Three lanthanide coordination polymers with nitrilotriacetic acid: hydrothermal syntheses, crystal structures and fluorescent property

摘要

Hydrothermal reactions of Sm_2O_3, Gd(ClO_4)_3 centre dot 6H_2O and Tb(ClO_4)_3 centre dot 6H_2O with nitrilotriacetic acid, give rise to three lanthanide coordination polymers, {[Sm(NTA)(H_2O)_2] centre dot H_2O}_n (1), {[Gd(NTA)(H_2O)] centre dot H_2O}_n (2) and {[Tb(NTA)(H_2O)] centre dot H_2O}_n (3). Their solid-state structures have been characterized by elemental analysis, and IR spectroscopy. X-ray single-crystal diffraction analyses indicated that 2 and 3 are isomorphous three-dimensional coordination polymers with eight-coordinate Gd(III) (or Tb(III)), while 1 forms a two-dimensional coordination polymer containing nine-coordinate Sm(III). The photophysical properties of 3 have been studied with excitation and emission spectra, which exhibit strong green emission.