Diversity of Lanthanide(III)–Organic Extended Frameworks with a 4,8-Disulfonyl-2,6-naphthalenedicarboxylic Acid Ligand: Syntheses, Structures, and Magnetic and Luminescent Properties

A sulfonate–carboxylate ligand, 4,8-disulfonyl-2,6-naphthalenedicarboxylic
acid (H4-DSNDA), and eight new lanthanide coordination
polymers {[Pr4(OH)4(DSNDA)2(H2O)12]­(H2O)10}n (1), [Ln­(H2-DSNDA)0.5(DSNDA)0.5(H2O)5]n (Ln = La­(2), Nd­(3), Sm­(4), Eu­(5), Gd­(6), and Dy­(7)),
and {[Er­(H-DSNDA)­(H2O)4]­(H2O)}n (8) have been synthesized.
Detailed crystal structures of these compounds have been investigated.
Compound 1 has a 3D framework featuring the unique cubane-shaped
[Pr4(μ3-OH)4] clusters and
is a binodal 4,8-connected network with (416·612)­(44·62)2 topology.
Compounds 2–7 are isostructural and
have 2D layered structures. Compound 8 is also a 2D layer
but belongs to different structural types. The luminescence behavior
of compound Eu­(5) shows that the π-rich aromatic
organic ligands efficiently transfer the absorbed light energy to
the Eu­(III) ions, thus enhancing the overall luminescent properties
of compound Eu­(5). The magnetic properties of all compounds
except for the diamagnetic La­(2) compound have been investigated.
In addition, elemental analysis, IR spectra, and thermogravimetric
analysis of these compounds are also described.