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Cathodic and anodic Tafel extrapolation data for the corrosion inhibition of iron in deaerated 1 M HCl at 22 °C are obtained for five synthesized phosphonium salts, 4-tolyltriphenyl-phosphonium chloride (TTPPC), 4-phenoltriphenylphosphonium chloride (PTPPC), 4-anilinetriphenylphosphonium bromide (ATPPB), 4-benzyl alcoholtriphenylphosphonium chloride (BATPPC), 4-hlorophenyltriphenylphosphonium bromide (CPTPPB), and two commercially available phosphonium salts, tetraphenylphosphonium bromide (TPPB) and methyltriphenylphosphonium bromide (MTPPB). The inhibitor concentrations ranged from 1 × 10−7 to 1 × 10−3 M. The inhibition of iron corrosion in 1 M HCl at 22 °C was found to be in the order TPPB > BATPPC > CPTPPB > PTPPC > MTPPB > TTPPC > ATPPB.

Single-crystalline microfibers of tetraphenylphosphonium bromide with length-to-diameter ratio over 104:1 are grown. Multiple-color frequency-conversion with is realized by continuous-wave pumped stimulated Raman scattering of the TPPB microfibers.

Multiple-phenyl phosphorous compounds are a group of chemical materials that have been used as reactants, pharmaceutical intermediates, extractants, and catalysts in organic synthetic reactions. However, the crystal growth of bulk crystals of multiple-phenyl phosphorous compounds, which may expand their applications in photonics technology, have been largely overlooked. In this article, the crystal growth of tetraphenylphosphonium bromide (TPPB) has been studied in organic solvents and water. The crystal structures and crystallization features are analyzed by X-ray diffraction data. By a slow temperature-lowering method, a single-crystal of TPPB (2H2O) with the size of 27 × 20 × 20 mm3 has been obtained in water. The basic thermal and optical properties were characterized. We find that the TPPB (2H2O) crystal shows excellent transparent property in the near-IR region. Large Raman shifts and strong Raman scattering intensity indicate that TPPB is a potential candidate in Raman-scattering-based nonlinearity applications.

Semithiobambusurils, which represent a new family of macrocyclic host molecules, have been prepared by a convenient, scalable synthesis. These new cavitands are double functional: they strongly bind a broad variety of anions in their interiors and metal ions at their sulfur-edged portals. The solid-state structure of semithiobambus[4]uril with HgCl2 demonstrates the ability of these compounds to form linear chains of coordination polymers with thiophillic metal ions. The crystal structure of semithiobambus[6]uril with tetraphenylphosphonium bromide exhibits the unique anion-binding properties of the host cavity and the characteristics of the binding site.

An unconventional reagent, tetraphenylphosphonium bromide, was employed as a phenyl source in the direct transformation of aromatic aldehydes to the corresponding phenyl esters under oxidative N-heterocyclic carbene (NHC) catalysis. The phenyl esters were obtained in moderate yields under mild and organocatalytic conditions.

The decolorization efficiency of four anionic dyes dissolved in aqueous solution using two quaternary phosphonium salts, ethyltriphenylphosphonium bromide, and tetraphenylphosphonium bromide, has been investigated by spectroscopic measurements in neutral, acidic and basic media. The NMR studies suggest possible formation of ion pairs of tetrasubstituted phosphonium salts with the reactive dyes. According to the results, the tetraphenylphosphonium bromide, which contains a more hydrophobic and bulky cation, exhibited a stronger tendency to associate with the dyes.

The complexes [Bu4N]2+[PtBr6]2− (I), [Ph4P]2+[PtBr6]2− (II), and [Ph3(n-Am)P]2+ (III) are synthesized by the reactions of tetrabutylammonium bromide, tetraphenylphosphonium bromide, and triphenyl(n-amyl)-tetraphenylphosphonium bromide, respectively, with potassium hexabromoplatinate (mole ratio 2: 1). After recrystallization from dimethyl sulfoxide, complexes I, II, and III transform into [Bu4N]+[PtBr5(DMSO)]− (IV), [Ph4P]+[PtBr5(DMSO)]− (V), and [Ph3(n-Am)P]+[PtBr5(DMSO)]− (VI). According to the X-ray diffraction data, the cations of complexes IV–VI have a slightly distorted tetrahedral structure. The N-C and P-C bond lengths are 1.492(7)–1.533(6) and 1.782(10)–1.805(10) A, respectively. The platinum atoms in the mononuclear anions are hexacoordinated. The dimethyl sulfoxide ligands are coordinated with the Pt atom through the sulfur atom (Pt-S 2.3280(18)–2.3389(11) A). The Pt-Br bond lengths are 2.4330(6)–2.4724(6) A.

Brown crystals of [PPh4]2[Se2Br6] (1) and [PEtPh3]2[Se2Br6] (2) were obtained when selenium and bromine reacted in acetonitrile solution in the presence of tetraphenylphosphonium bromide and ethyltriphenylphosphonium bromide, respectively. The crystal structure of 2 has been determined by X-ray methods and refined to R = 0.0420 for 4161 reflections. The crystals are monoclinic, space group P21/n with Z = 2 and a = 13.055(3) A, b = 12.628(3) A, c = 13.530(3) A, β = 92.40(3)° (293(2) K). In the solid state structure of 2 the dinuclear hexabromo-diselenate(II) anion is centrosymmetric and consists of two distorted almost square-planar SeBr4 units sharing a common edge through two bridging Br atoms. The terminal SeII–Br bond distances are found to be 2.419(1) and 2.445(1) A, the bridging μBr–SeII bond distances 2.901(1) and 2.802(1) A.

Tetraphenylphosphonium hexabromoosmate, [Ph4P]2[OsBr6] (I), has been structurally characterized after synthesis by interaction of sodium hexabromoosmate with tetraphenylphosphonium bromide in dimethyl sulfoxide. The phosphorus atoms of [Ph4P]+ cations have distorted tetrahedral coordination geometry (СPС angles are 106.23(11)113.23(10)), the PС bond lengths are 1.791(2)1.801(2) Å). In octahedral [OsBr6]2 anions the OsBr bond lengths equal 2.4752(2)-2.5020(3) Å, trans-BrOsBr angles are 180. Взаимодействием гексабромоосмата натрия с бромидом тетрафенилфосфония в диметилсульфоксиде синтезирован и структурно охарактеризован гексабромоосмат тетрафенилфосфония [Ph4P]2[OsBr6] (I). Атомы фосфора в катионах [Ph4P]+ имеют ис- каженную тетраэдрическую координацию (углы СPС 106.23(11) градусов -113.23(10)градусов), расстояния P -С составляют 1.791(2)градусов1.801(2) Å). В октаэдрических анионах [OsBr6]2длины связей Os-Br равны 2.4752(2)-2.5020(3) Å, углы транс-BrOsBr составляют 180 градусов. V.V. Sharutin, vvsharutin@rambler.ru O.K. Sharutina, sharutinao@mail.ru V.S. Senchurin, senvl@rambler.ru South Ural State University, Chelyabinsk, Russian Federation Шарутин Владимир Викторович – доктор химических наук, профессор, старший научный сотрудник УНИД, Южно-Уральский государственный университет. 454080, г. Челябинск,пр. им. В.И. Ленина, 76. E-mail: vvsharutin@rambler.ru Шарутина Ольга Константиновна – доктор химических наук, профессор, кафедра аналитической химии, Южно-Уральский государственный университет. 454080, г. Челябинск,пр. им. В.И. Ленина, 76. E-mail: sharutinao@mail.ru Сенчурин Владислав Станиславович – кандидат химических наук, кафедра органической химии, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: senvl@rambler.ru

The reaction of the K2[Fe3Q(CO)9] clusters (Q = Se or Te) with Rh2(CO)4Cl2 under mild conditions is accompanied by complicated fragmentation of cores of the starting clusters to form large heteronuclear cluster anions. The [PPh4][Fe4Rh3Se2(CO)16] and [PPh4]2[Fe3Rh4Te2(CO)15] compounds were isolated by treatment of the reaction products with tetraphenylphosphonium bromide. The structures of the products were established by X-ray diffraction. In both compounds, the core of the heteronuclear cluster consists of two octahedra fused via a common Rh3 face.

An unconventional reagent, tetraphenylphosphonium bromide, was employed as a phenyl source in the direct transformation of aromatic aldehydes to the corresponding phenyl esters under oxidative N-heterocyclic carbene (NHC) catalysis. The phenyl esters were obtained in moderate yields under mild and organocatalytic conditions.

Tetraphenylphosphonium triiodotetrabromide [PPh4][I3Br4] is obtained by the reaction of tetraphenylphosphonium bromide with iodine monobromide. It is the first example of an iodine rich, seven-membered polybromide. [PPh4][I3Br4] crystallizes triclinic in the space group P1 with a = 10.947(1) A, b = 11.945(1) A, c = 12.896(1) A, alpha = 66.80(1) degrees, beta = 77.21(1) degrees, gamma = 85.73(1) degrees, and two formula units per unit cell. The final R indices [I4 sigma(I)] are R1 = 0.0362 and wR2 = 0.0944.

Syntheses of 1,3-difluorobenzene and 2,6-difluorotoluene are described via chlorosulfonation, catalytic Halex-fluorination, and desulfination of 1,3-dichlorobenzene and 2,6-dichlorotoluene.

A new modified clay material, prepared by intercalating palladium chloride and tetraphenylphosphonium bromide into montmorillonite K10 clay, catalyzes the Heck reaction and affords trans -stilbenes in high yields.

A facile method for the preparation of biaryl compounds is described from readily accessible aryl halides and arylboronic acids using palladium chloride/tetraphenylphosphonium bromide intercalated clay as a new catalyst.

Reduction of tetraphenylphosphonium bromide with LiAlH(D)4 at room temperature affords first the monohydrophosphorane Ph4PH, then the dihydrophosphoranate anion Ph4PH2]− which decomposes to the dihydrophosphorane Ph3PH2, all of which are identified by 31PNMR. Reductions of other phosphonium salts appear to follow a similar path. At elevated temperatures none of these intermediates is observed and attempted isolation leads to extensive decomposition.

3,4-Difluorobenzonitrile has been prepared by a halogen- exchange reaction between 3,4-dichlorobenzonitrile and spray- dried potassium fluoride in the presence of tetraphenylphosphonium bromide in refluxing 1,3-dimethylimidazolidine-2- one. In the fluorination reaction, 4-chloro-3-fluorobenzonitrile seems to be a key intermediate. 3,4-Difluorobenzonitrile, 2-, 3-, and 4-fluorobenzonitriles have also been produced from the corresponding chlorobenzonitrile derivatives by halogen-exchange at 290 °C in DMI in a pressure reactor.

A facile method for the preparation of biaryl compounds is described from readily accessible aryl halides and arylboronic acids using palladium chloride/tetraphenylphosphonium bromide intercalated clay as a new catalyst.

3,4-Difluorobenzonitrile has been prepared by a halogen- exchange reaction between 3,4-dichlorobenzonitrile and spray- dried potassium fluoride in the presence of tetraphenylphosphonium bromide in refluxing 1,3-dimethylimidazolidine-2- one. In the fluorination reaction, 4-chloro-3-fluorobenzonitrile seems to be a key intermediate. 3,4-Difluorobenzonitrile, 2-, 3-, and 4-fluorobenzonitriles have also been produced from the corresponding chlorobenzonitrile derivatives by halogen-exchange at 290 °C in DMI in a pressure reactor.

A facile route for the synthesis of allylbenzenes is described from easily accessible allyl bromide and arylboronic acids using a new reusable catalyst system, palladium chloride and tetraphenylphosphonium bromide intercalated clay.

Tetraphenylphosphonium bromide was found to be a suitable catalyst for the reaction of m-nitroaryl derivatives carrying cyano, nitro, chlorocarbonyl, trifluoromethyl, and chlorosulfonyl groups with potassium fluoride in the presence of a stoichiometric amount of phthaloyl dichloride, giving the corresponding m-fluoro aromatic derivatives in good yields. The catalyst was also found to be efficient for the fluorodesulfonylation of m-(fluorosulfonyl)aryl derivatives to afford m-fluoro arenes by the use of a reaction-distillation technique.

A convenient synthesis of 5-fluorofuran-2-carboxylic acid has been achieved in two steps and 56% total yield. Fluorodenitration of commercially available benzyl 5-nitrofuran-2-carboxylate utilizing potassium fluoride and catalytic tetraphenylphosphonium bromide in sulfolane at 140 °C for 2 h furnished benzyl 5-fluorofuran-2-carboxylate. Hydrogenolysis of benzyl 5-fluorofuran-2-carboxylate gave the title compound.

Tetraphenylphosphonium triiodotetrabromide [PPh4][I3Br4] is obtained by the reaction of tetraphenylphosphonium bromide with iodine monobromide. It is the first example of an iodine rich, seven-membered polybromide. [PPh4][I3Br4] crystallizes triclinic in the space group P1 with a = 10.947(1) A, b = 11.945(1) A, c = 12.896(1) A, α = 66.80(1)°, β = 77.21(1)°, γ = 85.73(1)°, and two formula units per unit cell. The final R indices [I > 4σ(I)] are R1 = 0.0362 and wR2 = 0.0944.

Halogen-exchange of chloroaryl sulfonylchloride derivatives with spray-dried potassium fluoride was found to proceed efficiently by employing tetraphenylphosphonium bromide as a catalyst. Subsequent desulfonylation of the fluoroaryl sulfonyl derivatives readily afforded fluoroaromatics under acidic condition.

Comparative study of the role of solvent effects of aqueous methyl cellosolve and tetrahydrofuran solvent systems on the alkaline decomposition of tetraphenylphosphonium bromide was carried out. The reaction rate increases remarkably as the medium changes from purely aqueous to a water-organic cosolvent reaction mixture. The relative changes in the solvation states of both reactants and transition state as the structural properties of the two solvent binaries change were shown to be the direct reasons for the difference in the effects on rate and activation energies.

Differential accumulation of [/4C]imazalil and [14 C]fenarimol by germlings of wild-type and DMI-resistant isolates of Penicillium italicum was studied at various pH values. At pH 7 and 8 the low-resistant isolate E 300-3 accumulated 22~ and 35 %, respectively, less imazalil than the wild-type isolate W 5 . Imazalil accumulation at pH 5 and 6 was similar. Isolate E300_ 3 also accumulated less fenarimol as compared with the wild-type isolate. This difference was much more obvious than for imazalil and was observed at all pH values tested. Differences in accumulation of both imazalil and fenarimol between low (E30o.3) , medium (H 17) and high resistant (I 33) isolates were not observed. These results suggest that decreased accumulation of DMIs is responsible for a low level of resistance only and that additional mechanisms of resistance might operate in isolates with a medium and high degree of resistance. With all isolates fenarimol accumulation was energy-dependent. This was not obvious for imazalil. The wild-type and DMI-resistant isolates had a similar plasma membrane potential as determined with the probe [lac]tetraphenylphosphonium bromide ([14C]TPP +). Various test compounds, among which ATPase inhibitors, ionophoric antibiotics and calmodulin antagonists, affected the accumulation of [14C]TPP+, [14C]imazalil and [14C]fenarimol. No obvious correlation between the effects of the test compounds on accumulation levels of the fungicides and [14C]TPP+ could be observed. These results indicate that the plasma membrane potential does not mediate the efflux of DMI fungicides by P. italicum. Additional keywords: ATPase inhibitors, calmodulin antagonists, fenarimol, imazalil, ionophoric antibiotics, sterol 14a-demethylation inhibitors, tetraphenylphosphonium bromide.

Tetraphenylphosphonium bromide was found to be a suitable catalyst for the reaction of m-nitroaryl derivatives carrying cyano, nitro, chlorocarbonyl, trifluoromethyl, and chlorosulfonyl groups with potassium fluoride in the presence of a stoichiometric amount of phthaloyl dichloride, giving the corresponding m-fluoro aromatic derivatives in good yields. The catalyst was also found to be efficient for the fluorodesulfonylation of m-(fluorosulfonyl)aryl derivatives to afford m-fluoro arenes by the use of a reaction-distillation technique.

Activated nitro groups in aromatic systems are substituted with potassium fluoride in the presence of phthaloyl chloride and tetraphenylphosphonium bromide to give the corresponding fluorides, e.g. (II) or (IV).

The fulleride salt C60-tetraphenylphosphonium bromide is investigated as a function of temperature by single crystal X-ray diffuse scattering and diffraction. At room temperature, the C60 orientational disorder is found to be more complex than previously expected. Moreover, a structural phase transition, due to the C60 orientational ordering, is evidenced around 120 K. Its relation with the stabilization of a static Jahn-Teller effect is discussed.

Improved syntheses of tetraphenylphosphonium bromide and 1-phenyldibenzophosphole are described. Also described are syntheses of tetrakis(p-chlorophenyl)phosphonium bromide, tetrak is (p-tolyl)phosphonium bromide, 1-phenyldi-benzophosphole oxide, 1-phenyldibenzophosphole sulfide, 1-phenyldibenzophosphole selenide and 5-p-tolyl-2,8-dimethyldibenzophosphole oxide. These compounds were all characterized by elemental analyses and 31P {1H} NMR spectroscopy. An investigation of the relative catalytic efficiencies of NiBr2, [Ph2PH]4Ni and (Ph3P)2Ni(CO)2 in the synthesis of 1-phenyldibenzophosphole is also reported.

Meta-fluoroaromatic compounds were effectively synthesized from m-nitroaromatic or m-fluorosulfonylaromatic compounds by replacement reaction with potassium fluoride in the presence of a catalytic amount of tetraphenylphosphonium bromide.

The viscosities of aqueous solutions of Bu 4-n Ph n PBr n=0–4 have been measured over the concentration range 0.01–0.2 M at 15, 25 and 35°C, to examine the differences in ion-water interactions of these quaternary cations. The viscosity data were treated by the extended Jones-Dole equation, including the square term in solute concentration, Dc2. A decrease in the B coefficient with increase in the number of phenyl groups n, and with increasing temperature is observed. Nearly linear dependence of the B coefficient on n was found, in contrast with partial molal volumes for which non-linear relations with n have been found. D decreases with increasing temperature but becomes independent of n at higher temperatures.

PPh4[UBr6] und PPh4[UBr6] · 2CCl4 wurden aus UBr5 · CH3CN und Tetraphenylphosphonium-bromid in Dichlormethan erhalten, letzteres nach Zusatz von CCl4. Ihre Kristallstrukturen wurden durch Rontgenbeugung aufgeklart. PPh4[UBr6]: 2101 beobachtete Reflexe, R = 9,0%, Raumgruppe C2/c, Z = 4, a = 2315,5, b = 695,0, c = 1805,2 pm, β = 96,38°. PPh4[UBr6] · 2CCl4: 2973 Reflexe, R = 7,4%, Raumgruppe P21/c, Z = 4, a = 1111,5, b = 2114,2, c = 1718,7 pm, β = 95,42°. Uranpentabromid wird durch Schwefelwasserstoff zu Urantetrabromid reduziert. Losungen von UBr5 mit 1 bzw. mehr als 3 Molaquivalenten Acetonitril in Dichlormethan spalten beim Eindampfen Brom ab, dabei entsteht UBr4 · CH3CN bzw. UBr4 · 3CH3CN. Diese reagieren in Acetonitril mit PPh4Br unter Bildung von (PPh4)2[UBr6] · 4CH3CN, dessen Kristallstruktur bestimmt wurde (2663 beobachtete Reflexe, R = 5,0%): Raumgruppe P21/c, Z = 2, a = 981,8, b = 2010,1, c = 1549,3 pm, β = 98,79°. Die Reduktion von Uranpentabromid mit Tetramethylammonium-hydrogensulfid in Dibrommethan fuhrt zu (NEt4)2[U2Br10], das extrem hydrolyse- und sauerstoffempfindlich ist. Ebenso empfindlich ist (PPh4)2[U2Br10], das aus UBr4 und PPh4Br in CH2Cl2 erhalten wurde. Von seinem Oxidationsprodukt (PPh4)2[UO2Br4] · 2CH2Cl2 wurde die Kristallstruktur bestimmt (2163 Reflexe, R = 8,3%): Raumgruppe C2/c, Z = 4, a = 2006,3, b = 1320,6, c = 2042,5 pm, β = 98,78°. Die UBr-Bindungslangen in den oktaedrischen Anionen be tragen im Mittel 266,2 pm beim UBr6−, 276,7 pm beim UBr62− und 282,5 beim UO2Br42−. Reactions of Uranium Pentabromide. Crystal Structures of PPh4[UBr6], PPh4[UBr6] · 2CCl4, (PPh4)2[UBr6] · 4CH3CN, and (PPh4)2[UO2Br4] · 2CH2Cl2 PPh4[UBr6] and PPh4[UBr6] · 2CCl4 were obtained from UBr5 · CH3CN and tetraphenylphosphonium bromide in dichloromethane, the latter being precipitated by CCl4. Their crystal structures were determined by X-ray diffraction. PPh4[UBr6]: 2101 observed reflexions, R = 0.090, space group C2/c, Z = 4, a = 2315.5, b = 695.0, c = 1805.2 pm, β = 96.38°. PPh4[UBr6] · 2CCl4: 2973 reflexions, R = 0.074, space group P21/c, Z = 4, a = 1111.5, b = 2114.2, c = 1718.7 pm, β = 95.42°. Hydrogen sulfide reduces uranium pentabromide to uranium tetrabromide. Upon evaporation, bromide is evolved from solutions of UBr5 with 1 or more then 3 mol equivalents of acetonitrile in dichlormethane yielding UBr4 · CH3CN and UBr4 · 3CH3CN, respectively. These react with PPh4Br in acetonitrile affording (PPh4)2[UBr6] · 4CH3CN, the crystal structure of which was determined: 2663 reflexions, R = 0.050, space group P21/c, Z = 2, a = 981.8, b = 2010.1, c = 1549.3 pm, β = 98.79°. By reduction of uranium pentabromide with tetraethylammonium hydrogen sulfide in dichloromethane (NEt4)2[U2Br10] was obtained; (PPh4)2[U2Br10] formed from UBr4 and PPh4Br in CH2Cl2. Both compounds are extremely sensitive towards moisture and oxygen. The crystal structure of the oxydation product of the latter compound, (PPh4)2[U02Br4]· 2 CH2Cl2, was determined: 2163 reflexions, R = 0.083, space group C2/c, Z = 4, a = 2006.3, b = 1320.6, c = 2042,5 pm, β = 98.78°. Mean values for the UBr bond lengths in the octahedral anions are 266.2 pm for UBr6-, 276.7 pm for UBr62− and 282.5 pm for UO2Br42−

A process which can afford a large quantity of 4-fluorobenzaldehyde was developed from halogen-exchange of 4-chlorobenzaldehyde with potassium fluoride in aromatic hydrocarbon solvents in the presence of tetraphenylphosphonium bromide plus polyethylene glycol dimethyl ether. The features of the reaction are discussed.