Reactivity of Organolanthanide Derivatives Containing the <i>o</i>-Aminothiophenolate Ligand toward Carbodiimide

A series of lanthanocene derivatives containing the o-aminothiophenolate ligand have been synthesized, and their reactivities toward carbodiimide have been investigated. Reaction of N,N‘-diisopropylcarbodiimide (iPrNCNiPr) with [Cp2Yb(o-H2NC6H4S)]2·2THF (Cp = C5H5) (1) yields a centrosymmetric dimer, [Cp(THF)Yb(μ-η3:η1-SC6H4NC(NHiPr)NiPr)]2 (2), indicating that the adjacent NH2 group can add to the CN double bonds of carbodiimide and one cyclopentadienyl group is eliminated. [Cp2Dy(o-H2NC6H4S)]2·3THF, obtained by protolysis of Cp3Ln with o-aminothiophenol, reacts with 2 or 1 equiv of iPrNCNiPr in THF at room temperature to give the partial amino group addition product CpDy(THF)[μ-η3:η1-SC6H4NC(NHiPr)NiPr)](μ-η2:η1-SC6H4NH2)DyCp2·THF (4). When Cp3Dy reacts with o-aminothiophenol, and subsequently with iPrNCNiPr in toluene at room temperature, we isolated complex 4 and a small amount of [Cp2Dy(o-H2NC6H4S)]2·2THF (5) and [Cp(THF)Dy(μ-η3:η1-SC6H4NC(NHiPr)NiPr)]2 (6). Treatment of 2 equiv of iPrNCNiPr with 3 in THF under reflux temperature also gave 4; the residual NH2 group cannot continuously add into the CN bonds of other carbodiimide molecules. Reaction of Cp3Er with 2 equiv of o-aminothiophenol and subsequently with 2 equiv of iPrNCNiPr in THF at room temperature yields the bis-addition product (C5H5)Er[SC6H4NC(NHiPr)2]2 (7). However, when Cp3Er reacts with 2 equiv of o-aminothiophenol, and subsequently with 1 equiv of iPrNCNiPr, the organic disulfide (iPrHN)2CNC6H4SSC6H4NC(NHiPr)2 (8) can be isolated. These results indicate that the addition of the adjacent amino group into the CN double bonds of the carbodiimide molecule is strongly affected by the metal ion character and the steric hindrance of the ligands. All of the new compounds have been characterized by elemental analysis and spectroscopic properties. Their structures have also been determined through X-ray single-crystal diffraction analysis.