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

Abstract

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(H2dpstc)(trpy)·H2O] (1), [Co2(dpstc)(phen)2·4H2O]·2H2O (2), [Mn2(dpstc) (phen)2·5H2O] (3), [Mn2(dpstc)(bipy)2·3H2O]·H2O (4) and [Mn2(dpstc)(bpe)2·2H2O]·2H2O (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 π–π 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 (64·82) 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.