Six lanthanide(III) coordination polymers with 3,5-bis(4′-carboxy-phenyl)-1,2,4-triazole: syntheses, structures, and photoluminescence

Six 3-D lanthanide(III)-metal-organic frameworks (MOFs) through multidentate 3,5-bis(4-carboxy-phenyl)-1,2,4-triazole (H2BCPT); acetic acid (HOAc); and corresponding trivalent rare earth chloride, {[Ln(BCPT)(OAc)(H2O)]?(H2O)}(n) (Ln=Nd3+ (1); Sm3+ (2), Gd3+(3), Tb3+ (4), Ho3+ (5), Yb3+ (6)), have been synthesized. MOFs 1-6 were characterized via FT-IR spectroscopy, elemental analysis, X-ray single-crystal diffraction, thermal analysis, and fluorescence. MOFs 1-6 are isomorphous, which can be described as a 3-D construction containing a dinuclear cluster [Tb-2(CO2)(2)(O)(2)]. The 3-D structure with (4,4) topologies have been extended through BCPT2- using (4)-kO;kO;kO;kO coordination modes. Solid-state luminescence of 1-4 and 6 shows the characteristic bands of Nd3+, Sm3+, Tb3+, and Yb3+ from visible to near-infrared spectral regions.