Synthesis and reactivity of organolanthanide complexes containing phenothiazine ligand toward carbodiimide and isothiocyanate

The synthesis and reactivity of new lanthanocene complexes incorporating phenothiazine ligand are described. The reaction of phenothiazine (HPtz) with nBuLi in THF and subsequently with 1 equiv. of (C5H5)2LnCl(THF) gave the original complexes (C5H5)2LnPtz(THF) (Ln = Yb(1), Er(2), Dy(3), Y(4)). Treatment of complexes 1–4 with N,N′-diisopropylcarbodiimide results in mono-insertion of carbodiimide into the Ln–N(Ptz)-bond to yield the corresponding guanidinates (C5H5)2Ln[(iPrN)2C(Ptz)] (Ln = Yb (5), Er (6), Dy (7), Y(8)). Further investigations indicate that phenyl isothiocyanate react with complexes 1 and 4, giving the correspondent insertion products (C5H5)2Ln[SC(Ptz)NPh](THF) (Ln = Yb(9), Y(10)). All these complexes were characterized by elemental analysis and spectroscopic properties. The structures of complexes 2, 5 and 9 were also determined by the X-ray single crystal diffraction analysis. All these reactions provide a new strategy for introducing a functional substituent at the nitrogen atom of phenothiazine via forming a new C–N(ring) bond.