The variety of conformational isomerism of a flexible organic linker induced by the position and amounts of aromatic carboxylic groups

Five new coordination polymers, namely [Zn4(L)2(5-HIA)2]n·nH2O (1), [Cd2L(IPA)2]n·2nH2O (2), [Zn6L3(TPA)]n·4nH2O (3), [Zn8L4(TMA)8]n·nH2O (4) and [Co2L(TMA)2]n·3nH2O (5), have been hydrothermally prepared based on a tetrahedral linker, tetrakis(3-pyridyloxymethylene) methane (L), and different carboxylates (5-HIA = 5-hydroxyisophthalic acid, IA = isophthalic acid, TPA = terephthalic acid and TMA = trimesic acid). Complex 1 and 5 exhibit that L is sandwiched between two 2-D sheets, while 2 features a 3D structure with a (ZnL)n helix. Complex 3 exhibits a threefold interpenetration network. In 4, a 2D sheet is generated by intermolecular hydrogen bonds and is further linked into a 3D network. The thermal stability and photoluminescent properties of these polymers were investigated.

Graphical abstractFive new coordination polymers have been synthesized and structurally characterized from the tetrahedral linker tetrakis(3-pyridyloxymethylene) methane (L) and different carboxylates. In addition, the effect of the position and amounts of aromatic carboxylic groups on the conformational diversity of L and the luminescence of the polymers have been discussed in detail.Figure optionsDownload full-size imageDownload as PowerPoint slide