名称:
2-Benzothiazolylthioacetic acid and 4,4′-bipyridine as ligands in designing low-dimensional coordination polymers: Synthesis, architectures and magnetic properties
摘要:
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 {[Mn-3(BTTAA)(4)(4,4'-bipy)(4)](ClO4)(2)center dot 2H(2)O}(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 4(4) grid networks, whereas isomorphous complexes 2 and 3 exhibit a 2DI coordination architecture formed by the same 4(4) grid network. In 4-6, extended 1 D 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 anti ferromagnetic interactions in these complexes. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.