Linking iron(iii) carboxylates into high-nuclearity complexes by using Bis-tris

Abstract

We describe the synthesis, structure and magnetic properties of two decanuclear Fe(III) complexes with novel core topologies, assembled using the tetra-deprotonated form of Bis-tris {2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)propane-1,3-diol, H5L}.

Synthesis and characterisation of Fe6 and Fe12 clusters using bicine

“…This approach can be illustrated by Chart 1, which shows the ligands bis-tris, 1 bicine {BicH 3 , N,N-bis(2-hydroxyethyl)glycine} and diethanolamine (DEA), which all share the {N(CH 2 CH 2 OH) 2 } group. We have shown that bis-tris can assemble small fragments of iron(III) carboxylates into Fe 10 clusters [7]. Although the DEA ligand has not been reported as a ligand for Fe(III) complexes, replacing the NH group by an NR (R = Me, Et etc.,) group leads to some interesting polynuclear Fe(III) complexes, including Fe 6 wheels (e.g.…”

“…3 We note that in this Fe 6 cluster, one Fe 4 butterfly unit is capped by two {Fe(Bic)} units. It is interesting to compare this Fe 6 cluster to our Fe 10 clusters with bis-tris [7] where two Fe 4 butterfly units are bridged together by two {Fe(bis-tris)} units. Hence, we can show that clusters of different nuclearity and topology can be prepared by 5MeCN), in 12% yield, which crystallizes in the monoclinic space group C2/c (Fig.…”

“…Although the DEA ligand has not been reported as a ligand for Fe(III) complexes, replacing the NH group by an NR (R = Me, Et etc.,) group leads to some interesting polynuclear Fe(III) complexes, including Fe 6 wheels (e.g. R = Me [8], n Bu [9]) and in the presence of carboxylate co-ligands Fe 7 or Fe 22…”

Bis-tris propane as a flexible ligand for high-nuclearity complexes

“…However, the synthetic challenges involved in isolating such systems [18] and the search for emergent properties in larger and larger systems is also a major driving force [19][20][21][22][23]. We have a long-standing interest in the use of polydentate ligands [24] to direct the assembly of homo-and heterometallic complexes and in particular a series of structurally related ligands containing the Tris unit {(Tris = 2-amino-2-(hydroxymethyl) propane-1,3-diol} [25,26] such as Bis-tris {2-[bis(2-hydroxyethyl) amino]-2-(hydroxymethyl) propane-1,3-diol} [27][28][29]. This research led us to investigate Bis-tris propane {H 6 L = 2,2 0 -(propane-1,3-diyldiimino)bis [2-(hydroxymethyl)propane-1,3-diol} as a ligand.…”

Formation of cobalt- and lithium-containing heterometallic pyridonate carboxylate coordination polymers

“…1-4 Other polydentate donor ligands con taining various functional moieties are used to increase the nuclearity of such heteroatomic structures. 5, 6 Depend ing on the geometric arrangement of the donor centers and their electronic characteristics, both discrete polynu clear molecules 7-9 and coordination polymers 8,10,11 can be prepared. In the present study, we used 2 hydroxy pyridine and 2 hydroxy 6 methylpyridine as additional ligands, which can act as bridging or terminal O donor ligands in the pyridone form and can lead to the chelate bridging or bridging coordination through the nitrogen atoms and the deprotonated oxygen atom in the form of pyridonate anions.…”