Synthesis and crystal structure of mono-chelating (chiral) ether side chain cyclopentadienyl lanthanide complexes with a symmetric tetradentate ligand

Abstract

LnCl 3 reacted with three equivalents of methoxyethylcyclopentadienyl potassium in tetrahydrofuran (THF), followed by treatment with trans-(±)-2,2′-[1,2-cyclohexanediylbis(iminomethyl)] diphenol gave a binuclear mono(methoxyethylcyclopentadienyl)samarium complex [(η 5:η 1-Cp′Sm] [(μ:η-OC 20H 20N 2O)] 2[η 5-Cp′Sm] ( 1), and bis(methoxycyclopentadienyl) ytterbium, [Cp 2′Yb] 2(OC 20H 20N 2O) ( 2) (Cp′=MeOCH 2CH 2C 5H 4). The X-ray determination of complex 1 shows that the molecule is a dimer, in which two (MeOCH 2CH 2C 5H 4)Sm(μ:η 1-OC 20H 20N 2O) units are connected to two bridging oxygen atoms of Schiff base ligands. The average Sm–C distance is 2.769(7) Å, while that of Sm–O (bridging Schiff base oxygens) is 2.401(4) Å. Further studies on the reaction of Cp 2′DyCl (Cp′H=MeOCH 2CH 2CpH) with the disodium salt of trans-(±)-2,2′-[1,2-cyclohexanediylbis(iminomethyl)]diphenol resulted in an analogue of complex 1: [(MeOCH 2CH 2C 5H 4)Dy(OC 20H 20N 2O)] 2 ( 3). However, Cp 2″DyCl reacted with disodium salt of trans-(±)-2,2′-[l,2-cyclohexanediylbis(iminomethyl)]diphenol to give rise to the isolation of dinuclear bis(tetrahydrofurfurylcyclopentadienyl) dysprosium complex with one molecular ligand, (Cp 2″Dy) 2(OC 20H 20N 2O) ( 4) (Cp″H=C 4H 7OCH 2C 5H 5).