Fluorierung von Dioxa- und Oxazaphospholanen

Fluorination of Dioxa- and Oxazaphospholanes The fluoridolysis of cyclic esters and esteramides of phosphorous acid ( 1 , 2 , 4 , 5 , 7 , 11 , and 12 ,) using the acid fluorination reagent Et₃N · nHF (n > 1) or an excess of a basic composed agent (n < 1) yields in all cases HPF₅^? ( 3 ,). With stoichiometric amounts of fluoride, however, the fluorophospholanes ( 4 ,) and ( 5 ,) as well as fac.- and mer.-o- ( 6a, 6b ,) and the spirocyclic fluorohydridophosphate ( 8 ,) are obtained. ( 13 ,) reacts to ( 14 ,) and the spirocyclic compound ( 15 ,) gives ( 16 ,). The fluorophosphoranes ( 18 ,), ( 19 ,), and ( 21 ,) are obtained by oxidative fluorination of the spiro- or bicyclic P? H compounds 11, 12 , and 20 , with CCl₄/Et₃N · nHF (n < 1). The oxidative fluorination of the cyclic triesters of phosphorous acid 7 , and 23 , leads to the cyclic fluorophosphates ( 22 ,) and 16 , as well as 6. , The compounds 18, 19 , and 22 , are also formed by oxidative fluorination of elemental phosphorus, P₄, in the presence of the corresponding bifunctional nucleophile.     

Lösungsthermodynamik von FeCl2 in Mischschmelzen aus Alkalichloriden und LaCl3 bzw. CeCl3

Solution Thermodynamics of FeCl₂ in Molten Mixtures of Alkaline Chlorides and LaCl₃ or CeCl₃ Activity coefficients and the chemical excess potential of FeCl₂ dissolved in molten chloride mixtures were determined by EMF measurements with galvanic cells of the type in the concentration range from 0.01–5 mole-% at 720 and 820°C. An average cationic potential is defined and used to calculate a distance parameter () for the different solvent melt mixtures. may be estimated by equations of the type      

Perfluorovinyl Morpholine and Perfluorovinyl Pyrrolidine with Nucleophiles and Electrophiles

In this study, both monofunctional and bifunctional nucleophiles, as well as the electrophile FNO, are reacted with perfluorovinyl amines. The perfluorovinyl amines CF?CF₂ and CF?CF₂ have been reacted with dimethylamine and diethylamine in the presence of small amounts of water to give CHFC(O)N(CH₃)₂ ( 1 ), CHFC(O)N(CH₃)₂ ( 2 ), and CHFC(O)N(C₂H₅)₂ ( 3 ). With perfluorovinyl pyrrolidine and perfluorovinyl morpholine, ethanolamine gives the cyclized products CHF ( 4 ) and CHF ( 5 ), respectively. Reaction of the vinyl amines with (CH₃)₃SiOCH₂CF₃ in the presence of catalytic amounts of CsF results in the formation of cis- ( 6 ) and trans- ( 7 ) CF?CF(OCH₂CF₃) and cis- ( 8 ) and trans- ( 9 ) CF?CF(OCH₂CF₃). The electrophile FNO reacts slowly with perfluorovinyl pyrrolidine and perfluorovinyl morpholine, and more rapidly with (CF₃)₃CCF?CF₂ to give CF(NO)CF₃ ( 10 ), CF(NO)CF₃ ( 11 ) and (CF₃)₃CF(NO)CF₃ ( 12 ), respectively. Single crystal X-ray analysis is used to confirm the identity of the product obtained from the controlled hydrolysis of the sultone of perfluorovinyl pyrrolidine as the sulfonic acid anhydride C(O)CF₂OS(O)₂OCF₂C(O) ( 13 ). The X-ray crystal structure of perfluorosuccinic acid monohydrate ( 14 ), which is obtained when the perfluorovinyl pyrrolidine sultone is hydrolyzed in excess water, is also reported for the first time.     

Zur Reaktivität isomerer Heterodinuclearer Fischer-Carben-Komplexe mit Titanaoxetan- und Titanaoxolenteilstrukturen — Cycloreversions- und Insertionsreaktionen

Studies on the Reactivity of Isomeric Heterodinuclear Fischer-Carbene Complexes exhibiting a Titanaoxetan or Titanaoxolen Substructure – Cycloreversion and Insertion Reactions The reactivity of isomeric four- and five-membered carbene complexes Cp*₂ 3 and Cp*₂ 4 [ML_n: Cr(CO)₅ ( a ); W(CO)₅ ( b ); Cp*: C₅(CH₃)₅] has been investigated. A cycloreversion reaction, unusual for common metallaoxetanes, is found to dominate the chemical behaviour of 3 . The generation of vinylidene fragment [Cp*₂Ti?C?CH₂] 2 as an intermediate is proved either by trapping with ethylene and isocyanate or by protonation of the α-carbon atom. On the other hand no cycloreversion is observed for the titanaoxolene carbene complexes 4 . Ringenlargement is found by the reaction of 3 and 4 with isonitriles under formation of iminoacyl complexes. Accordingly 2,6-dimethylphenylisonitrile reacts with 3 b forming Cp*₂ 12 [Ar: 2,6-(CH₃)₂? C₆H₃]. A reversible insertion of cyclohexylisonitrile in 4a leads to isolation of the six-membered metallacycle Cp*₂ 16 (Cy: C₆H₁₁).     

Electric conductivity of polymer composites with 7,7,8,8-tetracyanoquinodimethan salts

The electric properties of polymer composites with highly conductive 7,7,8,8-tetracyanoquinodimethan (TCNQ) salts such as quinolinium–TCNQ complex salt (), acridinium–TCNQ complex salt (), and N-methylacridinium–TCNQ complex salt () were studied. Polyacrylonitrile (PAN), poly(N-vinylcarbazole) (PVK), and poly(4-vinylpyridine), (P4VP), etc., were chosen as matrix polymers. The resistivity (ρ) of the was 0.37 Ω cm at the content of 20 wt % in the film. When the content of was increased up to 40 wt%, a phase separation of the needle crystals was observed and the ρ value increased. When was dispersed into PAN or PVK, the separation was also observed and the samples showed low conductivity. The uniform films were obtained in the and systems, but the values of ρ were high because of the degradation of the TCNQ salts. Uniform films with the naked eye were obtained in the and systems, and the values of Ω were 0.37, 1.05, and 3.40 Ω cm, respectively. was stable even when dispersed into P4VP. The properties of the composites were influenced by the combination of the TCNQ salts and the polymers. The uniformity and the stability of the composites were necessary to obtain the high conductive composites.     

The Electronic Structure of Pentaprismane (C10H10), as Revealed by its Photoelectron Spectrum

The photoelectron (PE.) spectrum of the title compound has been assigned by comparison with the PE. spectrum of cubane ( 2 ), aided by ab initio STO-3G calculations using localized molecular orbitals. On the basis of the information available to date, the most satisfactory orbital sequence, Koopmans theorem implied, is, in descending order of energy: band system : (2e″₂, 3e′₂ 2e″₁, 3e′₁); band system : 3a′₁ (2e′₂, 2a″₂); band : 2e′₁.(Sequence of orbitals in parenthesis uncertain).     

Computer-simulated ESR spectra of irradiated poly(olefin oxides)—effect of glass transition temperature on the ESR spectra

Investigations on the effects of γ irradiation on poly(methylene oxide) (POM) and poly(ethylene oxide) (PEO) have been made employing electron spin resonance (ESR) spectroscopy. The ESR sextet and doublet spectra, recorded for POM and PEO, respectively, on irradition in air at room temperature are broadened as the temperature is lowered and show a reversible change in line shape with temperature. The spectra are analyzed by computer simulation, employing Lorentzian line-shape functions and the least-squares method of total curve fitting. The component spectra are evaluated and are assigned. Superposition of the component quartet, triplet, and doublet spectra, corresponding to the radicals ?H₃, ?H₂O , and O?HO , respectively, together with a singlet due to the radicals ?CH₂ is considered to be the best fit to the observed spectrum for POM. The doublet spectrum recorded for PEO has been assigned to the radicals ?HO . The reversible broadening of the spectra has been associated with the mechanism of molecular motions around the glass transition temperatures of these polymers.     

Trimethylsilylverbindungen der Vb-Elemente. VII. Die Kristallstrukturen von Lithium-bis(trimethylsilyl)bismutid · DME und Tetrakis(trimethylsilyl)dibismutan sowie Bemerkungen zur Kristallstruktur des Bis(4-methoxyphenyl)ditellans

Trimethylsilyl Derivatives of Vb Elements. VII. Crystal Structures of Lithium Bis(trimethylsilyl)bismuthide · DME and of Tetrakis(trimethylsilyl)dibismuthane as well as Some Comments on the Crystal Structure of Bis(4-methoxyphenyl)ditellane Colourless lithium bis(trimethylsilyl)bismuthide · DME

1 1,2-Dimethoxyethan (DME); Tetrahydrofuran (THF)

1 and green, metallic lustrous tetrakis(trimethylsilyl)dibismuthane 2 crystallize isotopic to their antimony homologues [1, 2]. As it is shown by crystal structure determinations { 1 : ?90°C; I 4 2d; a = 1017,3(4); c = 3738,0(26) pm; Z = 8; R _w = 0,065; 2 : + 20°C; P2 ₁ /c; a = 680,9(4); b = 1704,8(13); c = 1197,9 (10) pm; β = 119,46(6)°; Z = 2; R _w = 0,084} both compounds form chains which in the case of bismuthide 1 are built up as screws of alternating bismuth and lithium atoms; bonding further to two trimethylsilyl groups or to the chelating DME ligand both atoms gain coordination number 4 {Li? Bi 292(3); Bi? Si 263.3(14) pm; Bi? Li? Bi 132(1); Li? Bi? Li 148(1); φ(Li? Bi? Li? Bi) 83°}. In the case of dibismuthane 2 the centrosymmetric molecules are strung, their Bi-Bi groups forming nearly linear zigzag chains with shortened intermolecular contact distances {Bi-Bi 303.5(3); Bi …? Bi 380.4(3); Bi? Si 268 pm; Bi? Bi …? Bi 169; Bi? Bi? Si 97.4(5) and 92.0(5)°}. Structure and properties of 2 are compared with those of similar compounds; the crystal structure of brown, green metallic lustrous bis(4-methoxyphenyl)ditellane 5 already published by Ludlow and McCarthy[3] is reinvestigated with respect to very short intermolecular Te…?Te contacts.     

13C NMR spectra of 2,3-dihydro-1H-pyrrolo[1,2-c]imidazol-1,3-dione and its thione analogues

Analysis of the ¹³C NMR spectra of a series of 2,3-dihydro-1H-pyrrolo[1,2-c]imidazole derivatives has provided chemical shift data for (?184 ppm), (?173.5 ppm), (?158 ppm) and (?148 ppm) groups. A full analysis of the ¹³C chemical shifts of the C atoms of the pyrrole ring and of an N-phenyl substituent is described.     

Thermal stability of alcohols

3,3-Dimethylbutanol-2 (3,3-DMB-ol-2) and 2,3-dimethylbutanol-2 (2,3-DMB-ol-2) have been decomposed in comparative-rate single-pulse shock-tube experiments. The mechanisms of the decompositions are The rate expressions are They lead to D(iC₃H₇? H) – D((CH₃)₂(OH) C? H) = 8.3 kJ and D(C₂H₅? H) – D(CH₃(OH) CH? H) = 24.2 kJ. These data, in conjunction with reasonable assumptions, give and The rate expressions for the decomposition of 2,3-DMB-1 and 3,3-DMB-1 are and      

Effects of Non-planarity in the Radical Anions of Tribenzo[a,c,e]cyclooctenes

Reduction of tribenzo[a,c,e]cyclooctene ( 2 ) and its 2,3- and 1,4-dimethyl derivatives ( 4 and 5 ), as well as of 1,1-dimethyl-10,11-propane-2,2-diylidene-1H-benzo[5,6]cycloocta[1,2,3,4-def]fluorene ( 6 ) and its 5,6-didehydro derivative ( 7 ) was followed by cyclic voltammetry. The radical anions of these compounds and those of their derivatives (D) 2 , (D) 5 , and (D) 6 , deuteratsd at C(9) in 1 and 5 or in the corresponding position of 6, have been characterized with the use of ESR, ENDOR, and TRIPLE-resonance spectroscopy. The cyclic-voltammetric and proton-hyperfine data are consistent with the increasing deviations of the radical anions from planarity in the order These deviations, due to steric or interferences in the peri-positions 1?14 and 4?5, are removed in and by the introduction of bridging groups. The non-plalarity affects the thermodynamic and kinetic stabilities of the radical anions and causes a shift in the π-spin distribution away from that benzene ring which is linked to the two others by the essential single bonds C(4a)? C(4b) and C(14a)? C(14b). This finding suggests that the steric hindrance in , and is alleviated by twisting this ring out of coplanarity with the remaining (Z)-stilbene-like π-system.     

Assembly of Chiral Two- and Three-dimensional Copper(I) Pseudohalide Based Coordination Polymers with Asymmetrically Substituted Pyrazine and Pyrimidine Ligands

The coordination polymers [(CuCN)₂(μ-2 Mepyz)], [CuCN(μ-2 Mepyz)] and [CuCN(μ-4 Mepym)] ( 1 – 3 ) (2 Mepyz = 2-methylpyrazine; 4 Mepym = 4-methylpyrimidine) may be prepared by self-assembly in acetonitrile solution at 100 °C ( 1 , 3 ) or without solvent at 20 °C ( 2 ). All three contain [CuCN] chains that are bridged by the bidentate aromatic ligands into sheets in 1 and 3 D frameworks in 2 and 3 . Reaction of CuSCN with these heterocyclic diazines at 100 °C leads to formation of the lamellar coordination polymers [(CuSCN)(μ-2 Mepyz)] ( 4 ) and [CuSCN · (4 Mepym-κN1)] ( 5 ), which contain respectively [CuSCN] chains and trans-trans fused [CuSCN] sheets as substructures. The presence of an asymmetric substitution pattern in 2 Mepyz and 4 Mepym induces the adoption of a chiral structure by 2 and 5 (space groups P2₁2₁2₁ and P1).     

Über die oxidative Fluorierung von (CF3)(R) (R = CF3, Cl) und die Kristallstruktur von (CF3)(Cl)F+ AsF6−

Oxidative Fluorination of (CF₃)(R) (R = CF₃, Cl) and the Crystal Structure of (CF₃)(Cl) F⁺ AsF₆^? Oxidative fluorination of (CF₃)(R) (R = CF₃, Cl) with XeF⁺MF₆^? (M = As, Sb) in anhydrous HF results in formation of monofluorsulfonium hexafluorometalates. The salts are characterized by vibrational, NMR, and mass spectra. (CF₃)(Cl)F⁺ AsF₆^? crystallizes in the monoclinic space group P2₁/c with a = 9.955(10) Å, b = 11.050(5) Å, c = 12.733(15) Å, β = 97.77(5)°, and Z = 4.     

Beiträge zur Komplexchemie der Phosphine und Phosphinoxide,XXVIII. Übergangsmetall-aminoalkylphosphin-Komplexe Teil 2: Palladium- Und Platinkomplexe

On the Coordination Chemistry of Phosphines and Phosphine Oxides. XXVIII. Transition Metal Aminoalkylphosphine Complexes. Part II: Palladium and Platinum Complexes Aminoalkylphosphines – C₆H₅HP? CH₂ · CH₂? , (C₆H₅)₂P? CH₂ · CH₂ · CH₂? NH₂, (C₆H₅)₂P? CH₂ · CH₂ · CH₂? N?CHC₆H₅ – react with palladium and platinum salts to give coordination compounds of the type MX₂, MX₂()₂, and MX₂()₄ (M = Pd, Pt; X = Cl, BPh₄). The chelating activity of the ligands, structure and properties of the metal complexes are discussed.     

Integral–geometrical consideration of density matrices

The ensemble N-representability problem for the k-th order reduced density matrix (k-RDM ) as well as the problem of reconstruction of the N-particle system density matrices (N-DM ) from a given k-RDM are studied. The spatial parts of the k-RDM expansion in terms of spin tensorial operators Θ are represented using particular values (at specially chosen ) of the Radon transform of the N-DM spatial parts (or their sums) ??_Nλ(x′ | x″) (here, is a d-plane in the n-space ?ⁿ of x = (x′, x″)), with n = 6N, d = 3 (N ? k), x′ ≡ (r′₁, ?, r′_N), x′ ≡ (r₁″, ?, r″_N ()). In this way, the problem is reduced to investigation of the properties of the functions . For a normalizable N – DM , it is proved that are bounded functions. The properties of implied by the N-DM permutational symmetry, Hermiticity, and positive definiteness are found. A formal procedure of reconstruction of all N-DM corresponding to a given k-RDM is proposed. © 1995 John Wiley & Sons, Inc.     

The Radicals and Radical Dianions of Bridged [11]- and [15]Annulenyls as Compared with Those of Benzotropyl and 2,3-Naphthotropyl

The 1,6-methano[11]annulenyl ( 1 ·), 1,6:8, 14-propane-1,3-diylidene[15]annulenyl ( 2 ·), benzotropyl ( 3 ·) and 2,3-naphthotropyl ( 4 ·) radicals have been characterized by their ESR. spectra. The corresponding radical dianions, , , and , have also been studied both by ESR. and ENDOR. spectroscopy. Assignment of the coupling constants a_Hμ to protons in the individual positions μ of these radicals and radical dianions is to a large extent based on investigations of specifically deuteriated derivatives. The radicals 1· , 2· , 3· and 4· exist in temperature-dependent equilibria with ( 1 )₂, ( 2 )₂, ( 3 )₂ and ( 4 )₂, respectively, where ( 1 )₂ to ( 4 )₂ denote mixtures of dimers of 1 · to 4 ·. The dissociation enthalpies, ΔH°, of ( 1 )₂ (102 kJ/mol) and ( 2 )₂ (88 kJ/mol) are considerably smaller than those of ( 3 )₂ and ( 4 )₂ which do not significantly differ from the ΔH° value of bitropyl (139 ± 6 kJ/mol). This finding indicates that the gain in π-electron delocalization energies, Δ(DE)_π, upon dissociation markedly increases on going from bitropyl, ( 3 )₂ and ( 4 )₂ to ( 1 )₂ and ( 2 )₂, and thus points to an additional ‘resonance stabilization’ of 1 · and 2 ·, as compared with 3 · and 4 ·. A more pronounced π-spin localization on the 7-membered ring is observed in 3 ·, 4 ·, and relative to the corresponding species, 1 ·, 2 ·, and . It can be interpreted in terms of simple π-perimeter models without explicitly invoking substantial homoconjugative interactions between the bridged centres in 1 ·, 2 ·, and . However, the shortcomings of these crude models do not allow one to make a clear-cut statement about the contributions of the homotropyl structures to the π-systems of these paramagnetic species. The radical dianions and exhibit considerable hyperfine splittings from one ²³Na or ³⁹K nucleus of the counter-ion, whereas for and such splittings stem from two equivalent alkali metal nuclei. This finding is readily rationalized by different geometries of the bridged annulenyls and their benzo- and naphthotropyl analogues. Hyperfine data are also given for the radical anions of 7 H-benzocycloheptene, ( 3-H )\documentclass{article}\pagestyle{empty}\begin{document}$2^{\ominus \atop \dot{}}$\end{document}, and 6 H-(2,3-naphtho)cycloheptene, ( 4-H )\documentclass{article}\pagestyle{empty}\begin{document}$2^{\ominus \atop \dot{}}$\end{document}, as well as for the radical dianion of 1,6:8,14-bismethano[15]annulenyl, 5 \documentclass{article}\pagestyle{empty}\begin{document}$2^{\ominus \atop \dot{}}$\end{document}.     

H2S-promoted thermal isomerization of cis-2-pentene to 1-pentene and trans-2-pentene around 800 K

H₂S accelerates the thermal isomerization of cis-2-pentene (P2c) to 1-pentene (P1) and trans-2-pentene (P2t) to around 800 K. This effect is interpreted on the basis of a free radical mechanism in which 2-pentenyl and thiyl radicals are the main chain carriers. P1 formation is essentially explained by the competing processes: P2t formation is due to addition-elimination processes: the importance of which has been evaluated against process (?4μ): The following ratios of rate constants have been measured and are discussed: (RT in cal mol^?1).     

Beiträge zur Chemie der Oxidhalogenide von Molybdän und Wolfram. V. Molybdänoxidtetrachlorid und Molybdänoxidtrichlorid

The formation enthalpies were ascertained from the solution enthalpies in 2 n NaOH resp. 2 n NaOH + 1% H₂O₂. The results of equilibrium measurements in the systems give the formation enthalpies and standard entropies: . The value of the standard entropy of the gaseous MoOCl₄ was estimated to be 91 (±3) cl. From the enthalpies and entropies of sublimation the values were obtained.     

Über Chalkogenolate. 125. Untersuchungen über N-Cyanformamidinodithiocarbimidsäure 1. Darstellung und Eigenschaften von N-Cyanformamidinodithiocarbimaten,Umsetzung mit Säuren und elementarem Schwefel

On Chalcogenolates. 125. Studies on N-Cyanformamidino Dithiocarbimic Acid. 1. Synthesis and Properties of N-Cyanformamidino Dithiocarbimates, Reaction with Acids and with Elemental Sulfur N-Cyanguanidine reacts with carbon disulfide in the presence of the corresponding alkali metal hydroxide to form N-cyanformamidino dithiocarbimates M₂[S₂C?N? C(NH₂)?N? CN], where M = K and Rb. They react with acids to form and with elemental sulfur to yield . The potassium salt and the methyl compound were isolated. All compounds have been characterized by chemical and spectroscopic methods.     

Einfluß von Ringgröße und Substitution auf die oxidative Addition cyclischer Carbonsäureanhydride und -imide an den Rumpf (N N)Niº (N N = α, α′-Dipyridyl,Tetramethylethylendiamin)

Influence of Ring Size and Substitution on the Oxidative Addition of Cyclic Carboxylic Acid Anhydrides and Imides to the Moiety (N N)Ni^º (N N = bipy, tetramethylethylenediamine) (dipy)(COD) or a mixture of tmed/Ni(COD)₂ easily react with cyclic carboxylic acid anhydrides by an oxidative addition. After decarbonylation with succinic acid anhydride a five-membered, with glutaric acid anhydride a six-membered metallacycle are formed – or With diphenic acid anhydride we obtained a seven-membered chelate in the boat form ( XIV ). Along their bond axis the two aromatic rings are twisted by 127°, i.e. the conjugative interaction is weak. Itaconic acid anhydride, as a polar olefine, can coordinate to the moiety (tmed)Ni side-on. But also on oxidative addition, yielding the five-membered chelate ( XVI ), is possible. The five-membered chelate is the only Product of the reaction with (dipy)Ni(COD). 1.8-naphthalic acid anhydride (NSA), because of its rigidity, is not suitable for an oxidative addition to electron-rich nickel(O) complexes. But as a π acceptor ligand with a relatively low half wave potential NSA displaces COD of (dipy)Ni(COD) forming (dipy)Ni(NSA) · 0.25 THF ( XVIII ). One of the final products of the acidolysis of [(dipy)Ni]₂(PPI) · 1.5 THF ( XIX PPI=N-phenyl phthalimide) is benzanilide, a compound which might be an indicator of an oxidative additive connected with an -bond breaking in the course of the synthesis of XIX . But ir-data shows the framework of PPI to be preserved in the complex XIX . Evidently the bond breaking proceeds in the course of the acidolysis.