title: Field-induced slow magnetic relaxation in chiral seven-coordinated mononuclear lanthanide complexes.
abstract: Four couples of enantiomerically pure chiral seven-coordinated mononuclear lanthanide complexes, [(L(OEt))Dy((R,R)-Salphen)](2)·3H(2)O (1, L(OEt) = [(Cp)Co(P(O)(OEt)(2))(3)], Cp = cyclopentadiene, Salphen = N,N'-1,2-diphenylethylenebis(salicylideneiminato) dianion), [(L(OEt))Dy((S,S)-Salphen)](2)·3H(2)O (2), [(L(OEt))Dy((R,R)-5-Cl-Salcy)]·CH(3)OH·1/8H(2)O (3, Salcy = N,N'-(1,2-cyclohexanediylethylene)bis(salicylideneiminato) dianion), [(L(OEt))Dy((S,S)-5-Cl-Salcy)]·CH(3)OH·1/8H(2)O (4), [(L(OEt))Tb((R,R)-5-Cl-Salcy)]·CH(3)OH·1/8H(2)O (5), [(L(OEt))Tb((S,S)-5-Cl-Salcy)]·CH(3)OH·1/8H(2)O (6), [(L(OEt))Ho((R,R)-5-Cl-Salcy)]·CH(3)OH·1/8H(2)O (7) and [(L(OEt))Ho((S,S)-5-Cl-Salcy)]·CH(3)OH·1/8H(2)O (8), have been successfully synthesized by using tetradentate chiral salen-type ligands and the Kläui's tripodal ligand of L(OEt). Structural analyses reveal that all compounds have a typical double-decker sandwich structure, and the Ln(iii) ions exhibit a rare seven-coordinated mode, situating in a distorted monocapped triangular prism polyhedron. Circular dichroism (CD) spectra confirm the enantiomeric nature of the optically active complexes and demonstrate that the chirality is successfully transferred from the ligand to the coordination environment of the Ln(iii) ions. Field-induced slow relaxation of the magnetization is observed for complexes 1-4, suggesting that they can be rare chiral single-ion magnets (SIMs) based on the seven-coordinated lanthanide ions.
authors.affiliation: State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093, PR China.
authors.forename: Min-Xia
authors.initials: MX
authors.lastname: Yao
authors.forename: Qi
authors.initials: Q
authors.lastname: Zheng
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Yi-Zhi
authors.initials: YZ
authors.lastname: Li
authors.forename: You
authors.initials: Y
authors.lastname: Song
authors.forename: Jing-Lin
authors.initials: JL
authors.lastname: Zuo