Silandiamide Complexes of Lanthanides with N-Phenylbenzothiazole Substituents: Synthesis, Unexpected Products, Structure, and Luminescence
摘要
Deprotonation of SiMe2(HNPbt)2 proligand (1) by Li(NTms2) (Tms = SiMe3) base results in the formation of SiMe2(LiNPbt)2 (Pbt = 2-(1,3-benzothiazol-2-yl)phenyl) in solution, which further reacts with GdCl3 yielding [Li(THF)4][Gd(SiMe2(NPbt)2)2] complex (2). In an attempt to obtain 2 with the use of n-butyllithium as a base, an unexpected product with an intricate structure - [Gd{Me2Si(NPbt)(o-NC6H4-C(Bu)2(o-NHC6H4S))}(μ-NHPbt)Li(THF)] complex (3) is isolated and structurally characterized. The thiazole ring of one of the substituents of the silandiamide ligand is open in it, while two butyl groups are attached to the thiazole C2 carbon atom. In the reaction of 1 with an excess of butyllithium and YCl3, a product with the ligand also containing the C(Bu)2 moiety is formed, which is shown by 1H NMR. Apart from it, double complex salt [Li(THF)4][Y(SiMe2(NPbt)2)2] (4) crystallized as a solvate with Et2O is isolated from the reaction mixture. In an attempt to obtain a monosubstituted [Y(SiMe2(NPbt))Cl] complex, compound 4·2THF forms along with several crystals of [{Y(SiMe2(NPbt)2)}2(μ-OBu)2] complex (5) the structure of which is characterized by single crystal X-ray diffraction. The photophysical properties of compound 2 are studied in the THF solution and in the crystalline state.