Novel Antimony Complexes: [Ph4Sb]4 +[Sb4I16]4− · 2Me2C=O and [Ph4Sb]3 +[Sb5I18]3−

The [Ph₄Sb]₄ ⁺[Sb₄I₁₆]^4– · 2Me₂C=O and [Ph₄Sb]₃ ⁺[Sb₅I₁₈]^3– complexes were synthesized by reacting tetraphenylstibonium salts Ph₄SbX (X = I, OSO₂C₆H₄Me-4) with antimony triiodide in acetone. According to X-ray diffraction data, their tetra- and pentanuclear anions [Sb₄I₁₆]^4– and [Sb₅I₁₈]^3– have cyclic and linear structure, respectively.     

Mass spectrometric determination of the configuration of 2-methyl-and 1,2-dimethyl-4-vinyl-ethinyl(n-butyl)-4-hydroxyperhydroquinolines

The configuration at C-2 and C-4 in the molecules of 2-methyl- and 1,2-dimethyl-4-vinylethinyl(n-butyl)-4-hydroxyperhydroquinolines was determined by mass spectrometry. The principal conclusions concerning the stereochemistry were made on the basis of differences in the values of the I_[M?15]⁺/I_[M]⁺·, I_[M?17]⁺/I_[M]⁺·, I[_M?43]⁺/I_[M]⁺· and I_[M?57]⁺/I_[M]⁺· ratios in the mass spectra of the epimeric vinylethinylic alcohols, and of the I_[M?15]⁺/I_[M]⁺· and I_[M?15]⁺/I_[M]⁺· ratios in the case of the n-butylic alcohols.     

Mass spectrometric study of methyl-substituted 4-azaphenanthrenes and their nitration products

The mass spectral behavior of five derivatives of the 4-azaphenanthrene series — 1,3-dimethyl-(I), 2,3-dimethyl-(II), 1,2,3,-trimethyl-(III), 1,2,3-trimethyl-8-nitro-(IV), and 1,3-dimethyl-6,7-dinitro-4-azaphenanthrene (V) — was studied. The stabilities of the molecular ions with respect to gragmentation (W_M) are higher by a factor of two or more for the methyl-substituted I–III than for nitro derivatives IV and V. The intensity of the [M-H]⁺ ion peak in the mass spectra of I–V does not depend on the number of methyl groups but only on their positions: the presence of a CH₃ group in the 2 position leads to an [M-H]⁺ ion that is 1.5 times more intense than when there is a methyl group in the 1 position. The molecular ions of I–V do not eliminate HCN molecules; this constitutes evidence for the absence of randomization of their methyl groups. The presence of a CH₃ substituent in the 1 or 2 position does not affect the intensity of the [M-CH₃]⁺ ion peaks, while the simultaneous presence of CH₃ groups attached to the C₁ and C₂ atoms increases the intensity of the [M-CH₃]⁺ fragment peak by a factor of two. In the mass spectra of nitro derivatives IV and V, [M-O]⁺, [M-OH]⁺, [M-NO]⁺, and [M-NO₂]⁺ fragments are observed in the first step of the fragmentation of the M⁺ ion, whereas the [M-CO]⁺ ion peak characteristic for the dissociative ionization of 1-nitronaphthalene is also observed for 8-nitro-substituted IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1365–1369, October, 1977.     

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.     

The preparation and x-ray structure of [P(C2H5)4]+[N3]− and the attempted preparation of [PH4]+[N3]−

Tetraethylphosphonium azide, [P(C₂H₅)₄ ]⁺[N₃ ]⁻, was prepared from tetraethyl phosphonium bromide and silver azide. Single crystals of [P(C₂H₅)₄ ]⁺[N₃ ]⁻ were grown from dichloromethane/THF (10:1) solution. The structure was determined by single-crystal X-ray diffraction analysis. [P(C₂H₅)₄ ]⁺[N₃ ]⁻ crystallizes in the monoclinic space group C 2/c with Z = 4 and unit cell dimensions a = 12.961(6), b = 6.835(3), c = 12.378(6) Å, and β = 100.57(4)°. The attempted preparation of phosphonium azide [PH₄]⁺[N₃]⁻ from phosphonium iodide and silver azide lead instead to the formation of PH₃ and HN₃. The instability of [PH₄]⁺[N₃]⁻ with respect to PH₃ and HN₃ is in accord with thermodynamic considerations according to which the reaction PH₃(g) and HN₃(g) to yield [PH₄ ]⁺[N₃ ]⁻ is thermodynamically unfavorable. (Non SI units employed: kcal ≈ 4.184 J, Å = 10⁻¹⁰ m.) © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:129–132, 1998     

Bis{[phthalocyaninato(2–)]arsenic(III)} tetradecaiodotetraarsenic(III)

Crystals of the novel title arsenic(III) phthalocyanine complex, [As(C₃₂H₁₆N₈)]₂[As₄I₁₄] or [(AsPc)⁺]₂·[As₄I₁₄]²⁻, where Pc is phthalocyaninate(2−), have been obtained by the reaction of pure powdered As with phthalo­nitrile under a stream of iodine vapour at 493 K. The crystals are built up of separate but interacting [AsPc]⁺ cations and [As₄I₁₂]²⁻ anions. The As atom of the [AsPc]⁺ unit is bonded to the four iso­indole N atoms of the Pc macrocycle and lies 0.743 (2) Å out of the plane defined by these four N atoms. The anionic part of the complex consists of AsI₃ and [AsI₄]⁻ units joined together into an [As₄I₁₄]²⁻ anion. The arrangement of the oppositely charged moieties, [AsPc]⁺ and [As₄I₁₄]²⁻, in the crystal is determined mainly by ionic attraction and by donor–acceptor interactions between the [AsPc]⁺ and [As₄I₁₄]²⁻ ions.     

Synthesis and structure of bismuth-containing complexes [(Ph4BiO)2{2,5-(CH3)2C6H3S(O)}] 2 + [Ph2Bi2I6]2−,[(Ph4Bi]+[PhBi(C5H5N)I3]−, [Ph4Sb] 4 + [Bi4I16]4−⋅2(CH3)2 C=O, and [Ph4Sb] 3 + [Bi5I18]3−

The reactions of tetraphenylbismuthonium and -stibonium salts Ph₄EX (E = Bi, Sb; X = I, OSO₂ (C₆H₃(CH₃)₂-2,5), OSO₂C₆H₃(OH-4)(COOH-3)) with bismuth triiodide in acetone afford complexes [Ph₄Bi]⁺[PhBi(C₅H₅N)I₃]^-, [(Ph₄BiO)₂S(O){2,5-(CH₃)₂C₆H₃S(O)} [Ph₂Bi₂I₆]^2–, [Ph₄Sb [Bi₄I₁₆]^4-·2(CH₃)²C=O, and [Ph₄Sb] ₃₊ ⁺ [Bi₅I₁₈]^3-, whose structural units, according to the X-ray diffraction data, are tetraphenylbismuthonium (-stibonium) cations and mono-, di-, tetra-, and pentanuclear anions, respectively.     

Upon the hydrogen-bonding ability of the H4 and H5 protons of the imidazolium cation

The crystal and molecular structures of [Me₂Etim]Cl, [Me₂Etim]₂[CoCl₄], and [Me₂Etim]₂[NiCl₄] ([Me₂Etim]⁺ = 1,2-dimethyl-3-ethylimidazolium cation) all contain evidence that the H4 and H5 protons of the imidazolium cation enter into hydrogen bonds; the implications of this observation for the interactions in room-temperature chloroaluminate(III) ionic liquids are considered.     

Reduction of iodine by hydroxylamine within the pH range 0.7–3.5

The reduction of iodine by hydroxylamine within the [H⁺] range 3×10⁻¹–3×10⁻⁴ mol.L⁻¹ was first studied until completion of the reaction. In most cases, the concentration of iodine decreased monotonically. However, within a narrow range of reagent concentrations ([NH₃OH⁺]₀/[I₂]₀ ratio below 15, [H⁺] around 0.1 mol.L⁻¹, and ionic strength around 0.1 mol.L⁻¹), the [I₂] and [I₃⁻] vs. time curves showed 2 and 3 extrema, respectively. This peculiar phenomenon is discussed using a 4 reaction scheme (I₂+I⁻⇔︁I₃⁻, 2 I₂+NH₃OH⁺+H₂O→HNO₂+4 I⁻+5 H⁺, NH₃OH⁺+HNO₂→N₂O+2 H₂O+H⁺, and 2 HNO₂+2 I⁻+2 H⁺→2 NO+I₂+2 H₂O). In a flow reactor, sustained oscillations in redox potential were recorded with an extremely long period (around 24 h). The kinetics of the reaction was then investigated in the starting conditions. The proposed rate equation points out a reinforcement of the inhibition by hydrogen ions when [H⁺] is above 4×10⁻² mol.L⁻¹ at 25°C. A mechanism based on ion-transfer reactions is postulated. It involves both NH₂OH and NH₃OH⁺ as the reducing reactive species. The additional rate suppression by H⁺ at low pH would be connected to the existence of H₂OI⁺ in the reactive medium. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 785–797, 1998     

A kinetic study of the oxidation of 3- and 4-pyridinemethanol,and 3- and 4-pyridinecarboxaldehyde by chromium(VI) in acidic aqueous media

Oxidation of 3-pyridinemethanol (3-pyol), 4-pyridinemethanol (4-pyol), 3-pyridinecarboxaldehyde (3-pyal) and 4-pyridinecarboxaldehyde (4-pyal) by Cr^VI was studied under pseudo-first-order conditions in the presence of a large excess of reductant and at various H_aq ⁺ concentrations; [Cr^VI] = 8 × 10^–4 M, [reductant] = 0.025–0.20 M, [HClO₄] = 1.0 and 2.0 M (I = 1.2 and 2.1 M) or 0.5–2.0 (I = 2.1 M). A linear dependence of the pseudo-first-order rate constant (k _obs) on [reductant] and a parabolic function of k _obs versus [H⁺] lead to the rate law: –d[Cr^VI]/dt = (a + b[H⁺]²)[reductant][Cr^VI], where a and b describe the reaction paths via HCrO₄ ^– and H₃CrO₄ ⁺ species respectively, and are composite values including rate constants and equilibrium constants. The apparent activation parameters were determined from second-order rate constants at 1.0 and 2.0 M HClO₄, at three temperatures within the 293–323 K range. The presence of chromium species with intermediate oxidation states – Cr^V, Cr^IV and Cr^II, was deduced based on e.s.r. measurements and the kinetic effects of Mn^II or O₂ (Ar), respectively. The alcohols were oxidized to the aldehydes, and carboxylic acids and the aldehydes to the carboxylic acids. Chromium(III) was in the form of the [Cr(H₂O)₆]³⁺ complex.     

Kinetics and mechanism of the iodine oxidation of hydroxylamine

Studies of the stoichiometry and kinetics of the reaction between hydroxylamine and iodine, previously studied in media below pH 3, have been extended to pH 5.5. The stoichiometry over the pH range 3.4–5.5 is 2NH₂OH + 2I₂ = N₂O + 4I^? + H₂O + 4H⁺. Since the reaction is first-order in [I₂] + [I₃^?], the specific rate law, k₀, is k₀ = (k₁ + k₂/[H⁺]) {[NH₃OH⁺]₀/(1 + K_p[H⁺])} {1/(1 + K_I[I^?])}, where [NH₃OH⁺]₀ is total initial hydroxylamine concentration, and k₁, k₂, K_p, and K_I are (6.5 ± 0.6) × 10⁵ M^?1 s^?1, (5.0 ± 0.5) s^?1, 1 × 10⁶ M^?1, and 725 M^?1, respectively. A mechanism taking into account unprotonated hydroxylamine (NH₂OH) and molecular iodine (I₂) as reactive species, with intermediates NH₂OI₂^?, HNO, NH₂O, and I₂^?, is proposed.     

Equilibrium,kinetics, and mechanism of the malonic acid–iodine reaction

The equilibrium constant for the reaction CH₂(COOH)₂ + I₃^? ? CHI(COOH)₂ + 2I^? + H⁺, measured spectrophotometrically at 25°C and ionic strength 1.00M (NaClO₄), is (2.79 ± 0.48) × 10^?4M². Stopped-flow kinetic measurements at 25°C and ionic strength 1.00M with [H⁺] = (2.09-95.0) × 10^?3M and [I^?] = (1.23-26.1) × 10^?3M indicate that the rate of the forward reaction is given by (k₁[I₂] + k₃[I₃^?]) [HOOCCH₂COO^?] + (k₂[I₂] + k₄[I₃^?]) [CH(COOH)₂] + k₅[H⁺] [I₃^?] [CH₂(COOH)₂]. The values of the rate constants k₁-k₅ are (1.21 ± 0.31) × 10², (2.41 ± 0.15) × 10¹, (1.16 ± 0.33) × 10¹, (8.7 ± 4.5) × 10^?1M^?1·sec^?1, and (3.20 ± 0.56) × 10¹M^?2·sec^?1, respectively. The rate of enolization of malonic acid, measured by the bromine scavenging technique, is given by k_en[CH₂(COOH)₂], with k_en = 2.0 × 10^?3 + 1.0 × 10^?2 [CH₂(COOH)₂]. An intramolecular mechanism, featuring a six-member cyclic transition state, is postulated to account for the results on the enolization of malonic acid. The reactions of the enol, enolate ion, and protonated enol with iodine and/or triodide ion are proposed to account for the various rate terms.     

Mechanism of anation of chromium (III) by L-lysine

The kinetics of L-lysine anation of aquachromium(III) ions have been investigated in the acidity range 5.6 ≤ 10⁵[H⁺] ≤ 31.6 mol dm⁻. The reaction takes place with outer-sphere association between Cr³⁺/CrOH²⁺ and H₂L⁺ (L =⁺HGCH (⁺NH₃)(CO ₂ ^t- ), G being the side chain) followed by transformation of the outer-into an inner-sphere complex by slow interchange. The results are discussed in relation to the data of analogous systems and it is concluded that anation of [Cr(H₂O)₆]^{3 +} follows anI _a path whereas that of [Cr(H₂O)₅OH]_{2 +} follows anI _d path.     

The significance of field ionisation kinetics to ion structure: Isomerisation and decompostition of [C4H8]+· radical ions

The kinetics of formation of [C₃H₅]⁺[M ? CH₃]⁺, [C₃H₄]⁺·[M ? CH₄]⁺· and [C₂H₄]⁺·[M ? C₂H₄]⁺· from but-1-ene, cis- and trans-but-2-ene, 2-methylpropene, cyclobutane and methylcyclopropance following field ionisation have been determined as a function of time 20 (or 30) picoseconds to 1 nanosecond and at two points in the microsecond time-frame. The results are consistent with the supposition that at the shortest accessible times (20 to 30 picoseconds) the structure of the [C₄H₈]⁺· molecular ion qualitatively resembles that of its neutral precursor, but suggest that prior to decomposition within nanoseconds the various molecular ions (excepting cyclobutane where the processes are slower) attain a common structure or mixture of structures. Reaction pathways of the presumed known ion structures are delineated from the nature of decompostion at the shortest times.     

Hydrocarboxylation of isoprene catalyzed by iodo-carbonylrhodium derivatives. Spectroscopic evidence for participation of H+ ··· Rh(CO)2I2− tight ion pairs and cis-Rh(CO)2(H2O)I in catalysis

Hydrocarboxylation of isoprene catalyzed by iodocarbonylrhodium derivatives is described. Either 4-methyl-3-pentenoic (pyroterebic) acid or its lactone derivative (γ,γ-dimethyl-γ-butyrolactone) can be selectively produced in high yield depending on the experimental conditions. Spectroscopic evidence indicates the possible participation of H⁺ ··· Rh(CO)₂I₂⁻ tight ion pairs and/or cis-Rh(CO)₂(H₂O)I in the catalysis. The identification of these two new species is based on spectroscopic investigation of the interconversion reactions between solvent-separated [H₃O]⁺[Rh(CO)₂X₂]⁻ ions and [Rh(CO)₂X]₂ (X = Cl, I).     

Strongly Coupled Cyclometalated Ruthenium Triarylamine Chromophores as Sensitizers for DSSCs

A series of anchor‐functionalized cyclometalated bis(tridentate) ruthenium(II) triarylamine hybrids [Ru(dbp‐X)(tctpy)]^2? [ 2 a ]^2?–[ 2 c ]^2? (H₃tctpy=2,2′;6′,2′′‐terpyridine‐4,4′,4′′‐tricarboxylic acid; dpbH=1,3‐dipyridylbenzene; X=N(4‐C₆H₄OMe)₂ ([ 2 a ]^2?), NPh₂ ([ 2 b ]^2?), N‐carbazolyl [ 2 c ]^2?) was synthesized and characterized. All complexes show broad absorption bands in the range 300–700 nm with a maximum at about 545 nm. Methyl esters [Ru(Me₃tctpy)(dpb‐X)]⁺ [ 1 a ]⁺–[ 1 c ]⁺ are oxidized to the strongly coupled mixed‐valent species [ 1 a ]²⁺–[ 1 c ]²⁺ and the Ru^III(aminium) complexes [ 1 a ]³⁺–[ 1 c ]³⁺ at comparably low oxidation potentials. Theoretical calculations suggest an increasing spin delocalization between the metal center and the triarylamine unit in the order [ 1 a ]²⁺<[ 1 b ]²⁺<[ 1 c ]²⁺. Solar cells were prepared with the saponified complexes [ 2 a ]^2?–[ 2 c ]^2? and the reference dye N719 as sensitizers using the I₃^?/I^? couple and [Co(bpy)₃]^3+/2+ and [Co(ddpd)₂]^3+/2+ couples as [B(C₆F₅)₄]^? salts as electrolytes (bpy=2,2′‐bipyridine; ddpd=N,N′‐dimethyl‐N,N′‐dipyridin‐2‐yl‐pyridine‐2,6‐diamine). Cells with [ 2 c ]^2? and I₃^?/I^? electrolyte perform similarly to cells with N719 . In the presence of cobalt electrolytes, all efficiencies are reduced, yet under these conditions [ 2 c ]^2? outperforms N719 .     

Synthesis and structure of bismuth complexes [Ph3MeP] 2 + [BiI3.5Br1.5(C5H5N)]2− · C5H5N, [Ph4Bi] 4 + [Bi4I16]4− · 2Me2C=O, and [Ph3(iso-Am)P] 4 + [Bi8I28]4− · 2Me2C=O

Complexes [Ph₃MeP] ₂ ⁺ [BiI_3.5Br_1.5(C₅H₅N)]^2? · C₅H₅N(I), [Ph₄Bi] ₄ ⁺ [Bi₄I₁₆]^4? · 2Me₂C=O (II), and [Ph₃(iso-Am)P] ₄ ⁺ [Bi₈I₂₈]^4? · 2Me₂C=O (III) were synthesized by reactions of bismuth iodide with triphenylmethylphosphonium bromide, triphenylbismuthonium sulfosalicylate, and triphenylisoamylphosphonium iodide, respectively. The crystal structures of complexes I–III were determined by X-ray crystallography. The complexes contain, in addition to cations and solvent molecules, mono-, tetra-, and octanuclear anions, in which bismuth atoms are in octahedral coordination.     

Kinetics of anation of chromium(III) by L-phenylalanine

Summary The kinetics of anation of chromium(III) species, [Cr(H₂O)₆]⁴⁺ and [Cr(H₂O)₅OH]²⁺, by L-phenylalanine in aqueous acid has been studied spectrophotometrically. Effects of varying [substrate], [ligand], [H⁺], , % ethanol and temperature were investigated. The kinetic data suggest a mechanism where outersphere-associations [between chromium(III) species and phenylalanine in the zwitterionic form] precede anation. Comparison of the results with published data suggest an I_a path for the [Cr(H₂O)₆]³⁺ reaction and I_d path for the [Cr(H₂O)₅OH]²⁺ reaction.     

Neue Oxonium-Bromochalkogenate(IV) — Darstellung,Struktur und Eigenschaften von [H3O][TeBr5] · 3C4H8O2 und [H3O]2[SeBr6]

New Oxonium Bromochalcogenates(IV) — Synthesis, Structure, and Properties of [H₃O][TeBr₅] · 3 C₄H₈O₂ and [H₃O]₂[SeBr₆] Dark red crystals of the composition [H₃O][TeBr₅] · 3 C₄H₈O₂ ( 1 ) were isolated from a saturated solution of TeBr₄ in 1,4-dioxane containing a small amount of water. In this compound (space group P2₁/m, a = 8.922(4) Å, b = 13.204(7) Å, c = 9.853(5) Å, β = 91.82(4)° at 150 K) a square pyramidal [TeBr₅]^? anion has been isolated for the first time. The coordination sphere of the anion is completed to a distorted octahedron by weak interaction with a dioxane molecule of the cationic system. The [H₃O]⁺ cations are connected to chains by dioxane molecules. At room temperature the compound is stable only in its mother liquor. Crystalline [H₃O]₂[SeBr₆] ( 2 ) (space group Fm3m, a = 10.421(1) Å at 170 K) is a bromoselenous acid of high symmetry. The [H₃O]⁺ ion is only weakly coordinated by Br atoms of the anion. The anions are isolated octahedral [SeBr₆]^2? units. The structure is isotypic to the K₂[PtCl₆] structure. Despite being a halogenochalcogen(IV) acid, 2 exhibits a remarkable thermal stability. Both oxonium compounds were characterized by single-crystal X-ray structure analyses. Vibrational spectra of 2 are reported.     

Effects of stereoisomerism in the mass spectra of 2,4-disubstituted thiacyclohexanes

The mass spectra of cis- (Ia-c) and trans-2-methyl-4-R-thiacyclohexanes (IIa-c; a R = n-C₄H₉, b R = n-C₅H₁₁, c R = Ph) were studied. It was established that [M-CH₃]⁺ ions, which correspond to the loss of a methyl group from the 2 position, are formed more readily in the case of the less stable trans isomers IIa-c than in the case of cis isomers Ia-c. The three-dimensional structures of the substances have no effect on the degree of elimination of the R substituent. The relative ionization energies (RIE) for Ia,b and IIa,b and the relative appearance energies (RAE) of the [M-CH₃]⁺ ions were measured by the electron impact method. It was found that the RIE are almost 0.05 eV lower and that the RAE of the [M-CH₃]⁺ ions are 0.1 eV lower for trans isomers IIa,b than for cis isomers Ia,b.Communication 4 from the series Ionization and appearance energies in organic chemistry, See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 333–338, March, 1981.