The concentration controlled 1D and 2D supramolecular isomers of lanthanide with 2,2’-bipyridyl-3,3’-dicarboxylate and phenanthroline

The reactions of 2,2′-bipyridyl-3,3′-dicarboxylic acid (H2bpdc) and 1,10-phenanthroline (phen) with lanthanide (III) salts in different concentrations under hydrothermal conditions formed two series of supramolecular isomers of 1D zigzag chains of [Ln(bpdc)1.5(phen)(H2O)]n·3nH2O (1Ln·3H2O), and 2D frameworks of [Ln(bpdc)1.5(phen)(H2O)]n (2Ln), (Ln = Ho, Er, Tm, and Yb). At lower concentrations, the supramolecular isomers of 1Ln were formed, in which each isomer has a dinuclear centrosymmetric dimeric unit of [Ln2(phen)2(H2O)2(μ2-bpdc)2]2+, and the dimeric units are alternately connected by μ2-bpdc2− to form a 1D zigzag chain of 1Ln. At higher concentrations, the supramolecular isomers of 2Ln were formed. All the compounds of 2Ln are isomorphous, in which two μ3-bpdc2− bridge two [Ln(phen)(H2O)]3+ units to yield a 1D double-chains of [Ln2(phen)2(H2O)2(bpdc)2]n2n+, and [Ln2(phen)2(H2O)2(bpdc)2]n2n+ chains are further connected by μ4-bpdc2− to form a 2D network of [Ln(bpdc)1.5(phen)(H2O)]n. The 2D sheets are combined through the intersheet π–π interactions between the adjacent phen molecules to form a 3D structure of 2Ln. The compounds of Er(III), and Yb(III) exhibit corresponding characteristic photoluminescence in the near-infrared (NIR) region, in which 1Ln and 2Ln show obviously different emission intensity due to their different structures.

The hydrothermal reactions of 2,2′-bipyridyl-3,3′-dicarboxylic acid (H2bpdc), phen and lanthanide (III) salts with different concentration conditions gave two series of supramolecular isomers of 1D zigzag chains of 1Ln, and 2D frameworks of 2Ln.Figure optionsDownload as PowerPoint slide