Die Akzeptoreigenschaften von AsCl3, AsBr3, asJ3, SbCl3, SbBr3 und SbJ3

Zusammenfassung Es wurden die Enthalpien der Reaktionen von AsCl₃, AsBr₃, AsJ₃, SbCl₃, SbBr₃ und SbJ₃ mit Tributylphosphat, N,N-Dimethylacetamid und Hexamethylphosphorsäuretriamid bestimmt. Das Verhalten der Addukte bei Gegenwart eines Überschusses der Donoren wird beschrieben.

---

Acceptor properties of AsCl₃, AsBr₃, AsI₃, SbCl₃, SbBr₃, and SbI₃

The enthalpies of the reactions of AsCl₃, AsBr₃, AsI₃, SbCl₃, SbBr₃ and SbI₃ with tributylphosphate, N,N-dimethylacetamide and hexamethylphosphoric acid triamide were measured. The behavior of the adducts in the presence of excess donor molecules is described.

---

---

Mit 5 Abbildungen     

An improved synthesis of 3-deazaeytosine, 3-deazauracil, 3-deazacytidine,and 3-deazauridine

3-Dcazacytosine (4-amino-2-pyridone, 3 ), 3-doazauracil (4-hydroxy-2-pyridone, 5 ), 3-deaza-cytidine (4-amino-1-β-D-ribofuranosyl-2-pyridonc, 9 ), and 3-deazauridine (4-hydroxy-1-β-D-ribo-furanosyl-2-pyridone, 11 ) were prepared in high overall yields from 1-methoxy-1-buten-3-yne ( 1 ). Ethyl 3,5,5-triethoxy-3-pentenoate ( 2 ), obtained from acylatioti of 1 with diethyl carbonate and subsequent in situ conjugate addition of ethoxide, was cyelized with ammonia to provide 3 . Diazotization of 3 and subsequent in situ hydroxydediazotization afforded 5 . Nucleoside 9 was obtained from the stannic chloride-catalyzed condensation of bis-trimethylsilylated 3 and 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose ( 7 ), followed by ammonolysis of the blocking groups. Diazotization of 9 and subsequent in situ hydroxydediazotization afforded nucleosidc 11 .     

Intermolecular vibrational spectra of C3v CXY3 Molecular Liquids, CHCl3, CHBr3, CFBr3, and CBrCl3

We report the quality anisotropic intermolecular vibrational spectra within the frequency range 0.5-800 cm(-1) of four C(3v) CXY(3) molecular liquids, CHCl(3), CHBr(3), CFBr(3), and CBrCl(3), by means of femtosecond optical-heterodyne-detected Raman-induced Kerr effect spectroscopy. The results show that the first moment of the intermolecular vibrational spectrum is proportional to the square root of the value of the surface tension divided by the liquid density. This implies that the intermolecular vibrational spectrum reflects the bulk properties of the liquids. To understand the molecular-level aspects of the intermolecular vibrational spectra of the liquids, the spectra are compared with the molecular properties such as molecular weight, rotational constants, and bimolecular interaction energy. Overall, the first moment of the spectrum moderately correlates to the inverse square roots of both the molecular weight and the fast rotational constant. Therefore, the molecular properties are responsible for the intermolecular vibrational spectrum. Plots of the first moment of the intermolecular vibrational spectrum vs the square root of the value of the simple bimolecular interaction energy divided by the molecular surface area and the molecular weight show a linear correlation in the case of the oblate symmetric top molecular liquids, CHCl(3), CHBr(3), and CFBr(3). However, CBrCl(3), which is a prolate symmetric top molecular liquid, does not show the same correlation for the oblate molecular liquids.     

Syntheses and Crystal Structures of BaAgTbS3, BaCuGdTe3, BaCuTbTe3, BaAgTbTe3, and CsAgUTe3

Five new quaternary chalcogenides of the 1113 family, namely BaAgTbS₃, BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and CsAgUTe₃, were synthesized by the reactions of the elements at 1173–1273 K. For CsAgUTe₃ CsCl flux was used. Their crystal structures were determined by single‐crystal X‐ray diffraction studies. The sulfide BaAgTbS₃ crystallizes in the BaAgErS₃ structure type in the monoclinic space group C³,_2h‐C2/m, whereas the tellurides BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and CsAgUTe₃ crystallize in the KCuZrS₃ structure type in the orthorhombic space group D¹_,2⁷_,h‐Cmcm. The BaAgTbS₃ structure consists of edge‐sharing [TbS₆^9–] octahedra and [AgS₅^9–] trigonal pyramids. The connectivity of these polyhedra creates channels that are occupied by Ba atoms. The telluride structure features ²_∞[MLnTe₃^2–] layers for BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and ²_∞[AgUTe₃^1–] layers for CsAgUTe₃. These layers comprise [MTe₄] tetrahedra and [LnTe₆] or [UTe₆] octahedra. Ba or Cs atoms separate these layers. As there are no short Q ··· Q (Q = S or Te) interactions these compounds achieve charge balance as Ba²⁺M⁺Ln³⁺(Q^2–)₃ (Q = S and Te) and Cs⁺Ag⁺U⁴⁺(Te^2–)₃.     

Analysis of the intermolecular interactions between CH3OCH3, CF3OCH3, CF3OCF3, and CH2F2, CHF3

The intermolecular interaction energy curves of CH(3)OCH(3)-CH(2)F(2), CF(3)OCH(3)-CH(2)F(2), CF(3)OCF(3)-CH(2)F(2), CH(3)OCH(3)-CHF(3), CF(3)OCH(3)-CHF(3), and CF(3)OCF(3)-CHF(3) complexes were calculated by the MP2 level ab initio molecular orbital method using the 6-311G** basis set augmented with diffuse polarization functions. We investigate the fluorine substitution effects of both methane and dimethyl ether on intermolecular interactions. In addition, orientation dependence of intermolecular interaction energies is also studied with utilizing eight types of orientations. Our analyses demonstrate that partial fluorinations of methane make electrostatic interaction dominant, and consequently enhance attractive interaction at several specific orientations. On the contrary, fluorine substitutions of dimethyl ether substantially decrease the electrostatic interaction between ether and CH(2)F(2) or CHF(3); thus, there is no such characteristic interaction between the C-H of fluorinated methane and ether oxygen of CF(3)OCF(3) as conventional hydrogen bonding, due to reduced polarity of fluorinated ether. The combination of different pairs of the electrostatic interaction is therefore responsible for the intermolecular interaction differences among the complexes investigated herein and also their orientations.     

Structural, energetic, electronic, bonding, and vibrational properties of Ga3O, Ga3O2, Ga3O3, Ga2O3, and GaO3 clusters

The results of density functional theory based calculations on Ga3O, Ga3O2, Ga3O3, Ga2O3, and GaO3 clusters are reported here. A preference for planar arrangement of the constituent atoms maximizing the ionic interactions is found in the ground state of the clusters considered. The sequential oxidation of the metal-excess clusters increases the binding energy, but the sequential removal of a metal atom from the oxygen-excess clusters decreases the binding energy. The increase in the oxygen to metal ratio in these clusters is accompanied by increase in both electron affinity and ionization potential. The ionization induced structural distortions in the neutral clusters are relatively small, except those for Ga3O2. In anionic (cationic) clusters, the added (ionized) electron is shared by the Ga atoms, except in the case of GaO3. The vibrational frequencies and charge density analysis reveal the importance of the ionic Ga-O bond in stabilizing the gallium oxide clusters considered in this study.     

3, 3, 3-Trifluoropropyl(methyl)cyclosiloxanes

The influence of the number of 3, 3, 3-trifluoropropyl(methyl)siloxane links (Φ/Φ) in the cyclotetrasiloxanes Φ_mD_4-m, where D represents the dimethylsiloxane link and m=0–4, on the rearrangement of these compounds in acetone solution under the action of sodium siloxanolate has been studied. The rearrangement takes place with the formation of a linear polysiloxane the degradation of which yields, in addition to the initial ring, cyclosiloxanes with a different structure. The rate of rearrangement of Φ_mD_4-m and of the formation of a linear polysiloxane rises with an increase in m from 0 to 3. The equilibrium concentration of the linear polysiloxane formed from Φ_mD_4-m is inversely proportional to m. Results have been obtained on the kinetics of the formation of the cyclosiloxanes Φ_mD_n, where m=0–5, n=0–5, and m+n=3–6, in the rearrangement of the rings ΦD₃, Φ₂D₂, Φ₃D, and Φ₄. The reactivity of the siloxane links rises in the sequence ～ (CH₃)₂Si-O-Si(CH₃)₂ ～<～ (CF₃CH₂CH₂)-(CH₃) Si-O-Si(CH₃)₂ ～<(CF₃CH₂CH₂) (CH₃)Si-O-Si(CH₃) (CH₂CH₂CF₃) ～. Because of the negative inductive effect transferred through the siloxane links, the 3, 3, 3-trifluoropropyl groups strongly activate the siloxane ring with respect to nucleophiiic reagents.     

New layered materials: syntheses, structures, and optical and magnetic properties of CsGdZnSe3, CsZrCuSe3, CsUCuSe3, and BaGdCuSe3

Four new quaternary selenides CsGdZnSe3, CsZrCuSe3, CsUCuSe3, and BaGdCuSe3 have been synthesized with the use of traditional high-temperature solid-state experimental methods. These compounds are isostructural with KZrCuS3, crystallizing with four formula units in the orthorhombic space group Cmcm. Cell constants (A) at 153 K are CsGdZnSe3 4.1684(7), 15.765(3), 11.0089(18); CsZrCuSe3 3.903(2), 15.841(10), 10.215(6); CsUCuSe3 4.1443(7), 15.786(3), 10.7188(18); and BaGdCuSe3 4.1839(6), 13.8935(19), 10.6692(15). The structure of these ALnMSe3 compounds (A = Cs, Ba; Ln = Zr, Gd, U; M = Cu, Zn) is composed of 2 to infinity [LnMSe3(n-)] (n = 1, 2) layers separated by A atoms. The Ln atom is octahedrally coordinated to six Se atoms, the M atom is tetrahedrally coordinated to four Se atoms, and the A atom is coordinated to a bicapped trigonal prism of eight Se atoms. Because there are no Se-Se bonds in the structure, the oxidation state of A is 1+ (Cs) or 2+ (Ba), that of Ln is 3+ (Gd) or 4+ (Zr, U), and that of M is 1+ (Cu) or 2+ (Zn). CsGdZnSe3 and BaGdCuSe3, which are paramagnetic, obey the Curie-Weiss law and have effective magnetic moments of 7.87(6) and 7.85(5) muB for Gd(3+), in good agreement with the theoretical value of 7.94 muB. Optical transitions at 1.88 and 2.92 eV for CsGdZnSe3 and 1.96 eV for BaGdCuSe3 were deduced from diffuse reflectance spectra.     

3, 3, 3-Trifluoropropyl(methyl)cyclosiloxanes

The influence of the number of 3, 3, 3-trifluoropropyl(methyl)siloxane links (/) in the cyclotetrasiloxanes _mD_4-m, where D represents the dimethylsiloxane link and m=0–4, on the rearrangement of these compounds in acetone solution under the action of sodium siloxanolate has been studied. The rearrangement takes place with the formation of a linear polysiloxane the degradation of which yields, in addition to the initial ring, cyclosiloxanes with a different structure. The rate of rearrangement of _mD_4-m and of the formation of a linear polysiloxane rises with an increase in m from 0 to 3. The equilibrium concentration of the linear polysiloxane formed from _mD_4-m is inversely proportional to m. Results have been obtained on the kinetics of the formation of the cyclosiloxanes _mD_n, where m=0–5, n=0–5, and m+n=3–6, in the rearrangement of the rings D₃, ₂D₂, ₃D, and ₄. The reactivity of the siloxane links rises in the sequence (CH₃)₂Si-O-Si(CH₃)₂ < (CF₃CH₂CH₂)-(CH₃) Si-O-Si(CH₃)₂ <(CF₃CH₂CH₂) (CH₃)Si-O-Si(CH₃) (CH₂CH₂CF₃) . Because of the negative inductive effect transferred through the siloxane links, the 3, 3, 3-trifluoropropyl groups strongly activate the siloxane ring with respect to nucleophiiic reagents.For part I, see [3].     

Low-temperature heat capacity studies on DyFe3, DyCo3, DyNi3, and LaNi3

Low-temperature heat capacity measurements were made on DyFe₃, DyCo₃, DyNi₃, and LaNi₃ over the temperature range 1.4–15°K. Two anomalies, observed at 1.8 and 9.3°K, are ascribed to the presence of an oxide and a hydride. Another anomaly exists at 3.2°K, which may be due to hydroxide. The observed electronic specific heat coefficients are interpreted in terms of the band structure of these materials.     

3, 6-二取代-均三唑并[3, 4-b]-1, 3, 4-噻二唑的合成

研究了2-苯基-1, 2, 3-三唑-4-羧酸(1)与3-烷基/芳基-4-氨基-5-巯基-1, 2, 4-三唑(2a～o)在POCl~3催化下, 脱水缩合得到15个新的3-烷基/芳基-6-(2'-苯基-1', 2', 3'-三唑-4'-基)均三唑并[3,4-b]-1, 3, 4-噻二唑类化合物(3a～o)。     

3, 3, 3-Trifluoropropyl(methyl)cyclosiloxanes

The catalytic rearrangement of the cyclopentasiloxanes Φ_mD_5-m, where Φ represents a 3, 3, 3-trifluoropropyl(methyl)siloxane link and D a dimethylsiloxane link, and m=2–5 has been studied by the method described previously [1]. The rate of rearrangement and the rate of formation of a linear polysiloxane rise with an increase in m from 2 to 4. The equilibrium concentration of the linear polysiloxane formed from Φ_mD_5-m and from Φ_mD_4-m (m=0–4) [1] is inversely proportional to the molar fraction of Φ links in the ring and rises with an increase in the total concentration of siloxane links in solution. Results have been obtained on the kinetics of the formation of the cyclosiloxanes Φ_mD_n (where m=0–5, n=0–5, and m+n=3-6) during the rearrangement of the cyclopentasiloxanes Φ_mD_5-m. It has been established that at equilibrium a mixture of cyclosiloxanes Φ_mD_n containing practically constant ratios of tetramers, pentamers, and hexamers (m+n=4, 5, and 6) is obtained, regardless of the composition and structure of the initial cyclosiloxane and of the conditions of rearrangement (polymerization). The cyclopentasiloxanes Φ_mD_5-m are less active in the process of rearrangement than the cyclotetrasiloxanes Φ_mD_4-m. The activity of the cyclosiloxanes in rearrangement in the presence of a base rises in the sequence D₄?ΦD₃ ≈ Φ₂D₃<Φ₃D₂<Φ₄D < Φ₂D₂ < Φ₃D.     

Verfeinerung der Kristallstrukturen von KN3, RbN3, CsN3 und TIN3

Crystal structure refinements of KN₃, RbN₃, CsN₃, and TIN₃ The crystal structures of the isostructural compounds KN₃, RbN₃, CsN₃ and TIN₃ were refined by the method of least-squares using new X-ray diffraction data. The substances crystallize in a tetragonal variety of the CsCl type (space group I4/mcm) with four formula units per unit cell. The metal ions are surrounded by eight closest N atoms in a distorted quadratic antiprismatic arrangement at distances which correspond to the sum of the ionic radii. The azide ions are strictly linear and symmetrical with N — N bond lengths of 1.16 to 1,18 Å.     

AB initio study of the structure, isomerism, and vibrational spectra of LiClO3, NaClO3, and KClO3

The geometrical structure, force fields, and vibrational spectra of the ClO ₃ ^? ion and LiClO₃, NaClO₃, and KClO₃ molecules are studied using the Hartree-Fock (HF) method and second-order Möller-Plesset (MP2) perturbation theory in double-zeta basis sets complemented with polarization and diffuse functions. Routes of intramolecular rearrangements corresponding to migration of the M⁺ cations around the ClO ₃ ^? anion are investigated. The calculations showed that the molecular structure of alkaline metal chlorates changes in the series LiClO₃ → NaClO₃ → KClO₃. The LiClO₃ molecule has an essentially bidentate configuration of C_s symmetry; the KClO₃ molecule has tridentate coordination of C_3v symmetry. The NaClO₃ molecule exists as two isomeric forms having similar energies: tridentate (C_3v) and bidentate (C_s) forms separated by a low potential barrier (199 cm^?1 ? HF, 170 cm^?1 ? MP2); the energy differences between the isomers are ΔE(C_s ? C_3v)=?0.5 (HF), 0.4 kJ/mole (MP2). The theoretical vibrational spectra of molecules agree with the available experimental data.     

Parameterization of charge model 3 for AM1, PM3, BLYP,and B3LYP

We have recently developed a new Class IV charge model for calculating partial atomic charges in molecules. The new model, called Charge Model 3 (CM3), was parameterized for calculations on molecules containing H, Li, C, N, O, F, Si, S, P, Cl, and Br by Hartree-Fock theory and by hybrid density functional theory (DFT) based on the modified Perdew-Wang density functional with several basis sets. In the present article we extend CM3 to semiempirical molecular orbital theory, in particular Austin Model 1 (AM1) and Parameterized Model 3 (PM3), and to the popular BLYP and B3LYP DFT and hybrid DFT methods, respectively. For the BLYP extension, we consider the 6-31G(d) basis set, and for the B3LYP extension, we consider three basis sets: 6-31G(d), 6-31+G(d), and MIDI!6D. We begin with the previous CM3 strategy, which involves 34 parameters for 30 pairs of elements. We then refine the model to improve the charges in compounds that contain N and O. This modification, involving two new parameters, leads to improved dipole moments for amides, bifunctional H, C, N, O compounds, aldehydes, ketones, esters, and carboxylic acids; the improvement for compounds not containing N results from obtaining more physical parameters for carbonyl groups when the O=C-N conjugation of amides is addressed in the parameterization. In addition, for the PM3 method, we added an additional parameter to improve dipole moments of compounds that contain bonds between C and N. This additional parameter leads to improved accuracy in the dipole moments of aromatic nitrogen heterocycles with five-membered rings.     

Synthesis of (2S,3R)-[3',3',3'-2H3]-valine and (2S,3S)-4-fluorovaline

A new synthesis of (2S,3R)-[3',3',3'-2H3]-valine has been completed and (2S,3S)-4-fluorovaline has been synthesised for the first time. Both compounds have been prepared by routes involving stereoselective addition to the (S)-pyroglutamate derivative and are available for studies in several areas of bio-organic chemistry.     

Role of charge transfer configurations in LaMnO3, CaMnO3, and CaFeO3

A simple scheme is proposed to analyze the N-electron wave function obtained in embedded cluster calculations in valence bond terms such as ligand-to-metal charge transfer and non-charge-transfer determinants. The analysis is based on a unitary transformation of pairs of natural orbitals to optimal atomiclike orbitals. The procedure is applied to compare the degree of ionicity in NiO and MnO and to explain the existence or absence of Jahn-Teller distortions in LaMnO3, CaMnO3, and CaFeO3. The authors find that the ground state of LaMnO3 is dominated by non-charge-transfer configurations, whereas the charge transfer configurations dominate the ground state wave function in the other two perovskites.     

Condensation of 5-bromo-, 3-bromo-, and 3-iodoacenaphthenequinones with 3-hydroxythionaphthene and its derivatives

The oxidation of 3-bromo-and 3-iodoacenaphthene has given 3-bromo-and 3-iodoacenaphthenequinones. The condensation of 5-bromo-, 3-bromo-, and 3-iodoacenaphthenequinones with 3-hydroxythionaphthene and its derivatives has yielded indigoid dyes, and the main light absorption maxima of these dyes have been determined.     

Condensation of 5-bromo-, 3-bromo-, and 3-iodoacenaphthenequinones with 3-hydroxythionaphthene and its derivatives

The oxidation of 3-bromo-and 3-iodoacenaphthene has given 3-bromo-and 3-iodoacenaphthenequinones. The condensation of 5-bromo-, 3-bromo-, and 3-iodoacenaphthenequinones with 3-hydroxythionaphthene and its derivatives has yielded indigoid dyes, and the main light absorption maxima of these dyes have been determined.     

Theoretical characterization and many-body expansion analysis of BF3, BCl3, AlF3 and AlCl3 interactions

Summary Metalloid-nonmetal and Metal-nonmetal interactions of BF₃, BCl₃, AlF₃ and AlCl₃ were examined at the matrix Hartree Fock level ofab initio theory. Structural and energetic properties, many-body expansion convergence, short- and long-range components of interaction energies, and group-theoretical parameters were found to uniquely characterize these interactions.