Two zinc coordination polymers with photochromic behaviors and photo-controlled luminescence property

Two new coordination polymers, [Zn(3-NDI)0.5(NDC)(DMF)]n(1) and {[Zn1.5(3-NDI)0.5(BDC)1.5]•2.5DMF}n (2), were synthesized based on naphthalenediimide and aromatic dicarboxylic acids. (3-NDI = N, N'-bis (3-pyridine Methyl) -1,4,5,8-naphthalenediimide, H2NDC = 1,4-naphthalenedicarboxylic acid, H2BDC = terephthalic acid, DMF = N, N'- dimethylformamide). Complex 1 is a two-dimensional structure, whereas complex 2 is a three-dimensional structure with hex topology. Both complexes feature photochromic behaviors, which are proved by single-crystal X-ray diffraction, UV-vis spectra and EPR characterizations. Furthermore, both complexes have obvious fluorescence quenching behaviors upon irradiation by using a xenon lamp.