Structure and Magnetic Properties of a New Cobalt(II) Thiophenedicarboxylate Coordination Polymer Showing Unprecedented Coordination

A new carboxylato-bridged CoII network of formula {Co((κ1-κ1)-(κ1-μ2)-μ4-TDC)(μ2-H2O)0.5(H2O)}n (H2TDC = 2,5-thiophenedicarboxylic acid) has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, thermogravimetric analysis,
and IR and UV−visible spectroscopies. The title compound is made
of chains of CoII dimers interconnected by TDC2- ligands, showing
an unprecedented asymmetric tetradentate coordination mode of
the carboxylate functions. Magnetic measurements show weak
ferromagnetic interactions between the Co ions within the dimers.