobile phase.
Melting curves (temperature‐heat content curves) as criteria for purity
Authors: Smit W. M. 
Published: September 2010

AbstractMethods for calculating the purity of a given sample from its melting curve developed thus far have been derived by assuming that the contaminants are immiscible with the main component in the solid phase. These methods may give rise to serious errors when applied to arbitrary samples.In the present paper a discussion is given of the behaviour of systems with solid solutions (miscibility in the solid phase), and a method is developed, resemblingWichers' “comparative method”, that is applicable to both types of systems.In addition, errors occurring in the experimental determination of melting curves are briefly discussed.Cooling curves are considered to be less suitable for the determination of purity than heating curves.A description of a simple apparatus and procedure for the determination of heating curves is given.The quantity of substance needed for a determination is about 200 mg. It is shown that the smallest amount of contaminant (s) determinable with this apparatus varies (depending on the system investigated) from 0.1 to 0.01 mol. %. The sensitivity of the method may be improved by using more sensitive thermometers.
Dimerisation under the influence of 43 % sulphuric acid; comparison of the rates of similar dimerisations with propenyl‐ and isopropenylbenzene
Authors: van der Zanden J. M. , Rix Th. R. 
Published: September 2010

AbstractOn boiling with 43 % sulphuric acid isopropenylbenzene (V) dimerises much more rapidly than propenylbenzene (IV). This result is explained in the present paper and compared with the effect previously noted with the corresponding p‐methoxy‐compounds J. M. van der Zanden and Th. R. Rix, Rec. trav. chim. 75, 1166 (1956).
).
Syntheses of polychloro‐compounds with aluminium chloride. XV. The condensation of chloral with trichloroethene
Authors: Prins H. J. 
Published: September 2010

AbstractThis condensation leads to the formation of an addition compound of α,β,γ,γ,γ‐pentachloro‐n‐butyryl chloride with aluminium chloride and of a small amount of 1,1,1,3,4,4,4‐heptachlorobutanol‐2.The above mentioned addition‐compound may be decomposed into carbon monoxide, hydrochloric acid and 1,1,2,3,3‐pentachloropropene‐1.The corresponding acid can be transformed into chlorofumaric acid, α‐hydroxy‐β,γ,γ‐trichlorovinylacetic acid and into α,α‐dihydroxy‐γ,γ‐dichlorovinylacetic acid.The heptachlorobutanol can be oxidized to the corresponding ketone, which is converted by alkaline hydrolysis into chloroform and trichloroacrylic acid.