Coordination polymer

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

[Cu3(C6Se6)] n : The First Highly Conductive 2D π-d Conjugated Coordination Polymer Based on Benzenehexaselenolate.

Abstract: Nanocrystals of a 2D π-d conjugated copper bis(diselenolene) coordination polymer (Cu-BHS, BHS = benzenehexaselenolate) are synthesized via a simple homogeneous reaction between cupric ions and benzenehexaselenol (H6BHS). Its 2D extended hexagonal lattice is confirmed by powder X-ray diffraction, and further characterized by scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The electrical conductivity measured on compressed powder sample reaches 110 S cm-1 at 300 K, which is among the highest value ever reported for coordination polymers. Furthermore, the intrinsic metallic characteristics of Cu-BHS are confirmed by ultraviolet photoelectron spectroscopy and band structure calculation.

Solvent-templated supramolecular isomerism in 2D coordination polymer constructed by NiII2CoII nodes and dicyanamido spacers: drastic change in magnetic behaviours

Abstract: Two heterometallic coordination polymers (CPs) have been prepared using [NiIIL]2CoII (where H2L = N,N′-bis(salicylidene)-1,3-propanediamine) as nodes and dicyanamido spacers by varying the solvent for synthesis. Structural characterizations revealed that methanol assisted the formation of a two-dimensional (4,4) connected rhombic grid network of [(NiL)2Co(NCNCN)2]∞ (1a) whereas relatively less polar acetonitrile afforded a different superstructure {[(NiL)2Co(NCNCN)2]·CH3CN}∞ (1b) with a two-dimensional (4,4) connected square grid network. The presence of acetonitrile molecules in the structure of 1b seems to change the spatial orientation of the terminal metalloligands [NiL] from pseudo-eclipsed in 1a to staggered-like in 1b around the central Co(II). These structural changes in the nodes together with the conformationally flexible dicyanamido spacers, which are cis coordinated to the Co(II) in both trinuclear units, led to the differences in the final 2D network. Variable-temperature magnetic susceptibility measurements revealed that this supramolecular isomerism led to a drastic transition from spin-frustrated antiferromagnetism for 1a to a dominant ferromagnetic behaviour for 1b. The geometrical differences in Ni2Co coordination clusters (CCs) which are scalene triangular in 1a but nearly linear in 1b, are held responsible for the changes of the magnetic properties. The DFT calculations of exchange interactions between metal centres provide a clear evidence of the role played by the fundamental geometrical factors on the nature and magnitude of the magnetic coupling in these pseudo-polymorphic CPs.

Stability of complex coacervate core micelles containing metal coordination polymer.

Abstract: We report on the stability of complex coacervate core micelles, i.e., C3Ms (or PIC, BIC micelles), containing metal coordination polymers. In aqueous solutions these micelles are formed between charged-neutral diblock copolymers and oppositely charged coordination polymers formed from metal ions and bisligand molecules. The influence of added salt, polymer concentration, and charge composition was investigated by using light scattering and cryo-TEM techniques. The scattering intensity decreases strongly with increasing salt concentration until a critical salt concentration beyond which no micelles exist. The critical micelle concentration increases almost exponentially with the salt concentration. From the scattering results it follows that the aggregation number decreases with the square root of the salt concentration, but the hydrodynamic radius remains constant or increases slightly. It was concluded that the density of the core decreases with increasing ionic strength. This is in agreement with theoretical predictions and is also confirmed by cryo-TEM measurements. A complete composition diagram was constructed based on the composition boundaries obtained from light scattering titrations.

One‐, Two‐ and Three‐Periodic Metal–Organic Rotaxane Frameworks (MORFs): Linking Cationic Transition‐Metal Nodes with an Anionic Rotaxane Ligand

Abstract: A new singly charged pyridinium axle was prepared and combined with disulfonated dibenzo[24]crown-8 ether to form a [2]pseudorotaxane. The reaction of this new, anionic ligand with Zn(II) ions, under various crystallization conditions, resulted in the formation of three metal-organic rotaxane framework (MORF) solids; a one-periodic ML coordination polymer and two, two-periodic ML(2) square grid frameworks. The layers of square grids can be pillared to create full three-periodic MORF structures, which have completely neutral frameworks and are porous. These three-periodic materials represent the first examples of neutral porous MOFs in which one (or more) of the linkers is a mechanically interlocked molecule (MIM).

A catalytically active porous coordination polymer based on a dinuclear rhodium paddle-wheel unit

Abstract: Two new coordination polymers, DUT-82 and DUT-83 (DUT – Dresden University of Technology), were synthesized by a solvothermal reaction in methanol of rhodium(II) acetate and the tricarboxylic acid H3btc (btc – benzene-1,3,5-tricarboxylate) or H3btb (btb – benzene-1,3,5-tribenzoate), respectively. After drying using supercritical carbon dioxide, aerogels with specific surface areas of up to 1150 m2 g−1 and pore volumes of up to 2.26 cm3 g−1 were obtained. Although there is no long range order in the materials, the presence of rhodium paddle-wheel units and thus a local order was proven by X-ray absorption spectroscopy measurements. DUT-82 shows good performance in the adsorption of hydrogen and a high affinity for carbon monoxide, which is rarely observed for metal–organic frameworks. Catalytic investigations demonstrate the activity of DUT-82 in the heterogeneous hydrogenation of styrene as a model system. DUT-82 can be recycled for at least ten cycles underlining the stability during the course of reaction.