Synthesis and Characterization of Rigid Ditopic N-Heterocyclic Benzobisgermylenes and -stannylenes

A rigid ditopic benzobisgermylene, 4a, was prepared by the reaction of the 1,2,4,5-tetra(alkylamine)benzene 3a and Ge[N(SiMe 3 ) 2 ] 2 . The analogous reaction of two 1,2,4,5-tetra(alkylamine)benzenes, 3b, c, with Sn[N(SiMe 3 ) 2 ] 2 led to the oxidation of the tetramine ligand and formation of N -alkyl-2-(alkylamine)- N′ -alkyl-5-(alkylamine)-1,4-benzoquinonediimines ( 5b, c ) and tin(0). The p -benzoquinonediimines 5b, c subsequently react with remaining Sn[N(SiMe 3 ) 2 ] 2 to yield distannylene complexes of type [ N -alkyl-2-(alkylamino)- N′ -alkyl-5-(alkylamino)-1,4-benzoquinonediimine]di[bis(trimethylsilyl)aminotin(II)] ( 6b, c ). The 2,5-di(alkylamine)-1,4-benzoquinonediimines 5b, c can also be obtained directly by aerial oxidation of the 1,2,4,5-tetrakis(alkylamine)benzenes 3b, c . They react with two equivalents of Sn[N(SiMe 3 ) 2 ] 2 also under transmetalation and formation of [ N -alkyl-2-(alkylamino)- N′ -alkyl-5-(alkylamino)-1,4-benzoquinonediimine]di[bis(trimethylsilyl)aminotin(II)] ( 6b, c ). The molecular structures of 3b, 4a, 6b, and 6c have been established by X-ray diffraction.