Cationic rare-earth metal SALEN complexes

Abstract

Complexes (Salpren^tBu,tBu)Y[N(SiHMe₂)₂](thf) and (SALEN^tBu,tBu)La[N(SiHMe₂)₂](thf) (SALEN^tBu,tBu = Salcyc^tBu,tBu and Salpren^tBu,tBu) were prepared from Ln[N(SiHMe₂)₂]₃(thf)₂ and H₂SALEN^tBu,tBu. The yttrium complex was characterized by X-ray crystallography revealing intrinsic solid-state structural features: the metal centre is displaced by 1.05 Å from the [N₂O₂] least squares plane of a highly bent Salpren^tBu,tBu ligand (∠(Ph,Ph) dihedral angle of 80.4(1)°) and is coordinated asymmetrically by the silylamide ligand exhibiting one significant Y(HSi) β-agostic interaction (Y–N1–Si1, 106.90(9)°; YSi1, 3.2317(6) Å). Complexes (SALEN^tBu,tBu)Ln[N(SiHMe₂)₂](thf)_n (n = 1, Sc; n = 2, Y, La) react with ammonium tetraphenylborate to form the ion pairs [(SALEN^tBu,tBu)Ln(thf)_n][BPh₄]. The cationisation was proven by X-ray crystal structure analyses of [(Salpren^tBu,tBu)Sc(thf)₂][B(C₆H₅)₄]·2(thf) and [(Salpren^tBu,tBu)Ln(thf)₃][B(C₆H₅)₄]·4(thf) (Ln = Y, La), showing an octahedral and pentagonal-bipyramidal coordination geometry, respectively.