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Three‐Dimensional Lanthanide(III)–Copper(II) Compounds Based on an Unsymmetrical 2‐Pyridylphosphonate Ligand: An Experimental and Theoretical Study
Author(s) -
Ma YunSheng,
Li Hui,
Wang JunJie,
Bao SongSong,
Cao Rong,
Li YiZhi,
Ma Jing,
Zheng LiMin
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200601786
Subject(s) - isostructural , crystallography , octahedron , lanthanide , chemistry , tetrahedron , ligand (biochemistry) , space group , crystal structure , group (periodic table) , trigonal prismatic molecular geometry , stereochemistry , ion , x ray crystallography , physics , biochemistry , receptor , organic chemistry , diffraction , optics
Based on an unsymmetrical 2‐pyridylphosphonate ligand, two types of Ln III –Cu II compounds with three‐dimensional structures were obtained under hydrothermal conditions, namely, Ln 2 Cu 3 (C 5 H 4 NPO 3 ) 6 ⋅4 H 2 O ( 1⋅Ln ; Ln=La, Ce, Pr, Nd) and Ln 2 Cu 3 (C 5 H 4 NPO 3 ) 6 ( 2⋅Ln ; Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho). Compounds 1⋅Ln are isostructural and crystallize in chiral cubic space group I 2 1 3. In these structures, each Ln ion is nine‐coordinate and has a tricapped triprismatic geometry, while each Cu center is six‐coordinate with an octahedral environment. The {LnO 9 } polyhedra and {CuN 2 O 4 } octahedra are connected by edge sharing to form an inorganic open framework structure with a 3‐connected 10‐gon (10,3) topology in which the Ln and Cu atoms are alternately linked by the phosphonate oxygen atoms. Compounds 2⋅Ln are isostructural and crystallize in trigonal space group R $\bar 3$ . In these structures, the {LnO 6 } octahedra are triply bridged by the {CPO 3 } tetrahedra by corner sharing to form an infinite chain along the c axis. Each chain is connected to its six equivalents through corner sharing of {CPO 3 } tetrahedra and {CuN 2 O 2 } planes to form a three‐dimensional framework structure in which the Ln and Cu atoms are linked purely by O‐P‐O units. The formation of these two types of structures is rationalized by quantum chemical calculations, which showed that both the lanthanide contraction and the electron configuration of Cu II play important roles. When Cu II was replaced by Zn II , only the first type of compounds resulted. The magnetic properties of complexes 1⋅Ln and 2⋅Ln were investigated. The nature of Ln III –Cu II (Ln=Ce, Pr, Nd) interactions is illustrated by comparison with their Ln III –Zn II analogues.