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

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.