title: Series of dinuclear and tetranuclear lanthanide clusters encapsulated by salen-type and β-diketionate ligands: single-molecule magnet and fluorescence properties.
abstract: Three dinuclear [Ln2H2OL(1)2(acac)2]·solvent (1, Ln = Gd, solvent = 2CH2Cl2; 2, Ln = Tb, no solvent; 3, Ln = Er, solvent = (C2H5)2O), and two tetranuclear lanthanide clusters [Ln4(μ3-OH)2L(2)2(acac)6]·2(solvent) (4, Ln = Tb, solvent = CH3OH; 5, Ln = Dy, solvent = CH3CN) were characterized in terms of structure, fluorescence and magnetism. The dinuclear lanthanide complexes were constructed by a rigid salen-type ligand H2L(1) = N,N'-bis(salicylidene)-o-phenylenediamine and β-diketonate (acac = acetylacetonate) ligands, while the tetranuclear clusters were formed from the flexible ligand H2L(2) = N,N'-bis(salicylidene)-1,2-ethanediamine. Crystal structure analysis indicates that the rigid ligand favors the double-decker sandwich structure (Ln2L(1)2), in which the two lanthanide ions have different coordination numbers and geometry, while the more flexible ligand (H2L(2)) leads to planar tetranuclear clusters. The relationship between their respective magnetic anisotropy and ligand-field geometries and their fluorescence properties was investigated. The Dy and Tb-containing clusters exhibit typical visible fluorescence properties, and single-molecule magnet behavior is seen in complex 5.
authors.affiliation: Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education, Heilongjiang University, No. 74, Xuefu Road, Nangang District, Harbin 150080, PR China. wenbinsun@126.com
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Sun
authors.forename: Bing-Lu
authors.initials: BL
authors.lastname: Han
authors.forename: Po-Heng
authors.initials: PH
authors.lastname: Lin
authors.forename: Hong-Feng
authors.initials: HF
authors.lastname: Li
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Tian
authors.forename: Muralee
authors.initials: M
authors.lastname: Murugesu
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Yan
mesh_terms: D005029:Ethylenediamines / Q000737:chemistry*; D005453:Fluorescence; D006885:Hydroxybutyrates / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D060328:Magnetic Phenomena; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010422:Pentanones / Q000737:chemistry*
chemical_list: D005029:Ethylenediamines; D006885:Hydroxybutyrates; D028581:Lanthanoid Series Elements; D008024:Ligands; D009942:Organometallic Compounds; D010422:Pentanones; C049529:acetyl acetonate; C011452:disalicylaldehyde ethylenediamine