On the molecular solid-state boundary. A cyclic iron-sulfur cluster of nuclearity eighteen: synthesis, structure, and properties
| Autor: | B. S. Snyder, Richard H. Holm, Jing Feng You, Georgia C. Papaefthymiou |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
chemistry.chemical_classification
Degree (graph theory) Stereochemistry General Chemistry Crystal structure Electronic structure Triclinic crystal system Biochemistry Catalysis Crystallography Colloid and Surface Chemistry chemistry Cluster (physics) Molecule Connection (algebraic framework) Inorganic compound |
| Zdroj: | Journal of the American Chemical Society. 112:1067-1076 |
| ISSN: | 1520-5126 0002-7863 |
| DOI: | 10.1021/ja00159a028 |
| Popis: | The reaction system FeCl{sub 3}:3.15Na(PhNC(O)Me): 1.78Li{sub 2}S in ethanol/methanol (2:1 (V/v)) affords, after the addition of Pr{sub 4}NBr and a 5-day period of reaction and crystallization, the black compound (Pr{sub 4}N){sub 6}Na{sub 4}Fe{sub 18}S{sub 30} in 60-75% yield. When this material is very slowly crystallized from acetontrile/ether, the solvated compound (Pr{sub 4}N){sub 6}Na{sub 4}Fe{sub 18}S{sub 30} {times} 14MeCN is obtained. This compound crystallizes in triclinic space group P{anti 1} with a = 16.286 (8) {angstrom}, b = 16.718 (8) {angstrom}, c = 17.902 (9) {angstrom}, {alpha} = 115.28 (3){degree}, {beta} = 91.07 (4){degree}, {gamma} = 101.64 (4){degree}, and Z = 1. The structure was refined to R = 6.5%. The crystal structure consists of discrete Pr{sub 4}N{sup +} ions and two Na{sup +} ions weakly associated with the cluster (Na{sub 2}Fe{sub 18}S{sub 30}){sup 8{minus}}, which has a remarkable and unprecedented structure. It is constructed by the fusion of 24 nonplanar Fe{sub 2}s{sub 2} rhombs in edge- and corner-sharing modes such that there are 20 {mu}{sub 2}-S, 8 {mu}{sub 3}-S, and 2 {mu}{sub 4}-S, every FeS{sub 4} unit is tetrahedral, and the 18 Fe atoms are essentially planar. The result is a cyclic or toroidal structure, of lateral dimensions 13.3 {times}more » 16.0 {angstrom} and a maximum thickness of ca. 3.3 {angstrom}, in which there are no terminal ligands. Two Na{sup +} ions are bound to interior sulfur atoms of the cluster, whose framework can be considered to arise from the sequential connection of known Fe{sub 3}S{sub 4} and Fe{sub 6}S{sub 9} cluster cores. Alternative conceptions of cluster buildup in terms of shared Fe{sub 2}S{sub 2} rhombs and FeS{sub 4} tetrahedra are presented and illustrated.« less |
| Databáze: | OpenAIRE |
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