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.

---

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.

---

---

Mit 7 Abbildungen     

IR-Untersuchungen an B-Tris (dimethylamino) boroxin und B-Tris[dimethylamino (d6)] boroxin

Zusammenfassung In B-Tri(dimethylamino)boroxin zeigt — im Gegensatz zum B-Trimethoxyboroxin — die B–O-Hauptbande nur geringe Kopplung mit CH₃-Deformationsschwingungen. Die B–N-Valenzbande tritt hingegen mit _sCH₃ in Wechselwirkung, wodurch Banden mit gemischtem Schwingungscharakter entstehen. In der deuterierten Verbindung liegt BN verkoppelt mit BO bei 1461 cm^–1

---

In B-Tri(dimethylamino)boroxin coupling between the B–O ring stretching main-band and CH₃ is weak in contrast to B-trimethoxyboroxine. Interference between BN and CH₃ leads to bands of mixed character, one of them is above 1500 cm^–1. In [(CD₃)₂NBO] BN coupled with BO is at 1461 cm^–1.

---

---

Mit 2 Abbildungen     

Absorption spectra and bond type in Co(II) aquoamino complexes

Absorption spectra are reported for solutions containing Co(II) and ammonia. Spectra are calculated for five Co(II) aquoamino complexes. The spectra are used to determine Dq and B, parameters of the bonds in these compounds. It is found that Dq and B change nonlinearly and nonadditively. The parameters _c, Dt, Ds, and have also been established for [Co(H₂O)₆]²⁺ and [Co(NH₃)₆]²⁺. The parameter variation can be explained if the H₂O molecules form weaker bonds to the central atom than do the NH₃ molecules, but are capable of d-p interaction.     

Kinetics of acyl exchange of series of N- and O-acyl salts with 4-(p-dimethylamino)styrylpyridine-N-oxide

A study has been mode of the reaction of acyl exchange between a series of N- or O-acyl salts and 4-(p-dimethylamino)styrylpyridine-N-oxide in acetonitrile solution. Values of the rate constant (k₂) and activation characteristics (E_a, G, S, and H) have been obtained for these systems.Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 31, No. 2, pp. 86–89, March–April, 1995.This work was performed with financial support from the State Committee of the Ukraine for Matters of Science and Technology.     

The influence of pentaamminerhodium(III) on the1H n.m.r. spectra and pyrrole pKas of coordinated imidazoles and pyrazoles

Summary The following [(NH₃)₅RhLH]Cl₃ salts were preparedvia the [(NH₃)₅Rh(O₃SCF₃)](O₃SCF₃)₂ synthetic route; LH=1-methylimidazole (1CH₃imH), 2-methylimidazole (2CH₃imH), 4-methylimidazole (4CH₃imH), 5-methylimidazole(5CH₃imH), and pyrazole (pyzH). pK_a's at 25.0°C were determined for [(NH₃)₅RhLH]³⁺ complexes as follows: 2CH₃imH, 10.4±0.1; 5CH₃imH/4CH₃imH isomer mixture, 10.3±0.1; pyzH, 6.54±0.05. The influence on the pK_a's of imidazoles is dominated by withdrawal of the rhodium(III) centre and may be compensated by the presence of ring methylation by only 0.5log units for cobalt(III) and rhodium(III) derivatives, compared to 1.3 units for the -withdrawing ruthenium(III) centre. In the case of the -acceptor pyrazole ring, [(NH₃)₅Rh]³⁺ is observed to serve as a slight -donor and raises the pK_a above the cobalt(III) analogue. The¹H n.m.r. spectra of [(NH₃)₅RhLH]³⁺ complexes of the substituted imidazoles and pyrazole exhibit a deshielding order. C–2H>C–5H>C–4H for imidazoles and C–3H>C–5H>C–4H for pyrazole, as do their cobalt(III) analogues. The magnitude of values (=_{free L}-_complex) are virtually the same as in the cobalt(III) systems which shows that TIP influences are unimportant compared to ring rehybridization in estabilishing chemical shifts for both the cobalt(III) and rhodium(III) complexes. The imidazolato and pyrazolato complexes exhibit resonances upfield of the respective substituted imidazole or pyrazole complex in keeping with more negative charge on the rings; the influence is largest at C–2H of imidazolates and C–3H of pyrazolate.     

Complex formation constants and thermodynamic parameters for La(III) and Y(III)L-serine complexes

Summary The stoichiometric stability constants for La(III) and Y(III)L-serine complexes were determined by potentiometric methods at different ionic strengths adjusted with NaClO₄ and at different temperatures. The overall changes in free energy (G ^o), enthalpy (H ^o), and entropy (S ^o) during the protonation ofL-serine and that accompanying the complex formation with the metal ions have been evaluated.

---

Komplexbildungskonstanten und thermodynamische Parameter für La(III)- und Y(III)-L-Serin-Komplexe

Zusammenfassung Die stöchiometrischen Komplexbildungskonstanten für La(III)- und Y(III)-L-Serin-Komplexe wurden mittels potentiometrischer Methoden bei verschiedenen Ionenstärken (mit NaClO₄ adjustiert) und bei verschiedenen Temperaturen bestimmt. Die Änderungen in der freien Energie (G ^o), Enthalpie (H ^o) und Entropie (S ^o) während der Protonierung und der Komplexbildung mit den Metallionen wurden ermittelt.

     

Synthesis and structure of 1-benzoyl-2,5-dimethyl- and 1,2,5-trimethyl-4-arylpiperideins

Isomeric 1-benzoyl-2,5-dimethyl-³-piperidein and 1-benzoyl-2,5-dimethyl-⁴-piperidein were prepared from disubstituted -piperidols and were hydroxylated with osmium tetroxide. The isomeric 1,2,5-trimethyl-4-(p-nitrophenyl)-³- and-⁴-piperideins were obtained from trisubstituted -piperidols.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1200–1206, September, 1986.In conclusion, the authors would like to thank Yu. T. Struchkov and N. I. Lebedev for carrying out the x-ray structural study.     

Kinetics of the Ru(III) catalyzed oxidation of formaldehyde and acetaldehyde by alkaline hexacyanoferrate(III)

The kinetics of ruthenium(III) catalyzed oxidation of formaldehyde and acetaldehyde by alkaline hexacyanoferrate(III) has been studied spectrophotometrically. The rate of oxidation of formaldehyde is directly proportional to [Fe(CN) _3– ⁶ ] while that of acetaldehyde is proportional tok[Fe(CN) _3– ⁶ ]/{k +k[Fe(CN) _3– ⁶ ]}, wherek, k andk are rate constants. The order of reaction in acetylaldehyde is unity while that in formaldehyde falls from 1 to 0. The rate of reaction is proportional to [Ru(III)] _T in each case. A suitable mechanism is proposed and discussed.

---

Die Kinetik der Ru(III)-katalysierten Oxidation von Formaldehyd und Acetaldehyd mittels alkalischem Hexacyanoferrat(III)

Zusammenfassung Die Untersuchung der Kinetik erfolgte spektrophotometrisch. Die Geschwindigkeitskonstante der Oxidation von Formaldehyd ist direkt proportional zu [Fe(CN) _3– ⁶ ], währenddessen die entsprechende Konstante für Acetaldehyd proportional zuk[Fe(CN) _3– ⁶ ]/{k +k[Fe(CN) _3– ⁶ ]} ist, wobeik,k undk Geschwindigkeitskonstanten sind. Die Reaktionsordnung für Acetaldehyd ist eine erste, die für Formaldehyd fällt von erster bis zu nullter Ordnung. Die Geschwindigkeitskonstante ist in jedem Fall proportional zu [Ru(III)] _T . Es wird ein passender Mechanismus vorgeschlagen.

     

Reactivity of oxalates of La(III), Ba(II) and Cu(II) in ternary mixtures

Composites of cuprates of La(III) and Ba(II) were obtained by decomposing mixtures of oxalates of La(III), Ba(II) and Cu(II) prepared in 111 and 123 mol proportions respectively and sintering the oxide products at 1173 K. Reactions studied by TG, DTA and XRD techniques revealed the following features: (i) Decomposition of oxalates of La(III) and Ba(II) is drastically affected in mixtures. Decomposition temperature of organic part in the former (111) is shifted by 100 K while that of BaCO₃ in the case of latter (123) is shifted by 400 K towards lower temperature side. (ii) All exothermic peaks on DTA traces of both the mixtures are allotted to the decomposition of oxalates to Cu₂O, La₂O₂CO₃ and BaCO₃ phases while endothermic peaks around 863 and 1083 K are assigned for BaCuO₂ and La₂CuO₄ phases respectively in the case of former (111) and endothermic peaks at about 1068, 1136 and 1213 K are correlated with BaCuO₂, a composite of La₂O₃, La₂CuO₄ and La_0.5Ba_0.5CuO_3– (0.5) phases and LaBa₂Cu₃O_7– (0) phase respectively in the case of latter (123) and (iii) Lines of all cuprate compounds appear in XRD patterns of those samples preheated at temperatures 873 K. The following reaction is proposed in the case of 123 mixture: Authors are deeply thankful to the Authorities of Department of Atomic Energy (DAE), Goverment of India, for providing the funds for research project and to Professor A. V. Phadke, Department of Geology, University of Poona, for the valuable discussion.     

Conductance of iron(III) laurate solutions in binary liquid mixtures

Summary The specific conductivity of iron(III) laurate solutions in binary liquid mixtures shows that the soap aggregates into micelles and CMC is found to be independent of temperature and concentration of benzene, acetone and tetrachloromethane in 1-butanol. The variation of molecular conductance,, with soap concentration, C, is expressed by the equation: = 10^AC^B. Both constants A and B vary with solvent composition but B remains constant with increase in temperature. Several parameters such as molecular conductance at infinite dilution, , dissociation constant, K, heat of dissociation, H, entropy, S and free energy, G of dissociation of soap have been evaluated and the effect of the nature of solvents has been discussed.     

Thermal plasma synthesis of transition metal nitrides and alloys

Applications of arc plasma processing to high-temperature chemistry of Group V nitrides and Si and Ge alloys are studied. The transition metal nitrides -VN, -NbN, and -TaN are directly synthesized in a dc argon-nitrogen plasma from powders of the metals. A large excess of N₂ is required to form stoichiometric -VN, while the Nb and Ta can only be synthesized with a substoichiometric N content. In a dc argon plasma the alloys V₃Si, VSi₂, NbSi₂, NbGe₂, Cr₃Si, and Mo₃Si are obtained from powder mixtures of the corresponding elements. The compounds are identified by x-ray diffraction patterns and particle shape and size are studied by electron microscopy.     

Rate constant of unimolecular decomposition of the radical (CH3)2juvyCCH(CH3)2

The energy of activation of CH ₃ ^. radical rupture from the radical (CH₃)₂juvyCCH(CH₃)₂ is 142.2 kJ mol^–1; the selfcombination rate constant is k_c {(CH₃)₂juvyCCH(CH₃)₂}=10^7.3 dm³ mol^–1 s^–1.

---

CH ₃ ^. (CH₃)₂juvyCCH(CH₃)₂ 142,2 /, k_c {(CH₃)₂juvyCCH(CH₃)₂}=10^{7,3 3–1 –1}.

     

The phenomenon of conglomerate crystallization: XXXVII: The crystallization behavior of the Cr(III) and Co(III) amine carbonates [Cr(en)2CO3]I (I) and NH4{[cis-β-Co(trien)Co3]2}(PF6)3 (II)

[Cr(en)₂CO₃]I (I), ICoO₃N₄C₅H₁₆, crystallizes from water at 21°C in space groupP2₁/c (no. 14), with lattice constantsa=7.298(4),b=8.622(8),c=17.577(6)Å,=91.29(4)°;V=1105.59 ų andd(calc; MW=359.11, Z=4)=2.157 g cm^–3. A total of 2825 data points were collected over the range of 4°250°; of these, 1855 (independent and withI3(I)) were used in the structural analysis. Data were corrected for absorption (=37.657 cm^–1) and the transmission coefficients ranged from 0.4850 to 0.9991. The finalR(F) andR _w(F) residuals were, respectively 0.134 and 0.113. The cations exist in the lattice as the enantiomeric pair () and (). NH₄{[cis--Co(trien)CO₃]₂}(PF₆)₃ (II), Co₂P₃F₁₈O₆N₉C₁₄H₄₀, crystallizes from water at 21 °C in space groupP2₁/c (no. 14), with lattice constantsa=10.397(2),b=20.292(3),c= 27.082(4) Å,=100.30(3)°;V=3545.70 ų andd(calc; MW=983.29, Z=4)=1.842 g cm^–3. A total of 3724 data were collected over the range of 4°250°; of these, 2653 (independent and withI3(I)) were used in the structural analysis. Data were corrected for absorption (=12.031 cm^–1) and the transmission coefficients ranged from 0.8326 to 0.99985. The finalR(F) andR _w (F) residuals were, respectively 0.104 and 0.124. The cations exist in the asymmetric unit as() and()[cis--Co(trien)CO₃]⁺ pairs. The three independent PF₆ ^– anions exhibit the usual high thermal motion typical of these species and the NH₄ ⁺ cation is either disordered or exhibits high thermal motion also (its H atoms could not be found in difference maps).     

Temperature dependence of the volumetric properties of binary mixtures containing oxaalkane +n-heptane

Excess molar volumes of mixtures of n-heptane + 2,5-dioxahexane and n-heptane + 2,5,8-trioxanonane were determined from density measurentents at 5, 15, 25 and 35°C. These results allowed the following mixing quantities to be reported in all range of concentrations: , (v ^E /T) _P and (h ^E /P) _T , at 25°C. The obtained values were then compared with the calculated values by using the Flory theory and the Nitta-Chao theory of liquid mixtures. The results are discussed in terms of order or disorder creation.     

Synthesis of ferricinium bis[π-(3)-1,2-dicarbollyl]cobaltate(iii), [FeIII(η5-Cp)2]+{CoIII[π-(3)-1,2-B9C2H11]2}−

Ferricinium bis[-(3)-1,2-dicarbollyl]cobaltate(III), [Fe^III(⁵--Cp)₂]⁺{Co^III[-(3)-1,2-B₉C₂H₁₁]₂}^–, has been prepared by the reaction of Fe^III(⁵--Cp)₂]⁺ with the anion {Co^III[-(3)-1,2-B₉C₂H₁₁]₂}^–. It is a light-green amorphous precipitate that is stable as a dry solid up to 227 °C and unstable in solutions of acetonitrile and acetone.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No, 10, pp. 1810–1811, October, 1994.This work was supported by the Russian Foundation for Basic Research (Project No 93-03-5987).     

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.

---

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.

---

---

Mit 2 Abbildungen     

A simplified View of δ → δ* Transition Energies in Compounds with multiple metal-metal bonds: The isolated δ — δ* manifold model

The energetics of the * transition in quadruply bonded complexes are investigated using a very simple valence-bond formalism, called the isolated * manifold (IDDM) model. In this model all electrons except for those that occupy the or * molecular orbitals are ignored, as are explicit metal-ligand interactions. The resulting equations allow the calculation of transition energies very inexpensively, albeit with poor quantitative agreement: the * transition in prototypical quadruple-bond systems is predicted to occur at energies greater than 70,000 cm¹. The model incorporates configuration interaction between the two¹ A _1g configurations (|| and |**|) to roughly the same extent as do correlated all-electron calculations. The application of the method to systems that involve relative changes in * transition energies, such as the torsional twisting of quadruple bonds, is more successful quantitatively.     

Magnetische Untersuchungen an Komplexen von La(III), Pr(III) und Nd(III) mitSchiffschen Basen

Specific magnetic susceptibilities (_s) of several newly synthesized chelates of some of the lanthanons [La(III), Pr(III) and Nd(III)] are reported. These derivatives are of the general type,Ln(O-i-C₃H₇)_3–n (C₆H₅CHNRO) _n [where,Ln=La(III), Pr(III) or Nd(III);n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄] and have been prepared by the reaction of the alkoxides of the lanthanons withSchiff bases such as benzylidene-2-hydroxyethylamine (C₆H₅CHNCH₂CH₂OH), benzylidene-2-hydroxy-n-propylamine (C₆H₅CHNCH₂CHOHCH₃) and benzylidene-o-aminophenol (C₆H₅CHNC₆H₄OH) in different molar relations in dry benzene.The resulting crystalline derivatives are non-volatile, light to deep yellow or blackish in colour. These tend to polymerize on keeping as shown by their insoluble nature and higher melting points, the polymerisation possibly occurring by the intermolecular coordination through oxygen atoms as reported earlier¹.UsingGouy method², the bis-isopropoxy mono-Schiff base and mono-isopropoxy bis-Schiff base complexes of La(III) have been shown to be diamagnetic, with _s values being in the range of –0.32 to –0.45×10^–6 and –0.39 to –0.55×10^–6 c.g.s. units at 305 K respectively.In the remaining derivatives, Pr(O-i-C₃H₇)_3–n (C₆H₅CH NRO) _n and Nd(O-i-C₃H₇)_3–n (C₆H₅CHNRO) _n (where,n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄) the magnetic moment values range between 3.25 to 3.32 and 3.30 to 3.33 _B respectively indicating their paramagnetic nature.     

Configuration of benzoylpyridineoximes studied by 1H and 13C NMR. Effect of protonation of the pyridine nitrogen atom

A simple and convenient method is proposed for determining the configuration of E,Z-isomers of 2-, 3-, and 4-benzoylpyridines. The difference in chemical shifts (, ppm) in the system CCl₄-DMSO-D₆ and CCl₄-DMSO-CF₃COOD for the -H atoms or the , -C atoms of the pyridine ring can be used to determine the configuration. The shift () of the -H signals to weak field is greater for the Z-isomers than for the E-isomers due to protonation of the pyridine nitrogen atom. The reverse dependence is seen in the ¹³C NMR for the E,Z-isomers. The signals of the -C atoms shift to stronger field after protonation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1073–1077, August, 1990.     

Kernquadrupolkopplung in einigen Kobalt(III)-komplexen

Zusammenfassung Aus Messungen der magnetischen Kernresonanz (MKR) an Einkristallen von [Co (NH₃)₅ H₂O] (ClO₄)₃ (I) und NH₄ [Co (NO₂)₄ (NH₃)₂] (II) wurden die Quadrupolkopplungskonstanten e ² Qq/h von Co⁵⁹ gewonnen. Ferner wurden die Linienbreiten der MKR in wÄ\rigen Lösungen von I, II und trans-[Co en₂Cl₂] Cl (III) gemessen.Aus e ² Qq/h und wurden nach der Theorie der Quadrupolrelaxation in Flüssigkeiten die Korrelationszeiten _cder Komplexionen bestimmt. Diese wiederum wurden zusammen mit den ebenfalls gemessenen Linienbreiten der MKR von N¹⁴ in wÄ\rigen Lösungen von I, II und III benutzt, um e ² Qq/h von N¹⁴ zu erhalten.Darüber hinaus wurden mittels geschÄtzter Korrelationszeiten und gemessener Linienbreiten der MKR von Co⁵⁹ und N¹⁴ für eine grö\ere Zahl von Co(III)-Komplexen NÄherungswerte von e ² Qq/h erhalten. Auf Grund dieser Werte wird die Elektronenstruktur der Komplexionen diskutiert.Die chemischen Verschiebungen der untersuchten Kernresonanzlinien werden angegeben. In einem Einkristall von I wurde die Anisotropie der chemischen Verschiebung bestimmt.

---

Nuclear quadrupole coupling constants e ² Qq/h of Co⁵⁹ resulted from nuclear magnetic resonance (NMR) measurements on single crystals of [Co (NH₃)⁵ H₂O] (ClO₄)₃ (I) and NH₄ [Co (NO₂)₄ (NH₃)₂] (II). NMR line-widths were measured in aq. solutions of I, II, and trans-[Co en₂Cl₂] Cl (III). The correlation times _c of the complex ions resulted from e ² Qq/h and with the theory of quadrupole relaxation in liquids. These _c-values were used to obtain e ²Qq/h of N¹⁴ from NMR ine-width measurements of N¹⁴ in aq. solutions of I, II, and III.Approximate values for e ²Qq/h were obtained from NMR line-width measurements of Co⁵⁹ and N¹⁴ in a number of Co(III)-complexes with estimated correlation times. The electronic structure of the complex ions is discussed on the basis of the e ² Qq/h-values.The measured chemical shifts of the NMR-lines are listed. In a single crystal of I the anisotropy of chemical shift has been determined.

---

Résumé Les constantes de couplage quadripolaire e ² Qq/h du ⁵⁹Co ont été tirées des mesures de la résonance nucléaire magnétique de monocristaux de [Co (NH₃)₅ H₂O] (ClO₄)₃ (I) et NH₄ [Co (NO₂)₄ (NH₃)₂] (II). En outre, la largeur des raies a été mesurée dans les solutions aqueuses de I, II et trans-[Co en₂ Cl₂] Cl (III).Les périodes de corrélation _c en ont été déduites d'après la théorie de la relaxation quadripolaire dans les liquides. Des _cet des du ¹⁴N, mesurés dans les solutions de I, II et III, on calcule e ² Qq/h pour ¹⁴N.Des _cestimés et de ⁵⁹Co et ¹⁴N mesurés pour plusieurs complexes du Co³⁺ s'obtiennent des valeurs approximatives de e ² Qq/h. Sur base de ces valeurs la structure électronique des ions complexes est discutée.Les déplacements chimiques (chemical shift) des raies de résonance examinées sont données. L'anisotropie du déplacement dans un monocristal de I a été déterminée.

---

---

Herrn Professor Dr. P. Royen zum 60. Geburtstag gewidmet.