Synthesis, structural characterization and third-order non-linear optical property of new three-dimensional metal-organic framework K·Na·[M2II(μ6-btc)(μ2-ox)(H2O)2]·2H2O (M = Ni, Co)

The 3-D structures of metal-organic frameworks K·Na·[M2II(μ6-btc)(μ2-ox)(H2O)2]·2H2O (M = Co, Ni) with different size 1-D pore channels in each direction are built from the linkage of secondary building units of trinuclear [M3(CO2)3] clusters by a mixed connector of oxalate and pyromellitate.