Michael J Hayter

University of Sydney, Sydney, New South Wales, Australia

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Publications (7)25.13 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: New examples of nitrogen base adducts of dinuclear Co(II), Ni(II) and Cu(II) complexes of the doubly deprotonated forms of 1,3-aryl linked bis-beta-diketones of type [RC(=O)CH(2)C(=O)C(6)H(4)C(=O)CH(2)C(=O)R] (L(1)H(2)) incorporating the mono- and difunctional amine bases pyridine (Py), 4-ethylpyridine (EtPy), piperidine (pipi), 1,4-piperazine (pip), N-methylmorpholine (mmorph), 1,4-dimethylpiperazine (dmpip) and N,N,N',N'-tetramethylethylenediamine (tmen) have been synthesised by reaction of the previously reported [Cu(2)(L(1))(2)].2.5THF (R = Me), [Cu(2)(L(1))(2)(THF)(2)] (R = t-Bu), [Ni(2)(L(1))(2)(Py)(4)] (R = t-Bu) and [Co(2)(L(1))(2)(Py)(4)] (R = t-Bu) complexes with individual bases of the above type. Comparative X-ray structural studies involving all ten base adduct derivatives have been obtained and reveal a range of interesting discrete and polymeric molecular architectures. The respective products have the following stoichiometries: [Cu(2)(L(1))(2)(Py)(2)].Py (R = Me), [Cu(2)(L(1))(2)(EtPy)(2)].2EtPy (R = t-Bu), [Cu(2)(L(1))(2)(pipi)(2)].2pipi (R = t-Bu), [Cu(2)(L(1))(2)(mmorph)(2)] (R = t-Bu), [Cu(2)(L(1))(2)(tmen)(2)] (R = t-Bu) and {[Cu(2)(L(1))(2)(pip)].pip.2THF}(n), [Co(2)(L(1))(2)(tmen)(2)] (R = t-Bu), [Ni(2)(L(1))(2)(Py)(4)].dmpip (R = t-Bu), [Ni(2)(L(1))(2)(pipi)(4)].pipi (R = t-Bu) and [Ni(2)(L(1))(2)(tmen)(2)] (R = t-Bu). The effect of pressure on the X-ray structure of [Cu(2)(L(1))(2)(mmorph)(2)] has been investigated. An increase in pressure from ambient to 9.1 kbar resulted in modest changes to the unit cell parameters as well as a corresponding decrease of 6.7 percent in the unit cell volume. While a small 'shearing' motion occurs between adjacent molecular units throughout the lattice, no existing bonds are broken or new bonds formed.
    Dalton Transactions 03/2010; 39(11):2804-15. DOI:10.1039/b920199h · 4.20 Impact Factor
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    ABSTRACT: Viel Platz: Ein großer dreieckförmiger Dreikernkomplex mit zugänglichen Bindungszentren wurde synthetisiert, strukturell charakterisiert und in ein chirales Metall-organisches Gerüst eingebaut (siehe Bild). Im resultierenden 3D-Gerüst mit einem Triamin als verbrückender Gruppe beträgt der Anteil der Hohlräume 56 % des Volumens. In diesen Hohlräumen können Lösungsmittel und verschiedene Gase adsorbiert werden.
    Angewandte Chemie 02/2010; 122(6). DOI:10.1002/ange.200905497
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    ABSTRACT: Into the void: A large, cavity-containing trinuclear triangle with accessible binding sites has been synthesized, structurally characterized, and incorporated into a chiral metal-organic framework (see picture). The resulting 3D framework, with a afunctional amine bridging group, has a void volume of 56% that is accessible to solvent and adsorbs a variety of gases to various degrees. (Figure Presented)
    Angewandte Chemie International Edition 02/2010; 49(6):1075-8. DOI:10.1002/anie.200905497 · 11.26 Impact Factor
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    ABSTRACT: Neutral dimeric metallocyclic complexes of type [M(2)(L(1))(2)B(n)] (where M = cobalt(II), nickel(II) and zinc(II), L(1) is the doubly deprotonated form of a 1,3-aryl linked bis-beta-diketone ligand of type 1,3-bis(RC(O)CH(2)C(O))C(6)H(4) (R=Me, n-Pr, t-Bu) and B is pyridine (Py) or 4-ethylpyridine (EtPy)) have been synthesised, adding to similar complexes already reported for copper(II). New lipophilic ligand derivatives with R = octyl or nonyl were also prepared for use in solvent extraction experiments. Structural, electrochemical and solvent extraction investigations of selected metal complex systems from the above series are reported, with the X-ray structures of [Co(2)(L(1))(2)(Py)(4)] x 2.25CHCl(3) x 0.5H(2)O (R=Pr), [Co(2)(L(1))(2)(EtPy)(4)] (R=t-Bu), [Ni(2)(L(1))(2)(EtPy)(4)] (R=t-Bu), [Zn(2)(L(1))(2)(EtPy)(2)] (R=Me) and [Zn(2)(L(1))(2)(EtPy)(4)] (R=t-Bu) being presented. The electrochemistry of H(2)L(1) (R=t-Bu) and of [Fe(2)(L(1))(3)], [Co(2)(L(1))(2)(Py)(4)], [Ni(2)(L(1))(2)(Py)(4)], [Cu(2)(L(1))(2)] and [Zn(2)(L(1))(2)(Py)(2)] has been examined. Oxidative processes for the complexes are dominantly irreversible, but several examples of quasireversible behaviour were observed and support the assignment of an anodic process, seen between +1.0 and +1.6 V, as a metal-centred oxidation. The reduction processes for the respective metal complexes are not simple, and irreversible in most cases. Solvent extraction studies (water/chloroform) involving variable concentrations of metal, bis-beta-diketone and heterocyclic base have been performed for cobalt(II) and zinc(II) using a radiotracer technique to probe the stoichiometries of the extracted species in each case. Synergism was observed when 4-ethylpyridine was added to the bis-beta-diketone ligand in the chloroform phase. Competitive extraction studies show a clear uptake preference for copper(II) over cobalt(II), nickel(II), zinc(II) and cadmium(II).
    Dalton Transactions 06/2007; DOI:10.1039/b701575e · 4.20 Impact Factor
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    ABSTRACT: New examples of adducts between di- (and, in one instance, tetra-) functional nitrogen ligands and planar 'platform-like' dinuclear copper(II) complexes, [Cu2L2], incorporating the 1,3-aryl linked bis-beta-diketonato bridging ligand 1,1'-(1,3-phenylene)-bis(4,4-dimethylpentane-1,3-dione) (H2L) have been synthesised. The X-ray structures of six adduct species are reported. The interaction of [Cu2(L)2] with the ditopic ligand aminopyrazine (apyz) yielded the sandwich-like tetranuclear species [(Cu2L2(apyz))2]. A variable-temperature magnetochemical investigation of this product indicated weak antiferromagnetic coupling between the (five-coordinate) copper centres, mediated by the 2-aminopyrazine linkers. An analogous structure, [(Cu2L2(dabco))2] (dabco=1,4-diazabicyclo[2.2.2]octane), was generated when dabco was substituted for aminopyrazine while use of 4,4'-dipyridyl sulfide (dps) and 4,4'-(1,3-xylylene)-bis(3,5-dimethylpyrazole) (xbp) as the ditopic 'spacer' ligands resulted in polymeric species of type [Cu2L2(dps)]n and [Cu2L2(xbp)]n, respectively. These latter species exist as one-dimensional chain structures in which copper(II) centres on different dinuclear platforms are linked in a 'zigzag' fashion. In contrast, with 2,2'-dipyridylamine (dpa) a discrete complex of type [Cu2L2(dpa)2] formed in which one potential pyridyl donor from each 2,2'-dipyridylamine ligand remains uncoordinated. The use of the potentially quadruply-bridging hexamethylenetetramine (hmt) ligand as the linker unit was found to give rise to an unusual two-dimensional polymeric motif of type [(Cu2(L2)2)3(hmt)2]n. The product takes the form of a (6,3) network, incorporating triply bridging hexamethylenetetramine units.
    Dalton Transactions 10/2006; DOI:10.1039/b606523f · 4.20 Impact Factor
  • Michael J. Hayter · David J. Bray · Jack K. Clegg · Leonard F. Lindoy
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    ABSTRACT: The synthesis and characterization of six new aryl-linked, and in one instance xylyl-linked, bis-pyrazoles are reported. The X-ray structures of two of these derivatives are also presented.
    Synthetic Communications 04/2006; 36(6):707-714. DOI:10.1080/00397910500446845 · 0.93 Impact Factor
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    ABSTRACT: In the title complex, [Co(C5H5N)2(H2O)4](C2H3O2)2, the octa­hedral cation is hydrogen bonded to the acetate anions via the coordinated water mol­ecules. The cation and anions lie on a crystallographic mirror plane.
    Acta Crystallographica Section E Structure Reports Online 04/2006; 62(4). DOI:10.1107/S1600536806010257 · 0.35 Impact Factor