School of Chemistry - Research Publications

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    A cis-β-iron(iii) SALPN catalyst for hydrogen atom transfer reductions and olefin cross couplings
    Ricca, M ; Yao, S ; Le, T ; White, JM ; Donnelly, PS ; Rizzacasa, MA (ROYAL SOC CHEMISTRY, 2023-08-23)
    An inexpensive Fe(III) SALPN catalyst for MHAT reactions such as reductions of α,β-unsaturated carbonyl compounds and olefin cross couplings is reported. The majority of these reactions proceeded in good yields and high stereoselectivities with low catalyst loadings at room temperature.
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    Synthesis of acyloin natural products by Mukaiyama hydration
    Ricca, M ; Zhang, W ; Li, J ; Fellowes, T ; White, JM ; Donnelly, PS ; Rizzacasa, MA (ROYAL SOC CHEMISTRY, 2022-05-18)
    The acyloin natural products are a family of bioactive compounds isolated from fungi and myxobacteria. The total synthesis of 7 members of the acyloin family was achieved via a HWE reaction followed by Mukaiyama-Isayama hydration, using novel Co(II) and Co(III) Schiff base SALPN complexes as catalysts for the key enone hydration step. Furthermore, we have shown that a mild acyloin rearrangement is possible under Mukaiyama hydration conditions, which was crucial in the success of this approach.
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    Pre-targeting amyloid-β with antibodies for potential molecular imaging of Alzheimer's disease
    Morgan, KA ; de Veer, M ; Miles, LA ; Kelderman, CAA ; McLean, CA ; Masters, CL ; Barnham, KJ ; White, JM ; Paterson, BM ; Donnelly, PS (ROYAL SOC CHEMISTRY, 2023-02-21)
    With the aim of developing the concept of pretargeted click chemistry for the diagnosis of Alzheimer's disease two antibodies specific for amyloid-β were modified to incorporate trans-cyclooctene functional groups. Two bis(thiosemicarbazone) compounds with pendant 1,2,4,5-tetrazine functional groups were prepared and radiolabelled with positron emitting copper-64. The new copper-64 complexes rapidly react with the trans-cyclooctene functionalized antibodies in a bioorthogonal click reaction and cross the blood-brain barrier in mice.
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    Palladium-Mediated CO2 Extrusion Followed by Insertion of Allenes: Translating Mechanistic Studies to Develop a One-Pot Method for the Synthesis of Alkenes
    Yang, Y ; Spyrou, B ; White, JM ; Canty, AJ ; Donnelly, PS ; O'Hair, RAJ (AMER CHEMICAL SOC, 2022-07-11)
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    Cellular Up-regulation of Nedd4 Family Interacting Protein 1 (Ndfip1) using Low Levels of Bioactive Cobalt Complexes
    Schieber, C ; Howitt, J ; Putz, U ; White, JM ; Parish, CL ; Donnelly, PS ; Tan, S-S (AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 2011-03-11)
    The delivery of metal ions using cell membrane-permeable metal complexes represents a method for activating cellular pathways. Here, we report the synthesis and characterization of new [Co(III)(salen)(acac)] complexes capable of up-regulating the ubiquitin ligase adaptor protein Ndfip1. Ndfip1 is a neuroprotective protein that is up-regulated in the brain after injury and functions in combination with Nedd4 ligases to ubiquitinate harmful proteins for removal. We previously showed that Ndfip1 can be increased in human neurons using CoCl(2) that is toxic at high concentration. Here we demonstrate a similar effect can be achieved by low concentrations of synthetic Co(III) complexes that are non-toxic and designed to be activated following cellular entry. Activation is achieved by intracellular reduction of Co(III) to Co(II) leading to release of Co(II) ions for Ndfip1 up-regulation. The cellular benefit of Ndfip1 up-regulation by Co(III) complexes includes demonstrable protection against cell death in SH-SY5Y cells during stress. In vivo, focal delivery of Co(III) complexes into the adult mouse brain was observed to up-regulate Ndfip1 in neurons. These results demonstrate that a cellular response pathway can be advantageously manipulated by chemical modification of metal complexes, and represents a significant step of harnessing low concentration metal complexes for therapeutic benefit.
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    An icosanuclear silver(I) cluster supported by bis (thiosemicarbazonato) ligands
    Paterson, BM ; White, JM ; Donnelly, PS ; Koutsantonis, G (CSIRO PUBLISHING, 2022)
    The synthesis and structural characterisation of an icosanuclear silver(I) cluster complex is reported here. The complex includes twenty silver(I) ions supported by eighteen bis(thiosemicarbazonato) ligands. The cluster of silver(I) ions involves several close Ag⋯Ag contacts suggesting some degree of argentophilic interactions and the bis(thiosemicarbazonato) ligands are present in three different conformations highlighting the ability of thiosemicarbazone ligands to coordinate to metal ions in different modes.
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    Guest‐induced Assembly of Bis(thiosemicarbazonato) Zinc(II) Coordination Nanotubes
    Paterson, BM ; White, KF ; White, JM ; Abrahams, BF ; Donnelly, PS (Wiley, 2017-07-10)
    Abstract A ZnII complex of the dianionic tetradentate ligand formed by deprotonation of glyoxal‐bis(4‐phenyl‐3‐thiosemicarbazone) (H2gtsp) is a [3+3] trinuclear triangular prism. Recrystallization of this complex in the presence of either CO2, CS2, or CH3CN leads to the formation of [4+4] open‐ended charge‐neutral tetranuclear coordination nanotubes, approximately 2 nm in length and with internal dimensions large enough to accommodate linear guest molecules, which serve to template their formation. Upon removal of the templating molecules the nanotubes demonstrated reversible sorption of CO2 with an isosteric enthalpy of sorption of 28 kJ mol−1 at low loading.
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    Guest-induced Assembly of Bis(thiosemicarbazonato) Zinc(II) Coordination Nanotubes
    Paterson, BM ; White, KF ; White, JM ; Abrahams, BF ; Donnelly, PS (Wiley, 2017-07-10)
    A ZnII complex of the dianionic tetradentate ligand formed by deprotonation of glyoxal‐bis(4‐phenyl‐3‐thiosemicarbazone) (H2gtsp) is a [3+3] trinuclear triangular prism. Recrystallization of this complex in the presence of either CO2, CS2, or CH3CN leads to the formation of [4+4] open‐ended charge‐neutral tetranuclear coordination nanotubes, approximately 2 nm in length and with internal dimensions large enough to accommodate linear guest molecules, which serve to template their formation. Upon removal of the templating molecules the nanotubes demonstrated reversible sorption of CO2 with an isosteric enthalpy of sorption of 28 kJ mol−1 at low loading.
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    Synthesis of Homochiral Co-III- and Mn-IV-[2.2]Paracyclophane Schiff Base Complexes with Predetermined Chirality at the Metal Centre
    Loits, D ; Braese, S ; North, AJ ; White, JM ; Donnelly, PS ; Rizzacasa, MA (WILEY-V C H VERLAG GMBH, 2016-08-01)
    The planar chiral Schiff base ligand 2, derived from (Rp)‐5‐formyl‐4‐hydroxy‐[2.2]paracyclophane (FHPC) (1), was utilised to form a Λ‐CoIII cis‐β‐octahedral metal complex 3 with complete control of the metal‐centred chirality. In addition, a di‐µ‐oxo Λ,Λ‐MnIV complex 4 was synthesised with control of both metal‐centred and (P)‐helical chirality.
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    Rhenium and technetium complexes of thioamide derivatives of pyridylhydrazine that bind to amyloid-β plaques
    Fletcher, SP ; Noor, A ; Hickey, JL ; McLean, CA ; White, JM ; Donnelly, PS (SPRINGER, 2018-10)
    Age-associated deposition of amyloid-β in cerebral blood vessels, a condition referred to as cerebral amyloid angiopathy, can contribute to stroke and dementia. This research aimed to design new radioactive technetium-99 m complexes that bind to amyloid-β plaques that have the potential to assist in diagnosis of cerebral amyloid angiopathy using single-photon-emitted computed tomography (SPECT) imaging. Six new pyridylthiosemicarbazide ligands containing either benzofuran or styrylpyridyl functional groups that are known to selectively bind to amyloid plaques were prepared. Non-radioactive isotopes of technetium are not available so rhenium was used as a surrogate for exploratory chemistry. The new ligands were used to prepare well-defined [Re-oxo]3+ complexes where two pyridylthiosemicarbazide ligands were coordinated to a single metal ion to give bivalent complexes with two amyloid-β targeting functional groups. The interaction of the [Re-oxo]3+ complexes with synthetic amyloid-β1-42 and with amyloid plaques in human brain tissue was investigated. Two ligands were selected to develop methods to prepare their [99mTc-oxo]3+ complexes at the tracer level. These technetium-99 m complexes are likely to be isostructural to their rhenium-oxo analogues.