Metal and ligand control in di- and octa-nuclear cluster formation †

Abstract

Reaction of doubly negatively charged m-pyridinediyl spacered bis-bidentate ligands with iron() chloride in the presence of alkaline, alkaline earth, and rare earth metal cations (M nϩ ) yielded {2}-iron cryptates {Mʚ[Fe 2 (L) 3 ]} nϩ . The mono-, di-, and tri-valent guest cations are endohedrally encapsulated in the cavity of the bicyclic dinuclear host. In contrast, the ligands reacted with Mn 2ϩ , Co 2ϩ , and Cd 2ϩ (M II ) cations as pentadentate tritopic chelators to give octanuclear complexes [M II 8 O 2 (L) 6 ]. Similarly, a topological equivalent pentadentate tritopic ligand LЈ in the presence of Zn 2ϩ cations afforded the octanuclear cluster [Zn 8 O 2 (LЈ) 6 ]. However its reaction with iron() chloride and alkaline, alkaline earth, and rare earth metal cations did not lead to products of type {Mʚ[Fe 2 (L) 3 ]} nϩ .

Syntheses, structures and magnetic properties of tetranuclear and trinuclear nickel(II) complexes with β-diketone-functionalized pyridinecarboxylate ligand

“…The presence of transition metals in such systems yields the potential for exhibiting additional functionality, including unusual optical, magnetic, photoactive, catalytic and electrochemical properties. The pyridine containing b-diketones have been known in organic chemistry for a long time [8], but their uses to date in coordination chemistry have been very few [9][10][11][12][13][14]. Recently, metal complexes of functionalized b-diketones ligands have been well reviewed by Tamburini and co-workers [15], some polynuclear complexes and coordination polymers with bis-b-diketones have been reported [16][17][18][19][20][21][22][23][24].…”

New discrete and polymeric supramolecular architectures derived from dinuclear (bis-β-diketonato)copper(ii) metallocycles

“…7 More recently, interest in these and related (functionalised) derivatives has led to the investigation of the magnetic (copper(II)-lanthanide(III)) interactions occurring between neighbouring metal centres in such species 9 as well as of the luminescence properties of particular dinuclear lanthanide(III) complexes. 5 In addition, molecular triangles, 14 squares, 15 helices 6,16, 17 and tetrahedra 18 have all been obtained using such bis-b-diketone ligands.…”

Reprint of “A novel bis-β-diketonate ligand stabilizes a [Co(II)8] cage that encapsulates a (μ3-O)⋯H⋯(μ3-O) moiety”

“…The main topological difference with the cation of 1 is the presence in the latter of the (l 3 -O)Á Á ÁHÁ Á Á(l 3 -O) group in the cavity where the FeMoco is thought to interact with its substrate, N 2 , for its reduction to NH 3 . In turn, the [Co 8 ] topology featured by the cluster described here is strongly related to the octametallic clusters made with similar b-diketone ligands of the type H 2 L2 (Scheme I) and the metals Co(II), Mn(II), Zn(II) or Cd(II) [17,18], with the notable difference that the latter complexes are neutral and therefore, do not feature a H + nucleus trapped at their interior.…”

“…Vacant coordination sites in these assemblies are occupied by solvent molecules, S, or coordinating anions, A. This donor disposition has served to generate occasionally more complicate coordination assemblies of transition metals, including [Co 4 ] linear aggregates [15,16] or isostructural octametallic cages of Co(II), Mn(II), Zn(II) or Cd(II) [17,18]. We present here the first coordination chemistry reactions of the new ligand 1,3-bis-(1-oxo-3-(2-hydroxyphenyl)-propioyl)-2-pyridine, H 4 L, which we have prepared for the formation of polymetallic assemblies and heterometallic clusters.…”