Magnetic and luminescent properties of lanthanide coordination polymers with asymmetric biphenyl-3,2′,5′-tricarboxylate

Abstract

Eight isostructural lanthanide coordination polymers [Ln(bptc)(phen)(H2O)]n (Ln = Dy for , Eu for , Tb for , Gd for , Sm for , Nd for , Yb for , Pr for ) were successfully prepared based on bridging asymmetric polycarboxylate ligand biphenyl-3,2',5'-tricarboxylic acid (H3bptc) and chelating 1,10-phenanthroline (phen) coligand. Single crystal X-ray analysis reveals that complexes have a (3,6)-connected CdI2-type coordination network consisting of paddle-wheel dimers [Ln2(CO2)4]. The magnetic and fluorescent properties of have been investigated. Significantly, the Dy(iii) complex behaves with slow relaxation of the magnetization, where the frequency-dependent out-of-phase signals are noticed.

A dysprosium(III) complex based on Schiff-base ligand exhibiting two magnetic relaxation processes

“…6 H 13/2 transition is much stronger than that of the blue 4 F 9/2 ? 6 H 15/2 transition, suggesting that the ligand is suitable for the sensitization of yellow luminescence of Dy III , as are those in other similar complexes [13].…”

Two Series of Lanthanide Coordination Polymers with 2-Methylenesuccinate: Magnetic Refrigerant, Slow Magnetic Relaxation, and Luminescence Properties

“…The unsaturated magnetization together with the 19 nonsuperimposed M versus H/T curves ( Figure S12) suggest the existence of significant magnetoanisotropy and/or low-lying excited states. 6,10,19 (a) (b) …”

“…η 1 : η 1 , µ 3 -η 1 : η 1 : η 1 : η 1 and µ 3 -η 1 : η 1 : η 1 : η 1 (Scheme 1 6 ] n chain (Figure 2b). The adjacent chains are joined together by the chelating bidentate carboxylate groups of the MSA 2-ligands with modes II-IV to form the 2D layer strusture (Figure 2c and Figure S4).…”

“…5,6,20−22 As one small-size flexible polycarboxylate ligand, 2-Methylenesuccinic acid (H 2 MSA) could display various bridging modes and has rarely been documented to construct coordination polymers. 24 (2); Dy (3)) and two-dimensional (2D) {[Ln 2 (MSA) 3 (H 2 O) 4 ]·3H 2 O} n (Ln=Gd (4); Tb (5); Dy (6)). Here, the magnetic and photoluminescent properties have been investigated.…”

“…Upon excitation at 354 nm, complexes 2 and 5 exhibit green luminescence with characteristic Tb 3+ bands at ca 491, 547, 586, and 623 nm, which are attributed to the 5 D 4 → 7 F J (J = 6,5,4,3) transitions of Tb 3+ centers. 19 The most intense emission is centered at 547 nm and corresponds to the hypersensitive transition 5 D 4 → 7 F 5 , which is consistent with the Tb 3+ compounds reported previously.…”