1292767-69-1Relevant articles and documents
Lanthanide-based coordination polymers assembled from derivatives of 3,5-dihydroxy benzoates: Syntheses, crystal structures, and photophysical properties
Sivakumar, Sarika,Reddy,Cowley, Alan H.,Butorac, Rachel R.
, p. 4882 - 4891 (2011)
Two new aromatic carboxylic acids, namely, 3,5-bis(benzyloxy)- benzoic acid (HL1) and 3,5-bis(pyridine-2-ylmethoxy)benzoic acid (HL2), have been prepared by replacing the hydroxyl hydrogens of 3,5-dihydroxy benzoic acid with benzyl and pyridyl moieties, respectively. The anions derived fromHL1 and HL2 have been used for the support of a series of lanthanide coordination compounds [Eu 3+ = 1-2; Tb3+ = 3-4; Gd3+ = 5-6]. The new lanthanide complexes have been characterized on the basis of a variety of spectroscopic techniques in conjunction with an assessment of their photophysical properties. Lanthanide complexes 2, 4, and 6, which were synthesized from 3,5-bis(pyridine- 2-ylmethoxy)benzoic acid, were structurally authenticated by single-crystal X-ray diffraction. All three complexes were found to exist as infinite one-dimensional (1-D) coordination polymers with the general formula {[Ln(L2)3- (H2O)2] xH2O}n Scrutiny of the packing diagrams for 2, 4, and 6 revealed the existence of interesting two-dimensional molecular arrays held together by intermolecular hydrogen-bonding interactions. Furthermore, the coordinated benzoate ligands serve as efficient light harvesting chromophores. In the cases of 1-4, the lowest energy maxima fall in the range 280-340 nm [molar absorption coefficient (ε) = (0.39-1.01) × 104 M-1 cm-1]. Moreover, the Tb3+ complexes 3 and 4 exhibit bright green luminescence efficiencies in the solid state (φoverall = 60% for 3; 27% for 4) and possess longer excited state lifetimes than the other complexes (t = 1.16 ms for 3; 1.38 ms for 4). In contrast to the foregoing, the Eu3+ complexes 1 and 2 feature poor luminescence efficiencies.
