Interesting structures of self-assembled gadolinium coordination polymers with tuned stoichiometric ratios

Abstract

Hydrothermal reactions of gadolinium(III) salts with 2,6-naphthalenedisulfonate (nds) and 1,10-phenanthroline with varying mole ratios led to five different compounds, {Gd(phen)(nds)(OH)} _n (1), {[Gd₂(phen)₄(nds)₃(H₂O)₂]·7H₂O} _n (2), {[Gd(phen)₂(nds)_0.5(OH)(H₂O)]·0.5(nds)} _n (3), {[Gd₂(phen)₄(nds)₂(OH)₂(H₂O)₂]·2H₂O} _n (4), and {[Gd(nds)(phen)(H₂O)₄]·0.5(nds)·(phen)·2H₂O} _n (5). In the case of 1, nds coordinates as η ² μ ²–η ² μ ² bridging ligand to adjacent dimers, leading to a three-dimensional network. In 2, nds bridges with each SO₃ ⁻ coordinated as a η ³ μ ¹–bridging group, creating a two-dimensional polymer. For 3, 1-D infinite chains with dinuclear units connected by nds results in a 3-D framework based on hydrogen-bond interactions. 0-D 4 and 1-D 5 contain dinuclear clusters, which are further assembled into 3-D supramolecular networks via weak hydrogen bonds and aromatic packing interactions.

Keywords:

• Organodisulfonate complexes
• Stoichiometric ratios
• Gadolinium
• Self-assembly

Acknowledgments

We are thankful for financial support from NSFC (Grants 20971047 and U0734005), Guangdong Provincial Science and Technology Bureau (Grant 2008B010600009), and Key Research Program of Guangdong Provincial Universities Science and Technology innovation (Grant cxzd1020).