Macrocyclic versus open-chain carbazole receptors for carboxylate binding

Anion recognition properties of six synthetic acyclic and macrocyclic carbazole-based receptors have been studied by 1H-NMR as well as with COSMO-RS calculations towards acetate, benzoate, lactate, sorbate and formate. The...

Construction of 2D Interdigitated Polyrotaxane Layers and their Transformation to a 3D Polyrotaxane by a Photocycloaddition Reaction between Wheels

Following the pioneering work of Sauvage and Stoddart on rotaxanes, construction of higher dimensional polyrotaxanes in metal-organic frameworks (MOFs) via a modified protocol is challenging. We present the formation of a two-dimensional (2D) polyrotaxane and its conversion to a three-dimensional (3D) polyrotaxane MOF via a photoreaction between interdigitated "olefin wheels". For this purpose, a 2-fold entangled 2D MOF [Pb₂(bpp)(sdc)₂] (1), showing a 2D + 2D → 2D polyrotaxane motif, has been synthesized from the solvothermal reaction of lead(II) nitrate, 3,3'-stilbenedicarboxylic acid (H₂sdc) containing an olefin group, and 1,4-bis(4-pyridyl)piperazine (bpp). The single-crystal X-ray diffraction analysis of 1 revealed that the adjacent entangled 2D layers are interdigitated, with the separation of 3.72 Å between C═C bond pairs in adjacent layers satisfying Schmidt's criteria for the occurrence of a [2 + 2] photocycloaddition reaction. Irradiation of the single crystals of 1 under UV light resulted in formation of a 3D polyrotaxane, [Pb₂(bpp)(rctt-tccb)]_n (2), due to a [2 + 2] photocycloaddition reaction between two wheels via a single-crystal to single-crystal transformation. The photocycloaddition and partial thermal cleavage reaction between 1 and 2 were confirmed by ¹H NMR and powder X-ray diffraction (PXRD) in solution and the solid state, respectively. The present approach could contribute to the understanding of the construction of higher dimensional polyrotaxanes which are not accessible by the traditional routes.

Five transition metal coordination polymers driven by a semirigid trifunctional nicotinic acid ligand: selective adsorption and magnetic properties

Five coordination polymers have been synthesized by a new organic linker containing three distinct types of functional groups together with the mixed 2,2′-bipy or 4,4′-bipy co-ligand, revealing various framework structures and selective gas adsorption and magnetic properties.

Formation of a Dicopper Platform Based Polyrotaxane Whose "String" and "Bead" Are Constructed from the Same Components

The combination of the dicopper platform [Cu2(L)2(THF)2] (1·2THF), where H2L is 1,1'-(1,3-phenylene)-bis-4,4-dimethylpentane-1,3-dione, and 1,4-bis(4-pyridyl)piperazine (bpp), afforded the first example of a one-dimensional polyrotaxane {[(1)(μ2-bpp)][(1)2(bpp)2]}n whose "string" and "bead" are constructed from the same components. The bead of stoichiometry [(1)2(bpp)2] has a large rectangular cavity of dimensions 7.40 × 15.64 Å and is threaded onto a stair-like string of composition [(1)(μ2-bpp)]n. The formation of the polyrotaxane is driven by π-π stacking between the string and the beads with precise electronic and steric complementarity between these components. A pathway for the formation of the polyrotaxane is proposed.

Hydrothermal syntheses, structural characterizations, and magnetic properties of five MOFs assembled from C2-symmetric ligand of 1,3-di(2′,4′-dicarboxylphenyl)benzene with various coordination modes

Five new complexes with appealing structural features from 0D paddle wheel {Cu₂(COO)₄} SBUs to 3D frameworks were reported to better understand the synthon selectivity in multifunctional crystal structures.

Chiral or achiral: four isomeric Cd(ii) coordination polymers based on phenylenediacrylate ligands

The isomeric coordination polymers derived fromp- andm-phenylenediacrylates contain similar homochiral motifs (hydrogen-bonded layers or μ-O_carboxylatebridged helical chains), but only themligand, with assistance of hydrogen bonds, induces spontaneous resolution to generate 3D homochiral networks.

4-(4-Carboxyphenoxy)phthalate-based coordination polymers and their application in sensing nitrobenzene

Structural characterization of 4-(4-carboxyphenoxy)phthalate-based Cd²⁺ and Mn²⁺ coordination polymers are reported, and Cd²⁺ coordination polymer can serve as probe to sense nitrobenzene.

Guest dependent dielectric properties of nickel(ii)-based supramolecular networks

Nickel-based supramolecular compounds exhibit interesting guest dependent dielectric behaviour and high thermal stability. This study serves as a motivation to expand our research to create both high and low-κmaterials with a judicious selection of guest molecules.

Six new coordination polymers based on a tritopic pyridyldicarboxylate ligand: structural, magnetic and sorption properties

Using a rigid ligand, pyridine-3,5-bis(phenyl-4-carboxylic) acid, six new coordination polymers have been synthesized and characterized, and their magnetic, photoluminescence and gas adsorption properties have been studied.