Search

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.

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.

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.

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.

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.

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.

Rduction of As4Se4 by potassium in ethylenediamine in the presence of tetraphenylphosphonium bromide resulted in the formation of the compound P(C6H5)4·As7Se4 whose structure has been determined crystallographically.

The enthalpies of solution of some tetra-alkylammonium salts and of tetraphenylphosphonium bromide in hexamethylphosphotriamide (HMPT) at 298.15 K have been obtained. Ionic enthalpies of transfer from water to HMPT and from HMPT to propylene carbonate (PC) have been calculated on the basis of the extrathermodynamic assumption ΔH°tr(Ph4As+)=ΔH°tr(BPh–4). The results indicate that this assumption is valid for enthalpies of transfer from HMPT to PC, but not for transfer from water to HMPT. The enthalpies of transfer of tetra-alkylammonium ions from HMPT to PC are discussed in terms of the ability of HMPT to solvate alkyl chains.