Metal-Ligand Polyhedra
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| - | Metal ions with square planar coordination, when mixed with suitable ligands, can self-assemble into polyhedra of various sizes. Geometrical constraints limit the number of metal ions (vertices) to 6, 12, 24, 30, or 60 for entropically favored regular or semiregular polyhedra<ref>Coxeter, H. S. M., ''Regular Polytopes'', Dover Publications, New York, 3rd ed., 1973.</ref>. Shown at right (<scene name='Metal-Ligand_Polyhedra/Polyhedron_main_chains/4'>restore initial scene</scene>) is the "main chain" of a crystallographic model for the largest such structure reported as of May, 2010<ref>PMID: 20430973</ref>. <scene name='Metal-Ligand_Polyhedra/Polyhedron_main_chains/5'>24 palladium ions</scene> form the vertices of a 26-face polyhedron<ref>M24L48 forms a 26-faced ''rhombicubooctahedron'' with 18 square faces and 8 triangular faces. In this instance, the rectangular faces are very close to squares 13.35 Ångstroms on a side.</ref>. Three square faces and one triangular face meet at each vertex. | + | Metal ions with square planar coordination, when mixed with suitable ligands, can self-assemble into polyhedra of various sizes. Geometrical constraints limit the number of metal ions (vertices) to 6, 12, 24, 30, or 60 for entropically favored regular or semiregular polyhedra<ref>Coxeter, H. S. M., ''Regular Polytopes'', Dover Publications, New York, 3rd ed., 1973.</ref>. Shown at right (<scene name='Metal-Ligand_Polyhedra/Polyhedron_main_chains/4'>restore initial scene</scene>) is the "main chain" of a crystallographic model for the largest such structure reported as of May, 2010<ref name="sun-fujita-2010" >PMID: 20430973</ref>. <scene name='Metal-Ligand_Polyhedra/Polyhedron_main_chains/5'>24 palladium ions</scene> form the vertices of a 26-face polyhedron<ref>M24L48 forms a 26-faced ''rhombicubooctahedron'' with 18 square faces and 8 triangular faces. In this instance, the rectangular faces are very close to squares 13.35 Ångstroms on a side.</ref>. Three square faces and one triangular face meet at each vertex. |
Each palladium ion is coordinated by <scene name='Metal-Ligand_Polyhedra/Polyhedron_main_chains/6'>four nitrogens</scene>. The nitrogens are bridged by a <scene name='Metal-Ligand_Polyhedra/Single_main_chain_ligand/1'>dipyridylthiophene</scene> ("ligand"). There are two ligand molecules (L) per metal ion (M); hence, this structure is called '''M24L48'''. | Each palladium ion is coordinated by <scene name='Metal-Ligand_Polyhedra/Polyhedron_main_chains/6'>four nitrogens</scene>. The nitrogens are bridged by a <scene name='Metal-Ligand_Polyhedra/Single_main_chain_ligand/1'>dipyridylthiophene</scene> ("ligand"). There are two ligand molecules (L) per metal ion (M); hence, this structure is called '''M24L48'''. | ||
The models shown thus far are simplified, including only the "main chain". The actual M24L48 complex analyzed crystallographically contained a substituent of -OCH<sub>2</sub>CH<sub>2</sub>O- on each thiophene ring, PF<sub>6</sub><sup>-</sup> counterions bound to the surface of the polyhedron, and hydrogen atoms. Here is the <scene name='Metal-Ligand_Polyhedra/M2l1_with_och2ch2o_h_pf6/1'>chemically complete M2L1 subunit</scene> (but lacking the three additional nitrogens coordinating each palladium, and water, which was not resolved crystallographically). Here is the <scene name='Metal-Ligand_Polyhedra/Full_polyhedron/2'>complete M24L48 polyhedron</scene> (but lacking PF<sub>6</sub> and water). | The models shown thus far are simplified, including only the "main chain". The actual M24L48 complex analyzed crystallographically contained a substituent of -OCH<sub>2</sub>CH<sub>2</sub>O- on each thiophene ring, PF<sub>6</sub><sup>-</sup> counterions bound to the surface of the polyhedron, and hydrogen atoms. Here is the <scene name='Metal-Ligand_Polyhedra/M2l1_with_och2ch2o_h_pf6/1'>chemically complete M2L1 subunit</scene> (but lacking the three additional nitrogens coordinating each palladium, and water, which was not resolved crystallographically). Here is the <scene name='Metal-Ligand_Polyhedra/Full_polyhedron/2'>complete M24L48 polyhedron</scene> (but lacking PF<sub>6</sub> and water). | ||
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| + | ==Ligand Angle vs. Polyhedron Size== | ||
| + | The dipyridylthiphene ligand pictured above has a bend angle of 127<sup>o</sup><ref name="sun-fujita-2010" /> | ||
| + | |||
| + | ==Significance== | ||
| + | |||
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Revision as of 23:16, 13 June 2010
| For the date when the most recent work on this article was done, click on the history tab above. |
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Metal ions with square planar coordination, when mixed with suitable ligands, can self-assemble into polyhedra of various sizes. Geometrical constraints limit the number of metal ions (vertices) to 6, 12, 24, 30, or 60 for entropically favored regular or semiregular polyhedra[1]. Shown at right () is the "main chain" of a crystallographic model for the largest such structure reported as of May, 2010[2]. form the vertices of a 26-face polyhedron[3]. Three square faces and one triangular face meet at each vertex.
Each palladium ion is coordinated by . The nitrogens are bridged by a ("ligand"). There are two ligand molecules (L) per metal ion (M); hence, this structure is called M24L48.
The models shown thus far are simplified, including only the "main chain". The actual M24L48 complex analyzed crystallographically contained a substituent of -OCH2CH2O- on each thiophene ring, PF6- counterions bound to the surface of the polyhedron, and hydrogen atoms. Here is the (but lacking the three additional nitrogens coordinating each palladium, and water, which was not resolved crystallographically). Here is the (but lacking PF6 and water).
Contents |
Ligand Angle vs. Polyhedron Size
The dipyridylthiphene ligand pictured above has a bend angle of 127o[2]
Significance
To do:
- improve final scene: sticks, custom colors.
- color keys.
- significance
References and Notes
- ↑ Coxeter, H. S. M., Regular Polytopes, Dover Publications, New York, 3rd ed., 1973.
- ↑ 2.0 2.1 Sun QF, Iwasa J, Ogawa D, Ishido Y, Sato S, Ozeki T, Sei Y, Yamaguchi K, Fujita M. Self-assembled M24L48 polyhedra and their sharp structural switch upon subtle ligand variation. Science. 2010 May 28;328(5982):1144-7. Epub 2010 Apr 29. PMID:20430973 doi:10.1126/science.1188605
- ↑ M24L48 forms a 26-faced rhombicubooctahedron with 18 square faces and 8 triangular faces. In this instance, the rectangular faces are very close to squares 13.35 Ångstroms on a side.
Models
- M24L48 main chain atoms only: Image:M24L48 main chains.pdb
- M24L48 all atoms: Image:M24l48-single-polyhedron.pdb
