Isolation,purification, and characterization of cyclomaltodecaose (ε-CD)

-Cyclodextrin (-CD) is a cyclic oligosaccharide, composed of ten -1,4-linked D-glucoses reported by Frenchet al. in 1965¹⁾, but has not been studied because of the difficulty in the preparation and purification of large-ring CDs composed of more than nine -1,4-linked D-glucose units. This report describes the purification and characterization of -CD. Furthermore, the crystal and molecular structure of -CD hydrate -CD 19H₂O) was elucidated by X-ray analysis.     

The relative permittivity of 1,2-dimethoxyethane and N,N-dimethylformamide mixtures from −10 to 40°C

Binary solutions of N,N-dimethylformamide and 1,2-dimethoxyethane have been investigated by means of dielectric measurements at temperatures ranging from –10 to +40°C, and for nine mixtures covering the whole miscibility field expressed by the mole fraction of one component (0X₁1). The experimental data were used to study the dependence of on T and X₁, of the type = (T), = (X₁), and = (T,X₁). Further, the excess mixing function _E has been evaluated in order to identify particular patterns of interaction between unlike molecules and any other factor that could modify such patterns. The minimum in the _E vs. composition plots suggests the formation of an adduct of stoichiometric ratio DMFDME=11 at all the investigated temperatures.     

The electronic spectrum of acrylonitrile

The vapor absorption spectrum of acrylonitrile CH₂CHCN has been measured in the vacuum ultraviolet region. In addition, an all-valence-electron molecular orbital calculation has been used to calculate the electronic structure and spectrum of the molecule. On the basis of the MO calculation, as well as a vibrational analysis of the observed spectrum, several electronic transitions are assigned. The lowest energy absorption band (2107Å, = 150) is assigned as an n ^* transition. Absorption bands at 2030Å (=1600), 1725Å ( = 2100), and 1570Å ( = 1920) are assigned as 0–0 bands associated with transitions that are, respectively, ^*,^*, and ^* in character.

---

Zusammenfassung Das UV-Absorptionsspektrum von dampfförmigen Acrylnitril wurde gemessen und eine CNDO/2-Rechnung für die Elektronenstruktur durchgeführt. Auf dieser Basis konnten unter Zuhilfenahme der Analyse der Schwingungsstruktur im beobachteten Spektrum mehrere Banden zugeordnet werden: die 2107-Å-Bande ( = 150) einem n^*-Übergang, die drei Banden bei 2030Å ( = 1600), 1725Å ( = 2100) und 1570 Å ( = 1920)0-0-Übergängen von ^*-, ^*- bzw. ^*-Banden.

---

Résumé Mesure du spectre d'absorption en phase vapeur de l'acrilonitrile CH₂CHCN dans la région de l'ultraviolet. Par ailleurs, la structure électronique et le spectre de la molécule ont été calculés à l'aide d'une méthode des orbitales moléculaires semi-empirique pour tous les électrons de valence. Sur cette base, ainsi que sur une analyse vibrationnelle du spectre expérimental, on procède à l'attribution de plusieurs transitions électroniques. La bande d'absorption de plus basse énergie (2107 Å, = 150) est attribuée à une transition n ^*. Les bandes d'absorption à 2030Å ( = 1600), 1275Å ( = 2100) et 1570Å ( = 1920) sont considérées comme des bandes 0 - 0 associées à des transitions ^*, ^* et ^* respectivement.

     

Determination of various deformation processes in impact-modified PMMA at strain rates up to 105%/min

The deformation processes in impact-modified PMMA, which deforms homogeneously, were determined by means of the stress/strain experiment (, ) with simultaneous lateral strain measurement (_lat) in a wide range of strain rates () up to 10⁵%/min (impact stress). The elastic, plastic cavitation and plastic shear processes were determined as a function of strain. Therefore we calculated the elastic strain ( _el), the elastic volume expansion ( _{vol el}), the cavitation strain ( _cav), which is identical with the plastic volume expansion ( _{vol pl}), the shear strain ( _sh) and the energy densities (W_el, W_cav, W_sh) related to these three processes.For strains of 3 % onward it was found that plastic shear processes and plastic cavitation processes are responsible for a partial loss of elastically stored energy. Both plastic processes turn out to be mostly anelastic deformations, their amount depending strongly on the strain rate. The contributions of the processes to the total deformation of the unmodified PMMA in its strain range are similar to those of the impact-modified PMMA, and the high impact strength is caused by a shift of the catastrophic rupture to very high strains.     

Localization of Iα and Iβ phases in algal cellulose revealed by acid treatments

Highly crystalline I-rich type Cladophora cellulose, which had been kept in never-dried condition, was treated in 60wt% sulfuric acid at 100°C, for 1–48h. The cellulose microcrystals thus obtained were analysed by X-ray diffractometry, FT-IR, and transmission electron microscopy. The I component was found to be more degraded than the I component. The cellulose I/I ratios of the samples acid-treated for 0, 24, and 48 h were about 8:2, 6:4, and 4:6, respectively. After the acid treatment, the microcrystals became narrower in width, and very sharp at their ends. These results indicate that the I phase is mostly located at the surface of the microcrystals, which is morphologically more susceptible to the acid treatment.     

Studies of the energy spectrum of α, ω- substituted polymethine chains. II. Polymethine chains with odd number of methine groups

The analysis of the experimental data for the energy of the longest wavelength optical transitions _n,opt of substituted polymethines X (CH)_2n+1 X shows that in the asymptotic case (n) _,opt does not tend to zero, as it follows from the empirically established correlations, but has a finite, non-zero value. It is shown that the energy gap of odd polymethines is the same as that of the even polymethines - the polyenes (E 2 eV). The substituents (X N, O, B) are responsible for the appearance of levels in the gap. These, depending on the substituent character, are vacant (X B) or occupied (X N, O). The transition from or to such a level determines the longest wavelength optical transition energy of polymethines.     

Molecular dynamics and the structure of macrocycles —Solvent acetonitrile interactions

Microwave complex permittivities,* = -J, are reported in the 1–90 GHz frequency range for the macrocycles 18-crown-6 (18C6) and 15C5 added to acetonitrile in stoichiometric proportions, in the solvent CCl₄ at 25°C. Digitized infrared spectra of the CN stretch ₂ vibration of acetonitrile for the same systems are reported in the 2300–2200 cm^–1 spectral region. The macrocycle 12C4 added to CH₃CN has also been investigated in the infrared. Both the dielectric relaxation and infrared results are interpreted in terms of macrocycle-acetonitrile interactions, probably involving a methyl-hydrogen to ethereal-oxygen interaction. These interactions with CH₃CN diminish in strength according to the sequence: 18C6 > 15C5 > 12C4.This paper is dedicated to the memory of the late Dr C. J. Pedersen.     

Photometrische Bestimmung von Zirkoniumoxidchlorid in Speisesalz

Zusammenfassung 2-Chinolylfluoron bildet mit Zirkonium einen 14-Komplex, dessen Extinktionskoeffizient bei 539 nm _max=165000 ist. Das Bestimmungsverfahren für ZrOCl₂ in Speisesalz wird auf dieser Farbreaktion aufgebaut.

---

Photometric determination of ZrOCl₂ in table salt

2-Quinolylfluorone forms a 14-complex with zirconium. Owing to its high extinction coefficient _max=165000 at =539 nm the complex can be used for the determination of ZrOCl₂ in table salt.

     

Immobilized sol of cobalt(III) hydroxide as an efficient catalyst of water oxidation to dioxygen by the Ru(bpy)33+ complex

Catalysts of water oxidation to dioxygen by Ru(bpy) ₃ ³⁺ have been obtained by immobilization of colloidal Co(III) hydroxide on supports of the hydroxide types. These supports are found to be able either to enhance (Al(III), Bi(III), Sn(IV) and Ce(IV) hydroxides) or to weaken (Fe(III) and Mn(IV) hydroxides) the catalytic efficiency of the initial sol. The possible nature of the influence of the support is discussed.

---

Ru(bpy) ₃ ³⁺ Co(III). - , ( Al(III), Bi(III), Sn(IV), Ce(IV)), ( Fe(III), Mn(IV)) . .

     

Thermoanalytical investigations of silicone caoutchouc polymers and silicone rubbers,I

The investigations proved that isothermal thermogravimetry yields useful information on the thermal stability of silicone caoutchouc and silicone rubber. It was established that the thermal degradation is a first-order reaction. Measurements and calculations verified that in multicomponent systems the resultant degradation curve obtained by isothermal measurements is formed additively from the degradation curves of the components, i.e. the thermal decompositions of the components proceed independently of one another.

---

Zusammenfassung Die isotherme Thermogravimetrie liefert nützliche Informationen über die thermische Stabilität von Silkonkautschuk und Silikongummi. Der thermische Abbau verläuft nach einer Reaktion erster Ordnung. Messungen und Berechnungen haben bestätigt, daß in Vielkomponentensystemen die resultierende isotherme Zersetzungskurve sich additiv aus den Zersetzungskurven der Komponenten zusammensetzt, d. h., daß die thermische Zersetzung der Komponenten unabhängig voneinander verläuft.

---

, . . , , , , . . .

     

Eigenvalues of the real generalized eigenvalue equation perturbed by a low-rank perturbation

The low-rank perturbation (LRP) method solves the perturbed eigenvalue equation (B +V) _k = _k (C +P) _k , where the eigenvalues and the eigenstates of the related unperturbed eigenvalue equationB _i = _i C _i are known. The method is designed for arbitraryn-by-n matricesB, V, C, andP, with the only restriction that the eigenstates _i of the unperturbed equation should form a complete set. We consider here a real LRP problem where all matrices are Hermitian, and where in addition matricesC and (C +P) are positive definite. These conditions guarantee reality of the eigenvalues _k and _i . In the original formulation of the LRP method, each eigenvalue _k is obtained iteratively, starting from some approximate eigenvalue _k . If this approximate eigenvalue is not well chosen, the iteration may sometimes diverge. It is shown that in the case of a real LRP problem, this danger can be completely eliminated. If the rank of the generalized perturbation {V, P} is small with respect ton, then one can easily bracket and hence locate to any desirable accuracy the eigenvalues _k (k = 1, ...,n) of the perturbed equation. The calculation of alln eigenvalues requiresO(² n ²) operations. In addition, if the perturbation (V, P) is local with the localizabilityl p, then onlyO(² n) operations are required for a derivation of a single eigenvalue.     

Bestimmung des komplexen dielektrischen Faktors bei niedrigen Frequenzen und der logarithmischen Ableitung von dessen Realteil unter Zuhilfenahme von Messungen der zeitabhängigen Leitfähigkeit

Zusammenfassung Es wurden Näherungen aufgestellt, die dazu ienen, *() und die besonders für dielektrische Spektraluntersuchungen interessante negative logarithmische Ableitung von () mit Hilfe der zeitabhängigen Leitfähigkeiti(t) auch bei niedrigen, der direkten Messung schlecht zugänglichen Frequenzen bestimmen zu können. Diese Näherungen sind numerisch sehr einfach zu handhaben und ihre Genauigkeit ist durch Angabe der maximal möglichen Abweichungen sicher festgelegt. Es wurde gezeigt daß die Fehlergrenzen, die man für die Hamon-Näherung finden kann, groß sind, so daß diese als viel zu unsicher angesehen werden muß.Nach den angegebenen Beziehungen lassen sich () undd/dlog allein aus der zeitabhängigen Leitfähigkeit berechnen, wenn diese bis zu hinreichend kurzen Zeiten verglichen mit dem Kehrwert der Frequenz bekannt ist. Ist dies nicht der Fall, können bei höheren Frequenzen direkt gemessene -Werte zur Berechnung mit herangezogen werden. Es wurde gezeigt, daß im Gegensatz dazu nicht mit Sicherheit ausi(t) allein bestimmt werden kann, sondern nur die Änderung von über ein vom Zeitbereich der Leitfähigkeitsmessung abhängiges Frequenzintervall. Ist in einem kleinen Frequenzbereich bekannt, dann kann es mit Hilfe voni(t) auch bei niedrigen Frequenzen ausgerechnet werden. Die dazu nötigen Beziehungen wurden mitgeteilt.

---

Summary Formulae are derived for the approximative calculation of the dielectric permittivity ^*() and the logarithmic derivative of the storage component () with the aid of measurements of the transient currenti(t). These equations are numerically simple and of high accuracy. The error bounds for these equations can be given. It has been shown, that the error bounds for the well known Hamon formula are unreasonably high, indicating a great uncertainty of this relation.Some of the formulae given allow to calculate () andd/dlog from values of the transient current only, provided these are available up to values of time which are short enough compared with 1/. If this is not the case other formulae can be used for which direct measurements of at higher frequencies are necessary. Furthermore it has been shown that the knowledge of the transient current is not sufficient for calculations of . Formulae are given to obtain at lower frequencies with the aid of transient current and some values of at higher frequencies.

---

---

Mit 1 Abbildung und 5 Tabellen     

Influence of polarity of medium on the nature of charge transfer complex,kinetics, and mechanism of reaction with a one-electron transfer in a tetracyanoethylene-n-alkyl-substituted aniline system

The influence of the polarity of the medium (B, ) on the thermodynamic characteristics of the formation of a charge transfer complex (CTC) and one electron transfer from a donor D to and acceptor A was studied in N-alkyl-substituted aniline (D) — tetracyanoethylene (A) systems. It was shown that in systems with CTC in which [B]/[D] 1, the limiting step in the reaction with one electron transfer in weakly polar solvents (<20) is the formation of molecular (AD), and in strongly polar sovents (>20), of ionic (AD) CTC. A correlation was established between the spectral (VCT) characteristics of the formation of the CTC and the kinetic parameters (k_eff) of one electron transfer reaction and degrees of charge transfer in molecular and ionic CTC were determined.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 167–173, March–April, 1989.     

Temperature and velocity fields in a gas stream exiting a plasma torch. A mathematical model and its experimental verification

A mathematical model was developed to predict the velocity and temperature fields in a free plasma jet issuing from a D.C. plasma torch. It was assumed that the temperature and velocity at the torch nozzle were specified and the turbulent Navier-Stokes equations were solved in conjunction with a two-equation model of turbulence and the energy transport equation. The model was formulated in terms of the two-dimensional elliptic equations to facilitate its future extension to nonparabolic problems. The predictions of the model were compared with experimental measurements obtained from laser Doppler and spectroscopic techniques. Good overall agreement was found between the theoretical predictions and the experimental measurements for two sets of initial conditions corresponding to nitrogen/hydrogen and argon/hydrogen plasmas. Radiation was found to have a small effect on the overall heat transfer process, and it is suggested that the assumption of an optically thin radiation loss per unit volume is sufficiently accurate for most engineering applications. The significance of this work lies in the fact that, for the first time, it is possible to test the assumptions of the current model against a reliable set of experimental measurements.Notation C ₁,C ₂,C _D constants inK- turbulence model, Table III - C _P average specific heat of plasma at constant pressure - h ₁ length of integration region - h ₂ width of integration region - K turbulent kinetic energy per unit mass - P pressure - r radial coordinate - R ₀ internal radius of anode - S _K source term forK equation - S _R radiation loss per unit volume - S source term for equation - T ₀ temperature of plasma atz=0 - T temperature of plasma - T _a ambient temperature - u velocity inz direction - u ₀ velocity of plasma atz=0 - v radial velocity of plasma - z axial coordinate - dissipation rate of turbulence energy - , _eff, _t molecular, effective, and turbulent viscosities, respectively - density - _K, _T, Prandtl numbers forK, T, and, respectively     

Dielectric study of poly(methyl methacrylate) microcapsules in particular reference to the effect of the frequency dependence of the permittivity of the capsule wall

The dielectric behavior of poly(methyl methacrylate) (PMMA) microcapsules was analyzed theoretically by taking account of the frequency dependence of the relative permittivity _s and the electrical conductivity _s of the capsule wall. For comparison, similar analysis was applied to polystyrene (PS) microcapsules which have frequency-independent _s and _s . The behavior of _s and _s of the PMMA microcapsules was assumed to be represented by a dielectric relaxation of them-th power type on the basis of dielectric data on underwater PMMA films. By means of a theory of the interfacial polarization, some consideration was carried out regarding the effect of the frequency dependence of _s and _s on the dielectric behavior of the PMMA microcapsules. The consideration led to predictions that the frequency dependence of _s and _s causes (i) the variation in the relaxation intensity with the change in the conductivity of suspending medium, (ii) the frequency dependence of the permittivity at low frequencies and (iii) the frequency dependence of the conductivity at high frequencies. The theoretical prediction (i) was verified by observed data, (ii) and (iii) remaining unverified owing to the experimental difficulty.     

Investigation of dehydration process,II

The dehydration of hydrated calcium and strontium bromides and iodides was studied by thermogravimetry and differential thermal analysis. The melting in the crystallization water was distinguished from the dehydration in a self-generated atmosphere. The results of the TG and DTA curves made simultaneously were verified by measurements with a Du Pont DSC apparatus. This latter investigation was extended to the previously studied chlorides too. Correlations were found between the temperature of melting or of dehydration and the ionic radii of the respective cations and anions.

---

Zusammenfassung Die Dehydratisierung von Calcium- und Strontium-Bromid- und Jodidhydraten wurde mit den Methoden der Thermogravimetrie und Differentialthermoanalyse verfolgt. Das Schmelzen im Kristallwasser wurde von der Dehydratisierung in der selbsterzeugten Atmosphäre getrennt. Die Ergebnisse der simultan erhaltenen TG- und DTA-Kurven wurden durch Messungen mit einem Du Pont DSC-Gerät bestätigt, wobei die bereits schon untersuchten Chloride mit einbezogen wurden. Korrelationen zwischen den Schmelzoder Dehydratisierungstemperaturen und den Ionenradien der entsprechenden Kationen und Anionen werden beschrieben.

---

Résumé Etude de la déshydratation des bromures et iodures de calcium et de Strontium hydratés par thermogravimétrie et par analyse thermique différentielle. La fusion dans l'eau de cristallisation a été distinguée de la déshydratation en atmosphère auto-générée. Les résultats des courbes TG et ATD obtenues simultanément ont été vérifiés par des mesures effectuées à l'aide d'un analyseur calorimétrique différentiel (DSC) Du Pont. L'étude a également été étendue aux chlorures précédemment étudiés. On propose des corrélations entre les températures de fusion ou de déshydratation et les rayons ioniques des cations et anions respectifs.

---

, . . . . .

     

Dielectric study on pure and KOH-doped tetrahydrofuran clathrate hydrates

Complex dielectric permittivities of pure and KOH-doped (x = 1.8 x 10^–4) tetrahydrofuran clathrate hydrates were measured in the temperature range 20–260 K and in the frequency range 20 Hz-1 MHz. The relaxation time of the water reorientational motion was found to decrease drastically as a result of the doping; e.g., the relaxation time of the doped sample was 10^–9 times shorter than that of the pure sample at 70 K. The activation enthalpy of the motion was reduced to 7.4 kJ mol^–1. On cooling the crystal, the value of decreased suddenly at the 62 K phase transition to the ₂ value of the pure sample and at the same time disappeared. No dispersion effect due to the guest reorientation was observed below the transition. These data indicate that both the host and guest molecules become ordered or, at least, change their mobility drastically. In the pure sample, a relaxation phenomenon of ₀₂ was found around the glass transition region. The relaxation times agreed well with those derived from the enthalpy of relaxation in a calorimetric study.Dedicated to Dr D. W. Davidson in honor of his great contributions to the sciences of inclusion phenomena.     

Synthesis of the heptapeptide of the cyclopeptide moiety of polymixin B

Conclusions The synthesis of the heptapeptideN -BOC-N -pelargonyl-L-lysyl-N -Z-L-lysyl-D-phenylalanyl-L-leucyl-N -Z-L-lysyl-N -Z-L-lysyl-L-threonine, a linear analog of the cyclopeptide part of the antibiotic polymixin B, has been effected (yield 63%). The possibility of using this method for the synthesis of peptides on a polymer support without protecting the hydroxyl group of threonine has been shown.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 3, pp. 359–361, 1970     

IR spectroscopic determination of protonation heats of bases on catalyst surfaces

IR spectra of pyridine adsorbed on zirconium phosphate and zeolite HNaY were studied at temperatures of 400–500 K. Protonation heats of pyridine determined on the OH groups of zirconium phosphate and zeolite HNaY having theOH at 3640 cm^–1, are 65±6.0 and 172±16 kJ/mol, respectively.

---

400–500 K , HNaY. OH (Q=65±6, /) OH HNaY cOH 3640 ^–1 (Q=172±16 /).

     

Exciton Chirality. (A) Origins of and (B) Applications from Strongly Fluorescent Dipyrrinone Chromophores

Summary. (A) The origin of exciton interaction and examples of its application to organic stereochemistry are presented. (B) N,N-Carbonyl-bridged dipyrrinones constitute a new class of highly fluorescent chromophores suitable for investigations of stereochemistry and absolute configuration. N,N-Carbonylxanthobilirubic acid esters are strongly fluorescent, with a fluorescence quantum yield (_F) 0.8, but produce only weak exciton CD from the trans-1,2-cyclohexanediol template. The ester of an analog with benzoic acid replacing propionic, N,N-carbonyl-8-(4-carboxyphenyl)-3-ethyl-2,7,9-trimethyl-(10H)-dipyrrin-1-one, exhibits strong fluorescence (_F=0.68, _em=493nm, _ex=422nm in CHCl₃) and UV-Vis absorption (21000 at 424nm) in organic solvents. Its diester with (1S,2S)-cyclohexanediol is fluorescent and exhibits exciton circular dichroism (=+15dm³·mol^–1·cm^–1, =432nm; =–4dm³·mol^–1cm^–1, =380nm) that correlates with the Exciton Chirality Rule.