Coordination polymer

Résumé

A coordination polymer is an inorganic or organometallic polymer structure containing metal cation centers linked by ligands. More formally a coordination polymer is a coordination compound with repeating coordination entities extending in 1, 2, or 3 dimensions. It can also be described as a polymer whose repeat units are coordination complexes. Coordination polymers contain the subclass coordination networks that are coordination compounds extending, through repeating coordination entities, in 1 dimension, but with cross-links between two or more individual chains, loops, or spiro-links, or a coordination compound extending through repeating coordination entities in 2 or 3 dimensions. A subclass of these are the metal-organic frameworks, or MOFs, that are coordination networks with organic ligands containing potential voids. Coordination polymers are relevant to many fields, having many potential applications. Coordination polymers can be classified in a nu

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This thesis details the synthesis and characterization of dinuclear clathrochelates functionalized with groups suitable for supramolecular applications. Their successful incorporation into self-assembled discrete and polymeric structures is related. These novel dinuclear clathrochelate complexes possess several features that make them highly interesting metalloligands for applications in supramolecular chemistry: they are large, rigid, modular and easy-to-access building blocks, and they display additional properties (charge, luminescence) depending on the metals they are constituted of. Syntheses and characterization of pyridyl-functionalized clathrochelates, and their subsequent incorporation into supramolecular architectures, are described in Chapter 2. Two distinct approaches have been employed: a direct synthesis or the postsynthetic functionalization of brominated clathrochelates via Pd-catalyzed cross-coupling reactions, resulting in metalloligands with up to seven pyridyl groups. Reaction of linear, ditopic clathrochelates with Zn(II) resulted in the formation of polymeric two-dimensional coordination polymer, and pentatopic clathrochelates were shown to form networks of novel topologies. Furthermore, pentameric M10L5 barrel structures were obtained from tetratopic clathrochelates. Incorporation of carboxylic acid-appended clathrochelates into several metal-organic frameworks is described in the third chapter. Studies revealed that the gas sorption properties of Zr-based metal-organic frameworks constituted of ditopic clathrochelates were influenced by the lateral substituents of the dioximato ligands. Furthermore, some of these metal-organic frameworks showed high CO2 uptake. Chapter 4 entails the synthesis of clathrochelates functionalized with cyano groups and their subsequent incorporation into one-, two-, and three-dimensional silver(I)-based coordination polymers. One network, obtained from a pentatopic clathrochelate, displayed an unprecedented network topology and a very high topological density. The syntheses of clathrochelates with different functional groups are described in the last chapter. The modular nature of these clathrochelate ligands was demonstrated through the analysis of a complex mixture obtained from different metal ions and dioximato ligands. This study also revealed that heterometallic clathrochelates can be obtained.

EPFL2016

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Functionalised clathrochelate complexes as supramolecular building blocks

Matthew David Wise

The work presented in this thesis entails the synthesis and characterisation of new iron(II) tris(dioxime) clathrochelate complexes functionalised with apical capping groups suitable for supramolecular applications, and their subsequent incorporation into self-assembled structures. These complexes possess a number of desirable characteristics as supramolecular building blocks, such as their synthetic accessibility and broad scope for structural and functional modification, which are highlighted throughout. Chapter 1 introduces certain key concepts and background literature relevant to this thesis. Clathrochelate-based 4,4'-bipyridyl metalloligands are presented in Chapter 2. Simple complexes bearing 4-pyridyl capping groups were prepared from commercially available starting materials and their potential as building blocks for supramolecular architectures demonstrated through the preparation of a discrete molecular square and a 3D coordination polymer (CP). Furthermore, bent and extended linear 4,4'-bipyridyl metalloligands up to 5.4 nm in length were prepared by two distinct homologation strategies. Clathrochelate-based 3,3'-bipyridyl metalloligands are presented in Chapter 3. Simple complexes were prepared from commercially available starting materials and subsequently combined with Pd(II) ions to give unprecedented [Pd6L12]12+ octahedral cage structures by coordination-driven self-assembly. These assemblies were shown to bind the large, non-coordinating anion BPh4- in aqueous solvent mixtures. Furthermore, linear and bent bis(clathrochelate) complexes bearing 3-pyridyl apical capping groups were also prepared by a one-pot approach. Clathrochelate complexes bearing carboxylic acid-functionalised capping groups are presented in Chapter 4. Ditopic and tetratopic metalloligands were synthesised in good yields. A heterometallic 2D CP was prepared through combination of Zn(II) ions with a clathrochelate complex functionalised with phenyl-4-carboxylic acid groups and the structure of this material determined by single crystal X-ray diffraction. Clathrochelates bearing functional groups suitable for imine-based self-assembly are presented in Chapter 5. Complexes functionalised with amine or aldehyde moieties as well as complexes functionalised with 3-pyridine-4-carboxaldehyde groups, were prepared in either one or two steps. Preliminary investigations into the preparation of metal-organic cage architectures through a well-established subcomponent self-assembly approach combining imine-based DCC and coordination-driven self-assembly gave promising results, including the synthesis of an [Fe4L6]8+ cage, which was characterised by single crystal X-ray crystallography.

EPFL2015

Chargement

Syntheses, structures and properties of cobalt and manganese complexes based on pyridine-2,3,5,6-tetracarboxylic acid

Chi Wai Cheung, Hong-Ling Gao, Weijin Wang

Two new complexes based on pyridine-2,3,5,6-tetracarboxylic acid(H(4)pdtc) as ligand, {[Co-2(pdtc)(H2O)(4)]center dot H2O}(n) (1) and {Mn-2(pdtc)(H2O)(4)}(n) (2), have been obtained by hydrothermal syntheses and characterized by IR, elemental analysis, X-ray diffraction single crystal structure analysis, PXRD, thermal gravimetric analysis, and magnetic measurements. Complex 1 is 3D coordination polymer and complex 2 belongs to 2D grid structure by covalent bonds. In 1 and 2, the metal ions show antiferromagnetic interactions. (C) 2015 Elsevier B.V. All rights reserved.

Elsevier Science Bv2015

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