Self-Assembly of 2D→2D Interpenetrating Coordination Polymers Showing Polyrotaxane- and Polycatenane-like Motifs: Influence of Various Ligands on Topological Structural Diversity

Abstract

A series of mixed-ligand coordination complexes, namely, [Cd 2(bimb) 2(L (1)) 2] ( 1), [Cd(bpimb) 0.5(L (2))(H 2O)] ( 2), [Zn 5(bpib) 2(L (3)) 4(OH) 2(H 2O) 2] ( 3), [Zn(bpib) 0.5(L (4))] ( 4), and [Cd(bib)(L (4))] ( 5), where bimb = 1,4-bis((1 H-imidazol-1-yl)methyl)benzene, bpimb = 1,4-bis((2-(pyridin-2-yl)-1 H-imidazol-1-yl)methyl)benzene, bpib = 1,4-bis(2-(pyridin-2-yl)-1 H-imidazol-1-yl)butane, bib = 1,4-bis(1 H-imidazol-1-yl)butane, H 2L (1) = 4-((4-(dihydroxymethyl)phenoxy)methyl)benzoic acid, H 2L (2) = 4,4'-methylenebis(oxy)dibenzoic acid, H 2L (3) = 3,3'-methylenebis(oxy)dibenzoic acid, and H 2L (4) = 4,4'-(2,2'-oxybis(ethane-2,1-diyl)bis(oxy))dibenzoic acid, have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric (TG) analyses. In 1, (L (1)) (2-) anions link the metal-neutral ligand subunits to generate a 2-fold parallel interpenetrating net with the 6 (3) topology. In 2- 4, neutral ligands connect the various metal-carboxylic ligand subunits to give a 2-fold parallel interpenetrating net with (4,4) topology in 2, a 2-fold parallel interpenetrating net with (3,6)-connected topology in 3, and a 3-fold parallel interpenetrating net with (4,4) topology in 4. Compounds 1- 4 display both polyrotaxane and polycatenane characters. Compound 5 is a 5-fold parallel interpenetrating net with (4,4) topology. By careful inspection of these structures, we find that different topological structures showing both polyrotaxane and polycatenane characters have been achieved with increase of the carboxylic ligand length. It is believed that various carboxylic ligands and N-donor ligands with different coordination modes and conformations are important for the formation of the different structures. In addition, the luminescent properties of these compounds are discussed.

A new 2D 5-connected coordination polymer based on 3,4-bis(pyridin-4-ylmethoxy)benzoic acid ligand

“…4, compound 1 shows a maximum emission at 453 nm (λ ex = 340 nm). As reported in literatures [44,45], the photoluminescent spectra of free neutral ligands show the emission maxima at 389 nm (λ ex = 246 nm) for HL 2 , 360 nm (λ ex =480 nm) for 1,4-H 2 bdc, respectively. The emission of the HL 2 , 1,4-H 2 bdc ligands may be assigned to π* → n and π* → π transitions of the intraligands.…”

Synthesis, crystal structures, and properties of three metal complexes with N-phenylanthranilic acid

“…Complex 1 displays a peculiar trinuclear center-symmetrical unit with CdÁ Á ÁCd inter-distance 3.4872 Å, which built from connecting Cd II ions via the l 2 -oxygen (O5) and l 1 -oxygen (O2, O8). To the best of our knowledge, binuclear structures of Cd are relatively common [15][16][17][18], however trinuclear symmetrical structures are rare of reports. Scheme 1.…”

Synthesis and Crystal Structure of a New Zn(II) Interpenetrating Complex Based on 1,4-bis(2-methyl-imidazol-1-yl)butane and 5-bromoisophthalic Acid

“…[3][4][5] Among diverse entangled MOFs, interpenetration is the most familiar phenomenon. To date, considerable efforts have been invested in interpenetrating MOFs and a great many interpenetrating networks have been reported by many groups [6][7][8][9] and some comprehensive reviews have been made by Robson, Batten, and Ciani et al [10][11][12] Summarizing from the large amount of reported works, we can draw a conclusion that long and low steric hindrance ligands will lead to larger voids that may result in high-fold interpenetrating structures. [13] Therefore, the effective strategy for constructing interpenetrating MOFs is to use long and low steric hindrance ligands.…”