Paul Goddard

Abstract:

The reaction of MnCl2·4H2O with t-BuPO 3H2 in the presence of triethylamine afforded the tridecanuclear cage, [MnIIMnIII12(μ 4-O)6(μ-OH)6(O3P-t-Bu) 10(OH2)2(DMF)4] ·[2MeOH·4DMF] (1). The structural analysis of 1 reveals that it is a mixed-valent complex containing a [MnIIMnIII12(μ4-O)6] core. The centre of the core is occupied by a MnII ion which is surrounded by 12 MnIII ions. The latter are connected to each other by six μ-OH- and 10 t-BuPO32- ligands. The vacant coordination sites of six MnIII ions situated in the periphery are occupied by four DMF and two water molecules. Magnetic studies on 1 reveal a frequency-dependent response which is characteristic of single-molecule magnets. © 2014 Elsevier Ltd. All rights reserved.

Abstract:

Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. The synthesis, structure, and magnetism of a nonanuclear iron(III) phosphonate, [Fe 9 III (μ 3 -O) 4 (O 3 PC 5 H 9 ) 3 (O 2 CCMe 3 ) 13 ]·(EtOH) 0.5 ·(Et 2 O) 0.5 (1), is described. Compound 1 was obtained in the direct reaction of anhydrous ferric chloride, cyclopentylphosphonic acid, and pivalic acid in the presence of triethylamine. Compound 1 possesses a distorted icosahedral structure; nine of the vertices are occupied by Fe III , whereas three others are occupied by the phosphorus atoms of the cyclopentylphosphonate ligand. Mössbauer spectroscopy of 1 confirms the presence of high-spin Fe III . Low-temperature magnetic studies reveal the presence of strong antiferromagnetic coupling between the Fe 3+ ions. The reaction of anhydrous ferric chloride with cyclopentylphosphonic acid and pivalic acid in the presence of triethylamine at room temperature afforded a nonanuclear iron(III) phosphonate. It possesses a cage structure with a distorted icosahedral core. Mössbauer studies confirm high-spin Fe III , whereas magnetic measurements suggest strong antiferromagnetic couplings between the Fe 3+ ions.

Abstract:

Solid state techniques involving pressure and temperature have been used to synthesize the fluoride member of the CuX2(pyrazine) (X = F, Cl, Br) family of coordination polymers that cannot be crystallized by solution methods. CuF2(pyrazine) exhibits unique trans doubly-bridged Cu-F2-Cu chains that provide an opportunity to quantify magnetic superexchange in an isostructural Cu-X2-Cu series. © 2013 The Royal Society of Chemistry.