113 results for Henderson, William, Journal article

  • Study of metal scrambling in the trinuclear {Pt₂Se₂M} (M = Pt, Pd, Au) system using an electrospray mass spectrometry (ESMS) directed synthetic methodology; isolation and crystallographic characterization of {Pt₂(µ₃-Se)₂(PPh₃)₄[Pt(cod)]}{PF₆}₂ and {Pt(μ₃-Se)₂(PPh₃)₂[Pt(cod)]₂}{PF₆}₂ (cod = Cyclo-octa-1,5-diene)

    Yeo, Jeremy S.L.; Vittal, Jagadese J.; Henderson, William; Hor, T.S. Andy (2002)

    Journal article
    University of Waikato

    Pt₂(μ-Se)₂(PPh₃)₄ reacts with PtCl₂(cod) to give {Pt₂(μ₃-Se)₂(PPh₃)₄[Pt(cod)]}²⁺ and an unexpected cod-rich product that arises from metal scrambling, viz. {Pt(μ₃-Se)₂(PPh₃)₂[Pt(cod)]₂}²⁺. The formation of these species was detected and followed by electrospray mass spectrometry (ESMS) and subsequently verified by batch synthesis and crystallographic characterization. Other metal-scrambled aggregate products were successfully detected.

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  • Use of cyclometallated PdCl[PPh₂CH₂CH₂CHCH₂CH₂PPh₂] as a precursor to homo and heterometallic species directed by ESMS (Electrospray Ionisation Mass Spectrometry)

    Neo, Kian Eang; Neo, Yew Chin; Chien, Sheau Wei; Tan, Geok Kheng; Wilkins, Alistair L.; Henderson, William (2004)

    Journal article
    University of Waikato

    The cyclometallated Pd compound PdCl[PPh₂CH₂CH₂CHCH₂CH₂PPh₂] 1, obtained from PdCl₂(Ph₂P(CH₂)₅PPh₂) in refluxing DMF (N,N-dimethylformamide), was characterized by NMR and X-ray single-crystal diffraction analysis. The cyclometallation of MCl₂(Ph₂P(CH₂)₅PPh₂)(M = Pd, Pt) to give 1 and its Pt(II) analogue was probed using electrospray ionisation mass spectrometry (ESMS). The reactivity of 1 towards neutral ligands such as phosphines and pyridines as well as basic metal complexes such as pyridine-thiolate compounds of Au(I), Hg(II) and Pt(II) in solution was also investigated. The results showed that the chloride trans to the Pd–C bond is susceptible to ligand replacement. A number of entry metalloligands was examined in an attempt to establish a route to cyclometallated aggregates and clusters.

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  • Self-assembly of a columnar polymeric calcium phosphinate derived from camphene

    Henderson, William; Leach, Meto T.; Nicholson, Brian K.; Sabat, Michal (1995)

    Journal article
    University of Waikato

    (2,2-Dimethylbicyclo[2.2.1] hept-3-ylmethyl)phosphinic acid (RPO₂H₂), readily prepared from camphene and hypophosphorous acid, formed a polymeric calcium salt [{Ca(RPO₂H) ₂ (RPO₂H₂)(H₂O)}n], with both terminal and triply bridging phosphinate groups, and an overall columnar structure with an inorganic core and a pseudo-close-packed sheath of terpene moieties.

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  • E/Z isomerism in monoalkylated derivatives of [Pt₂(μ-S)₂(PPh₃)₄] containing 2,4-dinitrophenylhydrazone substituents

    Ujam, Oguejiofo Theophilus; Devoy, Sarah M.; Henderson, William; Wilkins, Alistair L.; Nicholson, Brian K. (2011)

    Journal article
    University of Waikato

    Alkylation of [Pt₂(m-S)₂(PPh₃)₄] with 2,4-dinitrophenylhydrazone-functionalized alkylating agents XC6H4C{¼NNHC₆H₃(NO₂)₂}CH2Br (X¼H, Ph) gives monoalkylated cations [Pt₂(m-S){m-SCH₂C{¼NNHC₆H₃(NO₂)₂}C₆H₄X}(PPh₃)₄]⁺. An X-ray diffraction study on [Pt₂(m-S){m-SCH₂C{¼NNHC₆H₃(NO₂)₂}Ph}(PPh₃)₄]BPh₄ shows the crystal to be the Z isomer, with the phenyl ring and NHC₆H₃(NO₂)₂ groups mutually trans. ¹H- and ³¹P{¹H} NMR spectroscopic methods indicate a mixture of Z (major) and E (minor) isomers in solution, which slowly convert mainly to the E isomer. Reaction of [Pt₂(m-S)₂ (PPh₃)₄] with the dinitrophenylhydrazone of chloroacetone [ClCH₂C{¼NNH(C₆H₃(NO₂)₂}Me] and NaBPh₄ gives [Pt₂ (m-S){m-SCH₂C{¼NNHC₆H₃(NO₂)₂}Me}(PPh₃)₄]BPh₄, which exists as a single (E) isomer.

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  • Synthesis and characterization of new trimetallic complexes with {Pt₂Au(μ-S) ₂} ⁿ⁺ (n=2, 3) cores containing C, N and N, N donor ligands

    White, Bradley C.; Henderson, William; Hor, T.S. Andy; Nicholson, Brian K. (2013)

    Journal article
    University of Waikato

    Reactions of the dinuclear platinum(II) sulfide complex [Pt ₂(μ-S) ₂(PPh ₃) ₄] with a range of gold(III) dichloride complexes [AuLCl ₂] containing C, N- or N, N-cycloaurated ligands L gives a new series of dicationic adducts [Pt ₂(μ-S) ₂(PPh ₃) ₄AuL] ²⁺, isolated as their PF ₆ - salts. The complexes investigated are [Au{C₆₋H ₄(CH ₂NMe ₂)-2}Cl ₂], [Au{C ₆H ₃(CH ₂NMe ₂)-2-(OMe)-5}Cl ₂], [Au{NC ₅H ₄(CH ₂C ₆H ₄)-2}Cl ₂], [Au{NC ₅H ₄(COC ₆H ₄)-2}Cl ₂] and [Au{NC ₅H ₄(CONH)-2}Cl ₂]. An X-ray structure determination on the picolinamide-derived complex [Pt ₂(μ-S) ₂(PPh ₃) ₄Au{NC ₅H ₄(CONH)-2}](PF₆) ₂ was not of sufficiently high quality for detailed discussion, but confirmed the atom connectivity. Reactions of [Pt ₂(μ-S) ₂(PPh ₃) ₄] with [AuCl ₂(bipy)]PF ₆ (L=bipy=2,2'-bipyridine) and [AuCl ₂(phen)]Cl (L=phen=1,10-phenanthroline) gives the corresponding tricationic adducts [Pt ₂(μ-S) ₂(PPh ₃) ₄AuL] ³⁺, also isolated as their PF ₆⁻ salts. The complexes are characterised by NMR spectroscopy, electrospray mass spectrometry and microelemental analyses. Biological assay data of a selection of these new complexes towards the P388 murine leukemia cell line, as well as a range of antimicrobial tests, reveals overall low activity compared to other cycloaurated gold(III) complexes.

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  • ‘Synthetic prospecting’ using an electrospray ionisation mass spectrometry directed survey of the alkylation and arylation chemistry of [Pt₂(μ-S)₂(PPh₃)₄]

    Henderson, William; Chong, Siew Huay; Hor, T.S. Andy (2006)

    Journal article
    University of Waikato

    Electrospray ionisation mass spectrometry (ESI-MS) has been used as an analytical tool in a wide-ranging scoping study of the alkylation and arylation reactions of [Pt₂(μ-S)₂(PPh₃)₄]. From these experiments, the factors that influence the formation of different product species – formed by mono- or di-alkylation – are determined. If the alkylating agent is an alkyl chloride or sulfate, monoalkylation followed by dialkylation of the two sulfido groups occurs, dependent on the alkylating power of the reagent used. For example, n-butyl chloride gives solely [Pt₂(μ-S)(μ-SBu)(PPh₃)₄]⁺ while dimethyl sulfate gives [Pt₂(μ-SMe)₂(PPh₃)₄]²⁺. This species, previously unisolated is stable in the absence of good nucleophiles, but the addition of potassium iodide results in rapid conversion to [Pt₂(μ-SMe)₂(PPh₃)₃I]⁺. This iodo complex is also observed from the reaction of [Pt₂(μ-S)₂(PPh₃)₄] with excess MeI, after the initial formation of mono- and di-methylated species. In these reactions, the iodide presumably displaces a phosphine ligand, which is then quaternised by excess alkylating agent. Changing the alkylating agent to a longer chain alkyl iodide or methyl bromide decreases the rate of alkylation of the sulfide in the initially formed [Pt₂(μ-S)(μ-SR)(PPh₃)₄]⁺. Mixed-thiolate species of the type [Pt₂(μ-SMe)(μ-SR)(PPh₃)₄]²⁺ are easily generated by reaction of [Pt²(μ-S)(μ-SR)(PPh₃)₄]⁺ with excess Me₂SO₄ and is also dependent on the avoidance of nucleophiles. Reactions towards α,ω-dialkylating agents are surveyed; the chain length is found to have a dramatic effect on the rate of the second intramolecular cyclisation process, illustrated by a competitive reactivity study involving a mixture of Br(CH₂)₄Br and Br(CH₂)₅Br; on completion of the reaction the former gives [Pt₂{μ-S(CH₂)₄S}(PPh₃)₄]²⁺ while the latter predominantly gives monoalkylated[Pt₂(μ-S){μ-S(CH₂)₅Br}(PPh₃)₄]⁺. The reactivity of o- and p-dihaloxylenes has been explored, with the reaction with p-BrCH₂C₆H₄CH₂Br giving the bridged species [(PPh₃)₄Pt₂(μ-S)(μ-SCH₂C₆H₄CH₂S)(μ-S)Pt₂(PPh₃)₄]²⁺. Arylation reactions of [Pt₂(μ-S)₂(PPh₃)₄] with halobenzenes and 2-bromoheterocyclic compounds (pyridine, thiophene) are also described.

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  • Thiourea monoanion and dianion complexes of rhodium(III) and ruthenium(II)

    Henderson, William; Nicholson, Brian K.; Dinger, Maarten B.; Bennett, Rachel L. (2002-10-01)

    Journal article
    University of Waikato

    The versatility of deprotonated thioureas as ligands is shown by the synthesis and characterisation of a range of rhodium(III) complexes of substituted thioureas, with support from a ruthenium(II) analogue in one case. Reaction of the complexes [LMCl(μ-Cl)]2 [M=Rh, L=η5-C5Me5 (Cp*); M=Ru, L=η6-p-cymene] with Na[MeNHC(S)NCN] and excess trimethylamine base gives the dinuclear complexes [LM{SC(=NCN)NMe}]2 containing chelate-bridging thiourea dianion ligands. The Ru complex was characterised by an X-ray diffraction study. The mononuclear complexes [Cp*Rh{SC(=NCN)NMe}(PPh3)] and [Cp*Rh{SC(=NPh)NPh}(PPh3)], containing chelating thiourea dianion ligands, were prepared by analogous reactions in the presence of triphenylphosphine. Reaction of [Cp*Rh{SC(=NCN)NMe}(PPh3)] with HCl, or [Cp*RhCl(μ-Cl)]2 with 2 equiv. of PPh3 and Na[MeNHC(S)NCN] (with no added base) gave the complex [Cp*RhCl{SC(=NCN)NHMe}(PPh3)], containing a (monodentate) S-bonded thiourea monoanion ligand, which was characterised by an X-ray diffraction study. The AsPh3 and SbPh3 analogues of this complex were also prepared and characterised. Reaction of [Cp*RhCl(μ-Cl)]2 with 2 equiv. of PPh3 or SbPh3 and PhNHC(S)NHPh or various trisubstituted thioureas PhNHC(S)NR1R2, triethylamine and NaBPh4 gave a range of cationic complexes [Cp*Rh{SC(=NR1R2)NPh}(EPh3)]+ (E=P, Sb), as their tetraphenylborate salts, in which the thiourea is bonded as a monoanion through the S and the NPh group. The corresponding reaction utilising 1,6-bis(diphenylphosphino)hexane (dpph) gave the dinuclear complex [Cp*Rh{SC(=N(CH2CH2)2O)NPh}]2(μ-η2-dpph) (BPh4)2.

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  • Platinum(II) complexes of chelating and monodentate thiourea monoanions incorporating chiral, fluorescent or chromophoric groups

    Henderson, William; Nicholson, Brian K.; Rickard, Clifton E.F. (2001-08-01)

    Journal article
    University of Waikato

    The reaction of cis-[PtCl2(PPh3)2] with trisubstituted thioureas [R1R2NC(=S)NHR3] in refluxing methanol with triethylamine base, followed by addition of NaBPh4 gives the salts [Pt{SC(=NR1R2)NR3}(PPh3)2]BPh4 in high yield; a range of thiourea substituents, including chiral, fluorescent and chromophoric groups can be incorporated. The azo dye-derived complex [Pt{SC(=N(CH2CH2)2O)NC6H4N=NC6H4NMe2}(PPh3)2]BPh4 has been characterised by a single-crystal X-ray diffraction study. The formation of a fluorescein-derivatised platinum-thiourea complex is also described. Reaction of cis-[PtCl2(PPh3)2] with PhNHC(S)NHPh or EtNHC(S)NHEt, triethylamine and NaBPh4 gives, respectively, [Pt{SC(=NHPh)NPh}(PPh3)2]+ and the known cation [Pt{SC(=NHEt)NEt}(PPh3)2]+, isolated as tetraphenylborate salts. Reaction of cis-[PtCl2(PPh3)2] with an excess of Na[MeNHC(S)NCN] in methanol gives the bis(thiourea monoanion) complex trans-[Pt{SC(=N---CN)NHMe}2(PPh3)2], characterised by NMR spectroscopy and an X-ray crystal structure determination. When cis-[PtCl2(PPh3)2] is reacted with 1 equiv. of Na[MeNHC(S)N---CN] in methanol, with added NaBPh4, a mixture of isomers of the [Pt{SC(=NHCN)NMe}(PPh3)2]+ cation is obtained.

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  • A combinatorial-like probe on the reactivity of the {Pt₂S₂} core of Pt₂(PPh₃)₄(μ-S)₂ by electrospray mass spectrometry. Synthesis and structures of novel heterometallic sulfide aggregates of gold(III), mercury(II), and tin(IV) with platinum(II)

    Fong, S.W. Audi; Yap, Woon Teck; Vittal, Jagadese J.; Hor, T.S. Andy; Henderson, William; Oliver, Allen G.; Rickard, Clifton E.F. (2001)

    Journal article
    University of Waikato

    Electrospray mass spectrometry (ESMS) provides a rapid and convenient technique for probing the nucleophilicity of the {Pt₂S₂} butterfly core. Positive-ion electrospray mass spectra have been recorded for a wide array of aggregates incorporating various metallo-fragments into the Pt₂(PPh₃)₄(μ-S)₂ 1 moiety. Such combinatorial-like screening allowed a large number of different metal–sulfur interactions to be studied and the resultant heterometallic aggregates postulated. Such postulations were subsequently confirmed by synthetic studies and single-crystal X-ray crystallographic analyses. This approach helped to minimize the wastage by focusing on the synthesis of aggregates that were supported by the ESMS evidence. It has resulted in the isolation of a series of novel aggregates such as {AuIIIPt₂S₂}, {HgIIPt₂S₂}, and {SnIVPt₂S₂} in good lab-scale yields. It also led to the trapping and characterization of the monoprotonated product of 1, which has eluded isolation.

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  • Influence of chain length on mono- versus di-alkylation in the reactivity of [Pt₂(μ-S)₂(PPh₃)₄] towards α,ω-dihalo-n-alkanes; a synthetic route to platinum(II) ω-haloalkylthiolate complexes

    Devoy, Sarah M.; Henderson, William; Nicholson, Brian K.; Hor, T.S. Andy (2010)

    Journal article
    University of Waikato

    The reactions of [Pt₂(μ-S)₂(PPh₃)₄] with a,x-dibromoalkanes Br(CH₂)nBr (n = 4, 5, 6, 8, 12) gave monoalkylated [Pt₂(μ-S){μ-S(CH₂)nBr}(PPh₃)₄]⁺ and/or di-alkylated [Pt₂(μ-S(CH₂)nS}(PPh₃)₄]²⁺ products, depending on the alkyl chain length and the reaction conditions. With longer chains (n = 8, 12), intramolecular di-alkylation does not proceed in refluxing methanol, with the mono-alkylated products [Pt₂ (μ-S){μ-S(CH₂)nBr}(PPh₃)₄]⁺ being the dominant products when excess alkylating agent is used. The bridged complex [{Pt₂(μ-S)₂(PPh₃)₄}₂{μ-(CH₂)12}]²⁺ was accessible from the reaction of [Pt₂ (μ-S)₂(PPh₃)₄] with 0.5 mol equivalents of Br(CH₂)12Br. [Pt₂(μ-S){μ-S(CH₂)₄Br}(PPh₃)₄]⁺ can be cleanly isolated as its BPh₄⁻ salt, but undergoes facile intramolecular di-alkylation at -18 degree C, giving the known species [Pt₂(μ-S(CH₂)₄S}(PPh₃)₄]²⁺. The reaction of I(CH₂)₆I with [Pt₂(μ-S)₂(PPh₃)₄] similarly gives [Pt₂ (μ-S){μ-S(CH₂)₆I}(PPh₃)₄]⁺, which is fairly stable towards intramolecular di-alkylation once isolated. These reactions provide a facile route to x-haloalkylthiolate complexes which are poorly defined in the literature. X-ray crystal structures of [Pt₂(μ-S){μ-S(CH₂)₅Br}(PPh₃)₄]BPh₄ and [Pt₂(μ-S(CH₂)₅S} (PPh₃)₄](BPh₄)₂ are reported, together with a study of these complexes by electrospray ionisation mass spectrometry. All complexes fragment by dissociation of PPh₃ ligands, and the bromoalkylthiolate complexes show additional fragment ions [Pt₂(μ-S){μ-S(CH₂)n_2CH=CH₂}(PPh₃)m]⁺ (m = 2 or 3; m – 4), most significant for n = 4, formed by elimination of HBr.

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  • Coordination isomerism in salicylhydroxamate complexes of platinum(II) and palladium(II)

    Henderson, William; Evans, Cameron; Nicholson, Brian K.; Fawcett, John (2003-01-01)

    Journal article
    University of Waikato

    The syntheses of a range of platinum(II) and palladium(II) complexes containing salicylhydroxamate ligands are described. The ancillary ligands, together with the synthetic route, influence the coordination mode of the salicylhydroxamate ligand. Reaction of cis-[PtCl₂(PPh₃)₂] with salicylhydroxamic acid and trimethylamine in hot methanol gave O,O′-bonded [Pt{OC( NO)C₆H₄OH}(PPh₃)₂], but [PtCl₂(cod)](cod = cycloocta-1,5-diene) gave N,O-bonded [Pt{OC₆H₄C(O)NOH}(cod)]. Ligand substitution gives other N,O bonded complexes, including [Pt{OC₆H₄C(O)NOH}(PPh₃)₂]. Reaction of K₂PtCl₄ with 2 equiv. of EPh₃(E = As or Sb), salicylhydroxamic acid and excess trimethylamine gives products whose structures depend on E; AsPh₃ gives [Pt{OC( NO)C₆H₄OH}(AsPh₃)₂], while SbPh₃ gives [Pt{OC₆H₄C(O)NOH}(SbPh₃)₂].

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  • Synthesis and characterisation of four- and eight-membered ring auralactam complexes

    Henderson, William; Nicholson, Brian K.; Oliver, Allen G. (2001-02-01)

    Journal article
    University of Waikato

    The reactions of the cyclo-aurated gold(III) dihalide complex [{C6H3 (CH2NMe2)-2-(OMe)-5}AuCl2] with N-cyanoacetylurethane [NCCH2C(O)NHCO2Et], 2-benzoylacetanilide [PhC(O)CH2C(O)NHPh] and acetoacetanilide [MeC(O)CH2C(O)NHPh], and [{C6H4 (CH2NMe2)-2}AuCl2] with acetoacetanilide in dichloromethane with excess silver(I) oxide gives the first examples of auralactam complexes, containing Au-NR-C(O)-CHR′ four-membered rings. A single-crystal X-ray diffraction study on the complex [{C6H4 (CH2NMe2)-2}Au{NPhC(O)CH(COMe)}] reveals similar structural features to related metallalactam complexes of platinum(II) and palladium(II). When a CDCl3 solution of the complex [{C6H3 (CH2NMe2)-2-(OMe)-5}Au{N(CO2Et)C(O)CHCN}] is allowed to stand for 18 h, a novel dimerisation reaction occurs, giving the insoluble product [{C6H3 (CH2NMe2)-2-(OMe) 5}Au{N(CO2Et)C(O)CHCN}]2 2CDCl3, characterised by an X-ray structure determination. The dimer contains an eight-membered Au-N-C(O)-C-Au-N-C(O)-C ring.

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  • Characterization of synthetic and commercial trisiloxane surfactant materials

    Bonnington, L. S.; Henderson, William; Zabkiewicz, J. A. (2004)

    Journal article
    University of Waikato

    The organosilicone surfactant Silwet L-77® (L-77), used as an agrochemical adjuvant, is a mixture comprised predominantly of [(CH₃)₃SiO]₂ (CH₃)Si (CH₂)₃ (OCH₂CH₂)n OCH₃ oligomers (n = 3-16, average n 7.5). The commercially available L-77 mixture was purified by reversed-phase high-performance liquid chromatography (HPLC) to obtain individual trisiloxane surfactant components. Pure oligomers (n = 3, 6 and 9) were also synthesized. Synthesis was achieved by hydrosilylation of monomeric ethoxylate monomethyl ether starting reagents. Pure hexa- and nona-ethylene glycols were produced by condensation of smaller oligomers. Atmospheric-pressure ionization mass spectrometry (MS) methods were used to characterize fully the commercial L-77 product and synthesized or isolated components. The application of Fourier-transform ion cyclotron resonance MS and online HPLC-electrospray ionization MS techniques to the analysis of this surfactant are described here. The application of these analytical techniques also enabled elucidation of the synthetic by-products present in the commercial formulation.

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  • Camphene-derived primary and hydroxymethyl phosphines

    Berrigan, Rebecca A.; Russell, Douglas K.; Henderson, William; Leach, Meto T.; Nicholson, Brian K.; Woodward, Gary; Harris, Christopher (2001-01-01)

    Journal article
    University of Waikato

    Thermal disproportionation of (2,2-dimethylbicyclo[2.2.1]hept-3-ylmethyl)phosphinic acid (endo-8-camphanylphosphinic acid, camPO₂H₂) yields the primary phosphine (2,2-dimethylbicyclo[2.2.1]hept-3-ylmethyl)phosphine (camPH₂). The compound has been characterised by NMR spectroscopy, and as its tris(hydroxymethyl)phosphonium chloride salt [camP(CH₂OH)₃]Cl, synthesised by reaction with excess formaldehyde and hydrochloric acid. The X-ray crystal structure of this phosphonium salt is reported, confirming the endo position of the phosphonium group. On treatment with triethylamine base, camP(CH₂OH)₃ ⁺Cl⁻ is converted to the hydroxymethylphosphine camP(CH₂OH)₂. The sulfide and selenide of this phosphine have been prepared, together with the platinum(II) complex cis-[PtCl₂{camP(CH₂OH)₂}₂]. The gas-phase decomposition of camPH₂ has been investigated using the technique of IR laser powered homogeneous pyrolysis. Results indicate the initial elimination of phosphine, followed by the rearrangement and decomposition of camphene through two distinct pathways.

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  • Bis[μ-bis(diphenylphosphino)methane-К²P:P’]bis[(saccharinato-КN)- palladium(I)] dichloromethane solvate

    Henderson, William; Nicholson, Brian K.; Chung, Dong C. (2002)

    Journal article
    University of Waikato

    The dimeric palladium(I) saccharinate complex [Pd₂(sac)₂(dppm)₂], has been characterized as its di¬chloro¬methane solvate, i.e. [Pd₂(C₇H₄NO₃S)₂(C₂₅H₂₂P₂)₂]•CH₂Cl₂. The complex features a Pd—Pd bond bridged by two dppm ligands, with the saccharinate ligands N-bonded trans to the Pd—Pd bond.

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  • Ferrocenyl hydroxymethylphosphines (η⁵-C₅H₅)Fe[η⁵⁻C₅H₄P(CH₂OH)₂] and 1,1′-[Fe{η⁵-C₅H₄P(CH₂OH)₂}₂] and their chalcogenide derivatives

    Henderson, William; Alley, Steven R. (2002)

    Journal article
    University of Waikato

    The ferrocenyl hydroxymethylphosphines FcP(CH₂OH)₂ [Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄)] and 1,1′-Fc′[P(CH₂OH)₂]₂ [Fc′=Fe(η⁵⁻C₅H₄)₂] were prepared by reactions of the corresponding primary phosphines FcPH₂ and 1,1′-Fc′(PH₂)₂ with excess aqueous formaldehyde. The crystal structure of FcP(CH₂OH)₂ was determined and compared with the known ferrocenyl hydroxymethylphosphine FcCH₂P(CH₂OH)₂. The chalcogenide derivatives FcP(E)(CH₂OH)₂ and 1,1′-Fc′[P(E)(CH₂OH)₂]₂ (E=O, S, Se) were prepared and fully characterised. Crystal structure determinations on FcP(O)(CH₂OH)₂ and FcP(S)(CH₂OH)₂ were performed, and the hydrogen-bonding patterns are compared with related compounds. The sulfide shows no hydrogen-bonding involving the phosphine sulfide group, in contrast to other reported ferrocenyl hydroxymethylphosphine sulfides. The platinum complex cis-[PtCl₂{FcP(CH₂OH)₂}₂] was prepared by reaction of 2 mol equivalents of FcP(CH₂OH)₂ with [PtCl₂(1,5-cyclo-octadiene)], and was characterised by 31P-NMR spectroscopy and negative ion electrospray mass spectrometry, which gave a strong [M+Cl]⁻ ion.

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  • The arylation of [Pt₂(μ-S)₂(PPh₃)₄]

    Deadman, Benjamin Jade; Henderson, William; Nicholson, Brian K.; Petchell, Laura Eleanor; Rose, Sarah L.; Hor, T.S. Andy (2009)

    Journal article
    University of Waikato

    Routes to the synthesis of the mixed sulfide-phenylthiolate complex [Pt₂(μ-S)(μ -SPh)(PPh₃)₄]⁺ have been explored; reaction of [Pt₂(μ-S)₂(PPh₃)₄] with excess Ph₂IBr proceeds readily to selectively produce this complex, which was structurally characterised as its PF₆⁻ salt. Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with other potent arylating reagents (1-chloro-2,4-dinitrobenzene and 1,5-difluoro-2,4-dinitrobenzene) also produce the corresponding nitroarylthiolate complexes [Pt₂(μ-S){μ -SC₆H₂(NO₂)₂X}(PPh₃)₄]⁺ (X = H, F). The complex [Pt₂(μ-S)(μ -SPh)(PPh₃)₄]⁺ reacts with Me₂SO₄ to produce the mixed alkyl/aryl bis-thiolate complex [Pt₂(μ-SMe)(μ -SPh)(PPh₃)₄]²⁺, but corresponding reactions with the nitroarylthiolate complexes are plagued by elimination of the nitroaryl group and formation of [Pt₂(μ-SMe)₂(PPh₃)₄]²⁺. [Pt₂(μ-S)(μ -SPh)(PPh₃)₄]⁺ also reacts with Ph₃PAuCl to give [Pt₂(μ-SAuPPh₃)(μ -SPh)(PPh₃)₄]²⁺.

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  • Tricarbonylrhenium(I) complexes of phosphine-derivatized amines, amino acids and a model peptide: structures, solution behavior and cytotoxicity

    Zhang, Jianyong; Vittal, Jagadese J.; Henderson, William; Wheaton, Jessica R.; Hall, Iris H.; Hor, T.S. Andy; Yan, Yaw Kai (2002)

    Journal article
    University of Waikato

    Modified Mannich reactions of amines, amino acids and a model peptide with Ph₂PH and CH₂O gave bis(diphenylphosphinomethyl)amines (Ph₂PCH₂)₂NR [R=Ph (1), CH₂CH₂OH (2), CH₂COOCH₂Ph (3), CH₂CONHCH₂COOCH₂Ph (4), CH2COOH (5)] and (Ph₂PCH₂)₂NCH₂CH₂N(CH₂PPh₂)₂ (6). Reaction with [ReBr₃(CO)₃]²⁻ under mild conditions led to [ReBr(CO)₃]{(Ph₂PCH₂)₂NR} [R=Ph (7), CH₂CH₂OH (8), CH₂COOCH₂Ph (9), CH₂CONHCH₂COOCH₂Ph (10), CH₂COOH (11)] and [ReBr(CO)₃(Ph₂PCH₂)₂NCH₂]₂ (12). All new complexes have been characterized by NMR and IR spectroscopy and for 7, 9 and 10, single-crystal X-ray diffraction analyses. Electrospray mass spectrometric studies show that the rhenium–phosphine chelates are very stable, especially in neutral methanolic solution. Hydrolysis of the ester and amide linkages slowly occur in acidic and basic solutions over several weeks; displacement of the bromide ligand also occurs in basic medium. Cytotoxicity testing of 7–10 and 12 showed that all the complexes are active against specific tumor cell lines, especially MCF-7 breast cancer and HeLa-S3 suspended uterine carcinoma.

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  • ‘User-friendly’ primary phosphines and an arsine: synthesis and characterization of new air-stable ligands incorporating the ferrocenyl group

    Henderson, William; Alley, Steven R. (2002)

    Journal article
    University of Waikato

    Reaction of FcCH₂CH₂P(O)(OH)₂ or FcCH₂P(O)(OH)(OEt) [Fc=Fe(η⁵-C₅H₄)(η⁵-C₅H₅)] with excess CH₂N₂ followed by reduction with Me₃SiCl–LiAlH₄ gives the air-stable primary phosphines FcCH₂CH₂PH₂ and the previously reported analogue FcCH₂PH₂ in high yields. Reduction of 1,1′-Fc′[CH₂P(O)(OEt)₂] [Fc′=Fe(η⁵-C₅H₄)₂] and 1,2-Fc″[CH₂P(O)(OEt)₂] [Fc″=Fe(η⁵-C₅H₅)(η⁵-C₅H₃)] similarly gives the new primary phosphines 1,1′-Fc′(CH₂PH₂)₂ and 1,2-Fc″(CH₂PH₂)₂, respectively. The arsine FcCH₂CH₂AsH₂, which is also air-stable, has been prepared by reduction of the arsonic acid FcCH₂CH₂As(O)(OH)₂ using Zn/HCl. An X-ray structure has been carried out on the arsine, which is only the second structure determination of a free primary arsine. The molybdenum carbonyl complex [1,2-Fc″(CH₂PH₂)₂Mo(CO)₄] was prepared by reaction of the phosphine with [Mo(CO)₄(pip)₂] (pip=piperidine), and characterized by a preliminary X-ray structure determination. However, the same reaction of 1,1′-Fc′(CH₂PH₂)₂with [Mo(CO)₄(pip)₂] gave [1,1′-Fc′(CH₂PH₂)₂Mo(CO)₄] and the dimer [1,1′-Fc′(CH₂PH₂)₂Mo(CO)₄]₂, characterized by electrospray mass spectrometry. 1,1′-Fc′[CH₂PH₂Mo(CO)₅]₂ and 1,2-Fc″[CH₂PH₂Mo(CO)₅]₂ were likewise prepared from the phosphines and excess [Mo(CO)₅(THF)].

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  • Synthesis and characterization of nickel(II) maltolate complexes containing ancillary bisphosphine ligands

    Alblawi, Jamal; Henderson, William; Nicholson, Brian K. (2011)

    Journal article
    University of Waikato

    Cationic nickel(II) complexes containing chelating O,O'-donor maltolate or ethyl maltolate ligands in conjunction with bidentate bisphosphine ligands Ph₂P(CH₂)nPPh₂ were prepared by a one-pot reaction starting from nickel(II) acetate, bisphosphine, maltol (or ethyl maltol), and trimethylamine, and isolated as their tetraphenylborate salts. An X-ray structure determination of [Ni(maltolate)(Ph₂PCH₂CH₂PPh₂)]BPh₄ shows that the maltolate ligand binds asymmetrically to the (slightly distorted) square-planar nickel(II) center. The simplicity of the synthetic method was extended to the synthesis of the known platinum(II) maltolate complex [Pt(maltolate)(PPh₃)₂]BPh₄ which was obtained in high purity.

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