1D molecular ladder of the ionic complex of terbium-4-sebacoylbis(1-phenyl-3-methyl-5-pyrazolonate) and sodium dibenzo-18-crown-6: Synthesis, crystal structure, and photophysical properties

Abstract

On the basis of the novel heterocyclic beta-diketone, 4-sebacoylbis(1-phenyl-3-methyl-5-pyrazolone (H2SbBP), three new lanthanide complexes Tb-2(SbBP)(3)(H2O)(2) (1), Gd-2(SbBP)(3)(H2O)(2) (2), and [Tb(SbBP)(2)] [Na(DB18C6)H2O] (3) have been synthesized and characterized by various spectroscopic techniques. The single-crystal X-ray diffraction analysis of 3 reveals that the complex crystallizes in the monoclinic space group C2/c with a = 25.300(6) angstrom, b = 19.204(7) angstrom, c = 15.391(3) angstrom, beta = 93.17(3)degrees, and V = 7466(4) angstrom(3). The crystal structure of 3 is heterodinuclear and features a Tb3+ center surrounded by two tetradentate bispyrazolone ligands in a somewhat distorted square-antiprismatic geometry. The Na+ coordination environment is distorted hexagonal pyramidal and involves six oxygen atoms furnished by DB18C6 and one oxygen atom from a water molecule. The X-ray diffraction study of 3 also revealed an interesting 1D molecular ladder structure based on C-H/pi, intra- and intermolecular hydrogen-bonding interactions. The photophysical properties of 1 and 3 in solid state have been investigated, and the quantum yields and D-5(4) lifetimes were found to be 4.82 +/- 0.01% and 18.13 +/- 0.82% and 1.11 +/- 0.01 and 2.82 +/- 0.02 ms, respectively.