Temperature-Controlled Synthesis of Metal-Organic Coordination Polymers: Crystal Structure, Supramolecular Isomerism, and Porous Property

Abstract

Five new supramolecular metal-organic coordination polymers (MOCPs), {[Ni(bipy) 5) (bipy = 4,4 0 -bipyridyl; 2,6-nds = 2,6-naphthalenedisulphonate) have been synthesized and structurally characterized. Compounds 1 and 5 were synthesized at room temperature in H 2 O/EtOH medium, whereas 2-4 were isolated under hydrothermal conditions. Compounds 1-4 were synthesized maintaining the same stoichiometric ratio of metal and ligand under different reaction temperatures, and the different structures of the compounds indicate that the temperature plays a significant role in the construction of the coordination polymers. Structural characterization reveals that the one-dimensional [M(bipy)(H 2 O) 4 ] 2þ cationic chain is a basic building unit for all of the MOCPs, while 2,6-nds remains as a counteranion. In all cases, 2,6-nds counteranions interact with water and bipy molecules through strong hydrogen-bonding and π-π interactions to afford threedimensional supramolecular structures. Compounds 1-4 have the same building unit with different network superstructures and are related as supramolecular isomers. Supramolecular isomerism in 3 and 4 is very interesting since they have the same molecular formula, {[Ni(bipy)(H 2 O) 4 ](2,6-nds)}, and are polymorphs. Compounds 4 and 5 are isomorphous. The thermogravimetric study suggests that the dehydrated compounds are stable up to 300 °C. Furthermore, sorption studies suggest that dehydrated compounds of 1 and 2 are permanently porous.

Syntheses, Crystal Structure, and Luminescence Properties of Three Metal–Organic Compounds Bearing Diverse Dimensionalities Based on Mixed N- and O-Donor Organic Ligands

“…Scheme 1 Coordination mode of pip 2-. a l 2 -g 1 :g 1 /l 1 g 1 :g 0 , b l 4 -g 2 :g 2 /l 3 g 2 :g 1 , c l 2 -g 1 :g 1 / l 2 g 1 :g 1 J Inorg Organomet Polym As shown in Fig. 6b, two adjacent Zn(II) are bonded together to generate a paddlewheel secondary building unit [SBU, Zn 2 (COO) 4 ] with Zn-O bonds length range from 2.0261(13) to 2.0584(15)Å , which are close to those reported for other zinc-carboxylate donor compounds [6,13]. The axial sites of such paddlewheel SBUs are occupied by the N atoms of pyridyl from pip 2-ligands with Zn-N bond length being 2.0347(15)Å .…”

“…calcd. for C 13 (6) Ba (1) (1) Single-crystal structure analysis reveals that compound 1 crystallized in the triclinic system, space group P-1. In compound 1, Ni(II) atom is coordinated by three O atoms of carboxylate from two pip 2-ligands, one N atom of pyridyl from pip 2-ligand and two O atoms from water molecules to form an octahedron geometry (Fig.…”

“…The variety of coordination interactions between metal ions/clusters and organic ligands lead to infinite structures and interesting properties of MOFs. In spite of the great progress has been achieved, the predicted and controlled synthesis of MOFs are still a major challenge at present because there are many factors which can affect the self-assembly of frameworks and final structures of MOFs, such as ligand structures, reaction solvents, temperatures, bridging auxiliary ligands and so on [10][11][12][13][14][15][16]. Among these factors, the selection of organic ligands and metal cations is an important approach to construct MOFs.…”

Synthesis, characterization and crystal structure of one Co(II) complex with 4,4′-bisimidazolylbiphenyl and m-phthalic acid

“…Even more remarkably, these applications can be combined and integrated into individual frameworks to form multifunctional MOFs [5][6][7][8][9][10]. Despite impressive progress in the area of MOFs has been made, it remains a significant challenge to build novel molecular architectures, because the geometries of the organic ligands have a great effect on the structural frameworks; thus, much effort has been devoted to modifying the building blocks and controlling the assembled motifs for required products via selecting different organic ligands [11][12][13].…”

Construction of six coordination networks based on a flexible bis(methylbenzimidazole) ligand and isomeric benzenedicarboxylates

“…Researches in this field have been concentrated on modifying the building blocks and controlling the assembled motifs for required products via selecting different organic ligands [8,9]. Therefore, selective design of organic ligands are usually crucial for the formation of novel frameworks.…”