A versatile V-shaped tetracarboxylate building block for constructing mixed-ligand Co(II) and Mn(II) complexes incorporating various N-donor co-ligands

Hydrothermal reactions of 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride with Co(II) or Mn(II) acetate and systematically varied N-donor co-ligands leads to the formation of a series of supramolecular complexes, namely, [Co(H(2)dpstc)(trpy)center dot H2O] (1), [Co-2(dpstc)(phen)(2)center dot 4H(2)O]center dot 2H(2)O (2), [Mn-2(dpstc) (phen)(2)center dot 5H(2)O] (3), [Mn-2(dpstc)(bipy)(2)center dot 3H(2)O]center dot H2O (4) and [Mn-2(dpstc)(bpe)(2)center dot 2H(2)O]center dot 2H(2)O (5), where dpstc 3,3',4,4'-diphenylsulfonetetracarboxylate, trpy 2,2':6',2 ''-terpyridine, phen = 1,10-phenthro- line, bipy = 2,2'-bipyridine and bpe = 1,2-di(4-pyridyl)ethylene. Single-crystal X-ray analysis reveals that complex 1 shows a simple 1D linear array, 2 exhibits a unique 1D chain with pendant arms, and 3 displays a binuclear core. Interestingly, such 1D or dimeric coordination motifs in 1-3 hold the recognition sites of hydrogen bonding and/or pi-pi stacking, which result in the extended 3D architectures. In contrast, complexes 4 and 5 represent a 2D (4,4) layer and a 3D 4-connected (6(4).8(2)) framework, respectively. By careful inspection of the structures for 1-5, it is clear that the tetracarboxylate with different coordination modes as well as the auxiliary N-donor ligands play a critical role in determining the coordination array and further packing modes of the final 3D lattice architectures. Magnetic susceptibilities of complexes 1-5 reveals the weak antiferromagnetic exchange interactions between the adjacent metal centers and their thermal stability has also been studied.