Solvent/Temperature and Dipyridyl Ligands Induced Diverse Coordination Polymers Based on 3-(2′,5′-Dicarboxylphenyl)pyridine

Abstract

Eleven new multidimensional transition coordination polymers, [Cd2(dcpy)2(H2O)] (1), [Cd(dcpy)]·H2O (2), [Cd(dcpy)(H2O)1.5]·2H2O (3), [Cd(dcpy)(bipy)0.5(H2O)]·5H2O (4), [Cd2(dcpy)2(bipy)(H2O)3]·2.5H2O (5), [Cd2(dcpy)2(bipy)]·4H2O (6), [Cd(dcpy)(bpa)0.5]·2H2O (7), [Ni(dcpy)(H2O)2] (8), [Ni(dcpy)(bpe)0.5(H2O)]·3H2O (9), [Ni(dcpy)(bpe)0.5(H2O)]·0.5H2O (10), and [Ni(dcpy)(bpa)0.5(H2O)2]·H2O (11), have been synthesized by using a tritopic ligand 3-(2′,5′-dicarboxylphenyl)pyridine acid (H2dcpy) and three different N-donor ancillary ligands (bipy = 4,4′-bipyridine, bpe = 1,2-bi(4-pyridyl)ethene, and bpa = 1,2-bi(4-pyridyl)ethane) in different solvents and temperatures. 1 is a four-connected three-dimensional (3D) framework based on two kinds of Cd–O–Cd and Cd–(COO)–Cd chains. 2 shows also a four-connected 3D framework with one-dimensional (1D) channels formed by double left- and right-handed helical chains. 3 displays a 3D microporous framework composed of Cd2O3 as a secondary building unit (SBU) with a (4,6)-connected net. 4 is a two-dimensional (2D) layer based on Cd2O2 SBU and further stacks to generate a 3D supramolecular framework with open channels. 5 is a rare 3D homochiral microporous framework with left-handed helical chains. 6 presents the first (3,4,6)-connected 3D self-penetrating framework based on 1D metal–organic nanotubes (MONTs). 7 is a (3,4)-connected 3D microporous pillar-layer framework with 1D square channels filled by left- or right-handed helical water clusters chains. 8 is a 2D (3,6)-connected net based on Ni2 dimers. 9 shows a wavelike 2D stacked layer framework possessing two types of open channels. 10 is a structural isomer of 9, showing an intriguing (3,4)-connected self-penetrating network, while 11 exhibits a 2D (3,4)-connected layer. The effects of solvents, temperatures, metal cations, and the lengths and rigidness/flexibility of the dipyridyl ligand on the crystal architectures are discussed. The solid-state photoluminescence for 1–7 and the magnetic properties for 8 were also investigated. Gas adsorption studies for 9 shows a high selective adsorption of CO2 over N2.