2-Benzothiazolylthioacetic acid and 4,4′-bipyridine as ligands in designing low-dimensional coordination polymers: Synthesis, architectures and magnetic properties

The combined use of 4,4′-bipyridine (4,4′-bipy) and 2-benzothiazolylthioacetic acid (HBTTAA) as ligands with Mn(II), Cd(II), Co(II) and Cu(II) ions afforded six polymeric complexes, namely {[Mn3(BTTAA)4(4,4′-bipy)4](ClO4)2 · 2H2O}n (1), [Mn(BTTAA)2(4,4′-bipy)2]n (2), [Cd(BTTAA)2(4,4′-bipy)2]n (3), [Cd(BTTAA)(4,4′-bipy)(NO3)(H2O)]n (4), [Co(BTTAA)2(4,4′-bipy)(H2O)2]n (5) and [Cu(BTTAA)2(4,4′-bipy)]n (6). All these complexes have been characterized by a combination of analytical, spectroscopic and crystallographic methods. Complex 1 is a novel 2D network formed by two different 44 grid networks, whereas isomorphous complexes 2 and 3 exhibit a 2Dl coordination architecture formed by the same 44 grid network. In 4–6, extended 1D chains are formed, with the 4,4′-bipy molecules acting as rigid rod-like links between adjacent metal centers. The carboxylato groups of BTTAA in these complexes exhibit four different coordination modes, namely monodentate, chelating, bridging and bridging-chelating modes. The magnetic properties of 1, 2, 5 and 6 were investigated in the temperature range 2.0–300.0 K. Variable temperature magnetic susceptibility measurements show weak antiferromagnetic interactions in these complexes.

A series of coordination polymers (1–6) based on HBTTAA and 4,4′-bipy ligands have been prepared and characterized. There are weak antiferromagnetic interactions between the metal centers bridged by 4,4′-bipy in 1, 2, 5 and 6.Figure optionsDownload as PowerPoint slide