title: Synthesis, crystal structure, and magnetic properties of the first nonanuclear lanthanide(III)-copper(II) complexes of macrocyclic oxamide [NaLn(2)Cu(6)] (macrocyclic oxamide = 1,4,8,11-tetraazacyclotradecanne-2,3-dione, Ln = Pr, Nd).
abstract: Two new nonanuclear lanthanide(III)-copper(II) complexes of macrocyclic oxamide [NaPr(2)(CuL)(6)(H(2)O)(6)](ClO(4))(6)Cl small middle dot6H(2)O (1) and [NaNd(2)(CuL)(6)(H(2)O)(6)](ClO(4))(6)Cl small middle dot8H(2)O (2) have been synthesized and characterized by means of elemental analysis, IR, and electronic spectra, where L = 1,4,8,11-tetraazacyclotradecanne-2,3-dione. The crystal structures of the two complexes have been determined. The structures of 1 and 2 consist of nonanuclear cations, perchlorate and chloride anions, and water molecules. In the two complexes, each copper(II) ion is connected to lanthanide(III) ion via the exo-cis oxygen atoms of the oxamido macrocyclic ligands, resulting in a tetranuclear subunit. The sodium ion links two tetranuclear subunits via the exo oxygen atoms of the oxamido macrocyclic ligands which results in a novel nonanuclear complex. The magnetic properties of the two complexes have been investigated. Preliminary treatment of the magnetic data by considering Ln(III) as free ion cannot give reasonable results, and accurate models involving both the orbital contribution and ligand field effect have to be developed.
authors.affiliation: Department of Chemistry, Nankai University, Tianjin 300071, P. R. China.
authors.forename: Jin-Kui
authors.initials: JK
authors.lastname: Tang
authors.forename: Yi-Zhi
authors.initials: YZ
authors.lastname: Li
authors.forename: Qing-Lun
authors.initials: QL
authors.lastname: Wang
authors.forename: En-Qing
authors.initials: EQ
authors.lastname: Gao
authors.forename: Dai-Zheng
authors.initials: DZ
authors.lastname: Liao
authors.forename: Zong-Hui
authors.initials: ZH
authors.lastname: Jiang
authors.forename: Shi-Ping
authors.initials: SP
authors.lastname: Yan
authors.forename: Peng
authors.initials: P
authors.lastname: Cheng
authors.forename: Liu-Fang
authors.initials: LF
authors.lastname: Wang
authors.forename: Geng-Lin
authors.initials: GL
authors.lastname: Wang