Lutetium complexes with tetraphenylethylene dianion.Synthesis and structure

摘要

The reactions of dipotassium and disodium salts of the tetraphenylethylene dianion with LuCl_3(THF)_3 or CpLuCl_2(THF)_3 yielded the homoleptic ate-complexes [Na(THF)_5][Lu(Ph_2CCPh_2)_2] (1) and [K(THF)_5][Lu(Ph_2CCPh_2)_2] (2) or the heteroleptic complex CpLu(Ph_2CCPh_2)(THF)_2 (4),respectively.Recrystallization of complex 1 from a diglyme-THF mixture afforded [Na(diglyme)_2][Lu(Ph_2CCPh_2)_2](THF)_(0.5) (3).Recrystallization of complex 4 from 1,2-dimethoxyethane gave [CpLu(Ph_2CCPh_2)(DME)](DME) (5).The structures of complexes 3 and 5 were established by X-ray diffraction analysis.In both complexes,the unusual eta~6-coordination of the (Ph_2CCPh_2)~(2-) dianion to lutetium is observed.The Lu-C distances vary from 2.441(2) to 2.643(2) A (3) and from 2.470(3) to 2.763(3) A (5).In complexes 3 and 5,a redistribution of the C-C bond lengths was observed in the Ph groups coordinated to lutetium.Studies by ~1H,~(13)C,and 2D NMR spectroscopy demonstrated that the eta~6-coordination of the tetraphenylethylene dianion in homoleptic ate-complexes 1 and 2 is retained in a THF solution,whereas the coordination of this dianion in heteroleptic complex 4 changes from eta~6 to eta~4.