Topologic equivalents of coronands, cryptands and their inclusion complexes: Synthesis, structure and properties of {2}-metallacryptands and {2}-metallacryptates

Rolf W. Saalfrank*, Andreas Dresel, Verena Seitz, Stefan Trummer, Frank Hampel, Markus Teichert, Dietmar Stalke, Christian Stadler, Jörg Daub, Volker Schünemann, Alfred X. Trautwein

*Korrespondierende/r Autor/-in für diese Arbeit
91 Zitate (Scopus)

Abstract

The synthesis and structural characterisation of two dinuclear iron(III) complexes are reported. The compounds of general structure [Fe2L3/1] [8; L1= dianion of 2,2'-dicyano-2,2'-isophthaloyldi(isopropyldicarboxylate)] and [K C Fe2L3/2]+ (PF6)- [10; L2 = 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 (Δ,Δ)-fac and (Δ,Δ)-fac configuration at the two iron bridgeheads. In contrast to racemic 8, the two iron centres in the meso-10 [(Δ,Δ)-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 γ-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.

OriginalspracheEnglisch
ZeitschriftChemistry - A European Journal
Jahrgang3
Ausgabenummer12
Seiten (von - bis)2058-2062
Seitenumfang5
ISSN0947-6539
DOIs
PublikationsstatusVeröffentlicht - 01.01.1997

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