Single-crystal to single-crystal photochemical structure transformation of a ladder-like coordination polymer with dinuclear Zn(II) platform

A new coordination polymer, namely [Zn(Hnbdc)2(bpe)]n (1) (H2nbdc = 3-nitrobenzene-1,2-dicarboxylic acid and bpe = 1,2-bi(4-pyridyl)ethylene), has been hydrothermally synthesized and characterized preliminarily by elemental analysis, infrared spectroscopy, thermal analysis, and X-ray diffractions. Single crystal X-ray diffraction showed that compound 1 possesses a ladder-like topology structure featuring carboxyl-bridged dinuclear Zn(II) spaced by parallel bpe coligand pairs and has the capacity of undergoing a 100% photochemical [2 + 2] cycloaddition reaction to transform into compound [Zn(Hnbdc)2(rctt-tpcb)]n (2) in a single-crystal to single-crystal form. In addition, the fluorescent property of 1 was also investigated.