The synthesis, structure, magnetic and Mössbauer spectral properties of an Fe–Zr carboxylate–alkoxide derivative containing an {Fe2Zr2(μ3-O)2} core

Iron(III)–Oxo Cluster Chemistry with Dimethylarsinate Ligands: Structures, Magnetic Properties, and Computational Studies

“…Therefore, we conclude this Fe 6 unit to be a favored structural unit in Fe/O/Me 2 AsO 2 – chemistry, even with some carboxylate incorporation. Within Fe/O/RCO 2 – cluster chemistry there are a number of Fe 6 topologies, many of them comprising linked triangular units with “chairlike”, “planar”, “twisted-boat”, stacked triangles, linked triangles, octahedral, and fused or extended butterflies, − but nevertheless, none of them are the same as the Fe 6 unit of 1 and 2 , most likely due to the η 2 :η 2 :μ 4 Me 2 AsO 2 – binding mode that supports it, which is unknown in Fe III carboxylate chemistry (vide infra).…”

14 Iron, cobalt and nickel

“…reacts with pyridine forming an initial product which appears to have a [Fe 4 (µ 3 -O) 2 ] 8ϩ core but which on recrystallisation rearranges to the hexanuclear structure [Fe 129 Another compound has been reported based on the "butterfly" [Fe 4 O 2 ] 8ϩ core, [Fe 4 O 2 (O 2 Et) 7 (bipy) 2 ]PF 6 ؒ2H 2 O, contains two different iron environments, one with FeO 6 , the other with FeN 2 O 4 co-ordination. 130 Magnetic investigations on the tetranuclear [Fe 4 (µ-byppnol) 2 (µ-O) 2 (µ-OAc) 2 ]-(BPh 4 ) 2 ؒMeCNؒ0.5H 2 O reveal two antiferromagnetic coupling pathways, one via the oxo-bridge (J = Ϫ 83 cm Ϫ1 ) and the other via an alkoxo bridge (J = Ϫ8.7 cm Ϫ1 ), the latter being very similar to that in the oxidised form of the purple acid phosphatases.…”

“…has a butterfly configuration with pyridine-coordinated Fe() ions forming the body positions. 134 Purple acid phosphatases (PAPs) are metalloproteins of wide occurrence with two antiferromagnetically coupled metal ions (Fe III -M II (M = Fe, Mn, Zn)), owing their colour to tyrosine-iron co-ordination. A diiron() complex with one acetate bridge and two methoxide bridges, [Fe 2 (BHA) 2 (µ-OMe) 2 (µ-OAc)](ClO 4 ), has been synthesised as a possible structural model for the active site of PAPs.…”

Formation of organically surface-modified metal oxo clusters from carboxylic acids and metal alkoxides: a mechanistic study

“…18, 19 A partly carboxylate-substituted trinuclear Zr compound is also known, in which longer (3.86 Å) and shorter Zr-Zr distances (3.37, 3.41 Å) were observed, depending on the bridging ligands. 20 Additionally, a cluster with the Zr 3 (µ 3 -O) unit was the product of a reaction of Zr(OPr) 4 with 2,4-dimethylpentane-2,4-diol. The resulting compound showed Zr-Zr distances of around 3.40 Å.…”