Selective Kinetic Determination of Cu2+ with Tetraazamacrocyclic Bis(Methylphosphonate) Ligand (Dipon)

A new macrocyclic ligand, 1,4,8,11-tetraazacyclotetradecane-1,8-bis(methylphosphonic acid) (refered to as dipon) exhibits high thermodynamic and kinetic selectivity for Cu²⁺ compared to other transition metal ions. The initial-rate method (=310nm, pH=3.75, c_L4.6×10^–3molL^–1) was chosen as an optimal experimental approach in order to achieve maximum sensitivity of determination. The dynamic range of the method is (5–200)×10^–6molL^–1, and the detection limit is 2.5×10^–6molL^–1. A standard addition procedure was applied to the kinetic determination of Cu²⁺ to eliminate the effect of interfering ions (e.g. Zn²⁺, Ca²⁺, Mg²⁺, Cd²⁺, Pb²⁺, Mn²⁺, Co²⁺, Ni²⁺, HCO^–₃, Cl^–, SO₄^2–, etc.). The method was tested on artificial and real samples (alloys, pure and spiked mineral water) and gave satisfactory results which are in agreement with the values for some certified materials. The advantage of the proposed method is rapidity, simplicity and robustness in the presence of other metal ions.     

Heterogeneous reactions of solid nickel(II) Complexes. XXII

The stoichiometry of thermal decomposition was studied for the following compounds: Ni(pyNO)Cl₂H₂O (I), (pyNO=pyridine N-oxide), Ni(2-MepyNO)Cl₂·2H₂O (II), Ni(3-MepyNo)Cl₂·2H₂O (III) and Ni(4-MepyNO)₂Cl₂·C₂H₅OH (IV). The heating of the compounds led first to the release of H₂O molecules (or C₂H₅OH molecules), with the formation of Ni(pyNO)Cl₂ (V), Ni(2-MepyNO)Cl₂(VI), Ni(3-MepyNO)Cl₂ (VII) and Ni(4-MepyNO)₂Cl₂ (VIII). In the next stage, decomposition of the heterocyclic liugands set in. The compositions and spectral and magnetic properties of these complexes indicate their dimeric (II, III, IV, VIII) of polymeric (I, V, VI, VII) structure with coordinated molecules of H₂O (or C₂H₅OH).

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Zusammenfassung Die Stöchiometrie der thermischen Zersetzung folgender Verbindungen wurde untersucht: Ni(pyNO)Cl₂·H₂O (I), (pyNO=Pyridin-N-oxid), Ni(2-MepyNO)Cl₂·2H₂O (II), Ni(3-MepyNO)Cl₂·2H₂O (III) und Ni(4-MepyNO)₂Cl₂·C₂H₂OH (IV). Beim Erhitzen erfolgt zunächst die Abspaltung von Wasser bzw. C₂H₅OH unter Bildung von Ni(pyNO)Cl₂ (V), Ni(2-MepyNO)Cl₂ (VI), Ni(3-MepyNO)Cl₂ (VII) und Ni(4-MepyNo)₂Cl₂ (VIII). Im nächsten Schritt setzt die Zersetzung der heterozyklischen Liganden ein. Aus den Zersetzungsreaktionen und den spektralen und magnetischen Eigenschaften dieser Komplexe folgt deren dimere (II, III, IV, VIII) oder polymere (I, V, VI, VII) Struktur mit koordinierten Wasser- bzw. C₂H₅OH-Molekülen.

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: Ni(pyNO)Cl₂-H₂O (I), (pyNO=H- ), Ni(2-MepyNO)Cl₂·2₂ (II), Ni(3-MepyNO)Cl₂-2H₂O (III) Ni(4-MepyNO)₂Cl₂-C₂H₅OH (IV). ( ) Ni(pyNO)Cl₂ (V), Ni(2-MepyNO)Cl₂ (VI), Ni(3-MepyNO)Cl₂ (VII) Ni(4-MepyNO)₂Cl₂ (VIII). . , (II, III, IV, VIII) (I, V, VI, VII) .

     

Synthesis,spectroscopic studies and magnetic properties of binuclear complexes of the first transition series cations bridged by 2,2′-bipyrimidine

Binuclear complexes [M₂Cl₄(-bpym)], where M = VO²⁺, Fe^II, Co^II or Cu^II and bpym = 2,2-bipyrimidine, and [M₂(hfacac)₄(-bpym)] complexes, where hfacac = hexafluoroacetylacetonate and M = Fe^II, Ni^II or Co^II have been synthesized and characterized by chemical analysis, conductance measurements, i.r., electronic and e.p.r spectroscopies and by magnetic susceptibility measurements (in the 4.2–291K range). Co^II and Fe^II are in a high spin state. [(VO)₂Cl₄(-bpym)] is paramagnetic, without significant interactions. [Fe₂Cl₄(-bpym)] shows a singular behaviour explained by an antiferromagnetic intradimer exchange and a ferromagnetic interdimer interaction. All other complexes are antiferromagnetic, with an intramolecular exchange parameter, J, varying from –3.3 cm^–1 for Co^II/math> to –109 cm^–1 for Cu^II.     

Thermodynamic properties of water-β-cyclodextrin-dodecylsurfactant ternary systems

Densities, heat capacities and conductivities of water-surfactant--cyclodextrin (-CD) ternary systems were determined at 25°C. The surfactants studied were sodium dodecylsulfate (NaDS) and dodecyltrimethylammonium bromide (DTAB). From conductivity data, apparent critical micelle concentrations (cmc^*) and degree of ionization of micelles were obtained at a fixed -CD concentration (m_CD). From the cmc^* value and that in water (cmc) the stoichiometry of the surfactant--CD complex was calculated. At a given m_CD, the apparent molar volume V_,CD and heat capacity C_,CD of -CD in the two surfactants were calculated as functions of surfactant concentration m_S. For both NaDS and DTAB, V_,CD increases with m_S up to about the cmc beyond which it decreases to a constant value at high m_S, the opposite is observed for C_,CD. With NaDS, a jump in the C_,CD vs, m_S trend was detected and ascribed to a structural NaDS micellar transition. The apparent molar volume V_S and heat capacity C_S of NaDS and DTAB in the water--CD mixture 0.017 m were also obtained. From these properties and those in pure water, the volume V_S and heat capacity C_S of transfer of the surfactant from water to water+-CD mixture as functions of m_S were calculated. For both surfactants, the V_S vs. m_S trends increase to the cmc and then decrease in a monotonic manner, whereas C_S increases regularly with m_S in the pre-micellar region and is essentially constant in the post-micellar region. The V_S vs. m_S trends were qualitatively explained in terms of dispersed, complexed and micellized surfactant contributions.     

Apparent molar heat capacity and relative enthalpy of aqueous NaOH between 323 and 523K

The apparent molar heat capacity, C _p,, of aqueous NaOH has been measured at temperatures between 50 and 250°C and molalities from 0.05 to 1.5 mol-kg^–1. Enthalpies of dilution L were also determined at 99°C and apparent molar relative enthalpies L were calculated up to 1.9 m. Measurements were performed by means of a flow calorimetric apparatus constructed in our laboratory and standardized for C _p, and L with aqueous Na₂SO₄ and with the formation of water from its ions, respectively. Characteristics and performance of this calorimeter are described in detail. Pitzer's semiempirical equations are used for the representation of the results and a general fitting of C _p, data is reported using also recent literature values measured between 4 and 55°C. The fitted parameters are finally utilized, through an integration procedure, to derive a general equation to calculate L at any temperature between 4 and 250°C.     

Das freie Volumen und die Änderung des Ausdehnungskoeffizienten und der Molwärme bei der Glasübergangstemperatur von Hochpolymeren

Zusammenfassung Die als Schnittpunkt von Volumen-Temperatur-Kurven für Schmelze und Glas ermittelte Glasübergangstemperatur wird als unterste Grenze der Schmelze angesehen. Diese wird entsprechend der Löchertheorie für Flüssigkeiten von Eyring und Hirai als eine mit Leerstellen gesättigte Mischung aufgefaßt.Es wird eine Verdünnungsentropie S₁ bestimmt, für die der athermische Ansatz von Flory und Huggins benutzt, und eine Verdünnungsenthalpie H₁, für die ein eigener Ansatz abgeleitet wird, der statt der üblichen mittleren Koordinationszahl z einen geometrischen Parameter a enthält. Dieser scheint realistischer die Größe und Gestalt der Mischungspartner zu berücksichtigen. Mit Hilfe der beiden Größen S₁ und H₁ sowie Volumen- und Enthalpiefunktionen lassen sich Ausdrücke für die Änderung des Ausdehnungskoeffizienten ^* und der Molwärme C_p bei der Glastemperatur entwickeln. Diese ermöglichen eine Berechnung des spez. freien Volumens ₁ ^* und des geometrischen Parameters a für 11 verschiedene Hochpolymeren. Dabei ergibt sich, daß a offenbar bei der Glastemperatur eine Konstante ist, während ₁ ^* nur sehr grob als Konstante angesprochen werden kann. Ein mittlerer Wert von ¯ ₁ ^* =0,0235 stimmt aber sehr gut mit dem von Williams, Landel und Ferry viskosimetrisch bestimmten Wert von ca. 0,025 überein. Diese Übereinstimmung läßt den Schluß zu, daß im Sinne der Löchertheorie nur die Leerstellen als freies Volumen anzusprechen sind und für translatorische Bewegungsmechanismen zur Verfügung stehen, nicht aber das Schwingungsausdehnungsvolumen.Die Inkonstanz von ₁ ^* bei genauerer Betrachtung zeigt aber, daß offenbar bei der Glastemperatur kein iso-freier Volumenzustand herrscht. Die gleiche Feststellung trifft auch Miller auf Grund viskosimetrischer Untersuchungen. Die Abweichungen der Meßdaten von der Simha-Boyer-Gleichung ^* · Tg=k lassen sich dadurch erklären, daß k gar keine Konstante ist, sondern eine Funktion von ₁ ^* . Dieses zeigt aber, daß Stoffe mit beweglicheren Kettenmolekülen ein kleineres ₁ ^* als Stoffe mit steiferen Kettenmolekülen besitzen. Die gleiche Beobachtung wird bei der analogen C_p-Beziehung gemacht. Das freie Volumen bei der Glastemperatur ₁ ^* ist demnach ein Maß für die Molekülsteifigkeit. Ferner gelingt es, Leerstellenvolumina von verschiedenen Hochpolymeren auszurechnen. Die Ergebnisse bestätigen vollauf die Annahme von Frenkel, daß die Leerstellen die Größe von kleinen Atomen haben und im Prinzip nichts mit der Molekülgröße zu tun haben.

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Summary The glass transition temperature, the intersection of volume-temperature-curves for melt and glass, is considered as lowest limit of the melt. In accordance with the hole-theory of Eyring and Hirai for liquids same is interpreted as a mixture saturated with holes.There is being defined an entropy of dilution S₁ for which the athermal concept of Flory and Huggins is taken, and an enthalpy of dilution H₁ for which an own concept is derived with a geometrical parameter a instead of the usual mean coordination number z. This parameter seems to consider more realistically the size and shape of the mixing components. By means of S₁ and H₁ as well as the functions of volume and enthalpy expressions for the change of the expansion coefficient ^* and the molar heat C_p at glass temperature can be evolved. Thus a calculation of the specific free volume ₁ ^* and of the geometrical parameter a is rendered possible for 11 high polymers. It can be stated that at glass temperature a evidently is a constant while ₁ ^* just roughly can be called a constant. A mean value of ¯ ₁ ^* =0.0235 corresponds, however, very well with the value of about 0.025 which was found by Williams, Landel and Ferry by viscosimetric measurements. In consideration of this conformity it can be concluded that in accordance with the hole-theory only the holes can be defined as free volume and that they are available for translationmechanisms and not the vibration-expansion-volume.When going into the matter it can be seen from the inconstancy of ₁ ^* that evidently no iso-free volume state is given at the glass temperature. The same conclusion is drawn by Miller on account of viscosimetric measurements. The deviation of the data from the Simha-Boyer-equation ^* · Tg=k can be explained by the statement that k is no constant but a function of ₁ ^* . This shows that material with flexible chain molecules have a smaller ₁ ^* than material with less mobile chain molecules. The same appearance can be observed with the analogous C_p-relation. Consequently the free volume at the glass temperature ₁ ^* is a measure for the stiffness of the molecules. Moreover it is possible to calculate hole volumes of various high polymers. The results confirm to a full extent Frenkel's assumption that the holes have the size of small atoms and, in principle, have nothing to do with the size of the molecules.

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Herrn Dr.H. Wilski, Frankfurt-Höchst, und meinem Kollegen Herrn Dr.K. H. Illers habe ich für die Überlassung einiger Meßdaten herzlich zu danken.

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Meinem Kollegen Herrn Dr.K. Apel danke ich besonders herzlich für die Programmierung und Durchführung von Rechnungen auf einem Tisch-Computer.     

A new rectangular Re4 cluster compound of the metallocyclodiyne Type

The compound (n-Bu₄N)₂[Re₄Cl₈(-Cl)₂(-O)₂ · 2THF] has been prepared from (n-Bu₄N)₂ Re₂Cl₈ by refluxing it in wet trifluoroacetic acid. It forms brown, block-shaped crystals in space group P , withZ = 2 in a cell of dimensions:a = 11.748(1) Å,b = 16.847(3) Å,c = 16.953(3) Å, = 97.53(1)° = 106.49(1)° = 101.25(1)°V = 3093(1) ų. There are two independent but practically identical tetranuclear anions, each on a crystallographic inversion center. The short, unbridged Re-Re edges, to which triple bonds are assigned have lengths of 2.280(1) Å and 2.276(1) Å and the longer edges, each with a -Cl and a -O atom have lengths of 2.611(1) Å and 2.615(1) Å, for molecules 1 and 2 respectively. This anion completes a series going from [Re₄Cl₈(-O)₂(-OMe)₂]^2– through [Re₄Cl₈(-O)₂(-OMe)(-Cl)]^2– to the present [Re₄Cl₈(-O)₂(-Cl)₂]^2–. These metallocyclobutadiynes can be viewed as products of the 2,2-cycloaddition of two Re-Re quadruple bonds, but the mechanistic details of how they arise remain obscure.     

The influence of solvent structure on the solvolysis oftrans-dichlorotetra (4-ethylpyridine) cobalt(III) perchlorate

Summary The solvolysis oftrans-[Co(4-Etpy)₄Cl₂]ClO₄, was followed spectrophotometrically in water/isopropanol at different temperatures. The activation energy varied nonlinearly with the mole fraction of the co-solvent, ₂. The plot of logk versus D _s ^–1 was also non-linear. These features were attributed to the differential solvation of the initial and transition states. On plotting H versus S, the points fall very close to straight line. The isokinetic temperature was found to be 334K, indicating that the solvolysis reaction is controlled by S and not H. The change in H and S with the mole fraction of the cosolvent shows extrema at the composition range where changes in solvent structure occur. The influence of the solvent structure on the complex ion in the transition state dominates over that in the initial state, where –G _t ⁰ [Co(4-Etpy)₄Cl]²⁺>–G _t ⁰ [Co(4-Etpy)₄Cl₂]⁺.     

Reversed phase liquid chromatographic retention behavior of polystyrene homopolymers

Summary Isocratic and gradient elution high performance liquid chromatographic measurements of the retention behavior of polystyrene homopolymers with molecular weights ranging from 2 kD to 390 kD were performed using mixed methylene chloride-methanol mobile phases of varying composition and a C-18 chemically bonded stationary phase supported on either 100 Å or 300 Å mean pore diameter silica. Isocratic measurements of the capacity factor, k, for different molecular weight homopolymers as a function of the volume fraction of methylene chloride, , permit determination of the critical composition, _c, which renders k=1 and the local slope, S=–lnk/_c of the lnk- isotherm at =_c, and also the dependence of _c and S on the degree of polymerization, M. Linear gradient elution measurements of _c and S were also performed and compared to the corresponding isocratic measurements. The general retention behavior and the dependence of _c and S on M compare favorably to the predictions of the theory of homopolymer retention and fractionation developed by Boehm, Martire, Armstrong, and Bui (BMAB). Comparison is also made between the present work and the experimental observations of other workers on related chromatographic systems involving hompolymer retention.     

Synthesis and magnetic properties of copper(II) bis(phenylsulphinyl)ethane complexes

Summary Two Cu^II complexes, [Cu₂(-L)Cl₄·H₂O (1) and Cu₂(-L)Cl₄ (2) [-L and -L = meso- and rac-PhS(O)(CH₂)₂S(O)Ph, respectively], were synthesized and characterized by elemental analysis, i.r. spectra and molar conductances. In each case, the Cu^II ion bonds to the 557-01 moiety through oxygen, and may be bridged by the ligand (-L or -L). From magnetic moment measurements at room temperature and variable temperature magnetic susceptibilities, we suggest that complexes (1) and (2) exhibit weak ferromagnetic behaviour.     

Metal bioaccumulation by the freshwater algaScenedesmus quadricauda

Bioaccumulation of six metals (Cu²⁺, Cu⁺, Mo⁶⁺, Mn²⁺, V⁵⁺, Ni²⁺) and their combinations by algaScenedesmus quadricauda was determined by using radio nuclide X-ray fluorescence (RXFA). The metals were added into the cultivation medium in concentrations corresponding with EC₅₀ value for each metal. The obtained results indicate that Ni²⁺, Cu²⁺ and Cu⁺ were accumulated in high amounts (20%, 17.5% and 15.19%) the Mo⁶⁺ ion (<0.2%) was accumulated in the lowest amount. For metal-metal interactions in accumulation of metal ions by algaS. quadricauda three types of answers were determined: inhibition (MoCu²⁺, Ni, Mn, V; VNi, Mn; MnNi, Cu²⁺, Cu⁺; Cu⁺Ni; Cu²⁺Ni; NiMn, V), enhancement (VCu⁺; Cu²⁺Mn;Cu⁺V, Mn; MnV; NiCu²⁺, Cu⁺) and neutral effect (VMo; Cu²⁺Mo; Cu⁺Mo; MuMo; NiMo).     

Crystal structure of copper(I) chloride π-complexes with diallylamine: (C6H12N)2Cu7Cl9·H2O and 2CuCl·C6H11N

For the first time we have synthesized and studied by X-ray structural analysis two novel copper(I) chloride -complexes with diallylamine (DAA): [H(DAA)]₂Cu₇Cl₉·H₂O (D) and 2CuCl·DAA (E). Compound D is isostructural to the complex [H(DAA)]₂Cu₇Br₉·H₂O studied earlier: space group Pnam, a=15.934(8), b=14.817(6), c=11.368(6) , V=2684(4) ³, and Z=4 for [(C₆H₁₂N)₂ Cu₇Cl₉·H₂O]. Crystals E are triclinic: space group P1, a=7.373(2), b=9.743(4), c=11.351(8) , =84.05(4), =101.26(4), =103.31(3)°, V=914(2) ³, and Z=2 for [Cu₄Cl₄·(C₆H₁₁N)₂]. The layers of the structure are formed by combining the armchair-shaped cycles Cu₄Cl₄ via the tridentate DAA molecules.I. Franko Lvov State University, Ukrainian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 6, pp. 43–48, November–December, 1993.Translated by T. Yudanova     

State of copper in massive Cu?V?Mo oxide systems

ESR data for X(CuO) V₂O₅·8.3 MoO₃ system heated at 400–550 °C indicate the occurrence of a copper state with d_Z ²-ground state. Copper ions are orbitally ordered apparently in –Cu²⁺–O–Cu¹⁺–O–Cu²⁺-chains.

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B X(CuO) V₂O₅·8,3 MoO₃ , 400–550°C d_Z ²- . , , –Cu²⁺–O–Cu¹⁺–O–Cu²⁺-.

     

The structures of macrocyclic heterocyclophane inclusion complexes

Crystal and molecular structures of (1:1) molecular complexes of N,N,N,N-tetramethyl-2, 11, 20, 29-tetraaza [3.3.3.3] paracyclophane (1) with CHCl₃, CH₂Cl₂, CH₃CN and CO₂ are reported. The macrocycle has square-box structure, giving hydrophobic cavity surrounded by four benzene rings. The guest molecules are included in the cavity. The uncomplexed1 was found to have a rectangular form, indicating large conformational flexibility of1. In solution,1 is achiral because rapid RS interconversion, but in solid, the macrocyclic conformation is frozen as R-conformer or S-conformer. The macrocycles with the same chirality are stacked alongb-axis to form chiral molecular columns, R-colums or S-columns. Complexes of1 crystallize differently depending on the guest molecules. R-columns (S-columns) packed alonga-axis produce R-layers (S-layers), which are further packed alongc-axis using R-layer to R-layer contact (RR) or SS and RS or SR. The crystals of1·CHCl₃ are formulated as--RRR--=[R]_n (Type I, chiral) and those of1·CH₃CN or1·CO₂ and1·CH₂Cl₂ are represented by [RS]_n (Type IIA, racemic) and [RRSS]_n (Type IIB, racemic), respectively.     

Temperature dependence of apparent molar volumes and viscosity B-coefficients of amino acids in aqueous potassium thiocyanate solutions from 15 to 35°C

Precise density and viscosity data at 15, 25 and 35°C for solutions of glycine, DL-alanine, L-threonine, -alanine, -aminobutyric acid and -aminocaproic acid in water and in (1m, 3m, 5m) aqueous potassium thiocyanate were measured and the limiting apparent molar volumes V ^o and the B-coefficients calculated. The V ^o and B values were split into the contributions from the NH ₃ ⁺ ,COO^– and CH₂ groups. These data are rationalized on the basis of hydrophillic and hydrophobic interactions between the various groups present in these solutions.Abstracted from the Ph.D Thesis of R. K. Goyal, University of Delhi, 1990.     

Sorption of palladium chloride complexes on Al2O3 surface

Three types of sorption interactions with the corresponding Pd aquachlorocomplexes [Pd(H₂O)₂Cl₂]⁰, [Pd(H₂O)Cl₃]^– and [PdCl₄]^2– have been discovered on -Al₂O₃ at surface concentrations for the active component and the competing HCl ranging within 0.05–1.25 and 1.2–4.8 mol m^–2, respectively.

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0,05–1,25 /² 1,2 4,8 /² -Al₂O₃ , : [Pd(H₂O)₂Cl₂]⁰, [Pd(H₂O)Cl₃]^– [PdCl₄]^2–.

     

Apparent molar heat capacities and volumes of electrolytes and ions int-butanol-water mixtures

The apparent molar volumes V and heat capacities C _p, of NaCl, LiCl, NaF, KI, NaBPh₄ and Ph₄PCl have been determined in solutions of H₂O containing up to 40 mass% t-butyl alcohol (TBA) by flow densitometry and flow microcalorimetry. Combination of these results with literature data allows calculation of V and C _p, for 16 ions in these mixtures using the assumption that _tX(Ph₄P⁺) = _tX(BPh ₄ ^– ) where X=V or C _p and _tX is the change in X for a species on transfer from H₂O to TBA-H₂O mixtures. These are the first reported single ion values for C _p, in a mixed solvent. While whole electrolyte volumes and heat capacities show relatively smooth changes with solvent composition, _tX(ion) exhibit two well-developed extrema at around 10 and 25 mass% TBA. The shape of the _tX(ion) curves shows considerable uniformity among the alkali metal cations and the halide ions but the extrema become more pronounced with increasing size among the tetraalkylammonium ions. These extrema are analogous to those observed in aqueous organic mixtures of surfactants and are probably indicative of microphase transitions in these strongly interacting solvent mixtures.     

Volumes and compressibilities of pentanol in aqueous alkyltrimethylammonium bromide solutions at different temperatures

Speed of sound and density properties of ternary water-tetradecyltrimethylammonium bromide-pentanol system at 15, 25 and 35°C and of water-hexadecyltrimethylammonium bromide-pentanol system at 25, 35 and 45°C were measured at fixed alcohol concentration as a function of surfactant concentration. The apparent molar volumes V_,R and isentropic compressibilities K _,R ^S of pentanol in micellar solutions as a function of the surfactant concentration show irregular behavior which depends on the alkyl chain length of the surfactant and tends to disappear with increasing temperature. These anomalies are ascribed to micellar transitions. For both surfactants at high concentrations, V_,R decrease and the magnitude of the change seems to depend on the type of densimeter used. This observation is tentatively explained in terms of a correlation between the micellar structure and features of the densimeter. From this work and literature data, the apparent molar isothermal compressibilities K _,R ^T of the alcohol in micellar solutions were calculated at 25°C. V_,R , K _,R ^S and K _,R ^T are interpreted in terms of the distribution constant of the alcohol between the aqueous and the micellar phases and of the apparent molar property of the alcohol in the micellar and the aqueous phases. For a given surfactant increasing the temperature increases V_,R and K _,R ^S in the micellar phase while the distribution constant is weakly dependent. At a given temperature, an increase in the alkyl chain length of the surfactant increases the apparent molar volume and slightly changes the apparent molar compressibility of the alcohol in the micellar phase.     

Copper(I) Acetylenide π-Complexes. Synthesis and Structure of Cluster Compound HAmp[Cu9Cl8(C≡CCH2OH)2] (HAmp is 4-Aminopyridinium Cation)

Crystals of the HAmp[Cu₉Cl₈(CCCH₂OH)₂] cluster compound (HAmp is the 4-aminopyridinium cation (NH₂–C₅H₄NH)⁺) were obtained through ac electrochemical synthesis and their structure was determined using X-ray diffraction analysis (DARCh autodiffractometer, /2 scan mode, 3435 independent reflections with F 4(F), R = 0.047). The crystals are triclinic: space group P , a = 12.547(5) Å, b = 12.502(4) Å, c = 8.201(2) Å, = 75.93(2)°, = 82.21(3)°, = 76.05(3)°, V = 1207(2) ų, Z = 2. Two crystallographically independent moieties ^–(CCCH₂OH) were detected in the complex structure. Each moiety acts as a double bridging ,-ligand and binds four or five Cu(I) atoms, thus forming the [Cu₄(CCCH₂OH)] and [Cu₈(CCCH₂OH)₂] clusters. The shortest Cu···Cu distance is equal to 2.337(4) Å.