Coordination polymers of d- and f-elements with (1,4-phenylene)dithiazole dicarboxylic acid

The new ditopic ligand [2,2′-(1,4-phenylene)bithiazole]-5,5′-dicarboxylic acid (H2TzPhTz) was synthesized in ∼ 70% yield through a classical Hantzsch synthesis. Isolation of the dimethyl ester intermediate Me2TzPhTz as the trifluoroacetic acid adduct Me2TzPhTz·2CF3CO2H allowed its crystal structure determination, revealing that the constituting molecules are interconnected through an extended hydrogen-bond network. Reaction of H2TzPhTz with suitable ZnII and UVI salts yielded the 1-D coordination polymers [Zn(TzPhTz)(H2O)2] (Zn_TzPhTz) and [UO2(TzPhTz)(DMF)]·DMF (U_TzPhTz). The former is characterized by zig-zag chains with cis-{Zn(OCOO)4(OH2O)2} nodes and μ-η2:η2-TzPhTz2- spacers, while in the latter TzPhTz-bridged {UO2(TzPhTz)(DMF)}2 dimeric units form polymeric strands. In the solid state, both H2TzPhTz and Zn_TzPhTz emit in the blue-green visible region (λem = 474 and 477 nm, respectively). The two coordination polymers witness the versatility of H2TzPhTz as a linker toward d and f metal ions, and they should be considered as the preliminary step toward the preparation of TzPhTz-based metal–organic frameworks for practical applications in the field of luminescence sensing.