Saalfrank, Rolf W. and Dresel, Andreas and Seitz, Verena and Trummer, Stefan and Hampel, Frank and Teichert, Markus and Stalke, Dietmar and Stadler, Christian and Daub, Jörg and Schünemann, Volker and Trautwein, Alfred X. (1997) Chelate complexes. 9. Topologic equivalents of coronands, cryptands and their inclusion complexes: Synthesis, structure and properties of {2}-metallacryptands and {2}-metallacryptates. CHEMISTRY-A EUROPEAN JOURNAL, 3 (12). pp. 2058-2062. ISSN 0947-6539, 1521-3765
Full text not available from this repository.Abstract
The synthesis and structural characterisation of two dinuclear iron(III) complexes are reported. The compounds of general structure [Fe2L31] [8; L-1 = dianion of 2,2'-dicyano-2,2'-isophthaloyldi(isopropyldicarboxylate)] and [K subset of Fe2L32](+)(PF6)(-) [10; L-2 = dianion of 1,1'-(2,6-pyridylene)bis-1,3-(4-dimethyl)pentanedione] are formed by the deprotonation of ligands 7 and 9 with triethylamine and potassium hydride respectively, followed by addition of iron(III) chloride and work up with water or aqueous potassium hexafluorophosphate. X-ray crystallographic studies reveal that 8 is a racemic mixture composed of triple helicates with (Delta,Delta)-fac and (Lambda,Lambda)-fac configuration at the two iron bridgeheads. In contrast to racemic 8, the two iron centres in the meso-10 [(Delta,Lambda)-fac] have opposite configuration. Investigations of the redox-active iron centres in {2}-metal-lacryptand 8 and {2}-metallacryptate 10 by cyclic voltammetry show slightly different behaviour. The peaks for the two consecutive reductions of the two iron centres of 8 can hardly be resolved, whereas 10 shows two well-separated peaks. Mossbauer measurements were performed on 8 and 10 between 4.2 and 300 K, with and without a field applied perpendicular or parallel to the gamma-beam. All zero-field and 20 mT spectra exhibit a broad and unresolved absorption pattern. Application of 5.3 T at 4.2 K results in well-resolved magnetic hyperfine patterns which are practically the same for 8 and 10.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SUPRAMOLECULAR CHEMISTRY; CHELATE COMPLEXES; TRIPLE-HELIX; METAL; MOLECULES; EXCHANGE; IONS; TRIETHYLAMINE; TETRANUCLEAR; PERSPECTIVES; iron; metallacryptands; metallacryptates; self-assembly; structure elucidation |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Organische Chemie > Alumni or Retired Professors > Prof. Dr. Jörg Daub |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 01 Mar 2023 11:45 |
| Last Modified: | 01 Mar 2023 11:45 |
| URI: | https://pred.uni-regensburg.de/id/eprint/50349 |
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