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

Abstract

Eleven new multidimensional transition coordination polymers, [Cd 2 (dcpy) 2 (H 2 O)] ( 1 ), [Cd(dcpy)]·H 2 O ( 2 ), [Cd(dcpy)(H 2 O) 1.5 ]·2H 2 O ( 3 ), [Cd(dcpy)(bipy) 0.5 (H 2 O)]·5H 2 O ( 4 ), [Cd 2 (dcpy) 2 (bipy)(H 2 O) 3 ]·2.5H 2 O ( 5 ), [Cd 2 (dcpy) 2 (bipy)]·4H 2 O ( 6 ), [Cd(dcpy)(bpa) 0.5 ]·2H 2 O ( 7 ), [Ni(dcpy)(H 2 O) 2 ] ( 8 ), [Ni(dcpy)(bpe) 0.5 (H 2 O)]·3H 2 O ( 9 ), [Ni(dcpy)(bpe) 0.5 (H 2 O)]·0.5H 2 O ( 10 ), and [Ni(dcpy)(bpa) 0.5 (H 2 O) 2 ]·H 2 O ( 11 ), have been synthesized by using a tritopic ligand 3-(2′,5′-dicarboxylphenyl)pyridine acid (H 2 dcpy) 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 Cd 2 O 3 as a secondary building unit (SBU) with a (4,6)-connected net. 4 is a two-dimensional (2D) layer based on Cd 2 O 2 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 Ni 2 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 CO 2 over N 2 .