Two Zn(II)-based metal-organic frameworks for selective detection of nitroaromatic explosives and Fe3+ ion

Two new luminescent Zn(II) metal-organic frameworks of [Zn(H2BPTC)](H2O)(2) (1) and [Zn-4(H2BPTC)(2)(SO4)(2)] L(CH3)(2)NH2](4)(H2O)(4) (2) were constructed using zinc salts and 3,3',5,5'-biphenyltetracarboxylic acid (H4BPTC) as building blocks. The resulted MOFs were characterized by IR spectroscopy, thermogravimetric analysis and single crystal X-ray crystallography, and they exhibit different structural topologies: 1 presents a three dimensional (4,4)-connected network with {4(2).8(4)} topology, while 2 can be described as a (4,6)-connected network with (3(2).6(2).7(2))(3(4).4(2).6(4).7(5)) topology. These differences show that counter-anions play an important role in modulating structural and luminescent properties. Both 1 and 2 possess strong luminescence in suspensions, which can be selectively quenched by some specific nitroaromatics, Fe3+ ion and acetone.