IR-Spektren von 2,4,6-Tris(dimethylamino)- und 2,4,6-Tris[dimethylamino(d6)]-borazinderivaten

Zusammenfassung Der Vergleich der Spektren von B-Dimethylaminoborazinen mit jenen der entsprechenden B-Hexadeuterodimethylaminoborazine zeigt starke Wechselwirkungen zwischen BN- und CH₃-Schwingungen, die ebenso wie in anderen N- und O-Methylborazinen zu einer Frequenzminderung der B–N-Hauptbande führen.

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By comparison of the IR-spectra of B-dimethylaminoborazines with those of their hexadeuterodimethylamino analogous shows strong interactions of BN and CH₃-frequencies. BN frequencies are decreased like in other O- and N-methylborazines.

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Mit 2 Abbildungen     

Some anomalies in the vibrational spectra of α, β-unsaturated ketones

Summary Some anomalies in the intensities of the bands of the C=C and C=O bonds in the vibrational spectra of , -unsaturated ketones have been explained by a difference in the sequence of the frequencies of the in-phase (_s) and out-of-phase (_as) vibrations of the multiple bonds in their cis (_s<_as) and trans (_s>_as) arrangements.     

Über die Wasserstoffbrückenbindungen zwischen der Phosphorylgruppe und phenolischem Hydroxyl

Zusammenfassung Mit Hilfe der IR-Spektroskopie wurde nachgewiesen, daß tertiäre Phosphinoxide mit Phenolen über Wasserstoffbrücken zu festen kristallinen Addukten assoziieren. Die Verschiebung der OH-Valenzschwingungsbande des Phenols ( OH) wurde bestimmt, wobei die Substituenten an der Phosphorylgruppe die Lage der Assoziationsbande bestimmen. Die P=O-Valenzschwingungsbande des Phosphinoxids erfährt ebenfalls eine Verschiebung nach einer kleineren Wellenzahl. Die P=O-Werte liegen zwischen 23 und 55 cm^–1 je nach eingesetzter phenolischer Verbindung.

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IR spectroscopy was used to demonstrate that tertiary phosphine oxides form solid crystalline adducts with phenols by way of hydrogen bonds. The shifts of the bands assigned to the phenolic hydroxyl groups were determined and found to depend on the substitutents of the phosphoryl group. The P=O stretching vibration is also shifted, if this group takes part in hydrogen bonding. The P=O values found range from 23 to 55 cm^–1 according to phenols used in adduct formation.

     

Triphenylphosphineoxide nitrosyl complexes of molybdenum

Summary The tetramethylthiourea (TMTU) complexes of cobalt(II) and nickel(II) halides have been studied in the solid state by electronic, i.r. and far i.r. spectroscopy and magnetochemically. The tetrahedral Co(TMTU)₂X₂ (X = Cl, Br, 1) and Ni(TMTU)₂X₂ (X = Cl, Br) complexes have normal magnetic moments, electronic spectra and crystal field parameters; Ni₂ (TMTU)₃I₄ is diamagnetic. The cobalt complexes have normal (CoX) and (CoX) vibrational frequencies. Ni(TMTU)₂Cl₂ and Ni₂(TMTU)₃I₄ have (NiX) frequencies corresponding to long or bridging Ni-X bonds, while Ni(TMTU)₂Br₂ has normal (NiBr) frequencies for terminal Ni-Br bonds. The (MS) frequencies are similar to those of cobalt(II) and nickel(II) complexes of other thioureas.     

α BB Resonance in the ν8 Band of Borazine –10B

The high-resolution FTIR spectrum of the fundamental ₈ of borazine ¹⁰B₃ ¹⁴N₃ ¹H₆ was reanalyzed taking into account the ^BB resonance with the combination band (₁₀ + ₁₇). A parameter set for the states ₈ = 1 and ₁₀ = ₁₇ = 1, respectively, is given, reproducing the observed spectrum at least up to J = 30 with experimental accuracy.     

Far infrared spectra (500–50 cm−1) of the 2,2′-bipyridine complexes of palladium and platinum halides

Summary The far-i.r. spectra of the title complexes have been examined. Band assignments are based on the shifts induced by ligand deuteration and halide substitution. Deuteration of bipyridine causes large shifts ( >10 cm^–1) in internal ligand modes, intermediate shifts between 2 and 9 cm^–1) in metal-nitrogen stretching and bending modes and small to zero shifts in metal-halide stretching and bending vibrations. Generally, the requirements for square planarC _2v synanetry [two (M–N) and two (M–X) bands] are observed. Previous ambiguities in the assignment of the (M–N) bands have been resolved by the isotopic labelling technique employed in this study.     

Application of thermokinetics in chemical process analysis,as illustrated by the reaction of phenyl isocyanate andn-Butanol

Shortening the time required for chemical process development from the first laboratory trial through technical and pilot plants to industrial installation is a long-standing aim. Knowledge of the reaction kinetics is of major importance for this purpose. The usefulness of thermokinetics in chemical process engineering is illustrated by reaction of phenyl isocyanate andn-butanol.

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Zusammenfassung Die Abkürzung der Verfahrensentwicklung vom ersten Laborversuch über Technikums- und Pilotanlagen bis zur großtechnischen Anlage ist ein seit langem erstrebtes Ziel. Dabei ist bekanntlich die Kenntnis der Reaktionskinetik von großer Bedeutung. Am Beispiel der Reaktion Phenylisocyanat undn-Butanol wird die Nützlichkeit der Thermokinetik in der chemischen Verfahrensentwicklung aufgezeigt.

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, , , . . -.

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Infrared spectroscopy of hydrogen bond and substituent effects in electron donor molecules

The frequency shift, , of the O—H stretching mode in the IR spectra of the H-complexes of phenol with electron donor molecules BX_i (B is the n- or -donor center and X_i are substituents; a total of eight series), the change in the Gibbs free energy, G, due to H-complexation, and the parameter (a measure of the ability of BX_i molecules to donate an electron pair; two series) are determined by both the electrostatic interaction and charge transfer in the formation of H-complex. The , G, and values depend not only on the inductive and resonance effects, but also the polarizability of substituents characterized by the parameters.     

Die IR-Spektren von B-Methoxy- und B-Trideuteromethoxyborazinen und-boroxinen und Tri[methoxy(d3)boran

Zusammenfassung In Methoxyverbindungen des Bors tritt eine Verminderung der Frequenz der B—O-Valenzschwingung gengenüber den entsprechenden Trideuteromethoxyverbindungen auf. Dies wird durch zufällige Entartung von B—O und CH₃ erklärt, die zu einer Abstoßung und zur Vermischung des Schwingungscharakters dieser beiden Schwingungen führt. Hiedurch werden die B—O-Valenzschwingungen zu tieferen und die CH₃-Deformationsschwingungen zu höheren Wellenzahlen verschoben. Ähnliche Erscheinungen sind auch in Methoxyborazinen durch Wechselwirkung von BN und CH₃ zu beobachten. Diese Deutung gibt auch Hinweise für Zuordnungen in den Spektren von N-Methylborazinderivaten.

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In methoxy substituted boron compounds bands arising from B—O stretching and (O)–CH₃ deformation modes show accidental degeneracy. The frequency of the CH₃ absorption is increased whereas BO is decreased compared to the corresponding CD₃-compounds. The spectra of B-methoxyborazines show similar effects between BN and (O)–CH₃ bands, which is analogous to interference between BN and (N)–CH₃ in N-methylborazines.

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Mit 7 Abbildungen     

Analysis of the Temperature and Composition Dependence of Viscosimetric Properties of 2-Butanone <Emphasis Type="Bold">+</Emphasis> 2-Butanol Solvent Mixtures

Kinematic viscosities were measured for 2-butanone + 2-butanol binary liquid mixtures with a capillary Ubbelohde routine viscometer in the temperature range from 273.15 to 353.15 K at atmospheric pressure, and covering the whole miscibility field (0x_i1). Experimental data have been correlated by means of different empirical or semiempirical relationships, such as =(T), =(x_i), and =(T, x_i). Viscosity deviations, , from ideal behavior are negative at all experimental conditions, confirming that structure breaking effects prevail in the liquids. Furthermore, the thermodynamics of viscous flow and excess Gibbs energy of activation of viscous flow, G*^E, have been calculated. As an alternative and complementary approach to such investigations, the fluidity () of this binary system has been analyzed by the modified—Batschinski theory. The results are discussed in terms of the specific molecular interactions between the mixture components.     

Vibrational isotope effect of linear and planar molecules: Deuterated bromoethenes

Linear (planar) molecules A and B which are identical except for isotopic substitutions at the atomic sites are considered. Stretching (bending, out-of-plane) frequencies _k and normal modes _k of the isotopically perturbed molecule B are expressed in terms of stretching (bending, out-of-plane) frequencies _i and the corresponding normal modes _i of the unperturbed molecule A. Complete specification of the unperturbed normal modes is not required. All that is needed are stretching (bending, out-of-plane) amplitudes | _i of the normal modes _i at those sites that are affected by isotopic substitution. The rule which interlaces frequencies _k of molecule A with frequencies _i of molecule B is derived. Given two isotopic molecules A and B that differ by a single isotopic substitution at site , the inversion relation is derived. This relation expresses unperturbed stretching (bending, out-of-plane) amplitudes at the site in terms of stretching (bending, out-of-plane) frequencies of molecules A and B . As an example, out-of-plane vibrations of deuterated bromoethene were considered. In the simplest method 12 out-of-plane frequencies of four polydeuterated bromoethenes were calculated from 12 out-of-plane frequencies of bromoethene and three monodeuterated bromoethenes. Standard deviation of thus calculated frequencies from experimental frequencies is =2.74 cm^–1. In another method, 15 out-of-plane frequencies of four polydeuterated bromoethenes and selected monodeuterated bromoethene are calculated from 9 out-of-plane frequencies of bromoethene and the remaining two monodeuterated bromoethenes. Depending on which monodeuterated bromoethene is selected (1-, cis- or trans-), standard deviation of thus obtained frequencies from experimental frequencies is 1=2.84 cm^–1, c=2.96 cm^–1 and t=2.72 cm^–1.     

Die PO-Bindung in den Phosphiten von Alkali- und Erdalkalimetallen

Zusammenfassung Auf Grund der Infrarotspektren der Phosphite von sieben Metallen der I. und II. Hauptgruppe des Periodischen Systems wurden die Werte der die PO-Bindung in den untersuchten Phosphiten charakterisierenden Parameter (Aufspaltung der Absorptionsbande der antisymmetrischen Valenzschwingung , Kraftkonstantenk _PO, Bindungslänger _PO und BindungsordnungN _PO) festgestellt. Es zeigte sich, daß die Kationen in der Abhängigkeit von ihrer Größe das Phosphitanion deformieren. Die Deformation des Anions erweist sich am deutlichsten in den Werten . Die Bindungsordnungen zeigen einen bedeutenden Anteil der -Bindungen in der PO-Bindung der untersuchten Phosphite.

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ThePO-bond in alkali metal phosphites and alkaline earth metal phosphites

The IR absorption spectra of seven phosphites of metals of groups I and II of the periodic table were recorded. From the spectra obtained, the values of the parameters characterizing the PO-bond in the compounds studied (splitting of the absorption band of the antisymmetric stretching vibration , force constantk _PO, bond lengthr _PO and bond orderN _PO) were calculated. It was shown that deformation of the phosphite anion by the cations is a function of the size of the latter. The deformation of the anion is revealed most clearly in the values . The values of the bond orderN _PO reveal a substantial degree of -bonding in the PO-bonds of the phosphites studied.

     

Diffuse-Reflectance IR Spectra of Methane Adsorbed on NaZSM-5 and HZSM-5 Zeolites

Diffuse-reflectance IR spectra of methane adsorbed on high-silica NaZSM-5 and HZSM-5 zeolites point to a stronger adsorption of methane on sodium cations than on protons. For the asymmetric stretching vibration ₃, this form of adsorption is characterized by a doublet with band maxima at 2980 and 3010 cm^–1. For the fully symmetric stretching vibration ₁, it is characterized by a singlet with a maximum at 2880 cm^–1. Methane is also adsorbed on NaZSM-5 in a weaker form, which is characterized by absorption bands with maxima at 3002 (₃) and 2887 (₁) cm^–1. The weaker form of methane adsorption on acidic bridging hydroxy groups of HZSM-5 is characterized by absorption bands at 3001 and 2887 cm^–1 (₃ and ₁, respectively). A difference between this form of adsorption and weak adsorption on sodium-exchanged zeolite reveals itself in the somewhat higher intensity of the band at 2887 cm^–1. For methane adsorbed on NaZSM-5, the frequencies of deformational vibrations and a spectrum in the near IR region are obtained for the first time. It was found that the perturbance of adsorbed methane molecules is seen in the spectrum as in the low-frequency shifts of most of the bands that appear due to composite vibrations and overtones and as new adsorption bands that were not observed for gaseous methane.     

Die Phosphor-Wasserstoff-Bindung im Infrarot

Zusammenfassung An 23 primären und sekundären Phosphinen wird die Lage der , - und -PH-Schwingung im Bereich von 2–15 untersucht. Durch Austausch des Wasserstoffs am Phosphor gegen Deuterium, der leicht mit Deuteriumoxyd gelingt, war auch die Untersuchung der PD-Bindung möglich. In Verbindungen vom Typ R₃P·HX wird an Hand des Auftretens einer PH-Bande die kovalente Bindung des Wasserstoffs an den Phosphor und damit die Oniumstruktur dieser Verbindung aufgezeigt.Mit 2 Abbildungen     

Kinetics of triphenylphosphite ozonide consumption in reaction with triphenylphosphite

Kinetic regularities of triphenylphosphite ozonide reaction with triphenylphosphite have been studied at T=–75°C to –40°C. The rate of ozonide consumption is estimated as W=k₁[(C₆H₅O)₃P·O₃]+k₂[(C₆H₅O)₃P·O₃][(C₆H₅O)₃P], where k₁=(2.03±0.39)×10^–5s^–1(–50°C), 1gk₂=(3.82±0.33)–(6.61±0.32)/gq dm³/mol s and =2.303RT kcal/mol.

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–75°C –40°C . : W=k₁[(C₆H₅O)₃P·O₃]+k₂[(C₆H₅O)₃P·O₃][(C₆H₅O)₃P], k₁=(2,03±0,39)·10^–5–1(–50°C); 1g k₂=(3,82±0,33)–(6,61±0,32)/ /·, =2,303·RT /

     

Charge control of phenol complexation with unsaturated compounds containing organosilicon substituents. Thiophene derivatives

The frequency shifts of the O-H stretching modes and the resonance components _R of these shifts in the IR spectra of H-complexes of phenol with thiophene derivatives having organic and organosilicon substituents have been analyzed. Relationship of and _R parameters to values calculated by nonempirical methods that characterize the electronic effect of organic substituents on the effective charges of the thiophene ring atoms has been established. It has been shown that in the complexation of phenol (hard acid) with thiophene derivatives charge control prevails over frontier orbital control. The changes in the effective charges of the thiophene ring atoms due to the effect of organosilicon substituents have been calculated.For the previous publication of this series see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2163–2168, December, 1994.This work was supported by the Russian Foundation for Basic Research, Project No. 93-03-18725.     

Relative enthalpies and related thermodynamic functions of some organic compounds by drop calorimetry

The values of thermodynamic functions of the following eight organic compounds under non-reacting conditions within the temperature range 298.15 – 550 K are given: N,N dimethylformamide, CHO · N(CH₃)₂; 4-nitro-1-chlorobenzene, Cl · C₆H₄ · NO₂; sodiump-nitrophenoxide, NO₂ · C₆H₄ · ONa; 1-methyl-2-pyrrolidone, 4,4-dinitrodiphenyl ether, (NO₂ · C₆H₄)₂O; 4,4-diaminodiphenyl ether, (NH₂ · C₆H₄)₂O; bis-(4-aminophenyl)methane, (NH₂ · C₆H₄)₂CH₂; bis(4-maleic acidimidphenyl)methane, The relative enthalpy was obtained from calorimetric data by drop calorimetry. The heat capacity and relative entropy are functions derived from the foregoing. The equations of the temperature variation of the relative enthalphy were obtained by computer processing of the calorimetric data by the least squares method. The parameters of solid-liquid transitions were determined from the discontinuity of the temperature variation of the relative enthalpy.

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Zusamenfassung Die Werte der thermodynamischen Funktionen folgender 8 organischer Verbindungen werden unter nicht-reagierenden Bedingungen im Temperaturbereich von 298.15 bis 550 K angegeben: Dimethylformamid, CHO · N(CH₃)₂;p-Nitrochlorbenzol, Cl · C₆H₄NO₂; Natrium-p-Nitrophenoxid, NO₂ · C₆H₄ONa; N-Methylpyrrolidon, 4-4-Dinitrodiphenyläther, (NO₂ · C₆H₄)₂O; 4-4-Diaminodiphenyläther, (NH₂C₆H₄)₂O; 4-- 4-Diaminodiphenylmethan, (NH₂ · C₆H₄)₂CH₂; 4-4-bis-Maleinimid-Diphenylmethan, Die relative Enthalpie wird aus kalorimetrischen Daten der Temperaturgefällekalorimetrie erhalten. Die Wärmekapazität und die relative Entropie sind Funktionen der erwähnten Werte. Die Gleichungen der Temperaturänderung der relativen Enthalpie wurden mittels Computerverarbeitung der kalorimetrischen Daten, mit der Methode der kleinsten Quadrate erhalten. Die Parameter der fest-flüssig Übergänge wurden an Hand der Diskontinuität der Temperaturänderung der relativen Enthalpie bestimmt.

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Résumé On donne les valeurs des fonctions thermodynamiques des 8 composés organiques suivants, en conditions non réactionnelles, dans l'intervalle de températures 298.15–550 K: diméthylformamide CHO · N(CH₃)₂,p-nitrochlorobenzène Cl · C₆H₄ · NO₂,p-nitrophé noxysodium NO₂ · C₆H₄ · ONa, N-méthylpyrrolidone dinitrodiphényl-4,4 éther (NO₂ · C₆H₄)₂O, diaminodiphényl-4,4 méthane (NH₂ ·H ₄CH₂, 4-4 bis maléinimide diphénylméthane L'enthalpie relative a été obtenue à partir de données calorimétriques fournies par un calorimètre à chute. La chaleur spécifique et l'entropie relative sont des fonction dérivées de la précédente. Les équations donnant la variation de l'enthalpie relative en fonction de la température sont obtenues par traitement des données calorimétriques sur ordinateur par la méthode des moindres carrés. Les paramètres des transitions solide-liquide ont été déterminés à partir de la discontinuité de la variation de l'enthalpie relative avec la température.

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, 298,15–550 , : — · N(CH₃)₂;- — l · ₆₄ · NO₂.- -NO₂·₆₄·ONa; N-—₃·N··₂·₂₂; 4,4- — (NO₂·₆₄)₂; 4,4- — (NH₂·₆₄)₂; 4,4- — (NH₂·₆₄)₂₂; 4,4-- —(₆₄.N. . :. )₂₂. . , . . - .

     

Frequencies and integral intenstities of the lactone and ester carbonyls of natural guaianolides

The frequencies and integral intensities of the IR bands of the stretching vibrations of lactone and acyclic ester carbonyls at C-8 of ten natural guaianolides and their derivatives, and of three model compounds have been studied. The most probable interpretation of the change in the value of A_C=O and _C=O of the lactone carbonyl have been suggested. In elegin and some of its derivatives, acroptilin, chlorohyssopifolin B, and eleganin, a lowering of the values of A_C=0 and _C=0 in comparison with dihydroelegin, hexahydroelegin, and the hydroxylactone of cynaropicrin is caused by nonvalent interactions of the lactone carbonyl with the -exocyclic double bond. The increase in A_C=O and _C=O in dihydroelegin, hexahydroelegen, and the hydroxylactone of cynaropicrin is due to the angular strain of the -lactone ring. It has been shown that in an acyclic side chain at C-8 an increase in the integral intensity and in the frequency of the ,-unsaturated ester carbonyl relative to guaianolides in which the terminal vinyl group at C-17 is absent is due to a conjugation effect.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 805–811, November–December, 1987.     

IR Spectroscopic Study of Alkane Interaction with the Brønsted Acid Sites of Hydrogen-Exchanged Zeolites

Diffuse-reflectance IR spectroscopy is used to study the interaction of C₃ and C₆ alkanes (propane, n-hexane, 3-methylpentane, and cyclohexane) with the Brønsted acid sites of hydrogen-exchanged mordenite, ferrierite, ZSM-5, and faujasite. It is found that a shift of the absorption band of the stretching vibrations of acidic Si(OH)Al groups toward lower frequencies (OH) due to the formation of a hydrogen bond with adsorbed alkanes increases in the following series: OH(propane) < OH(n-hexane) = OH(3-methylpentane). The accessibility of Si(OH)Al groups to alkane molecules is determined by the dimension of rings through which molecules enter zeolite channels and cavities. It follows from the measured OH values that the strength of Brønsted acid sites decreases in the following series: HZSM-5 > H-mordenite H-ferrierite HY. The difference between the three high-silica zeolites is not great. The results obtained are compared with the published IR data on Si(OH)Al groups of zeolites with adsorbed alkanes and other weak bases.     

Capacité calorifique molaire du composé Bi.4 Te.6 dans les états solide et liquide

The heat capacities of Bi.4Te. 6 in the solid and liquid states are calculated from the results of the experimental drop calorimetric method, and the heat of fusion of the compound is deduced.

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Zusammenfassung Die Wärmekapazitäten von Bi.4Te. 6 in fester und flüssiger Phase werden aus experimentellen Daten berechnet, die mit der tropfenkalorimetrischen Methode erhalten wurden. Die Schmelzwärme der Verbindung wird abgeleitet.

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« » Bi₄Te₆ , .