Massenspektrometrische Untersuchung von Pleiocarpamin-Derivaten. 9. Mitteilung über das massenspektrometrische Verhalten quartärer Stickstoffverbindungen [1]

Mass spectrometric analysis of quaternary nitrogen compounds has shown that three principal thermal processes occur, namely dealkylation, Hofmann degradation and substitution. Only in the cases of dealkylation and the Hofmann degradation has direct chemical evidence been previously obtained. The first part of this paper presents mass spectrometrical and chemical evidence for the pyrolytic formation of a substitution product, e. g. 5 . By means of different deuterated derivatives the mechanisms of fragmentation of the mavacurine derivative ϵ₂-dihydromavacurine methochloride ( 8 ) and of the corresponding Hofmann base ( 14 ) have been formulated.     

Reactions of protoberberine-type alkaloids—XI : Synthesis of optically active ochotensanes

Treatment of l(14S)-β-canadine methochloride (1b) and d(14R)-β-canadine methochloride (1c) with organometals gave d- (2b) and l-2,3-methylenedioxy-9,10-dimethoxyochotensanes (2c), respectively. The structures of these derivatives were proved by chemical and spectral means. The CD spectra of 2b showed Davydov split extrema centered at 284 nm with a positive first Cotton effect, while 2c showed the antipodal curve of 2b. Consequently, the absolute configurations of 2b and 2c were concluded the 14R and 14S, respectively.Application of the anionic rearrangement to N-methyltharictricavine chloride (15) led to 2,3 - methylenedioxy - 9,10 - dimethoxy - 13 - methylochotensane (18) together with the Hofmann methines 16 and 17. The stereochemistry of 18 was confirmed in terms of the nuclear Overhauser effects.     

The Structure of C-Alkaloid-O,a Constituent of Calabash Curare. Part 187. Papers on organic natural products

The structure of C-alkaloid-O ( 1 =his HCL-salt) was established on the basis of spectral data and comparison with the analogous compound 2 , synthesized from a natural product of known absolute configuration. Internally consistent ¹³C-NMR. assignments are given for 1, 2 , huntrabrine methochloride (4) and its diacetate derivative 5 .     

Crystal structure of salts of indole alkaloid norfluorocurarine

Single crystal XRD is used to study the crystals of salts of indole alkaloid norfluorocurarine: hydrochloride recrystallized from absolute alcohol, dihydrate hydrochloride recrystallized from water, methochloride monohydrate recrystallized from water, solvate form of methochloride obtained from ethanol, and methobromide monohydrate. Intra- and intermolecular hydrogen bonds are analyzed in these crystals. The crystal structures of norfluorocurarine methochloride and methobromide monohydrates are isomorphic. In norfluorocurarine salts, the orientation of the carbonyl group is determined by the intramolecular C19=O…H-N1 hydrogen bond that is absent in the solvate form with ethanol.     

Excitonic Bands in the Spectra of Some Organic-Inorganic Hybrid Compounds Based on Metal Halide Units

 The optical absorption, photoluminescence, and photoconductivity spectra of some compounds of the formulas [R(CH₂) _n NH₃] _x M _y X _z , [R(CH₂) _n NH(CH₃)₂] _x M _y X _z , [R(CH₂) _n S(CH₃)₂] _x M _y X _z , [R(CH₂) _n SC(NH₂)₂] _x M _y X _z , and [R(CH₂) _n SeC(NH₂)₂] _x M _y X _z (R = organic residue; M = Bi(III), Pb(II), Sn(II), Cu(I), Ag(I) etc; X = I, Br, Cl; n, x, y, z = 0, 1, 2, 3, …) are briefly reviewed, and some new results are reported. The position, intensity, and shape of the excitonic bands depend on the dimensionality and size of the inorganic network as well as on the nature of the M, X, R, and onium moieties.     

Atomic electron-pair distances and subshell radii in position and momentum space

For the 53 neutral atoms from He to Xe in their ground states, the average distances < u> _{n l , n ′ l ′} in position space and < v> _{n l , n ′ l ′} in momentum space between an electron in a subshell nl and another electron in a subshell n ^′ l ^′ are studied, where n and l are the principal and azimuthal quantum numbers of an atomic subshell, respectively. Analysis of 1700 subshell pairs shows that the electron-pair distances < u> _{n l , n ′ l ′} in position space have an empirical but very accurate linear correlation with a one-electron quantity U _{n l , n ′ l ′}≡L _r +S _r ²/(3L _r ), where L _r and S _r are the larger and smaller of subshell radii < r> _{n l} and < r> _{n ′ l ′}, respectively. The correlation coefficients are never smaller than 0.999 for the 66 different combinations of two subshells appearing in the 53 atoms. The same is also true in momentum space, and the electron-pair momentum distances < > _{n l , n ′ l ′} have an accurate linear correlation with a one-electron momentum quantity V _{n l , n ′ l ′}≡L _p +S _p ²/(3L _p ), where L _p and S _p are the larger and smaller of average subshell momenta < p> _{n l} and < p> _{n ′ l ′}, respectively. Trends in the proportionality constants between < u> _{n l , n ′ l ′} and U _{n l , n ′ l ′} and between < > _{n l , n ′ l ′} and V _{n l , n ′ l ′} are discussed based on a hydrogenic model for the subshell radial functions. Received: 8 April 1998 / Accepted: 6 July 1998 / Published online: 18 September 1998     

Relationships on the effect of water on glass transition temperature and young's modulus of nylon 6

The glass transition temperature T_g of nylon 6 decreases monotonically toward a finite value T_gl upon increase of the moisture content. The mechanism of this decrease entails the reversible replacement of intercaternary hydrogen bonds in the accessible regions of the polyamide. The limiting glass transition temperature T_gl is approached when the moisture content approaches W_l, which corresponds to the amount of water required for complete interaction with all accessible amide groups. Denoting with T_g0 the glass transition temperature of the dry polymer, the effect of water on T_g is represented by the equation, T_g = (ΔT_g)₀ exp{?[ln(ΔT_g)₀]W/_τW_l} + T_gl, where (ΔT_g)₀ = T_g0 ?T_gl, and τ = W(T_gl+1)/W_l. This equation appears to be generally applicable to hydrophilic polymers, since correspondingly calculated data are also in very good agreement with experimental data for polymers such as nylon 66, poly(vinyl alcohol), and polyN-vinylpyrrolidone. The effect of water of Young's modulus E of nylon 6 is represented by an analogous relationship, and the quantity In[(E?E_l)/(T_g?T_gl)] is a linear function of the moisture content.     

Preparation of bisdiazoalkane and related complexes from the reactions of diazo compounds with the dinitrogen complexestrans-[M(N2)2(Ph 2PCH2CH2PPh 2)2] (M=Mo or W)

Summary Reactions oftrans-[M(N₂)₂(dppe)₂] (A;M=Mo, W;dppe=Ph ₂PCH₂CH₂PPh ₂) with ethyldiazoacetate, N₂CHCOOEt, yield the bisdiazoalkane speciestrans-[M(N₂CHCOOEt)₂(dppe)₂], upon simple replacement of the dinitrogen ligand by ethyldiazoacetate. However, diazomethane, N₂CH₂, reacts withA with loss of N₂ to give products which we tentatively formulate as containing methylene ligands,trans-[M(CH₂)₂(dppe)₂].

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Herstellung von Bisdiazoalkan- und ähnlichen Komplexen aus den Reaktionen von Diazoverbindungen mit Distickstoffkomplexen des Typstrans-[M(N₂)₂(Ph ₂PCH₂CH₂PPh ₂)₂] mitM=Mo oder W

Zusammenfassung Die Reaktion vontrans-[M(N₂)₂(dppe)₂] (A:dppe=Ph ₂PCH₂CH₂PPh ₂ undM=Mo oder W) mit Ethyldiazoacetat, N₂CHCOOEt, ergab nach einfachem Austausch des Distickstoffliganden mit Ethyldiazoacetat die Bisdiazoalkanetrans-[M(N₂CHCOOEt)₂(dppe)₂]. Diazomethan (N₂CH₂) hingegen reagierte mitA unter Verlust von N₂ zu Produkten, die tentativ alstrans-[M(CH₂)₂(dppe)₂] mit Methylenliganden formuliert wurden.

     

New Organic Derivatives of O,O′-(o-, m-, and p-Ditolyl)/Dibenzyldithiophosphates: Synthesis and Characterization

Reactions of (m- and p-ClC ₆ H ₄ NH ₂ ), (p-BrC ₆ H ₄ NO ₂ ), and (p-ClCOC ₆ H ₄ NO ₂ ) with sodium O,O′-ditolyl/dibenzylphosphorodithionates, (ArO) ₂ PS ₂ Na, (Ar = o?, m?, and p?CH ₃ C ₆ H ₄ or –C ₆ H ₅ CH ₂ ) in 1:1 molar ratio in refluxing toluene under anhydrous conditions resulted in the formation of the compounds (ArO) ₂ PS ₂ C ₆ H ₄ L and (ArO) ₂ PS ₂ COC ₆ H ₄ L (L = NH ₂ or NO ₂ ) in 87–94% yield. These viscous compounds were characterized by elemental analyses, molecular weight determination, and IR and NMR ( ¹ H, ¹³ C, and ³¹ P) spectroscopic studies, which revealed a monodentate mode of bonding of the dithiophosphate moiety with the carbon of the phenyl ring of the organic moiety leading to a P–S–C linkage.     

Polyfluorophenylamino Germanes and Their Titanium (IV) Chloride Adducts

Disproportionation reactions between (CF ₃ CH ₂ O) ₃ GeNHC ₆ H _{5 ? n} F _n and TiCl ₄ in petroleum ether (40?60°C) at 0° to ?10°C give (CF ₃ CH ₂ O) ₂ Ge(NHC ₆ H _{5 ? n} F _n ) ₂ ^.2TiCl ₄ and (CF ₃ CH ₂ O)Ge(NHC ₆ H _{5 ? n} F _n ) ₃ ^. 2TiCl ₄ adducts. However, complete disproportionation of (CF ₃ CH ₂ O) ₃ Ge(NHC ₆ H _{5 ? n} F _n ) (n = 1,2) occurs at ?55 to ?60°C to give Ge(NHC ₆ H _{5 ? n} F _n ) ₄ ^.3TiCl ₄ . These complexes give double adducts on reactions with CH ₃ NO ₂ and CH ₃ CN. All the products are characterized by elemental analyses and IR, ¹ H, and ¹⁹ F NMR spectroscopy. A comparative disproportionation of the germanamines and analogous silanamines is discussed.     

ORGANOSTANNOXANE MOTIFS IN CAGES AND SUPRAMOLECULAR ARCHITECTURES

The reactions of n-butyl stannonic acid with(PhO) ₂ P(O)H leads to the formation of a hexameric tin cage [{(n-BuSn) ₃ (PhO) ₃ O} ₂ {HPO ₃ } ₄ ].This reaction involves an in situ P─O bond cleavage and the generation of a [HPO ₃ ] ^2? ion. A direct reaction of six equivalents of n-BuSnO(OH) acid with six equivalents of C ₆ H ₅ OH and four equivalents of H ₃ PO ₃ also leads to the formation of same cage structure. A tetranuclear organooxotin cage[(PhCH ₂ ) ₂ Sn ₂ O(O ₂ P(OH)-t-Bu) ₄ ] ₂ has been assembled by debenzylation involving the reaction of (PhCH ₂ ) ₂ SnCl ₂ ,(PhCH ₂ ) ₂ SnO·H ₂ O or (PhCH ₂ ) ₃ SnCl with two equivalents of t-BuP(O)OH ₂ . A half-cage intermediate [(PhCH ₂ ) ₂ Sn ₂ O(O ₂ P(OH)-t-Bu) ₄ ] has been detected. New organotin cations of the type [n-Bu ₂ Sn(H ₂ O) ₄ ] ²⁺[2,5-Me ₂ -C ₆ H ₃ SO ₃ ]^? ₂ and {[n-Bu ₂ Sn(H ₂ O) ₃ LSn(H ₂ O) ₃ (n-Bu) ₂ ] ²⁺[1,5-(SO ₃ ) ₂ -C ₁₀ H ₆ ] ^2?} have been obtained in the reactions of n-Bu ₂ SnO or (n-Bu ₃ Sn) ₃ O with 2,5-dimethyl sulfonic acid and 1,5-naphthalene disulfonic acid respectively. These organotin cations form interesting supramolecular structures in the solid state as a result of O─H─···O hydrogen bonding.     

Evidence for Cluster Orbital Formation in CsSn2X5 Compounds (X=Cl, Br)

The formation of cluster orbitals in CsSn₂Br₅ is discussed and related more generally to tetragonal compounds of the type AB₂X₅ (A=monovalent cation; B=Sn, Pb; X=Cl, Br, I). The crystal structures of CsSn₂Cl₅ and CsSn₂Br₅ have been solved by single-crystal X-ray diffraction. These compounds are isostructural with each other and a range of AB₂X₅ structural analogues. In many AB₂X₅ compounds where B is a subvalent main group metal a tetragonal cell is observed with space group I4/mcm. The structures of CsSn₂Br₅ and CsSn₂Cl₅ are layered with polymeric sheets of [Sn₂X₅]ⁿ⁻_n separated by the Cs⁺ cations. Stereochemical considerations suggest that stabilization of this structural form, rather than the more ionic NH₄Pb₂Cl₅ or NaSn₂Cl₅ structures, is through interaction of the “nonbonding” valence electron pairs on tin with low-lying empty d-orbitals on neighboring X atoms. Electronic structure calculations based on the structural data confirm the likelihood of cluster orbital formation. Crystal data: CsSn₂Cl₅, tetragonal, I4/mcm, a=8.153(1) Å, c=14.882(4) Å, Z=4, R₁=0.0215, wR₂=0.0503 [I>2σ(I)], R₁=0.0393, wR₂=0.0536 (all data); CsSn₂Br₅, tetragonal, I4/mcm, a=8.483(6) Å, c=15.28(2) Å, Z=4, R₁=0.0607, wR₂=0.1411 [(I>2σ(I)], R₁=0.1579, wR₂=0.1677 (all data).     

Platinum Indolylphosphine Fluorido and Polyfluorido Complexes: An Interplay between Cyclometallation,Fluoride Migration,and Hydrogen Bonding

The reaction of [PtCl₂(COD)] (COD=1,5-cyclooctadiene) with diisopropyl-2-(3-methyl)indolylphosphine (iPr₂P(C₉H₈N)) led to the formation of the platinum(ii ) chlorido complexes, cis-[PtCl₂{iPr₂P(C₉H₈N)}₂] ( 1 ) and trans-[PtCl₂{iPr₂P(C₉H₈N)}₂] ( 2 ). The cis-complex 1 reacted with NEt₃ yielding the complex cis-[PtCl{κ²-(P,N)-iPr₂P(C₉H₇N)}{iPr₂P(C₉H₈N)}] ( 3 ) bearing a cyclometalated κ²-(P,N)-phosphine ligand, while the isomer 2 with a trans-configuration did not show any reactivity towards NEt₃. Treatment of 1 or 3 with (CH₃)₄NF (TMAF) resulted in the formation of the twofold cyclometalated complex cis-[Pt{κ²-(P,N)-iPr₂P(C₉H₇N)}₂] ( 4 ). The molecular structures of the complexes 1–4 were determined by single-crystal X-ray diffraction. The fluorido complex cis-[PtF{κ²-(P,N)-iPr₂P(C₉H₇N)}{iPr₂P(C₉H₈N)}] ⋅ (HF)₄ ( 5 ⋅ (HF)₄) was formed when complex 4 was treated with different hydrogen fluoride sources. The Pt(ii ) fluorido complex 5 ⋅ (HF)₄ exhibits intramolecular hydrogen bonding in its outer coordination sphere between the fluorido ligand and the NH group of the 3-methylindolyl moiety. In contrast to its chlorido analogue 3 , complex 5 ⋅ (HF)₄ reacted with CO or the ynamide 1-(2-phenylethynyl)-2-pyrrolidinone to yield the complexes trans-[Pt(CO){κ²-(P,C)-iPr₂P(C₉H₇NCO)}{iPr₂P(C₉H₈N)}][F(HF)₄] ( 7 ) and a complex, which we suggest to be cis-[Pt{C=C(Ph)OCN(C₃H₆)}{κ²-(P,N)-iPr₂P(C₉H₇N)}{iPr₂P(C₉H₈N)}][F(HF)₄] ( 9 ), respectively. The structure of 9 was assigned on the basis of DFT calculations as well as NMR and IR data. Hydrogen bonding of HF and NH to fluoride was proven to be crucial for the existence of 7 and 9 .     

A variation principle for energy differences between states of two different Hamiltonians

A modification of a variation principle due to Delves, is derived which permits the direct calculation of energy differences between states of two different Hamiltonians: [Δ ??] = 〈X₀| ??_x – W_x|X₁〉 – 〈Y₀|??_y – W_y|y₁〉 + 〈X₀| Δ ??|Y₀〉 · 〈X₀| Y₀〉^?1. Δ ?? = ??_y – ??_x, |X₀〉 and |Y₀〉 are the wave functions for the X and Y states and |X₁〉 and |Y₁〉 are functions defined in the text. The principle is applied to a few simple examples.     

The hard-sphere model for linear and regular star polybutadienes

The dilute solution properties of linear, 18-arm, and 270-arm star polybutadienes have been studied in a theta solvent and in a good solvent. Values of the radius of gyration R_G, the second virial coefficient A₂, the intrinsic viscosity [η], and the diffusion coefficient D₀ have been measured for each polymer. The ratios R_T/R_G, R_V/R_G, and R_H/R_G for each type of polymer are used to compare the four dilute solution properties. R_T is termed the “thermodynamic radius.” It is the radius of the hard sphere with the same excluded volume as the polymer coil. R_T is calculated from A₂ by R_T = (3A₂M₂/16ηN_A)^1/3. R_V and R_H are equivalent hard spheres defined for the intrinsic viscosity and translational diffusion coefficient, respectively. R_T/R_G, R_V/R_G, and R_H/R_G increase from about 0.7 for linear polymer coils as the number of arms in the star increases. Values of the ratios for the 18-arm stars are less than the value for the hard-sphere, but the values of the ratios of the 270-arm stars are equal to the hard-sphere limit within experimental error.     

Three Inter‐Alkali Metal Acetylides: KNaC2, KRbC2, and NaRbC2: Syntheses,Crystal Structures,and Structural Systematics

Three alkali metal acetylides, namely KNaC₂, KRbC₂, and NaRbC₂, were synthesized and characterized by means of X‐ray powder diffraction. KNaC₂ and KRbC₂ crystallize as a variant of the anti‐PbCl₂‐type structure (Pnma, Z = 4), whereas NaRbC₂ crystallizes as a variant of the anti‐PbFCl‐type structure (Pmmn, Z = 2). Based on a simple systematic approach developed by Sabrowsky et al. for inter‐alkali metal chalcogenides all known inter‐alkali metal acetylides can be classified into two classes: variants of the anti‐PbCl₂ type structure and variants of the anti‐PbFCl type structure. Acetylides with Q(ABC₂) ≤ 1.45 crystallize in the anti‐PbCl₂‐type structure, whereas for Q(ABC₂) > 1.45 the anti‐PbFCl‐type structure is found (Q(ABC₂) = V_m(A₂C₂)/V_m(B₂C₂) with V_m(A₂C₂) > V_m(B₂C₂); V_m: molar volume, A, B = alkali metals).     

Relationship between kinetic chain length and radical polymerization rate

In the copolymerization of monomers M₁ and M₂ which form polymer radicals of chain length n of N¹_n with electron on a M₁ type and N²_n with one on a M₂ type, it is assumed that the specific rates of termination between N¹_n and N¹_n and N¹_s, N¹_n and N²_s, and N²_n and N²_s are k_α(ns)^?a, k_β(ns)^?a, and k_γ(ns)^?a, respectively, where k_α, k_β, and k_γ are the rate constants of reaction between segment radicals in the respective termination, and a is constant. The relation between kinetic chain length n? and polymerization rate R_p is derived as: 1/n? = 1/n?₀ + const. (R_p)^A(a), where n?₀ is the kinetic chain length of the polymer formed by transfer and A (a) is unity (predominance of transfer) and 1/(1–2a) (no transfer). In the copolymerization between methyl methacrylate (M₁) and styrene (M₂) at 60°C, when R_p → 0, k_r12/k₁₂ + k_r21/k₂₁ = 5.9× 10^?5 is obtained, where k_r12 and k_r21 are the rate constants of transfer of N¹ to M₂ and N² to M₁, and k₁₂ and k₂₁ are the rate constants of propagation of N¹ to M₂ and N² to M₁. In the absence of transfer, the a value is found to be 0.065 ± 0.008, from the relation between n? and R_p, regardless of the monomer composition. Such a value is also estimated by setting b = 0.72 in a = 0.153 (2b–1), where b is the constant in the Mark-Houwink equation. Further, the value of k_β is found to be 1.18 × 10⁹l./mole-sec, which is comparable with the diffusion-controlled rate of reaction between small molecules. The rate of reaction between segment radicals is fivefold larger than the polymer-polymer termination when transfer predominates.     

Molecular weight-dependence of free volume in polystyrene studied by positron annihilation measurements

Positron annihilation lifetime measurements are reported for four monodisperse polystyrenes with molar mass M = 4,000, 9,200, 25,000, and 400,000. The temperature dependences of orthopositronium (o-Ps) lifetime (τ₃) and intensity (I₃) were measured from 5°C to T_g + 30°C for each sample. From these data, the free volume hole size, 〈v_f(τ₃)〉, and fractional free volume h_ps=CI₃〈v_f(τ₃)〉 were calculated. The temperature dependences of τ₃, 〈v_f(τ₃)〉 and h_ps show a discrete change in slope at an effective glass transition temperature, T_g,ps, which is measurably below the conventional bulk T_g. This suggests that τ₃ is sensitive to large holes which retain their liquid-like mobility in the glassy state. Good agreement was found for T > h_g,ps between h_ps and the theoretical free volume fraction h_th deduced from experimental P-V-T data for polystyrene using the statistical mechanical theory of Simha and Somcynsky. Below T_g,ps, deviations between h_ps and h_th are observed, h_ps falling increasingly below h_th as temperature decreases. Whereas h_ps and h_th depend strongly on M in the melt, each essentially independent of M in the glass. A free volume quantity, computed from the bulk volume, which is in good numerical agreement with the Simha-Somcynsky h-function in the melt, gives improved agreement with h_ps in the glassy state. © 1994 John Wiley & Sons, Inc.     

Interaction between two double layers for Na3PO4 types electrolytes at y0 > yd > 0

Interaction between two double layers for the Na₃PO₄ type electrolytes at y ₀ > y _d > 0 were investigated with the aid of λ parameter methods and the accurate numeral results were given. The maximum of the interaction energies between two double layers for A_v+ B_v- A_{v_ + } B_{v_ - } type electrolytes at y ₀ > y _d > 0 is independent of y ₀, but increases with y _d . The interaction energies between two double layers for NaCl, CaCl₂, FeCl₃, Na₂SO₄ and Na₃PO₄ type electrolytes at y ₀ = 5 and y _d = 2 were compared. If the negative or positive ions for A_v+ B_v- A_{v_ + } B_{v_ - } type electrolytes have the same charge number, the maximum of their interaction energies increases with the charge number of the ions of opposite charge. If the negative or positive ions of the electrolytes have different charge numbers, the relative heights of the maxima of their interaction energies are indefinite. For the in pairs conjugate type electrolytes like CaCl₂ and Na₂SO₄ or FeCl₃ and Na₃PO₄, the larger the charge number of the negative ions of the electrolytes is, the higher the maximum of their interaction energies is. The results for Na₃PO₄ type electrolytes at y ₀ > y _d > 0 can also be applied to FeCl₃ type electrolytes at y ₀ > y _d > 0.