Tellurium Difluoride

Fluorination of diaryl sulfides, selenides, and tellurides leads to the formation of diarylsulfur, selenium, and tellurium difluorides, all of... 

Bis[dialkylamino] tellurium dihalides are moisture-sensitive liquids (R = C2HS) or solids. Bis[diethylamino] tellurium difluoride decomposes at 20°. 

Bis[piperidinyl] tellurium difluoride (dec. 104°) was similarly obtained in 94% yield2. 

To isolate bis[dielhylamino] tellurium difluoride (71 % yield), the filtered reaction mixture was evaporated and the residue distilled under reduced pressure. The compound, a colorless liquid that decomposes within 24 h to elemental tellurium, boiled at 6570.035 torr2. 

A suspension of bis[morpholino] tellurium difluoride condensed with arenesulfonamincs to precipitate bis[morpholino] tellurium arenesulfonimides. ... 

Although it has not been possible to replace the fluorine atoms in bis[dialkylamino] tellurium difluorides by dialkylamino groups1, the fluorine atoms in dimorpholino tellurium difluoride did react with Ar,Ar-bis[trimethylsilyl]arenesulfonamides to form arenesulfonimino dimorpholino tellurium derivatives1. 

Benzcnesulfonimino Dimorpholino Tellurium1 3.38 g (10 mmol) of bis[morpholino] tellurium difluoride are suspended in 40 ml of anhydrous benzene, the suspension is stirred, and a solution of 3.3 g (11 mmol) of N,N-bis[trimethylsilyl]benzenesulfonamide in 20 ml of benzene is added. The mixture is stirred until all the solid has dissolved and then allowed to stand for 10 h. The precipitated crystals are filtered, washed with diethyl ether, and recrystallized from benzene yield 4.4 g (96%) m.p. 114°. 

Arenesulfonimino tellurium difluorides and A-trimethylsilylmorpholine reacted at 20° to form arenesulfonimino dimorpholino tellurium derivatives2. 

Bis fluoroalkoxy] dimorpholino tellurium compounds were prepared2 from bis[fluoro-alkoxy] tellurium difluoride or tetrakis[fluoroalkoxy] tellurium compounds and two molar equivalents of iV-trimethylsilylmorpholine in a medium of diethyl ether at 5°. 

The compound with n = 1 was also obtained (84% yield) from bis[fluoroalkoxy] tellurium difluoride and (V-trimethylsilylmorpholine. 

When a suspension of benzenesulfonimino tellurium difluoride and bis[trimethyl-silyljbenzenesulfonamide was boiled in benzene for six hours, bis benzenesulfonimino] tellurium precipitated on cooling of the reaction mixture2. 

Refluxing of equimolar amounts of bis[2,2,3,3-tetrafluoropropoxy] tellurium difluoride and Af,Af-bis[trimethylsilyl]benzenesulfonamide in benzene yielded benzenesulfonimino bis[tetrafluoropropoxy] tellurium1. 

Benzenesulfonimino Tellurium Difluoride2 A mixture of 12.8 g (30 mmol) of bis[2,2,3,3-tetrafluoropropoxy] tellurium difluoride and 4.7 g (30 mmol) of benzenesulfonamide is heated at 63°/0.035 torr for 40 min and at 95o/0.035 torr for 1 h. After all the alcohol has distilled off, benzene is added to the mixture, the deposited solid is filtered off, washed several times with small portions of hot benzene, and dried. The product should be stored with protection from moisture yield 9.4 g (98%) m.p. 237-240°. 

When benzenesulfonimino tellurium difluorides and bis[trimethylsilyl]benzenesulfonamide were refluxed in benzene, bis[benzenesulfonimino] tellurium was isolated1. 

Methylbenzenesulfonimino tellurium difluoride and A trimethylsilylmorpholine in benzene solution formed dimorpholino 4-methylbenzenesulfonimino tellurium1. 

Arenesulfonimino tellurium difluorides were hydrolyzed by boiling water to tellurium dioxide, arenesulfonamide, and hydrogen fluoride1. 

When refluxed in benzene equimolar amounts of bis[fluoroalkoxy] tellurium difluorides and fluoroalkoxytrimethylsilane produced tris[fluoroalkoxy] tellurium fluorides2. 

Bisffluoroalkoxy] tellurium difluorides are moisture-sensitive, distillable liquids with good thermal stability. 

Heating tellurium tetrafluoride and fluoroalkoxytrimethylsilane (1 2 molar ratio) in benzene for 2h produced bis[fluoroalkoxy] tellurium difluorides in high yields1. 

When equimolar amounts of fluoroalkoxy tellurium trifluorides and fluoroalkoxytrimeth-ylsilanes were heated in benzene at 70° for two hours and the reaction mixtures worked up as described for the reactions between tellurium tetrafluoride and fluoroalkoxy trimeth-ylsilanes, bis[fluoroalkoxy] tellurium difluorides were obtained1. 

Heating a bis[fluoroalkoxy] tellurium difluoride with an equimolar amount of fluoroalk-oxytrimethylsilane in benzene at 80° produced tris[fluoroalkoxy] tellurium fluorides1. 

Heating bispfluoroalkoxy] tellurium difluorides with benzenesulfonamide produced ben-zenesulfonimino tellurium difluorides1. 

Refluxing bisffluoroalkoxy] tellurium difluorides in benzene with AvV-bis[trimethyl-silyljbenzenesulfonamide yielded bis[fluoroalkoxy] tellurium benzenesulfonimides1. 

V-Trimethylsilylmorpholine (2 mol) reacted with bis[2,2,3,3-tetrafluoropropoxide] tellurium difluoride (1 mol) in diethyl ether at 5° to yield dimorpholino tellurium bis(fluoroalkoxide)2. 

Bis[fluoroalkoxy] tellurium difluorides were hydrolyzed by water at 60° to tellurium dioxide, fluoroalkanol, and hydrogen fluoride2. 

Pentaalkoxy tellurium monofluorides were formed by fluorination of tctramethoxy tellurium1, by reaction of m-tetramethoxy tellurium difluoride with sodium methoxide in methanol1, by the action of anhydrous hydrogen fluoride on hexamethoxy tellurium2, and by the condensation of primary alcohols with tellurium hexafluoride1. None of these compounds was isolated. Their presence in the reaction mixture was detected by 19F-NMR spectroscopy. 

Tetraalkoxy tellurium difluorides exist as cis- and // mu-isomers. Several derivatives belonging to this class of compounds were prepared, but few were isolated in pure form. 

Tetramethoxy tellurium difluoride was observed by 19F-NMR spectroscopy as one of the products of the interaction of hexamethoxy tellurium in anhydrous hydrogen fluoride at 60° for 24 h2. 

Trifluoroethanol had not formed any tetraalkoxy tellurium difluoride after 9 days. After 28 days the mixture contained 29% of this compound. In reactions with prop-2-en-l-ol, decomposition occurred after five days. The reaction between tellurium hexafluoride and n-propanol produced no tetrapropoxy tellurium difluoride1. 

Bis[2-chloroethoxy] tellurium tetrafluoride reacted with ethanol to give bis[2-chloroethoxy] ethoxy tellurium trifluoride. However, this compound could not be obtained from 2-chloroethoxy ethoxy tellurium difluoride and 2-chloroethanol. Diethoxy tellurium tetrafluoride and 2-chloroethanol were also found to be unreactive1. 

Dimethyl Tellurium Difluoride1 3 The apparatus shown in the Figure is set up. 4.7 g (30 mmol) of dimethyl tellurium and 175 ml of fluorotrichloromethane are placed in the 500 ml reaction flask which is cooled to — 78° in an ethanol/dry ice bath. The rotameter and pressure controls are set to deliver a fluorine/nitrogen (or argon) mixture (1/10, v/v). The gas mixture is passed at a flow rate not exceeding 100 m//min through a metal spiral immersed in a — 78° cooling bath and then into the stirred solution of dimethyl tellurium. The reaction is complete after 75 mmol of fluorine have been passed into the flask. Dimethyl tellurium difluoride precipitates as a white solid. The solvent is removed by vacuum distillation under an inert atmosphere and the moisture-sensitive residue is pure dimethyl tellurium difluoride yield 1.3 g (22%) m.p. 82° sublimes at 40D/0.001 torr. 

---