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(SiMe3)(2)](2). The analogous reaction of two 1,2,4,5-tetra-(alkylamine)benzenes, 3b,c, with Sn[N(SiMe3)(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(SiMe3)(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(SiMe3)(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.