DERIVES N-GERMANIES DE LA 2,4,6-TRIFLUOROANILINE: GERMYLAMINES, GERMA-IMINE, CYCLODIGERMAZANE

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Abstract
Germyl derivatives of N-2,4,6-trifluoroaniline were synthesized either by dehydrohalogenation between halogermanes and 2,4,6-trifluoroaniline over DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) or by elimination between halogermanes and 2,4,6-trifluoroanilinolithium. Dimesitylfluorogermyl N-2,4,6-trifluoroanilino-lithium stabilized by THF slowly eliminated lithium fluoride leading to 2,4(2,4,6-trifluorophenyl)-1,3-tetramesitylcyclodigermazane, mainly through intermolecular elimination while in the presence of MgBr2 or tBuMgBr the corresponding germa-imine was formed. Dimesitylchlorogermyl-2,4,6-trifluoroanilino lithium also led to cyclodigermazane while the corresponding bromogermyl lithium or magnesium compound gave mainly the stable 2,4,6-trifluorophenyl dimesitylgerma-imine by intramolecular elimination. The same stable germa-imine was also obtained by exchange reaction between dichlorodimesitylgermane and N-bis(triethylgermyl)2,4,6-trifluoroaniline. Reactivities of monomeric germa-imine and its dimer cyclodigermazane are compared. The dimer is almost inert towards water and methanol and does not react with chloroform and N-tert-butylphenyl nitrone while the germa-imine leads to the corresponding adducts. The adduct with chloroform through α-elimination of dichlorocarbene gave N-dimesitylchlorogermyl trifluoroaniline. The electron withrawing effects of the trifluorophenyl group on nitrogen stabilize the germa-imine, preventing its dimerization, but also induce a decrease in reactivity of germanium nitrogen compounds within the series.