Coordination polymer

About: Coordination polymer is a research topic. Over the lifetime, 11988 publications have been published within this topic receiving 212219 citations.

Crystallographic Evidence for Reversible Symmetry Breaking in a Spin‐Crossover d7 Cobalt(II) Coordination Polymer

Abstract: This work was supported by the DST and CSIR, India. J.S.C. thanks the Spanish MICINN through CTQ2009-06959 for the research fellowship “Juan de la Cierva” (18-08-463B-750). J.R. also thanks the Spanish MICINN through CTQ2009-07264.

New tricopper(II) cores self-assembled from aminoalcohol biobuffers and homophthalic acid: synthesis, structural and topological features, magnetic properties and mild catalytic oxidation of cyclic and linear C5–C8 alkanes

Abstract: Two new crystalline materials [Cu3(μ2-H3bis-tris)2(μ2-Hhpa)2]·H2O (1) and [Cu3(μ2-H2tea)2(μ2-hpa)(μ3-hpa)]n (2) bearing distinct tricopper(II) cores were easily generated by the aqueous medium self-assembly method from copper(II) nitrate, bis(2-hydroxyethyl)amino-tris(hydroxymethyl)methane (H5bis-tris) or triethanolamine (H3tea) aminoalcohol biobuffers and homophthalic acid (H2hpa). The obtained products were characterised by IR, UV-vis and EPR spectroscopy, ESI-MS(±), thermogravimetric, elemental and single crystal X-ray diffraction analysis. Apart from possessing different dimensionality, the crystal structures of the discrete 0D trimer 1 and the zigzag 1D coordination polymer 2 show distinct symmetric [Cu3(μ-O)4(μ-COO)2] and asymmetric [Cu3(μ-O)3(μ-COO)2] tricopper(II) cores, respectively. An intense pattern of intermolecular O–H⋯O hydrogen bonds provides a 0D → 3D (1) or 1D → 2D (2) extension of the structures into intricate topologically unique H-bonded nets. After additional simplification, these were classified as a uninodal 6-connected 3D framework with the snk topology in 1 and a binodal 3,5-connected 2D layer with the 3,5L50 topology in 2. Variable-temperature magnetic susceptibility studies indicate a predominant ferromagnetic coupling [J = 39.1(1) and 29.5(1) cm−1 for 1 and 2, respectively] within the mixed-bridged tricopper(II) cores. Both compounds 1 and 2 were also applied as rather efficient bio-inspired pre-catalysts for the mild homogeneous oxidation, by aqueous H2O2 at 50 °C in acidic MeCN–H2O medium, of cyclic (cyclopentane, cyclohexane, cycloheptane and cyclooctane) and linear (n-pentane, n-hexane, n-heptane and n-octane) alkanes to the corresponding alcohols and ketones with overall yields up to 26% based on the alkane. The effects of different reaction parameters (type of pre-catalyst and acid promoter, reaction time and substrate scope) and various selectivity features were investigated and discussed, supporting a free-radical mechanism in the present alkane oxidations.

Novel Coordination Polymer Containing a Mixed Valence Copper(I,II) Phosphonate Unit: CuI2CuII(hedpH2)2(4,4‘-bpy)2·2H2O (hedp = 1-Hydroxyethylidenediphosphonate)

Abstract: This paper reports the synthesis and crystal structure of a novel mixed valence copper(I,II) compound, CuI2CuII(hedpH2)2(4,4‘-bpy)2·2H2O (1), where hedp represents 1-hydroxyethylidenediphosphonate The structure is composed of {CuI2CuII(hedpH2)2} trimer units and 4,4‘-bipyridine linkages, forming a two-dimensional brick-wall-like layer structure in the ab plane The layers are stacked along the [001] direction with strong interlayer hydrogen bonds and π−π interactions, thus leading to the construction of a three-dimensional network

Highly responsive nature of porous coordination polymer surfaces imaged by in situ atomic force microscopy.

Abstract: The ability of porous coordination polymers to undergo reversible structural transformations in response to the presence of guest molecules has been intensively investigated for applications such as molecular separation, storage, sensing and signalling processes. Here we report on the direct observation of the highly guest-responsive nature of the surface of a single-crystalline porous coordination polymer, which consists of paddlewheel zinc clusters and two types of ligand, by in situ liquid-phase atomic force microscopy. Observations were carried out in solution at constant temperature (28 °C) by high-speed atomic force microscopy with lattice resolution. A sharp and reversible response to the presence or absence of biphenyl guest molecules was observed, under conditions that can scarcely induce the transformation of the bulk crystal. Additionally, by modulating the surface coordination equilibrium, layer-by-layer delamination events were captured in real time at every ~13 s per frame. Some porous coordination polymers (PCPs) are known to be flexible and guest-responsive. Now, the guest-induced sharp, reversible structural transformation of the surface of a single-crystalline PCP has been visualized by in situ liquid-phase atomic force microscopy. This local response occurred at a guest concentration that was too low to trigger changes to the bulk crystal.

Facile Synthesis of Nitrogen Tetradentate Ligands and Their Applications in CuI-Catalyzed N-Arylation and Azide-Alkyne Cycloaddition

Abstract: Five new tetradentate ligands [NNNN] with benzimidazolyl-imine or amine nitrogen donors have been synthesized in good yields under mild conditions from easily available substrates. trans-N,N'-bis(1-Ethyl-2-benzimidazolylmethylene)cyclohexane-1,2-diimine is the best accelerating ligand in this series that supports the Cu(I)-catalyzed Ullmann N-arylation and the direct three-component azide-alkyne cycloaddition reaction to give the corresponding substituted imidazole, pyrazole, and triazole in high yields. Single-crystal X-ray diffraction analysis of its complex with CuI reveals a novel one-dimensional coordination polymer of the metal chain bridged alternately by the [NNNN] ligand and diiodides.