Reductive cleavage of the halogen–phosphorus and sulfur–phosphorus bonds with alkali metals

The reduction of thiophosphorus acid chlorides with alkali metals (Na, K) in liq. NH₃/THF solution, potassium anthracenide, and potassium naphthalenide was investigated. It was found that these types of phosphorus compounds easily undergo reduction to >P S⁻ anions. It was also demonstrated that >P O⁻ and >P S⁻ anions as well very efficiently undergo sulfurization with elementary sulfur in liquid ammonia to yield >P(O)S⁻ and >P(S)S⁻ anions, respectively. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:330–339, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10040     

Synthetic and mechanistic aspects of preparation of phosphinito‐ and phosphito‐mercuries

A >P O⁻ ( 1 ) type of anion has been used as an efficient synthetic precursor of four‐coordinated compounds: R₂P(O) Hg (O)PR₂ ( 5 ) and R₂P(O) Hg Bz ( 3 ) (R = alkoxy, alkyl, aryl). They were obtained in good yield. Bis(t‐butyl‐phenylphosphinito‐P)mercury (meso and rac) ( 5c,d ) selectively decomposed into 1,2‐di‐t‐butyl‐1,2‐diphenyldiphosphane 1,2‐dioxide (meso and rac) ( 6c,d) . Furthermore, some mechanistic aspects of the synthesis of mentioned compounds are elaborated.© 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:234–237, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20409     

Rate constants for the reactions of C2H5O,i‐C3H7O,and n‐C3H7O with NO and O2 as a function of temperature

The rate constants of the reactions of ethoxy (C₂H₅O), i‐propoxy (i‐C₃H₇O) and n‐propoxy (n‐C₃H₇O) radicals with O₂ and NO have been measured as a function of temperature. Radicals have been generated by laser photolysis from the appropriate alkyl nitrite and have been detected by laser‐induced fluorescence. The following Arrhenius expressions have been determined: (R₁) C₂H₅O + O₂ → products k₁ = (2.4 ± 0.9) × 10⁻¹⁴ exp(−2.7 ± 1.0 kJmol⁻¹/RT) cm³ s⁻¹ 295K < T < 354K p = 100 Torr (R₂) i‐C₃H₇O + O₂ → products k₂ = (1.6 ± 0.2) × 10⁻¹⁴ exp(−2.2 ± 0.2 kJmol⁻¹/RT) cm³ s⁻¹ 288K < T < 364K p = 50–200 Torr (R₃) n‐C₃H₇O + O₂ → products k₃ = (2.5 ± 0.5) × 10⁻¹⁴ exp(−2.0 ± 0.5 kJmol⁻¹/RT) cm³ s⁻¹ 289K < T < 381K p = 30–100 Torr (R₄) C₂H₅O + NO → products k₄ = (2.0 ± 0.7) × 10⁻¹¹ exp(0.6 ± 0.4 kJmol⁻¹/RT) cm³ s⁻¹ 286K < T < 388K p = 30–500 Torr (R₅) i‐C₃H₇O + NO → products k₅ = (8.9 ± 0.2) × 10⁻¹² exp(3.3 ± 0.5 kJmol⁻¹/RT) cm³ s⁻¹ 286K < T < 389K p = 30–500 Torr (R₆) n‐C₃H₇O + NO → products k₆ = (1.2 ± 0.2) × 10⁻¹¹ exp(2.9 ± 0.4 kJmol⁻¹/RT) cm³s⁻¹ 289K < T < 380K p = 30–100 Torr All reactions have been found independent of total pressure between 30 and 500 Torr within the experimental error. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 860–866, 1999     

Two pathways of initiation in the intermolecular iodine atom transfer addition reaction (I‐ATRA) initiated by AIBN

Detection of 4‐iodo‐2,2‐dimethyloctanenitrile and 2‐iodo‐2‐methylpropanenitrile proved an operation of two types (I and II) of initiation in the I‐ATRA reaction. 4‐Iodo‐2,2‐dimethyloctanenitrile, resulting from the isobutyronitrile radical attack onto 1‐hexene followed by the iodine atom transfer (type II), was formed in reactions of EWG‐CH(R)‐I [R = H, Me; EWG = (EtO)₂P(O), (−)−(MenthylO)₂ P(O), CN, Br‐C₆H₄C(O), MeO(O)C, allyl] with 1‐hexene. Nitriles of analogous structures were also detected in reactions of (EtO)₂P(O)CH(R)‐I with 1‐heptene, 1‐heptyne, cyclopentene, cyclohexene, and propargyl alcohol. 2‐Iodo‐2‐methylpropanenitrile as the product of the isobutyronitrile attack onto iodine atom of the starting iodide was detected for the first time in the reaction of allyl iodide and 1‐hexene and proved an operation of the cooperating pathway of initiation (type I). EPR experiments, performed directly in the spectrometer cavity, confirmed extremely low concentration of reacting radical species (for a sample of c = 0.1 mol/dm³, <10⁻⁸ mol/dm³, or <10⁻¹² moles of spins in a sample) in I‐ATRA reactions involving low reactive 1‐iodoalkylphosphonates. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:246–253, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20116     

Absolute rate constants for F + CH3CHO and CH3CO + O2, relative rate study of CH3CO + NO,and the product distribution of the F + CH3CHO reaction

Using a pulse-radiolysis transient UV–VIS absorption system, rate constants for the reactions of F atoms with CH₃CHO (1) and CH₃CO radicals with O₂ (2) and NO (3) at 295 K and 1000 mbar total pressure of SF₆ was determined to be k₁=(1.4±0.2)×10⁻¹⁰, k₂=(4.4±0.7)×10⁻¹², and k₃=(2.4±0.7)×10⁻¹¹ cm³ molecule⁻¹ s⁻¹. By monitoring the formation of CH₃C(O)O₂ radicals (λ>250nm) and NO₂ (λ=400.5nm) following radiolysis of SF₆/CH₃CHO/O₂ and SF₆/CH₃CHO/O₂/NO mixtures, respectively, it was deduced that reaction of F atoms with CH₃CHO gives (65±9)% CH₃CO and (35±9)% HC(O)CH₂ radicals. Finally, the data obtained here suggest that decomposition of HC(O)CH₂O radicals via C C bond scission occurs at a rate of <4.7×10⁵ s⁻¹. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 913–921, 1998     

Tetrakis(trimethysilyl)hypophosphate P2O2(OTMS)4: Synthesis,reactivity and application as flame retardant

The preparation of tetrakis(trimethy‐ silyl)hypophosphate, P₂O₂(OTMS)₄ (TMS = SiMe₃), which is easily obtained from cheap starting materials, is reported. Reaction with protic substrates (H₂O, alcohols) proceeds under stepwise cleavage of silylethers, ROTMS, and formation of hypophosphoric acid, P₂O₂(OH)₄. Amines in the presence of molecular sieves lead to desilylation and formation of ammonium salts of the [P₂O₂(OTMS)₂(O⁻)₂] dianion. On cotton fabrics, P₂O₂(OTMS)₄ hydrolyzes to give P₂O₂(OH)₄ within about 1 h when exposed to air, and this compound acts as an efficient flame retardant (limiting oxygen index >26%) even at low loadings (P content <3%). © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:721–731, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20373     

Direct measurement of the C2H5C(O)O2 + NO reaction rate coefficient using chemical ionization mass spectrometry

The rate coefficient for the reaction of the peroxypropionyl radical (C₂H₅C(O)O₂) with NO was measured with a laminar flow reactor over the temperature range 226–406 K. The C₂H₅C(O)O₂ reactant was monitored with chemical ionization mass spectrometry. The measured rate coefficients are k(T) = (6.7 ± 1.7) × 10⁻¹² exp{(340 ± 80)/T} cm³ molecule⁻¹ s⁻¹ and k(298 K) = (2.1 ± 0.2) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹. Our results are comparable to recommended rate coefficients for the analogous CH₃C(O)O₂ + NO reaction. Heterogeneous effects, pressure dependence, and concentration gradients inside the flow reactor are examined. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet: 31: 221–228, 1999     

Anion exchange in trimethyl‐ and triphenyltin complexes with chromogenic ligands: solution equilibria and colorimetric anion sensing

A series of organotin(IV) compounds R₃Sn(A) where R = Me or Ph and A is a chromogenic nitrophenolate ligand were prepared and studied as possible colorimetric sensors for anions (F⁻, Cl⁻, Br⁻, AcO⁻, H₂PO₄⁻). Equilibrium constants for a complete set of reactions between R₃Sn(A) with A = 2‐amino‐4‐nitrophenolate (ANP) or 4‐nitrophenolate and anions (X⁻) involving formation of complexes R₃Sn(A)(X)⁻ and substitution products R₃Sn(X) and R₃Sn(X)₂⁻ were determined by UV‐vis and ¹H NMR titrations in MeCN and DMSO. The binding selectivity was AcO⁻ > F⁻ > H₂PO₄⁻ > Cl⁻ ≫ Br⁻ in both solvents and both for R = Me and Ph with higher affinity for R = Ph. Compounds with A = ANP were found to have the optimum properties as anion sensors allowing optical detection of F⁻, AcO⁻ and H₂PO₄⁻ anions in the 5–100 µM range by appearance of an intense absorption band of free ANP resulting from its substitution with the analyte. Selectivity and affinity of anion interactions with R₃Sn(ANP) are similar to those for thiourea receptors, but the organotin receptor produces a much larger naked eye detected optical signal, operates equally well in nonpolar and polar solvents and tolerates the presence of up to 20% vol. of water in DMSO. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis and structure of the coordinatively unsaturated boron subphthalocyanine cation, [B(SubPc)]+

The boron subphthalocyanine cation, B(SubPc)⁺, has been prepared as a salt of a weakly coordinating carborane anion, CHB₁₁Me₅Br₆⁻, by a metathesis reaction of Et₃Si(CHB₁₁Me₅Br₆) with B(SubPc)Cl. The separation of the cation and anion in the X‐ray structure indicates coordinative unsaturation at the boron center, and this is corroborated by DFT calculations. A strongly Lewis acidic nature for the B(SubPc)⁺ cation is indicated by its hydrolysis to an unusual product, the di‐meso‐N‐protonated μ‐oxo dimer, [H(SubPc)B‐O‐B(SubPc)H]²⁺. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:209–216, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20223     

Gas phase reactions of Cl2O with X−(D2O)n=0–4 (X = O,OD, O2, DO2, and O3)

The reactions of Cl₂O with the cluster ions X⁻(D₂O)_n=0–4 (X = O, OD, O₂, DO₂, and O₃) were studied in a He buffer gas at temperatures within the range 171–298 K and pressures of 0.27–0.51 Torr, using a flow-tube apparatus. All ions were found to react with Cl₂O at rates slower than predicted by the collision rate and the charge center was transferred from X⁻ to Cl⁻ or ClO⁻. The primary product ions Cl⁻(DOCl) and ClO⁻(DOCl) were observed to react further to produce the ions Cl₃O⁻ and Cl₃O₂⁻. The rate constants for the observed reactions are reported and the role that thermodynamics plays in determining possible reaction channels is discussed.     

Enolization of the phosphoryl group

Enolization of the phosphoryl group has been studied where Y = PPh₃, CN, Ts, COOEt, CONEt₂; R and R′ = Et, Bu, Ph, EtO, BuO, PhO; and X = Cl, Br, ClO₄, BF₄. It has been established that substances with are phosphaenols, but in substances with Y = CONEt₂ the phosphoryl group cannot be enolized under any conditions. Phosphaenolization is favored by a high acidifying ability of the Y group, the ability of the X anion to stabilize the phosphaenolic form due to formation of a hydrogen bond OH…X with the anion, and a low electronegativity of R and R′ groups. To evaluate the acidifying ability of Y, this article defines specific σ⁻ constants dependent on the number of substituents at the α-carbon atom: σ_CH3⁻, σ_CH2⁻ and σ_CH⁻. Their sums characterize the enolization ability of the phosphoryl group. The enolic structure in the solid state is possible if ∑_CHn⁻ > 2. If this sum lies in the range of 2 < ∑_CHn⁻ < 2.6 the phosphoryl–phosphaenol tautomerism can be expected in appropriate solutions. Acidic properties of the investigated compounds in MeNO₂ and EtOH (absolute) have been determined. Calculations of the acidity of the phosphoryl CH forms (A) and of the phosphaenol OH forms (B) have been carried out.     

Reaction model for methane oxidation on reduced SnO2 (110) surface

A reaction model for methane oxidation on a reduced SnO₂ (110) crystal surface has been proposed theoretically using a point‐charge model. The geometric and electronic structures for all the molecules along the four reaction channels have been calculated by means of the MP2/6‐311++G(2d, p) level of theory. On the basis of the optimized geometries in the gas phase, the single‐point calculations of the energies on the point‐charge model are carried out. The results indicate that the energetically favorable reaction paths to yield methanol and formaldehyde on the reduced SnO₂ surface are via the reactant complex CH₃O H₂O and via the secondary production of methanol oxidation, respectively. It is also found that CH₃O⁻ is a stable anion on the surface due to having the high barriers of about 70 kcal/mol in both hydrogen abstraction with O⁻ and thermal decomposition, which is favorable to yield methanol and also is consistent with X‐ray photoelectron spectroscopy (XPS) experiments. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 74: 423–433, 1999     

Structural stabilities of water‐soluble MnTDCSPP,MnTSPP, and supported analogues toward hydrogen peroxide and sodium hypochlorite

This article describes the structural stabilities of 5,10,15,20‐tetrakis(2,6‐dichloro‐3‐sulfonatophenyl)porphinatomanganese(III) X (X: OH⁻, H₂O) (MnTDCSPP), 5,10,15,20‐tetra(4‐sulfonatophenyl)porphinatomanganese(III) X (X: OH⁻, H₂O) (MnTSPP) and their supported analogues toward H₂O₂ and NaOCl or HOCl depending on pH. The supports employed were hexadecyltrimethylammonium bromide (CTAB), 2,6‐ionene, 2,10‐ionene and a poly(vinylbenzyltrimethylammonium chloride) latex, which all contain quaternary ammonium groups. In the strong basic medium, both manganese porphyrins showed high stabilities toward NaOCl but relatively lower stabilities toward H₂O₂, and the resistance of MnTDCSPP to degradation was higher than that of MnTSPP. In the acidic solution, both porphyrins showed increasing stabilities toward H₂O₂ as the pH went down. Toward HOCl, MnTSPP did not show any stability in the neutral and acidic solutions, whereas MnTDCSPP showed some. The supports made some influence on their stabilities. In general, the ionenes affected their stabilities adversely, and the latex and CTAB did positively. Especially when they were bound to CTAB, they were not degraded by H₂O₂ at pH < 2. The pseudo‐first‐order degradation rate constants of MnTDCSPP, MnTSPP, and their supported analogues at different pHs at 30°C were determined. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 271–278, 2000     

Reactivity of the >P‐O− nucleophiles toward arylmethyl chloride systems*†

The reactions of sodium dimethyl and diisopropyl phosphite, as well as dibenzylphosphinite with 4‐nitrobenzyl chloride, 9‐chlorofluorene, and diphenylchloromethane were studied in detail by the isolation and identification of all the products, and the examination of the effects of the solvents on the product distribution. The results of the performed experiments are compatible with the proposed mechanism: a >P‐O⁻ anion acts toward an arylmethyl chloride as a base and abstracts a proton to form a carbanion, which can then participate in the SET processes to produce carbon‐centered radicals. Additionally, the >P‐O⁻ reagent can act as a carbon‐centered radical trap if it is present in a high enough concentration. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 431–439, 1999     

Synthesis and characterization of organophosphoryl polyoxotungstates [RP(O)]2X n+W11O39 (8−n)− (X n+ = P5+, Si4+, Ge4+, Ga3+)

In the presence of n-Bu₄NBr acting as phase-transfer reagent, n-Bu₄N⁺ salts of organophosphoryl polyoxotungstate derivatives [RP(O)]₂X ⁿ⁺W₁₁O₃₉ ^(8–n)– [R = PhCH₂CH₂P(O), X = P, Si; R = C₆H₁₁P(O); X = Ge, Ga] have been prepared and characterized by elemental analysis, i.r., ³¹P- and ¹⁸³W-n.m.r. spectroscopy. According to the elemental analysis and spectroscopic data, the hybrid anions consist of an -[XW₁₁O₃₉] framework on which are grafted two equivalent organophosphoryl groups through P—O—W bridges; these new species still retain the Keggin structure. The six-line ¹⁸³W spectrum indicates that hybrid anions possess C _s symmetry in MeCN.     

Preparation of polyzirconoxane from zirconium oxychloride octahydrate and ethylene glycol as a precursor for zirconia ceramics

An Erratum has been published for this article in Applied Organometallic Chemistry 2001; 15(4):317. The preparation of polyzirconoxanes (EG‐PZO) was investigated by a one‐pot reaction of zirconium oxychloride octahydrate with ethylene glycol. Triethylamine was added dropwise into a mixture of zirconium oxychloride octahydrate, ethylene glycol and methanol to give EG‐PZO with a good spinnability and stability to self‐condensation. The ¹H NMR spectrum, IR spectrum, analytical data and expanded X‐ray absorption fine‐structure analysis indicated that EG‐PZO consisted of Zr < (OH)₂ > Zr linkages as a main chain with pendant 2‐hydroxyethoxy groups, chloro groups and water. The 3Y₂O₃–97ZrO₂ ceramic fibers were prepared by sintering the precursor fibers after the addition of <?tw=97%>Y(acac)₃ (acac = acetoacetate) to EG‐PZO. Copy‐<?tw>­right © 2000 John Wiley & Sons, Ltd.     

Kinetics of the reaction of the sulfate radical with the oxalate anion

The kinetics of the reaction of the sulfate radical, SO₄⁻, with the oxalate anion C₂O₄²⁻ was studied in aqueous solution and second-order rate constants, corrected for the effects of ionic strength, derived. Measurements were carried out over the temperature range 24–60°C resulting in the expression k₀ = 2.10 ± 0.96 × 10⁸ exp(−1080 ± 140/T) L mol⁻¹ s⁻¹. © 1996 John Wiley & Sons, Inc.     

CrIII-Phthalocyaninate: Darstellung,Eigenschaften und Kristallstruktur von l-Bis(triphenylphosphin)iminium-trans-di(nitrito(O))phthalocyaninato(2–)-chromat(III)

Cr^III Phthalocyaninates: Synthesis, Properties, and Crystal Structure of l-Bis(triphenylphosphine)iminium trans-Di(nitrito(O))phthalocyaninato(2–)chromate(III) [Cr(H₂O)₂Pc^2?]I_x reacts with excess (PNP)NO₂ in dimethylformamide to yield less soluble greenblack l-bis(triphenylphosphine)iminium trans-di(nitrito(O))phthalocyaninato(2–)chromate(III), ^l(PNP)^trans[Cr(ONO)₂Pc^2?], which crystallizes in the triclinic space group P1 (No. 2) with Z = 2. The Cr atom is in the center of the Pc^2? ligand and the two nitrite ions are monodentate O-coordinated in a mutually trans arrangement to the Cr atom. The Cr? O and Cr? N_iso bond distances are 1.9898(14) und 1.981(2) Å, respectively. The geometric data of the coordinated nitrite ion are: d(N? O) = 1.307(2) Å; d(N? O) = 1.205(2) Å; ?(O? N? O) = 113.7(2)°; ?(Cr? O? N) = 116.85(12)°. The non-bonding O atoms are trans to the Cr atom. The Pc^2? ligand is slightly saddled. Three weak spin-allowed trip-quartet(TQ) transitions (in 10³ cm^?1): TQ1 (8.20) < TQ2 (11.3) < TQ3 (20.33) and the characteristic π-π* transitions of the Pc^2? ligand: B (14.68) < Q₁ (27.1) < Q₂ (29.0) < N (35.4) are observed in the UV-VIS-NIR spectrum. Prominent luminescence spectra are obtained by excitation within the TQ1 region, in which the spin-forbidden trip-sextet transition at 7376 cm^?1 dominates at low temperatures (T < 50 K). The vibrational spectra are discussed. In coincidence of the excitation lines with TQ3, v_s(Cr? O) at 378 cm^?1 is selectively resonance Raman (RR) enhanced. v_as(Cr? O) is observed in the FIR spectrum at 391 cm^?1. The following internal vibrations (in cm^?1) of the nitrito ligand are in the MIR spectrum: v_as(N? O)/1447 > v_as(N? O)/1018/1029 > δ(O? N? O)/828 and in the RR-spectrum: v_s(N? O)/1410 > v_s(N? O)/952, the last followed by three overtones.     

Nitration of 1,1-dichlorodifluoroethylene with nitrogen dioxide. The infrared spectra of difluoronitroacetyl chloride and 1,1-dichlorodifluoro-1,2-dinitroethane

Gas-phase nitration of CF₂CCl₂ with NO₂ at 323–353 K gave difluoronitroacetyl chloride, O₂NCF₂C(O)Cl, and 1,1-dichlorodifluoro-1,2-dinitroethane, O₂NCF₂CCl₂NO₂, which were isolated by fractional condensation and characterized by molecular weight determinations and infrared spectra. [O₂NCF₂C(O)Cl]/[O₂NCF₂CCl₂NO₂] = [k′ ([CF₂CCl₂] + γ_NO2[NO₂] + γ_P[P] + γ_X[X])]⁻¹, where k′ = 3.3±0.7x10⁻² torr⁻¹, P is the sum of the products, X = C₂F₅Cl, CCl₃F, CF₄ or N₂ and γ are the relative collisional efficiency coefficients of each gas.     

Pulse and steady‐state radiolysis studies of some homonuclear copper(II) and heteronuclear copper(II)‐molybdenum(VI) peroxo compounds containing a simple peptide molecule

The reactions of e_aq⁻, OH·, CO₂⁻·, and N₃· radicals with some novel homo nuclear and hetero nuclear peroxo peptide complexes viz: copper peroxo glycylglycine, [Cu(O₂)(H₂L)₂]; molybdenum oxoperoxo glycylglycine, [Mo(O)(O₂)₂(H₂L)₂]; Cu,Mo oxoperoxo glycylglycine [CuMo(O)(O₂)(L)₂] and Cu,Mo, oxo glycylglycine, [CuMo(O)₂(L)₂] (H₂L=glycyl glycine) in aqueous solutions were investigated by pulse radiolysis. Three types of reactions were observed: (1) reduction of Cu(II) to Cu(I) by e_aq⁻ and CO₂⁻·, (2) oxidation of Cu(II) to Cu(III) by N₃⁻·, and (3) formation of a radical on H abstraction from the ligand by OH· radical. Rate constants were reported for formation and decomposition of all intermediates. In case of one electron reduced complexes of hetero atoms, CuMo(O)₂L₂ and CuMo(O)(O₂)L₂, prepared via the reduction of the corresponding complexes by e_aq⁻, formation of a new dimer radical anion complex was observed. It is also noteworthy to mention the possibility of the effect of peroxo ligand on intermediate steps during the formation of Cu clusters. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 159–168, 1999