1,4-Dihalides furans, tetrahydro

The moisture-sensitive complexes 215 and 217c have been prepared from dilithium perfluoropinacolate and the appropriate dihalide in tetrahydro-furan. One molecule of THF is also coordinated to the metal 64). 

Bis(cyclopentadienyl) complexes CP2M (M = Ge, Sn, Pb) have been prepared by reaction of cyclopentadienylsodium and an appropriate dihalide in tetrahydro-furan. Electron diffraction shows that in the vapour these molecules have angular structures on account of the electron pair on the metal. In the solid state the germanium compound polymerizes within 3 h at ambient temperature, the tin compound within five days. The cyclopentadienyl groups are coordinated in a symmetrical pentahapto fashion (p. 191). Association through the rings occurs in the crystalline lead compound to give a polymeric chain structure (Fig. 4.8). 

Diorgano tellurium dihalides, when refluxed with silver fluoride in toluene, tetrahydro-furan, or acetone, precipitate silver halides. The diorgano tellurium difluorides crystallize upon cooling the filtrate of the reaction mixture or evaporating the filtrate under vacuum. 

Lithium telluride, prepared from tellurium and lithium triethylborohydride in tetrahydro-furan, and sodium telluride, obtained from sodium and tellurium in a dipolar, aprotic solvent or from tellurium - and Rongahte in aqueous sodium hydroxide reacted with aliphatic and aromatic dihalides to produce polymeric organo tellurium compounds. 

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