TY - JOUR
T1 - Topologic equivalents of coronands, cryptands and their inclusion complexes: Synthesis, structure and properties of {2}-metallacryptands and {2}-metallacryptates
AU - Saalfrank, Rolf W.
AU - Dresel, Andreas
AU - Seitz, Verena
AU - Trummer, Stefan
AU - Hampel, Frank
AU - Teichert, Markus
AU - Stalke, Dietmar
AU - Stadler, Christian
AU - Daub, Jörg
AU - Schünemann, Volker
AU - Trautwein, Alfred X.
PY - 1997/1/1
Y1 - 1997/1/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0031460767&partnerID=8YFLogxK
U2 - 10.1002/chem.19970031222
DO - 10.1002/chem.19970031222
M3 - Journal articles
AN - SCOPUS:0031460767
SN - 0947-6539
VL - 3
SP - 2058
EP - 2062
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 12
ER -