Dynamic Equilibria in Solvent‐Mediated Anion, Cation and Ligand Exchange in Transition‐Metal Coordination Polymers: Solid‐State Transfer or Recrystallisation?

Cui, Xianjin; Khlobystov, Andrei N.; Chen, Xinyong; Marsh, Dan H.; Blake, Alexander J.; Lewis, William; Champness, Neil R.; Roberts, Clive J.; Schröder, Martin

doi:10.1002/chem.200900796

Cited by 120 publications

(124 citation statements)

References 113 publications

(53 reference statements)

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“…If we exclude the potentially structure-determining influence of non-solvent organic molecules [18,19] other than 4,4'-bipy, the number of coordination polymers decreases to about a dozen. These include (4,4) square grid (Scheme 1(d)) [20][21][22][23][24] and 'T-shape' [20] 2D coordination networks, as well as linear chain (Scheme 1(a)) [19,20,25,26] and molecular antenna [19,21] 1D coordination polymers. The term molecular antenna commonly refers to a 1D coordination polymer with the underlying topology of the linear chain (Scheme 1(a)) bearing two additional, terminally monodentate-bound 4,4'-bipy ligands at each metal node [19,21,[27][28][29][30][31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

A Molecular Antenna Coordination Polymer from Cadmium(II) and 4,4’-Bipyridine Featuring Three Distinct Polymer Strands in the Crystal

et al. 2011

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Compound 1 crystallizes in the non-centrosymmetric, monoclinic space group C2 with three similar, crystallographically independent, cationic coordination polymer strands in the unit cell, which essentially differ only in the conformations of the 4,4'-bipyridyl ligands. Consistent with the similarity of the local coordination environments of the three independent Cd atoms in the structure, 113 Cd MAS NMR spectroscopy reveals a single resonance line at 89 ppm.

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Section: Introductionmentioning

confidence: 99%

A Molecular Antenna Coordination Polymer from Cadmium(II) and 4,4’-Bipyridine Featuring Three Distinct Polymer Strands in the Crystal

et al. 2011

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“…Coordination polymers (CPs) and metal-organic frameworks (MOFs) are well-known crystals constructed by an organic compound and a metal. Porous CPs (PCPs) and MOFs, in particular, are highly potential materials for gas storage, [22][23][24] ion exchange, [25][26][27][28] heterogeneous catalysis, [29][30][31] separation, 29,[32][33][34][35][36] and non-linear optics, [37][38][39] because of the nanospace separated from bulk space.…”

mentioning

confidence: 99%

Solvent-dependent Assembly of Discrete and Continuous CoCl2 Adamantane-based Ligand Complexes: Observations by CSI–Mass Spectrometry and X-ray Crystallography

et al. 2013

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773Significant attention has recently been given to coordination chemistry, which has found applications in the construction of complicated or nano-sized structures, catenanes, 1,2 rotaxanes, [3][4][5] helices, 6,7 molecular squares, 8-10 tetrahedral hosts, [11][12][13][14][15][16] and so on. 17-21Coordination compounds exist not only as discrete molecules in solution, but also as compounds with infinite periodicity in the crystal state. Coordination polymers (CPs) and metal-organic frameworks (MOFs) are well-known crystals constructed by an organic compound and a metal. Porous CPs (PCPs) and MOFs, in particular, are highly potential materials for gas storage, 22-24 ion exchange, 25-28 heterogeneous catalysis, 29-31 separation, 29,[32][33][34][35][36] and non-linear optics, 37-39 because of the nanospace separated from bulk space.Structure construction with a coordination bond plays a critical role in the formation of a complicated structure and the introduction of functionality into the structure for basic research and industrial applications. In structure control, it is important to adjust the metal-ligand stoichiometry based on the number of coordination sites or the coordination environment. For example, Lehn and coworkers 40 demonstrated the spontaneous formation of a cylindrical complex from five ligands and six metal ions, in which two hexaazatriphenylene derivatives acting as the planar molecule and three bisbipyridyl ligands linked at the 5,5′ positions acting as the pillar molecule were connected by three copper ions. The structure was characterized by 1 H NMR spectroscopy, fast atom bombardment mass spectrometry (MS), and single-crystal X-ray structure analysis. The concept of adjusting metal-ligand stoichiometry has been widely accepted in discrete complexes and CPs, depending on the metal coordination geometry and the ligand binding site. However, complex preparation relies on many factors, such as the temperature, concentration, and the counter ion. For instance, Fujita and coworkers 41 demonstrated the treatment of Pd(NO3)2 and a ditopic bidentate ligand assembled into a mixture of M4L8 and M3L6 box-like structures, depending on the ratio of dimethylsulfoxide to acetonitrile.In such an environment-dependent complex formation, advanced functions, including molecular switching and molecular catch and release, for instance, have been obtained in recent years. However, structure elucidation of obtained complexes is generally difficult by using only 1 H NMR analysis in the case that the numbers of ligands and metals are not known. Therefore, limited studies of environment-dependent complexes have been reported up to the present. [42][43][44][45][46] Conventional MS using electron ionization, chemical ionization, fast atom bombardment, and electro-spray ionization cannot detect large coordination complexes because the weak coordination bonds dissociate during ionization. Cold-spray ionization MS (CSI-MS) is one of the most promising solutions to this problem, 47 as it can detect coordination complexes w...

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“…It is therefore worth noting that some of these uptake phenomena are likely to be solvent-mediated and may involve concerted small-scale dissolution and recrystallization of the MOF as has been demonstrated for some anion-exchange processes in MOFs. 99 The uptake of metals or metal complexes by MOFs allows for the manipulation of MOF properties in a number of areas including luminescence and sensing, catalysis, gas binding, and cation exchange and binding; hence, it will be an important and fruitful area in the continued development of MOF chemistry.…”

Section: Transmetallationmentioning

confidence: 99%

Metal‐Organic Frameworks: Metal‐Uptake

Hardie

2014

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Metal‐organic frameworks (MOFs) contain metal cations that are inherent to their framework structure and may also be intrinsic to material properties such as magnetism, catalysis, and luminescence. Uptake of additional metals by a MOF has the potential to introduce new functionality or to alter functionality and thus finds a variety of potential applications. For example, catalysis, luminescence or color changes for sensors, ion exchange, removal of metal contaminants from the atmosphere or solution, altering gas‐binding properties of a MOF by creation of electric dipoles on the framework surface, and ion transport for battery applications. Post‐synthetic modification (PSM) involves the solid‐state MOF framework being chemically altered. PSM of MOFs may occur such that additional or new heterometallic cations or metal‐containing moieties are taken up by the MOF. There are a number of mechanisms to effect metal uptake in MOFs. Direct grafting of metal cations onto the MOF frameworks can occur at pendant, unmetallated sites embedded within the framework linker ligand. For example, through pendant thiols or alcohol groups lining framework pores, or through unmetallated chelating or macrocyclic groups embedded in the framework. Organometallic fragments can be directly grafted onto the arene rings of MOF ligands. PSM of pendant organic functional groups can be used to either create a new ligand group for metal binding, or to directly tether a metal complex. Other mechanisms for forming pendant metal‐binding groups are to demetallation a nonstructural metal cation site, for example, within a linking metal‐salen ligand, or to use a ligand defect approach where ligands with additional binding sites are doped into the MOF during its synthesis. Ion exchange of counter‐anions within the pores of anionic MOFs is another method for metal uptake, and often involves the exchange of an organic counter‐cation for a metal. Metal‐containing guest molecules can be absorbed into the pores of MOFs through solution immersion or chemical vapor deposition techniques. Such complexes are often precursors to form metal@MOFs hydrid materials where metal nanoparticles are embedded in the pores. Exchange may also occur between structural components of a MOF, and metal cation metathesis, also referred to as transmetallation, is where metal cations within the framework are substituted for a different cation, usually with retention of the gross original framework structure.

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Dynamic Equilibria in Solvent‐Mediated Anion, Cation and Ligand Exchange in Transition‐Metal Coordination Polymers: Solid‐State Transfer or Recrystallisation?

Cited by 120 publications

References 113 publications

A Molecular Antenna Coordination Polymer from Cadmium(II) and 4,4’-Bipyridine Featuring Three Distinct Polymer Strands in the Crystal

A Molecular Antenna Coordination Polymer from Cadmium(II) and 4,4’-Bipyridine Featuring Three Distinct Polymer Strands in the Crystal

Solvent-dependent Assembly of Discrete and Continuous CoCl2 Adamantane-based Ligand Complexes: Observations by CSI–Mass Spectrometry and X-ray Crystallography

Metal‐Organic Frameworks: Metal‐Uptake

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