Structure, sensing and photocatalytic properties of two multifunctional 3D luminescent coordination polymers based on an N-heterocyclic carboxylic acid

Abstract

Two novel luminescent coordination polymers, namely, {[Zn(tmlb)(H₂tmlb)]·H₂O}_n (1) and [Zn(tmlb)(bbibp)]_n (2) ((bbibp = bis(benzoimidazo-1-ly)biphenyl), H₂tmlb = (1H-1,2,4-triazol-1-yl)methylenebis(benzoic acid)), have been rationally designed and successfully solvothermally synthesized. Complexes 1 and 2 have been characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric (TG) analysis and powder X-ray diffraction (PXRD). Complex 1 possesses a 2-fold interpenetrating 3-connected 3D framework with a point symbol of (6³) topology. Complex 2 exhibits a two-fold interpenetrating uninodal 4-connected 3D framework with a (6⁵·8) topology. The luminescence studies reveal that complexes 1 and 2 display highly sensitive and selective luminescent sensing towards Cr(VI) (CrO₄²⁻ and Cr₂O₇²⁻) anions, and complex 2 displays highly sensitive and selective luminescence sensing towards Fe(III) cations. In addition, photocatalytic studies show that complex 1 could be a good candidate for the photocatalytic degradation of methylene blue (MB), and complex 2 could be a good candidate for the photocatalytic degradation of methylene violet (MV) and Rhodamine B (RhB).