Synthesis and structural characterisation of metallated aminomethylanilines

Reaction of [1-{Me3SiNH}-2-{Me3SiNHCH2}]C6H4 (1) and [1-{tBuMe2SiNH}-2-{tBuMe2SiNHCH2}]C6H4 (2) in tetrahydrofuran with two equivalents of n-butyllithium gave the lithium amides [1-{Me3SiN(Li)}-2-{Me3SiN(Li)CH2}]C6H4(thf)3 (3) and [1-{tBuMe2SiN(Li)}-2-{tBuMe2SiN(Li)CH2}]C6H4(thf)2 (4). The molecular structures of both 3 and 4, which were established by X-ray diffraction studies, differ in the number of thf molecules coordinated to the Li centres. Depending on the size of the amidomethyl-bonded silyl groups two (4) or three thf-coligands (3) were found to bind to the lithium centres rendering them tri- or tetracoordinate, respectively. In the Me3Si-substituted derivative 3 a rare example of a thf molecule as a bridging ligand was found which appears to pertain as such in solution. The reaction of the lithium amides 3 and 4 with two molar equivalents of TlCl in n-pentane gave the thallium(I) amides [1-{Me3SiN(Tl)}-2-{Me3SiN(Tl)CH2}]C6H4 (5) and [1-{tBuMe2SiN(Tl)}-2-{tBuMe2SiN(Tl)CH2}]C6H4 (6) which are stable in hydrocarbon solutions but rapidly decompose in polar solvents.