Beiträge zur Chemie des Hydrazins und seiner Derivate. XVIII. Darstellung und Eigenschaften von Salzen des Triazans

The reaction of N₃H₇SO₄ with barium compounds BaX₂ in aqueous solutions yields under precipitation of BaSO₄ solutions which contain the corresponding salts of triazane N₃H₆X (X = NO, ClO, Cl^?, CH₃COO^?, N₃, CN^?, Br^?, OH^?). Due to the instability of the triazanium ion, NH₂? NH₂? \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm N}\limits^{\rm + } $\end{document}H₂, the solid triazanium salts could only be isolated in mixture with the also formed BaSO₄. The properties of these compounds are described.     

On the Complexes of Bis(trifluoromethyl)ditellurium,Te2(CF3)2, with Halide Ions – A Crystallographic Study of the Pseudo‐trihalides [PNP][(TeCF3)2X] (PNP = Bis(triphenylphosphoranyliden)ammonium; X = Cl,Br, I)

The anions [(TeCF₃)₂X]^? (X = Cl, Br, I) resemble the trihalides [I₂X]^? in the solid state and show similar dynamic behaviour in solution. All three compounds crystallize iso‐structurally in the triclinic space group with Z = 2 and exhibit cell dimensions according to the sizes of the halogen atoms.     

Stereospecific polymerization of methacrylonitrile. III. Some new catalysts for isotactic polymethacrylonitrile

Some classes of organometallic catalysts what induce stereospecific polymerization of methacrylonitrile have been found. They include organolithium aluminum compounds of the type LiAlR₄, Li[R₃AlOAlR₂], and Li[R₃AlN(R)AlR₂], organosodium aluminum compounds of the type NaAlR₄, organolithium zinc compounds of the type LiZnR₃ and Li₂ZnR₄, organomagnesium aluminum compounds of the type RMg[AlR₄] and Mg[AlR₄]₂, and organomagnesium compounds containing an Mg? N bond, such as and their related compounds. One of the features of the polymerization with these catalysts was that the crystalline polymers were formed at moderately high temperatures. Total conversion, solubility index, and molecular weight of the polymer increased with increasing polymerization temperature, as observed in the case of polymerization with diethylmagnesium catalyst. Catalysts with an Mg? N bond were found to be highly effective for the stereospecific polymerization. The acetone-insoluble fractions of the polymers gave x-ray diagrams identical to the crystalline polymer produced with diethylmagnesium. This indicates that the acetone-insoluble crystalline polymers produced with these catalysts have an isotactic structure. The viscosity–molecular weight relationship for crystalline polymer was conveniently determined in Cl₂CHCOOH at 30°C.; [η] = 2.27 × 10^?4 M^0.754.     

Crystal structure,DFT study,antimicrobial properties and DNA cleavage potential and thermal behavior of some new mercury complexes

In this study, a new bidentate Schiff base ligand (L) entitled as N,N’-bis(dimethylaminocinnamaldehyde)-2,2-dimethyl-1,3-propanediamine and its mercury complexes were synthesized. The Schiff base ligand and its complexes were characterized using FT-IR, ¹H-, ¹³C-NMR spectroscopy, molar conductivity and electronic spectral study. Regarding physical and spectral data, the general formula for the complexes was suggested as HgLX₂ (L = Schiff base ligand and X = Cl^?, Br^?, I^?, SCN^?, N₃ ^?). For structural identification of these complexes, crystal structure of mercury iodide complex was analyzed as typical one. In the structure of this complex, Hg ion is surrounded by 2 iodide ions and 2 N atoms from the Schiff base ligand to form a four-coordinated mercury complex in triclinic system with space group of P ₁. Angular index (τ ₄) value was evaluated equal to 0.85, so the geometry around the mercury ion in this complex can be described as trigonal pyramid. A layered supramolecular structure for HgLI₂ complex is stabilized by C–H···I and C–H···π interactions in solid state. DFT study on the ligand and its complexes was also carried out, and then some calculated and experimental structural parameters of HgLI₂ were compared. Thermal behaviors of the titled compounds were investigated by thermogravimetric analyses. Furthermore, biological properties of the ligand and its complexes were examined against some Gram-negative and Gram-positive bacteria and also against 2 fungi. Finally, the interaction of the ligand and its complexes with DNA was investigated by electrophoresis method.     

Synthesis, structural elucidation and biological activities of organotin(IV) derivatives of (E)-3-(4-methoxyphenyl)-2-(4-chlorophenyl)-2-propenoic acid

A new series of di- and tri-organotin(IV) compounds with the general formula R_4?n SnL _n , where R?=?Me (1,2), Et (3), n-Bu (4,5), n-Oct (6), Ph (7) and L?=?(E)-3-(4-methoxyphenyl)-2-(4-chlorophenyl)-2-propenoate, were synthesized by reaction of silver salt of ligand or ligand acid with diorganotin dichloride/oxide and triorganotin chloride in 2:1 and 1:1 molar ratio, respectively. These compounds were characterized by elemental analyses, FT-IR, multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR and mass spectrometry. The spectroscopic results revealed that all the diorganotin(IV) compounds possess trigonal bipyramidal structures in solution and octahedral geometry in the solid state around the tin atom. A linear polymeric trigonal bipyramidal structure in the solid state and a tetrahedral environment around the tin atom in non-coordinating solvents has been proposed for the triorganotin(IV) compounds. All synthesized compounds were tested in vitro against a number of microorganisms to assess their biocidal activity. These studies revealed that ligand acid and some of its organotin compounds show promising activity against different strains of bacteria and fungi but lowered than reference drugs.     

Ligand Dynamics in the Solid: Lithium‐fluorenide and Lithium‐benzo[b]fluorenide N,N,N′,N′‐Tetramethylethylenediamine (tmeda) Complexes

The dynamic behavior of the N,N,N′,N′‐tetramethylethylenediamine (tmeda) ligand has been studied in solid lithium‐fluorenide(tmeda) ( 3 ) and lithium‐benzo[b]fluorenide(tmeda) ( 4 ) using CP/MAS solid‐state ¹³C‐ and ¹⁵N‐NMR spectroscopy. It is shown that, in the ground state, the tmeda ligand is oriented parallel to the long molecular axis of the fluorenide and benzo[b]fluorenide systems. At low temperature (<250 K), the ¹³C‐NMR spectrum exhibits two MeN signals. A dynamic process, assigned to a 180° rotation of the five‐membered metallacycle (π‐flip), leads at elevated temperatures to coalescence of these signals. Line‐shape calculations yield ΔH^?=42.7 kJ mol^?1, ΔS^?=?5.3 J mol^?1 K^?1, and =44.3 kJ mol^?1 for 3 , and ΔH^?=36.8 kJ mol^?1, ΔS^?=?17.7 J mol^?1 K^?1, and =42.1 kJ mol^?1 for 4 , respectively. A second dynamic process, assigned to ring inversion of the tmeda ligand, was detected from the temperature dependence of T_1ρ, the ¹³C spin‐lattice relaxation time in the rotating frame, and led to ΔH^?=24.8 kJ mol^?1, ΔS^?=?49.2 J mol^?1 K^?1, and =39.5 kJ mol^?1 for 3 , and ΔH^?=18.2 kJ mol^?1, ΔS^?=?65.3 J mol^?1 K^?1, and =37.7 kJ mol^?1 for 4 , respectively. For (D₁₂)‐ 3 , the rotation of the CD₃ groups has also been studied, and a barrier E_a of 14.1 kJ mol^?1 was found.     

Molecular fragmentations: Part IV. The mass spectral fragmentation of carbon tetrachloride

MINDO/3 calculations have been made of the molecular structures and energies of seven isomeric forms of the molecular cation (CCl₄)⁺, of the mass spectral fragment pairs:

and also of a number of neutral fragment pairs. Reaction energy profiles have been calculated for two fragmentations of (CCl₄)⁺, into [(CCl₂)⁺ + Cl₂], and into [(CCl₃)⁺ + Cl^?], in the latter of which the reaction proceeds via a rather stable intermediate; for the fragmentation of three electronic states of (CCl₃)⁺ into [(CCl₂)⁺ + Cl^?], where the ground singlet state and first triplet state of (CCl₃⁺ yield the ground doublet state of (CCl₂)⁺, but the first excited singlet of (CCl₃)⁺ yields the first excited doublet of (CCl₂)⁺ ; and for the fragmentation of the ground state of (CCl₃)⁺ into [(CCl)⁺ + Cl₂].     

Darstellung und spektroskopische Charakterisierung von Fluoro-Chloro-Iridaten(V)

Preparation and Spectroscopic Characterization of Fluoro-Chloro-Iridates(V) By careful oxidation of the pure fluoro-chloro iridates(IV) with BrF₃ in dichloromethane the corresponding pentavalent complexes [IrF₅Cl]^?, cis-[IrF₄Cl₂]^?, and fac-[IrF₃Cl₃]^? are formed without replacements of Cl ligands. The vibrational spectra of these mixed ligand complexes are assigned according to point groups C_4v, C_2v, and C_3v. The increased bond strength compared with the corresponding Ir^IV compounds is indicated by a significant shift to higher energy by about 5–15%. The anomalous intensities of some of the Raman active fundamentals are attributed to the resonance Raman effect. The electronic absorption spectra are measured on the solid tetraethylammonium salts of the fluoro-chloro iridates(V) at 10 K. The strong bands in the UV/VIS region are assigned to charge transfer transitions from π(t_1u, t_2u) and σ(t_1u) Cl orbitals into the π(t)Ir^V level. The intraconfigurational transitions within the t configuration of Ir^V are split by spin orbit coupling and lowered symmetry, observed in the ranges 3000, 5100–6400, 10900–13000, and 18200 cm^?1. The O? O transitions are deduced from the vibrational fine structure; in some cases they are confirmed by electronic Raman bands. With increasing number of F ligands all absorption bands are shifted systematically to higher energies.     

The first transition metal iodato peroxido complex: the synthesis, vibrational spectra and crystal structure from powder diffraction data of K3[V2O2(O2)4(IO3)]·H2O

The first transition metal iodato peroxido complex, K₃[V₂O₂(O₂)₄(IO₃)]·H₂O (I), was prepared by crystallization from the KVO₃ — KIO₃ — H₂O₂ — H₂O — ethanol (HNO₃) solution. The dinuclear anion is immediately decomposed in aqueous solution; the ⁵¹V NMR spectrum exhibits signals corresponding to [VO(O₂)₂(H₂O)]^?, [V₂O₂(OH)(O₂)₄]^3? and H₂VO₄ ^? species only. The IR and Raman spectra contain all characteristic bands of the VO(O₂)₂ group and the coordinated IO₃ ^? ligand. Based on the positions of bands assigned to the vibrations of the VO(O₂)₂ groups a pentagonal pyramidal arrangement around the vanadium atoms can be supposed. The crystal structure was solved from X-ray synchrotron powder data by direct space method and refined by energy minimization in the solid state employing a hybrid PBE0 functional. This crystal and molecular structure, has confirmed the presence of hexacoordinated vanadium atoms and revealed asymmetric dinuclear structure of the [V₂O₂(O₂)₄(IO₃)]^3? ion. The coordination spheres of vanadium atoms are different — the IO₃ ^? anion is coordinated only to one vanadium center. A thermal analysis of the complex confirmed the presence of water molecules in the crystal structure and revealed a considerable stability of the dehydrated complex.      

Through bond mechanism versus exciplex formation in the photochemistry of fullerene / ferrocene donor-bridge-acceptor dyads

A systematic fluorescence and flash photolytic investigation of a series of covalently linked fullerene / ferrocene based donor-bridge-acceptor dyads is reported as a function of the nature of the bridge between the donor site and acceptor site. The fluorescence of the investigated dyads 2 (Φ_rel = 0.17 × 10^?4, 3 (Φ_rel = 0.78 × 10^?4), 4 (Φ_rel = 1.5 × 10^?4), 5 (Φ_rel = 0.7 × 10^?4), and 6 (Φ_rel = 2.9 × 10^?4) were substantially quenched, relative to N-methyl fulleropyrrolidine (1) (Φ_rel = 6.0 × 10^?4). Photolysis of N-methyl fulleropyrrolidine (1) in toluene revealed formation of the excited singlet state which was followed by a rapid intersystem crossing to the excited triplet state. On the other hand, the fate of the excited singlet state of 2, 3, 4, 5, and 6 was found to be governed by rapid intramolecular quenching, with rate constants of 28×10⁹ s^?1, 6.9×10⁹ s^?1, and 3.4×10⁹ s^?1, 14×10⁹ s^?1, 2.3×10⁹ s^?1 respectively. The electron transfer process and the charge separation were confirmed by monitoring the characteristic π-radical anion bands at λ_max = 400 and 1055 nm in degassed benzonitrile with τ_1/2 = 1.8 μs (3) and 2.5 μs (4).     

Studies on the composition and kinetics of chromium(III)-alanine system

Kinetics of the complex formation of chromium(III) with alanine in aqueous medium has been studied at 45, 50, and 55°C, pH 3.3–4.4, and μ = 1 M (KNO₃). Under pseudo first-order conditions the observed rate constant (k_obs) was found to follow the rate equation: Values of the rate parameters (k_an, k, K_IP, and K) were calculated. Activation parameters for anation rate constants, ΔH^≠(k_an) = 25 ± 1 kJ mol^?1, ΔH^≠(k) = 91 ± 3 kJ mol^?1, and ΔS^≠(k_an) = ?244 ± 3 JK^?1 mol^?1, ΔS^≠(k) = ?30 ± 10 JK^?1 mol^?1 are indicative of an (I_a) mechanism for k_an and (I_d) mechanism for k routes (‥substrate Cr(H₂O) is involved in the k route whereas Cr(H₂O)₅OH²⁺ is involved in k′ route). Thermodynamic parameters for ion-pair formation constants are found to be ΔH°(K_IP) = 12 ± 1 kJ mol^?1, ΔH°(K) = ?13 ± 3 kJ mol^?1 and ΔS°(K_IP) = 47 ± 2 JK^?1 mol^?1, and ΔS°(K) = 20 ± 9 JK^?1 mol^?1.     

Control of Oxidation States of Transition Elements (Cr,Mn) in Nitridometalates and the Solid Solution Series Li6(Ca1‐xSrx)2[Mn2N6]

The formation of ternary nitridometalates from the elements in the case of the systems Li—Cr, V, Mn—N leads to compounds which contain the transition metals in the highest (V^V, Cr^VI) or a comparably high (Mn^V) oxidation state. In the corresponding calcium and strontium systems, the transition metals show a lower oxidation state (V^III, Cr^III, Mn^III). Transition metals with intermediate oxidation states (Cr^V, Mn^IV) are present in the quaternary (mixed cation) compounds Li₄Sr₂[CrN₆], Li₆Ca₂[MnN₆], and Li₆Sr₂[MnN₆] (R3¯(#148), a = 585.9(3) pm, c = 1908.6(4) pm, Z = 3), as well as in the solid solution series Li₆(Ca_1—xSr_x)₂[MnN₆].     

The unimolecular thermal decomposition of oxetane and its methyl derivatives: An Ab initio and RRKM calculations

Quantum mechanical and Rice-Ramsperger-Kassel-Marcus (RRKM) calculations are carried out to study the thermal unimolecular decomposition of oxetane (1), 2-methyloxetane (2), and 2,2-dimethyloxetane (3) at the MPW1PW91/6-311 + G** level of theory. The results of the calculations reveal that decomposition reaction of compounds 1?C3 yields formaldehyde and the corresponding substituted olefin. The predicted high-pressure-limit rate constants for the decomposition compounds 1?C3 are represented as 6.61 × 10¹³exp(?32472/T), 9.33 × 10¹³exp(?29873/T), and 4.79 × 10¹³exp(?27055/T) s^?1, respectively. The fall-off pressures for the decomposition of compounds 1?C3 are found to be 9.42 × 10^?2, 3.67 × 10^?3, and 7.26 × 10^?4 mm Hg, respectively. As the fall-off pressure of the decomposition process of compounds 1?C3 are in the following order: P _1/2(1) > P _1/2(2) > P _1/2(3); therefore the decomposition rates are as follow: rate(1) < rate(2) < (3).     

Intramolecularly coordinated organoantimony(III) carboxylates

The reactions of organoantimony chlorides L^1,2SbCl₂1 and 2 ([2,6-(ROCH₂)₂C₆H₃]⁻, R = Me; L¹ and R = t-Bu; L²) with silver salts of selected carboxylic acids resulted to corresponding organoantimony carboxylates L^1,2Sb(OOCR′)₂, 1a-c (for L¹) and 2a-c (for L²), where R′ = CH₃ for 1a, 2a; R′ = CHCH₂ for 1b, 2b and R′ = CF₃ for 1c, 2c. All compounds were characterized by the help of elemental analysis, ESI-MS, ¹H and ¹³C NMR spectroscopy. The solid state structure investigation using single crystal X-ray diffraction techniques (2a, c) and IR spectroscopy revealed significant differences in coordination mode of both O,C,O chelating ligand and carboxylic groups in this set of compounds. The structure of all compounds in solution of non-coordinating solvent (CDCl₃) was determined by means of variable temperature ¹H, ¹³C, ¹⁹F NMR spectroscopy and IR spectroscopy.     

Synthesis,structure, and thermal expansion of sodium zirconium arsenate phosphates

Sodium zirconium arsenate phosphates NaZr₂(AsO₄) _x (PO₄)_3?x were synthesized by precipitation technique and studied by X-ray diffraction and IR spectroscopy. In the series of NaZr₂(AsO₄) _x (PO₄)_3?x , continuous substitution solid solutions are formed (0 ≤ x ≤ 3) with the mineral kosnarite structure. The crystal structure of NaZr₂(AsO₄)_1.5(PO₄)_1.5 was refined by full-profile analysis: space group R \(\bar 3\) c, a = 8.9600(4)Å, c = 22.9770(9) Å, V = 1597.5(1) ų, R _wp = 4.55. The thermal expansion of the arsenate-phosphate NaZr₂(AsO₄)_1.5(PO₄)_1.5 and the arsenate NaZr₂(AsO₄)₃ was studied by thermal X-ray diffraction in the temperature range of 20–800°C. The average linear thermal expansion coefficients (α_av = 2.45 × 10^?6 and 3.91 × 10^?6 K^?1, respectively) indicate that these salts are medium expansion compounds.     

Magnesium chloride supported high-mileage catalysts for olefin polymerization. X. Effect of hydrogen and catalytic site deactivation

The effect of H₂ on propylene polymerization initiated by a MgCl₂/EB/PC/AlEt₃/TiCl₄–3 AlEt₃/MPT catalyst was studied. Hydrogen increases significantly the initial rate during the early stage of the polymerization to give a higher yield of polymer than reactions without H₂. But H₂ reduces the yield toward the latter stages so that the net effect on the total yield can be quite small. There is no appreciable effect of H₂ on either the isotacticity index or polydispersity of the products. It decreases molecular weight proportional to (p_H2)^1/2. The chain transfer by H₂ resulted in a decrease of total metal polymer bond concentration with time of polymerization. The rate constants of hydrogen chain transfer for the two kinds of isospecific and nonspecific sites are = 5.1 × 10^?3, = 2.7 × 10^?3, = 7.5 × 10^?3, = 4.4 × 10^?3, in units of torr^1/2 sec^?1 at 50°. Hydrogen assists in the deactivation of the catalytic sites as does propylene; rates of the former and the latter vary with (p_H2)^1/2 and [C₃H₆]^1/2, respectively, with k = (12.1 ± 0.9) M^?1 torr^?1/2 sec^?1 and k = (65.3 ± 3.3) M^?3/2 sec^?1 at 50° and A/T = 167. The mechanism for deactivation of catalytic sites are discussed.     

Polymerization of mono- and α,ω-dicarbanionic polystyryl-barium—II. Effect of added lithium salt in THF

The propagation rate of polystyryl-barium was studied in THF at 20°, in the presence of small amounts of lithium chloride. These kinetic results furnish a new method for the determination of triple ion formation in both mono- and α,ω-dicarbanionic polystyryl-barium. The constant of triple ion association of monocarbanionic (PS^?)₂Ba, K_T, was found to be 3.7 × 10⁵ l M^?1, close to the value calculated from published data.

The triple ion association constant of α,ω-dicarbanionic PS^2?Ba²⁺, K_DT, is about 1.2 × 10⁶ l M^?1.

Taking into account the cyclic structure of α,ω-dicarbanionic PS^2?Ba²⁺ and a statistical factor 3 between K_T and K_DT, it is concluded that mono- and dicarbanionic polystyryl-barium have similar abilities for triple ion formation. Nevertheless, stronger associations are observed for dicarbanionic oligomers with a degree of polymerization lower than 5–7.     

Kinetic isotope effect in the protonation of anthracenide salts by MeOH and MeOD role of counterions and solvents

Kinetics of protonation of Li⁺, Na⁺, K⁺, and Cs⁺ salts of anthracene radical anions (A^?_·,Cat⁺) and dianions (A^2?, 2Cat⁺) by MeOH and MeOD in tetrahydrofuran (THF) and dimethoxyethane (DME) led to the determination of the isotope effect (k_H/k_D) in the following reactions: Studies of cation and solvent influence on the rate constants of these reactions and on the magnitude of the isotope effect permitted us to draw some conclusions about the structure of the pertinent transition states. It seems that only the tight A^?·,Na⁺ pairs participate in the protonation, and on this basis the fraction of tight ion paris of A^?·,Na⁺ in DME was estimated. Our results have been compared with data reported in the literature.     

Synthesis and optical behaviors of 2-(9-phenanthrenyl)-, 2-(9-anthryl)-, and 2-(1-pyrenyl)-1-alkylimidazole homologues

Eight 2-(9-phenanthrenyl)-, 2-(9-anthryl)- and 2-(1-pyrenyl)-1-alkyl-benzimidazole compounds, three 2-(9-anthryl)-1-alkylphenanthroimidazole compounds and five 4,5-diphenyl-1-alkyl-2-(9-anthryl)imidazole compounds were synthesized by alkylation reactions of the corresponding benzimidazole, phenanthroimidazole or imidazole compounds. 2-(10-Bromo-9-anthryl)-1-alkyl-benzimidazole compounds were prepared by bromination reaction of 2-(9-anthryl)-1-alkylbenzimidazole compounds. All the synthesized compounds were characterized by elemental analysis, ¹H NMR, ¹³C NMR, MS or HRMS; their absorption coefficients (), maximum absorption λ_amax, fluorescence emission maximum λ_em, Stokes shifts and fluorescence quantum yields (Φ_F) in ethyl acetate were determined; their fluorescent lifetimes (T₁ and T₂) were measured in ethyl acetate and in solid state, respectively. The crystal structure of 2-(9-anthryl)-1-n-butyl-4,5-diphenylimidazole (12a) was determined to be triclinic, space group P-1 types, using single crystal X-ray crystallography technique. The results showed that these compounds exhibited moderate fluorescence-emission abilities and higher solubility in most organic solvents than their corresponding starting materials. The relationships between the optical behaviors and structures for these compounds were discussed.     

Sublimation and Dissociation of Thl4 and ThOl2 from Knudsen Cells

The sublimation pressure of ThI₄ has been measured by the Knudsen effusion method and found to be . Simultaneously with the sublimation of ThI₄ there is a small dissociation to lower iodide and iodine. The dissociation pressure associated with the reaction 2 ThOI₂ = ThO₂ + ThI₄ is The molar heat capacity of solid ThI₄ has been determined calorimetrically to be 146 J K^?1 mol^?1, the heat of fusion is approximately 48 kJ mol^?1. The standard entropy of solid ThOI₂ is calculated to be 145 J K^?1 mol^?1.