Water-induced reversible dissolution/reorganization transformations of Cu(Ⅱ)-K(I) heterometallic coordination polymers

Three new heterometallic coordination compounds, namely, [KCu(I3)(L)2(H2O)2]n(1), [KCu(I3)(L)2(H2O)]n(2) and [CuK4(I3)2(L′)4]n(3), were prepared and characterized(HL=5-methylpyrazine-2-carboxylic acid, HL′=p-tolylacetic acid). Structural studies revealed that 1 and 2 exhibit 3D frameworks with rectangular channels occupied by triiodide ions. Both compounds can be symbolized as a 5-connected net with pcu topology. In compound 3, a one-dimensional polyhedral chain is connected by hexanuclear mask like clusters [Cu2K4O8]. These chains are further linked each other via rare(1,1,3,3)-triiodide ion-bridging units to generate a 3D(4,5,6)-connected net with the point symbol of {12}2{4·122}4{46}{48·62}4{49·66}4. It is noteworthy that water-induced reversible dissolution/reorganization processes occur between 1/2 and [Cu(L)2(H2O)]n·3nH2O. The thermal and photoluminescence properties of compounds 1, 2, and 3 were investigated as well.