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.

Graphical abstractA 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 full-size imageDownload as PowerPoint slide