Arsonium Research Articles

A facile synthesis of ω-substituted conjugated polyenones via arsonium salt and its application towards the synthesis of navenone A

In the presence of K 2CO 3, a variety of aldehydes condensed with the arsonium bromide 8 at 0–3°C to give exclusively ω-substituted polyenones 1 in good yields, and the synthesis of navenone A was achieved by this procedure.

Studies on the pyrolysis-gas chromatography of model quaternary arsonium compounds

Pyrolysis-gas chromatography has been used to investigate the thermal decomposition of simple quaternary arsonium salts. The results indicate that this technique is particularly suitable for the study of highly alkylated compounds, and in contrast to the phosphorus analogues, tertiary arsines, and not arsine oxides, are observed even in the presence of oxygen-containing species. Highly arylated compounds, however, give both tertiary arsine and arsine oxide and this is explained in terms of the thermal stabilities of intermediate species.

ChemInform Abstract: Facile Formylolefination of Aldehydes by Means of Arsonium Salt.

AbstractDie Aldehyde (II) reagieren mit dem Arsoniumsalz (I) zu den Olefinen (III), aus dem Dialdehyd (V) entsteht das Dien (VI).

Facile formylolefination of aldehydes by means of arsonium salt

A facile formylolefination of a variety of aldehydes was achieved by using formylmethyltriphenylarsonium bromide with K2CO3(trace H2O) at room temperature to give highly stereoselectively (E) α,β-unsaturated aldehydes in excellent yields.

Synthesis and resolution of an asymmetric arsonium cation. Crystal and molecular structures of (R)-Benzyl(methyl)(4-methylphenyl)(naphthalen-1-yl)- arsonium bromide and hexafluorophosphate

The (�)-benzyl(methyl)(4-methylphenyl)(naphthalen-1-yl)arsonium cation has been synthesized and subsequently resolved by fractional crystallization of monohydrogen [R-(R*,R*)]-2,3-bis(benzoyloxy)- butanedioate salts. The separated diastereoisomers were converted into the corresponding optically active arsonium bromides by ion-exchange column chromatography. The absolute configuration of the arsonium cation exhibiting a positive rotation at 589 nm (sodium D line) has been established as (R) by single-crystal X-ray analysis of both the bromide and hexafluorophosphate salts. The arsonium bromide with [α]D + 54.8�(c, 0.62 in CH2Cl2) crystallizes in the orthorhombic space group P212121 (D24, No.19) with a 22.472(8), b 15.724(7), c 12.585(5) � and U 4447(3) �3. The corresponding hexafluorophosphate with [α]D + 19.3� (c, 0.5 in CH2Cl2) crystallizes in the same space group with a 23.56(2), b 16.40(1), c 13.12(1) � and U 5067(6) � 3. Benzylidene transfer to benzaldehyde from the arsonium ylide derived from either of the arsonium salts produced optically pure (–)-(S)-methyl(4-methylphenyl)(naphthalen-1-yl)arsine, [α]D - 115.9� (c, 0.593 in CHCl3), and partly resolved [R-(R*,R*)]-2,3-diphenyloxiran.

Oxotrihalogenoselenate(IV): Darstellung, Struktur und Eigenschaften von P(C6H5)4SeOCl3, P(C6H5)4SeOBr3 und As(C6H5)4SeOBr3

The novel oxotribromosolcnate(IV) SeOBr3- anion was prepared from the reaction of stoichiometric quantities of SeOBr2 and bromide in acetonitrile solution, and it was isolated as the tetraphenylphosphonium and -arsonium salts in crystalline form. For the synthesis of the analogous SeOCl3- as P(C6H5)4SeOCl3, SeCl4 was reacted in the presence of a small quantity of H2O with P(C6H5)4Cl in acetonitrile. Complete X-ray structural analyses of P(C6H5)4SeOCl3 (space group P1̄, a = 10.981(3), b = 11.0511(3), c = 10.358(3) Å, α = 73.77(2)°, β = 83.33(2)°, γ = 80.51(2)°, V = 1187.9(6) Å3) and of P(C6H5)4SeOBr3 (space group P 21/c, a = 11.719(4), b = 16.088(4), c = 13.124(4) Å, β = 94.72(3)°, V = 2400(1) Å3) show dimeric centrosymmetric Se2O2Cl6 2- and Se2O2Br6 2- anions being present in the solid. In the anions two square-pyramidal (Ψ-octahedral) SeOHal4 groups are connected through a common Hal-Hal edge. The axial oxygen ligands (So-O: 1.597(4) and 1.584(0) Å) cause a pronounced stereochemical trans-activation of the inert pairs at the Se atoms. As(C6H5)4SeOBr3 is isotypic with P(C6H5)4SeOCl3.

Cathodic Reduction of Some Arsonium Salts in Presence of Carbonyl Compounds

Cathodic Reduction of Some Arsonium Salts in Presence of Carbonyl Compounds

ChemInform Abstract: REACTION OF PHENACYLTRIPHENYLARSONIUM BROMIDES WITH N‐METHYLANILINE AND N,N‐DIMETHYLANILINE

AbstractDie Arsoniumbromide (Ia) und (Ib) reagieren bei Gegenwart von HBr mit Dimethylanilin (II) zu den N‐Methylindolen (III).

Reaction of Phenacyltriphenylarsonium Bromides with N-Methylaniline and N,N-Dimethylaniline

Abstract Reaction of phenacyltriphenylarsonium bromide with N-methylaniline furnished 2-phenylindole predominantly together with 1-methyl-2-phenylindole. The corresponding reaction of the arsonium salt with N,N-dimethylaniline did not give any indole, instead a simple nucleophilic substituted product, α-4′-(dimethylamino)deoxybenzoin was obtained. But, the latter reaction on being carried out in presence of hydrobromic acid afforded 1-methyl-2-phenylindole by the demethylation of N,N-dimethylaniline.

ChemInform Abstract: TRANSYLIDATION REACTIONS IN ARSONIUM YLIDES

AbstractQuatemisierung von Triphenylarsin mit substituierten Benzylbromiden führt zu den Arsoniumbromiden (I), die bei Behandlung mit NaH in Benzol unter Dehydrohalogenierung die nicht isolierbaren, in Lösung stabilen Ylide (II) liefern.

Transylidation Reactions in Arsonium Ylides

Abstract Some substituted benzylidenetriphenylarsenanes have been generated from their precursors and treated with acid chlorides or acid anhydrides to afford intermediate arsonium salts which in the presence of starting ylides undergo transylidation to give carbonyl stabilized arsonium ylides in fair to good yields. The structures of these stabilized ylides were confirmed on the basis of their spectral data.

ChemInform Abstract: PROTON SPIN‐LATTICE RELAXATION STUDY OF MOLECULAR MOTION IN TETRAMETHYLARSONIUM HALIDES

Tetramethylarsonium chloride, bromide and iodide have been prepared and their spin–lattice relaxation times measured by proton magnetic resonance pulse spectrometry in the temperature range 77–540 K. The two minima in T1 found for each salt have been assigned to reorientation of methyl groups about the carbon to central atom bonds and to a tumbling motion of the whole cation which approximates isotropic reorientation but is probably reorientation in random sequence about each of the four threefold axes of the tetrahedral cations. The activation energies and other relaxation parameters have been calculated. The activation energies have been compared with those of the corresponding ammonium and phosphonium salts, and where possible, the variations from compound to compound related to the crystal structures. To this end, the X-ray powder diffraction photographs of the arsonium salts were examined and the chloride and bromide indexed in the hexagonal system. The unit cell dimensions are calculated. The iodide is apparently of lower symmetry. At least three phase transitions have been noted in the iodide.

Proton spin–lattice relaxation study of molecular motion in tetramethylarsonium halides

Tetramethylarsonium chloride, bromide and iodide have been prepared and their spin–lattice relaxation times measured by proton magnetic resonance pulse spectrometry in the temperature range 77–540 K. The two minima in T1 found for each salt have been assigned to reorientation of methyl groups about the carbon to central atom bonds and to a tumbling motion of the whole cation which approximates isotropic reorientation but is probably reorientation in random sequence about each of the four threefold axes of the tetrahedral cations. The activation energies and other relaxation parameters have been calculated. The activation energies have been compared with those of the corresponding ammonium and phosphonium salts, and where possible, the variations from compound to compound related to the crystal structures. To this end, the X-ray powder diffraction photographs of the arsonium salts were examined and the chloride and bromide indexed in the hexagonal system. The unit cell dimensions are calculated. The iodide is apparently of lower symmetry. At least three phase transitions have been noted in the iodide.

Partial asymmetric synthesis of substituted trans-2,3-diaryloxirans using optically active arsonium ylides

Ylides derived from optically active arsonium salts react with aromatic aldehydes to give trans-2,3-diaryl-oxirans in high chemical yields and with optical purities of between 4·7 and 38%.

Tetraorganophosphonium and tetraphenylarsonium salts of B 5H 8− and B 6H 9−

Eight new quaternary phosphonium or arsonium salts of the polyhedral borane anions B 5H 8 − and B 6H 9 − have been prepared in order to study the influence of cation size on stability. The salts are, indeed, considerably more stable than those previously prepared, the most stable being the tetraphenylphosphonium and tetraphenylarsonium derivatives. IR and NMR data are reported.

Arsenic-75 nuclear magnetic resonance. A study of some arsenic salts

The 75 As NMR spectra of a series of arsonium salts have been measured. The 75 As chemical shifts show a dependence on the nature of the alkyl chain in a way similar to that for 13 C chemical shifts. The changes in the linewidths of the 75 As resonances in the fully symmetrical species AsR 4 +Br − (R = Me, Et, Pr, Bu) may be accounted for in terms of changes in the molecular correlation time. The existence of the AsH 4 + ion in HF solution is proved.

The phosphonium - sulfonium - and arsonium — salts of TaF 6− and Ta 2F 11−

The phosphonium - sulfonium - and arsonium — salts of TaF 6− and Ta 2F 11−

Ruthenium(III) and ruthenium(II) complexes containing triphenylarsine and other ligands

The reactions of [RuCl 3(AsPh 3) 3] with ligands containing nitrogen (alkyl and aryl cyanides, pyridine, α-picoline N.N′-bipyridyl, 1,10-phenanthroline), oxygen (ketones, aldehydes, N,N-dimethylformamide, tetrahydrofuran, dimethylsulphoxide and nitroalkanes) and sulphur (CS 2 and Me 2S) donor atoms have been studied. The reactions of [RuCl 3(AsPh 3) 3] with tetra alkyl and aryl ammonium and arsonium salts have also been explored. The compounds obtained have been characterised by analyses, conductivity measurements, magnetic measurements and IR spectra. The electronic spectra of the complexes are discussed in terms of possible structures. An equilibrium between hexacoordinated and pentacoordinated species is suggested on the basis of electronic spectral studies.

Excited state decay of tetrahalomanganese(ii) complexes

The excitation and emission spectra and decay times of several MnX 2- 4 (X = Cl −, Br −, 1 −) complexes of various tetraalkylammonium, -phosphonium, and -arsonium salts have been measured for the pure solids at 298°K and 77°K. High luminescence quantum yields (0.3-1.0) reveal that lifetimes fairly accurately reflect radiative decay rates. An impressive correlation exists between the lifetime, τ, of the 4T 1 (G) → 6 A 1 emission and the ligand, X: for X = Cl −, τ = 1.2 - 3,5 x 10 −3 sec; X = Br −, τ = 0.35 - 0.43 X 10 −3 sec; X =l −, τ = 0.036 – 0.055 X 10 −3 sec. We attribute this decreasing lifetime largely to the enhanced spin-orbital coupling associated with the heavier halide. We find that direct population of high energy charge-transfer (CT) states gives smaller emission yields than excitations in the ligand-field (LF) region.

Anionic dimethylplatinum(iv) schiff-base chelate complexes

Summary Anionic dimethylplatinum(IV) complexes with bidentate N -organosalicylaldimines of the form [Me 2 PtX 2 (Sal=N-R)] − (X=Br, Cl) have been synthesized from Me 2 PtX 2 and isolated as thallium, tetraalkylammonium and tetraphenyl arsonium salts. The 1 H NMR and infrared spectra indicate an octahedral structure with the halogen atoms mutually trans. Measurement of 195 Pt- 1 H coupling constants has been used to study some aspects of coordination of the Schiff-bases in these complexes. A binuclear complex involving a quadridentate Schiff-base ligand is also reported.