Structure Modulation in Zn(II)–1,4-Bis(imidazol-1-yl)benzene Frameworks by Varying Dicarboxylate Anions

Abstract

In the field of metal–organic frameworks (MOFs), one of the challenges is the fabrication of novel materials that display/correlate the prediction of structures and functionality. Usually, the structures of MOFs are influenced by the skeleton of ligands. In this article, five different dicarboxylic acids, namely, fumaric dioic acid (H2FUM), 2-aminoterephthalic acid (2-H2ATA), 1,4-naphthalenedicarboxylic acid (1,4-H2NAPDC), 1,2-benzenedicarboxylic acid (1,2-H2BDC), and oxalic acid (H2OX) are employed as the secondary auxiliary ligands to perform a systematic study on the structure diversities in the Zn(II)–1,4-bis(imidazol-1-yl)benzene (L) frameworks. By introducing various secondary dicarboxylate anions in the Zn(II)-L system, six new complexes {Zn(L)(FUM)}∞ (1), {Zn2(L)(2-ATA)2}∞ (2), {Zn(L)(1,4-NAPDC)·H2O}∞ (3), {Zn2(L)(1,4-NAPDC)2·2DMF}∞ (4), {Zn(L)(1,2-BDC)}∞ (5), and {Zn3(L)2(OX)3·H2O}∞ (6) were obtained. Complexes 1 and 3 possess three-dimensional (3D) 5-fold interpenetrating diamond frameworks. Complex 2 is a 3D 3-fold interpenetrating α-Po framework constructed by dinucear {Zn2} secondary building units (SBUs). Complex 4 exhibits a 3D 2-fold interpenetrating α-Po framework when DMF acts as the reaction solvent. Complex 5 shows a 3D framework with diamondoid topology, which includes L/Zn(II)/L helical chains. Complex 6 presents an interesting 3D structure constructed from {Zn(II)-OX-Zn(II)} rod-shaped SBUs and L ligands as pillars. The diverse structures of these six complexes indicate that the skeleton of dicarboxylate anions plays a great role in the assembly of such different frameworks. Moreover, the fluorescence properties of the complexes 1–6 were investigated in the solid state.

Structural modulation of Co(II) coordination polymers with flexible bis(benzimidazole) and different dicarboxylate ligands

“…The red-shifted emission for 1 is caused by the coordination of the ligands to the metal centers. However, the emission bands of the carboxylate ligands originated from the nÀp * transition are weak, and it is considered that the carboxylate ligands have no significant contribution to the fluorescence emission of complexes 1 and 2 in the presence of the N-donor ligand [7].…”

“…From a synthetic point of view, the judicious selection of appropriate organic ligands is proved to be one of the most effective ways to manipulate the diverse structures of MOFs. Among multitudinous organic ligands, benzimidazole-containing ligands, in particular, have proven to be good candidates for the construction of novel MOFs due to their remarkable coordination ability and versatile conformations [7][8][9][10]. To date, some bis(benzimidazole) derivatives such as 1,1-(1,4-butanediyl)bis-1H-benzimidazole, 1,1-(1,4-butanediyl) bis(2-methyl-benzimidazole have been reported in the assembly of preparing such crystalline materials [11][12][13][14][15].…”

Structural modulation and properties of silver(I) coordination polymers from 2,6-naphthalenedicarboxylic acid and flexible N-donor linkers

“…However, since many factors, such as the selection of auxiliary N-donor organic ligands, coordination preferences of the metal nodes, temperature, solvent, reactant concentrations, and non-covalent supramolecular interactions [5][6][7], can influence the topological architectures and properties of these crystalline materials, it has become a long-term challenge for chemists to rationally synthesize and control the structures and compositions of target products in crystal engineering or supramolecular chemistry.…”

Three complexes of manganese(II) based on a new semirigid tetracarboxylate and N-containing ligands: Synthesis, crystal structures and magnetic properties

“…Many factors, such as solvent, temperature, pH value, as well as the choice of ligands, have a subtle impact on the crystallization process [9][10][11], which makes obtaining target coordination compounds with desired architectures and properties still a tremendous challenge. Among the factors mentioned above, the appropriate selection of organic ligands manipulates the final structures and properties of MOFs to some degree [12].…”