Unexpected 4-Fold [2 + 2] Interpenetration and Polycatenation Behaviors in Porous Luminescent Zinc Metal–Organic Frameworks Constructed from Flexible 3,5-Bis(4-pyridylmethoxy)benzoate Ligand

Abstract

Six zinc metal–organic frameworks, namely, [Zn­(bpmb)­(HCOO)] n ·[Zn(bpmb)­(OH)] n ·​4nH2O (1), [Zn­(bpmb)­(HCOO)] n (2), [Zn2­(bpmb)2­(fum)] n ·​9nH2O (3), [Zn3­(bpmb)2­(d-cam)2] n (4), [Zn2­(bpmb)­(1,3,5-btc)] n ·​nDMA (5), and [Zn­(bpmb)­(1,2,4,5-H2btec)] n ·​4nH2O (6) (Hbpmb = 3,5-bis­(4-pyridyl­methoxy)­benzoic acid; H2fum = fumaric acid; d-H2cam = d-camphoric acid; 1,3,5-H3btc = 1,3,5-benzenetricarboxylic acid; 1,2,4,5-H4btec = 1,2,4,5-benzenetetracarboxylic acid; DMA = N,N-dimethylacetamide), were synthesized under solvothermal conditions. Their structures were characterized by EA, IR, PXRD, TG, and single-crystal XRD. Complex 1 is constructed of two independent neutral 3D MOFs with large 1D nanosized square channels, which are further entangled by each other to give an unexpected 4-fold [2 + 2] interpenetrating architecture. Complex 2 is a 3D MOF constructed from tetradentate bpmb and bidentate formate ligands, which is an isomer of the [Zn(bpmb)­(HCOO)] n piece in 1. Complex 3 displays a 2D double-layered network that possesses 1D nanosized pores. Each 2D double layer is further interlocked with two neighboring ones to form an interesting 3D polycatenation array. Complex 4 possesses a 2D network constructed from a trinuclear [Zn3­(COO)6­N4] cluster and Zn–cam double-helical chain. Complex 5 is a 3D porous MOF constructed from tridentate bpmb and hexadentate 1,3,5-btc ligands. Complex 6 exhibits a 2-fold interpenetrating 2D wavelike (4,4) network constructed from bidentate bpmb and 1,2,4,5-H2btec ligands. The bpmb ligand adopts four types of coordination modes in 1–6. The secondary carboxylate ligands have obvious effects on their coordination architectures. Tetrahedral-, octahedral-, and trigonal-bipyramidal geometries around Zn(II) ions are observed. A general solvothermal method is proposed for preparing carboxylate complexes in DMF−H2O solution without any basic additive. In the preparation of 3, maleic acid is converted to a fumarate ligand. The thermal stabilities of six complexes and N2 adsorption behaviors of 1 and 3 are investigated. All the Zn(II) complexes emit blue luminescence originating from ligand-centered emission.

Significantly Enhancing the Lithium Ionic Conductivity of Metal–Organic Frameworks via a Postsynthetic Modification Strategy

“…The bottom of the tetragonal pyramid is constituted of O1#2, O2#3, O5#1, and O6, and the apex position is occupied by N1. The Zn–O bond lengths range from 2.020(2) to 2.151(3) Å and the Zn–N bond distance is 2.030(3) Å; the O–Zn–O and O–Zn–N bond angles are in the range of 82.56(11)–158.11(10)°, all of which are similar to those reported for other Zn­(II) compounds. , As shown in Figure a, for the H 3 BTC ligand, two of the carboxylic acid groups are coordinated with Zn 2+ ions using the μ 2 -η 1 :η 1 mode and another one is free. Meanwhile, according to the crystal data, the distance between the O atom of the free H 2 O solvent molecule and the hydroxyl O of the free carboxylic acid group is about 4.8 Å, so there is no intermolecular force between H 2 O and the free carboxylic acid group.…”

“…The cycle performance of Zn-MOF-COOLi was measured using cells of LiFePO 10)°, all of which are similar to those reported for other Zn(II) compounds. 29,30 As shown in Figure 1a, for the H 3 BTC ligand, two of the carboxylic acid groups are coordinated with Zn 2+ ions using the μ 2 -η 1 :η 1 mode and another one is free. Meanwhile, according to the crystal data, the distance between the O atom of the free H 2 O solvent molecule and the hydroxyl O of the free carboxylic acid group is about 4.8 Å, so there is no intermolecular force between H 2 O and the free carboxylic acid group.…”

Syntheses and Structures of Four Pairs of Coordination Polymers Based on 2,2′-((5-(Methoxycarbonyl)-1,3-phenylene)bis(oxy))dipropanoic Acid

“…The rational design and synthesis of metal–organic frameworks (MOFs) currently attracted great attention due to their tunable structures and versatile properties, which may have potential applications in biological and material science fields. − Among the numerous complexes, homochiral metal–organic frameworks (HMOFs) aroused considerable interest recently as potent candidates for enantiomorph recognition and separation, asymmetric catalysis, chiral drug delivery, nonlinear optics (NLO), luminescence, and sensors. − Up to now, notable work has been accomplished in the construction and application of HMOFs. , Generally, three strategies are widely employed to build HMOFs. , As the first strategy, totally achiral components are used to prepare chiral coordination polymers via self-resolution in the crystal growth process. In the second scheme, chiral coordination polymers can also be obtained by the reactions of achiral ligands with metal salts under chiral influence such as templates.…”

Synthesis, Crystal Structure and Catalytic Activity of a 1D Chained Ca(II) Coordination Polymer with 3,5-Bis(4-pyridylmethoxy)benzoate Ligand

“…Coordination polymers (CPs) materials have attracted great interest during the past two decades [1][2][3][4][5][6] because they show intriguing structures and excellent properties in many aspects, such as gas adsorption [7], fluorescence [8], magnetic [9], catalysis [10,11], biological activity [12], and so on. In previous studies, N-heterocyclic and polycarboxylate ligands have often been used to build coordination polymer materials as multidentate ligands [13][14][15][16].…”