Collisional activation spectra of quarternary ammonium cations produced by field desorption

Collisional activation spectra of quarternary ammonium cations produced by field desorption are reported. The principal fragmentation pathways of these ions are discussed. Furthermore, it is demonstrated that collisional activation in conjunction with field desorption is useful for the elucidation of the structure of complex organic cations.     

Synthesis of bismuth complexes from bismuth iodide and ammonium and phosphonium salts

The complexes [Et₂NH₂] ₃ ⁺ [BiCl₆]^3? (I), [NH₄]⁺[BiI₄(C₅H₅N)₂]^?·2C₅H₅N (II), [Ph₃MeP] ₂ ⁺ [BiI₅]^2? (III), [Ph₃MeP] ₂ ⁺ [BiI₅(C₅H₅N)]^2?·C₅H₅N (IV), [Ph₃MeP] ₃ ⁺ [Bi₃I₁₂]^3? (V), [Ph₃(i-Pr)P] ₃ ⁺ [Bi₃I₁₂]^3?·2Me₂C=O (VI), [Ph₃BuP] ₂ ⁺ [Bi₂I₈·₂Me₂C=O]^2? (VII), and [Ph₃BuP] ₂ ⁺ [Bi₂I₈·2Me₂S=O]^2? (VIII) were obtained by reactions of bismuth iodide with ammonium and phosphonium iodides in acetone, pyridine, or dimethyl sulfoxide.     

Reactions of bismuth iodide with ammonium,phosphonium, and bismuthonium salts

The reactions of ammonium, phosphonium, and bismuthonium salts with bismuth iodide were used to synthesize a series of complex compounds with bismuth-containing anions: [(HOC₂H₄)₃NH]⁺ ₄[Bi₄I₁₆]^4?, [Ph₃EtP] ₃ ⁺ [Bi₂I₉]^3?, and [Ph₄Bi] ₃ ⁺ [Bi₅I₁₈]^3?. X-ray diffraction data show that the nitrogen atoms in the two types of crystallographically independent cations of the nitrogen-containing complex possess a distorted tetrahedral coordination [the CNC angles are 110.3(9)°–113.2(9)°]. In the tetranuclear centrosymmetric [Bi₄I₁₆]^4? anion, the bismuth atoms have an octahedral coordination: Two types of groups, BiI₂ and BiI₃, are bound with one another by four μ₂-and two μ₃-iodine bridges (the Bi-I-μ₂, Bi-I-μ₃, and Bi-I-μ₁ distances are 3.1296(10), 3.2808(8); 3.3210(8) and 2.8670(8)–2.9108(9) Å, respectively). The coordination of the phosphorus atom in the [Ph₃EtP]⁺ cations of the phosphorus-containing complex is close to tetrahedral (the CPC angles are 107.5°–114.1°). In the binuclear [Bi₂I₉]^3? anions, the bismuth atoms have an octahedral coordination. The axial I-Bi-I angles are 167.52(2)°, 169.84(2)°, and 174.97(2)°. The terminal BiI₃ fragments [Bi²-I^7,8,9 2.9238(7), 2.9236(7), and 2.9522(7) Å] are in the eclipsed conformation.     

On the transition state of the thermal propene elimination from allylphosphines

Diallyltetramethylpiperidinophosphine 1, diallyldiisopropylaminophosphine 2, and diallylmesitylphosphine 3 were pyrolyzed in a stirred flow reactor over the temperature range 400–450°C, using toluene as carrier gas, producing, in all cases, mixtures of phosphorus-containing products. The pyrolysis of 1 produced 1-tetramethylpiperidino-1-phosphabutadiene, in addition to a mixture of phosphines and polyphosphines. Compound 2 produced the azadiphosphole 4, the phosphinine 5, allylphosphine, and diisopropylaminophosphine as major phosphorated products. The pyrolysis of 3 produced a mixture of phosphines and polyphosphines. The complex mixture generated by the three diallylphosphines indicates the formation of free radicals during their pyrolyses. AM1 calculations on the transition state of an expected retroenetype propene elimination reaction showed that, due to the phosphaalkene character of the transition state, the structure of the latter is very rigid and sensitive to steric effects. Steric hindrance of the substituents on the phosphorus atom compels the molecule to distort the half-chair transition structure, causing a rise in the activation energy to values in the range of a homolytic P(SINGLE BOND)C bond dissociation energy. © 1997 John Wiley & Sons, Inc.     

Synthesis of pyrimidine betaines with phosphonium and cycloammonium cations

Previously undescribed pyrimidine betaines with cycloammonium and triphenylphosphonium cations were obtained. A study of the UV, IR, PMR, and mass spectra made it possible to draw a conclusion regarding the noncyclic structure of betaines stabilized by an intramolecular donor-acceptor interaction of the charge-transfer complex (CTC) type.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1687–1690, December, 1978.     

Transition structure for the retroene-type elimination reaction of propene from allylamines

The transition-state geometries of retroene elimination reactions of propene from allylamines have been calculated by using the semiempirical AM1 method. The most favored geometry resembles a half chair or a flattened boat. It is also found that the transition states are of polar character and that the negative charge on the N atom decreases in the transition state; thus, the reaction is favored by electron donor substituents on the nitrogen atom, as observed experimentally. © 1997 John Wiley & Sons, Inc.     

含氟膦、胂叶立德的质谱研究

本文报道37个含氟膦.胂羰基的叶立德衍生物的电子轰击(EI)和8个含氟胂羟基叶立德的甲烷化学电离(Cl)正.负离子质谱. 研究其断裂规律,氧和氟原子重排以及不同取代基对一些特征离子强度的影响.     

Comparison of physicochemical properties of new ionic liquids based on imidazolium, quaternary ammonium, and guanidinium cations

More than 50 ionic liquids were prepared by using imidazolium, quaternary ammonium, and guanidinium cations and various anions. In these series, different cationic structures such as 1-benzyl-3-methylimidazolium [Bzmim]+, 1,3-dibenzylimidazolium [BzmiBz]+, 1-octyl-3-methylimidazolium [C8mim]+, 1-decyl-3-methylimidazolium [C10mim]+, tricapryl-methylammonium [Aliquat]+, benzyltriethylammonium [BzTEA]+, phenyltrimethylammonium [PhTMA]+, and dimethyldihexylguanidinium [DMG]+ were combined with anions, p-toluenesulfonate [TSA](-), dicyanoamide [DCA]-, saccharine (2-sulfobenzoic acid imide sodium salt) [SAC]-, trifluoroacetate [TFA]-, bis(trifluoromethanesulfonyl)imide [Tf2N]-, trifluoromethanesulfonate [TfO]-, and thiocyanate [SCN]-. Important physical data for these ionic liquids are collated, namely solubility in common solvents, viscosity, density, melting point and water content. Apart from the viscosity, the Newtonian and non-Newtonian behavior of these ionic liquids is also disclosed. Stability of these ionic liquids under thermal, basic, acidic, nucleophilic, and oxidative conditions was also studied. The features of the solid-liquid phase transition were analyzed, namely the glass transition temperature and the heat capacity jump associated with the transition from the non-equilibrium glass to the metastable supercooled liquid. A degradation temperature of each ionic liquid was also determined. Comparisons of the properties of various ionic liquids were made.     

Self association of some quaternary ammonium and phosphonium salts in benzene

From the dependence of the molal osmotic coefficients of (hept)₄NX (X = Cl, Br, J), (hept)₄NNO₃ and (oct)₄PNO₃, in benzene at 33, 40 and 50°C, on the solute concentration, the dimerization constants of solute ion-pairs and the corresponding thermodynamic functions of dimerization, ΔG°, ΔH° and ΔS° have been calculated. The thermodynamic data are discussed in terms of a simple electrostatic model of association.     

Induction of thermotropic bicontinuous cubic phases in liquid-crystalline ammonium and phosphonium salts

Two series of wedge-shaped onium salts, one ammonium and the other phosphonium, having 3,4,5-tris(alkyloxy)benzyl moieties, exhibit thermotropic bicontinuous "gyroid" cubic (Cub(bi)) and hexagonal columnar liquid-crystalline (LC) phases by nanosegregation between ionophilic and ionophobic parts. The alkyl chain lengths on the cationic moieties, anion species, and alkyl chain lengths on the benzyl moieties have crucial effects on their thermotropic phase behavior. For example, triethyl-[3,4,5-tris(dodecyloxy)benzyl]ammonium hexafluorophosphate forms the thermotropic Ia3d Cub(bi) LC phase, whereas an analogous compound with trifluoromethanesulfonate anion shows no LC properties. Synchrotron small-angle diffraction intensities from the Ia3d Cub(bi) LC materials provide electron density maps in the bulk state. The resulting maps show convincingly that the Ia3d Cub(bi) structure is composed of three-dimensionally interconnected ion nanochannel networks surrounded by aliphatic domains. A novel differential mapping technique has been applied successfully. The map of triethyl-[3,4,5-tris(decyloxy)benzyl]ammonium tetrafluoroborate has been subtracted from that of the analogous ammonium salt with hexafluorophosphate anion in the Ia3d Cub(bi) phases. The differential map shows that the counteranions are located in the core of the three-dimensionally interconnected nanochannel networks. Changing from trimethyl- via triethyl- to tripropylammonium cation changes the phase from columnar to Cub(bi) to no mesophase, respectively. This sensitivity to the widened shape for the narrow end of the molecule is explained successfully by the previously proposed semiquantitative geometric model based on the radial distribution of volume in wedge-shaped molecules. The LC onium salts dissolve lithium tetrafluoroborate without losing the Ia3d Cub(bi) LC phase. The Cub(bi) LC materials exhibit efficient ion-transporting behavior as a result of their 3D interconnected ion nanochannel networks. The Ia3d Cub(bi) LC material formed by triethyl-[3,4,5-tris(decyloxy)benzyl]phosphonium tetrafluoroborate shows ionic conductivities higher than the analogous Ia3d Cub(bi) material based on ammonium salts. The present study indicates great potential of Cub(bi) LC nanostructures consisting of ionic molecules for development of transportation nanochannel materials.     

Infrared spectra of thiopyrylium and pyrylium cations

Normal coordinate analysis has been carried out for the in-plane and out-of-plane vibrations of thiopyrylium (1) and pyrylium (2) cations which are isoelectronic with benzene, in order to investigate the structural characteristics (the contribution of the carbonium ion structures and the Kekulé structures to their resonance hybrid). Several sets of parameters for the double bond stretching constants have been chosen considering the delocalization of the positive charge. As a result, much more delocalization of the positive charge in 1 than in 2 has been found.     

A mechanistic investigation into the elimination of phosphonium salts from rhodium-TRIPHOS complexes under methanol carbonylation conditions

Phosphine modified rhodium complexes are currently the topic of considerable research as methanol carbonylation catalysts, but often suffer from poor stability. This paper reports on an investigation into how coordination mode affects the elimination of phosphonium salts from rhodium complexes, namely [trans-RhCl(CO)(PPh(3))(2)] , [RhCl(CO)(dppe)] , [RhCl(CO)(dppb)](2), [Rh(TRIPHOS)(CO)(2)]Cl . These complexes are all potential pre-catalysts for methanol carbonylation. The reaction of these complexes with methyl iodide at 140 degrees C under both N(2) and CO atmospheres has been studied and has revealed clear differences in the stability of the corresponding Rh(iii) complexes. In contrast to both monomeric and dimeric that react cleanly with CH(3)I to give stable Rh(iii) acetyl complexes, forms a novel bidentate complex after the elimination of the one arm of the ligand as a quaternised phosphonium salt. The structure of this complex has been determined spectroscopically and using X-ray crystallography. The mechanism of formation of this novel complex has been investigated using (13)CH(3)I and strong evidence that supports a dissociative mechanism as the means of phosphine loss from the rhodium centre is provided.     

Infrared spectra and rotational isomerism of epifluorohydrin and other propene oxide derivatives

The infrared spectrum for the vapour, liquid and solid states of epifluorohydrin has been studied, and evidence has been obtained for the presence of rotational isomers. The dominant conformer in all phases corresponds to a gauche structure, which was the only form identified in the vapour by microwave spectroscopy [1]. Similar evidence for conformational equilibria has been found for the chloro, bromo and iodo derivatives, and the enthalpy differences between the rotational isomers of these compounds were measured respectively as 4580 ± 970, 3950 ± 400, and 2350 ± 170 J mol^?1 respectively. At low temperatures, epiiodohydrin was found to crystallize in one of two possible crystalline phases. These two phases correspond to the two rotational isomeric conformations of the molecule.     

Absorption,excitation and fluorescence spectra of lead activated ammonium chloride

A systematic study of absorption, excitation and fluorescence spectra of ammonium chloride activated by varied amounts of lead concentration have been made for the first time. Absorption bands at 6.08, 5.69, 4.73 and 4.57 eV at room temperature and fluorescence bands at 3.62 and 2.85 eV at liquid nitrogen temperature have been observed. These investigations provide an experimental evidence for the existence of two types of centres involved in the luminescence process.     

Nano-biphasic ionic liquid systems composed of hydrophobic phosphonium salts and a hydrophilic ammonium salt

A combination of a phosphonium-type-zwitterions-lithium bis(trifluoromethanesulfonyl)imide complex and a hydrophilic ammonium salt provides a nanosegregated liquid-crystalline matrix consisting of hydrophilic ionic liquid (IL) domains and hydrophobic IL domains.     

Catalytic phosphorylation of polyfluoroalkanols 13. Some ammonium and phosphonium salts as phosphorylation catalysts

It was shown that it is possible to use a series of ammonium and phosphonium salts as effective catalysts for the preparative synthesis of tris(polyfluoroalkyl) phosphates. The effect of the structure of substituted ammonium salts on their catalytic activity was studied in the phosphorylation of 1,1-dihydroperfluorobutanol by phosphorus oxychloride. It was determined that the reaction rate is affected not only by the solubility of the salt, but also by the nature of the ion pair and the steric access of the onium center for solvation by phosphoryl compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2789–2792, December, 1989.