A Novel Nanostructured Open-Channel Coordination Polymer with an Included Fused-Polyiodide Ring
✍ Scribed by Jack Y. Lu; Vaughn Schauss
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 88 KB
- Volume
- 2002
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
A novel three-dimensional nanostructured open-channel metal-organic framework polymer with inclusion of a polyiodide cluster has been synthesized via an oxidation reaction mechanism under hydrothermal conditions.
The synthesis of new metal-organic polymers via self-assembly processes is a topical and important subject. [1] The diversities of the structures and new topologies discovered in metal-organic polymers are due to the wide variety of metal centers and organic building blocks used. Metal centers play a key role in molecular recognition processes in extended materials and biological systems. [2] We and others have recently demonstrated that copper ions and carboxylate ligands form metal-organic frameworks in which the copper() atoms display either a mixed octahedral/ square pyramidal geometry in a triple-layer two-dimensional (2-D) open-framework, [3a] a square pyramidal coordination 2-D net in an interpenetrating 2-D/3-D structure, [3b] a square planar motif, [3c] or a trigonal bipyramidal geometry in a mixed-bonding 3-D network; [3d] the copper oxidation states are ϩ1, [2a] ϩ2, [4a] mixed-valence, [4b,4c] and/ or with CuϪCu bonds. [2a,4b,4c] The interest in copper arises mainly from its attractive magnetic [4b] and photoluminescence properties, [2a] novel structural features [2b,3,4a,4b] and its biological relevance in the binuclear ''Cu A '' site of cytochrome oxidases and related model compounds. [4c,5] The synthetic methods used for preparing metal-organic network structures are conventional solution methodology in organic solvents or hydrothermal/solvothermal reactions under pressure. In most cases, a reduction or oxidation reaction mechanism has not been invoked during the self-assembly of metal-organic polymers. It has been found that Cu II ions can be reduced to Cu I by pyridine [6a] or pyridylcarboxylate [6b] under hydrothermal conditions. Often, fascinating structures and reaction chemistry can be achieved from the reduction of copper valence states. [4b,6] Hydrothermal processes are therefore considered to be necessary conditions for these reductions. It may not be surprising that the synthesis utilizing oxidation reaction route under [a