Two Calcium Coordination Polymers with Multi-Stimuli-Responsive Properties

Two skeleton isomers, [CaL(H2O)(DMF)(2)]center dot DMF (1) (H2L=5-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)isophthalic acid) with a 1 dimensional chain structure and [CaL(DMF)(1.72)]center dot (DMF)(0.28) (2) with a 2 dimensional layer structure were synthesized. Mechanochromic luminescence studies reveal that 1 and 2 exhibit luminescent red-shift and blue-shift respectively under grinding stimuli. The different influence of grinding stimuli on the pi center dot center dot center dot pi interaction in the two structures are proposed to be the main reason for such different responses. In addition, 1 has a rare broad sensing ability for halogenated hydrocarbons and can distinguish seven halogenated hydrocarbons out of 17 solvents. 1 can also be used for rapid detection of trace water in DMF with a calculated detection limit of 0.0078 v/v %. The relevant recognition mechanism is the decomposition of the structure during the recognition process due to the water instability of the ionic bond. The above results reveal that both compounds have the potential to be used as multi-stimulus-responsive materials.