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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  • Orthomercurated and cycloaurated derivatives of the iminophosphorane Ph3P NPh

    Brown, Samuel D.J.; Henderson, William; Kilpin, Kelly Joan; Nicholson, Brian K. (2007-03-01)

    Journal article
    University of Waikato

    Ortho-lithiation of Ph3P NPh followed by reaction with HgCl2 gave good yields of [Hg{C6H4(PPh2 NPh)-2}Cl], 3, which was characterised spectroscopically and by an X-ray crystal structure determination. This is an isomer of the product of direct mercuration of Ph3P NPh which occurs on the N-bonded phenyl ring [J. Vicente, J.A. Abad, R. Clemente, J. Lopez-Serrano, M.C. Ramirez de Arellano, P.G. Jones, D. Bautista, Organometallics, 22 (2003) 4248]. Transmetallation of 3 with [AuCl4]− gave the corresponding cycloaurated complex [Au{κ2-C,N-C6H4(PPh2 NPh)-2}Cl2], with a five-membered metallocyclic ring incorporating four different elements.

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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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  • 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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  • ‘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, characterisation, supramolecular aggregation and biological activity of phosphine gold(I) complexes with monoanionic thiourea ligands

    Henderson, William; Nicholson, Brian K.; Tiekink, Edward R. T. (2006-01-01)

    Journal article
    University of Waikato

    A series of phosphine gold(I) complexes containing monoanionic thiourea ligands has been synthesised by reaction of the appropriate precursor chloro complex, Ph₃PAuCl, Cy₃PAuCl, dppf(AuCl)₂ [dppf = Fe(η⁵-C₅H₄PPh₂)₂] or dppe(AuCl)₂ (dppe = Ph₂PCH₂CH₂PPh₂) with the thiourea and Me₃N base in methanol solution. The complexes have been fully characterised by elemental analysis, NMR spectrometry, electrospray mass spectrometry, and in several cases, by single-crystal X-ray diffraction studies. The crystallographic studies show that the ligands coordinate as a thiolate in each case with systematic variations in geometric parameters being readily ascribed to the influence of the N-bound substituents. In four of the structures, discernable supramolecular aggregation patterns are evident, leading to loosely associated dimers or chain motifs, the latter mediated by either Au S, N–H N or C–H O interactions. Cytotoxicity data, against the P388 leukemia cell line, and anti-microbial data are also reported.

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  • Platinum(II) complexes containing ferrocene-derived phosphonate ligands; synthesis, structural characterisation and antitumour activity

    Henderson, William; Alley, Steven R. (2001)

    Journal article
    University of Waikato

    Platinum ferrocenyl–phosphonate complexes, containing four-membered Pt---O---P(O)---O rings, have been synthesised by the reactions of cis-[PtCl₂(PPh₃)₂] with the ferrocene-derived phosphonic acids Fc(CH₂)nP(O)(OH)₂(n=0–2) [Fc=(η⁵-C₅H₄)Fe(η⁵-C₅H₅)] and 1,1′-Fc′[P(O)(OH)₂]₂ [Fc′=Fe(η⁵-C₅H₄)₂] in the presence of Ag₂O. The complexes have been characterised by NMR spectroscopy, together with crystal structure determinations on [Fc(CH₂)nPO₃Pt(PPh₃)₂] (n=1, 2) and [1,1′-Fc′{PO₃Pt(PPh₃)₂}₂]. The complexes [Fc(CH₂)nPO₃Pt(PPh₃)₂] (n=1, 2) show moderate activity against P388 leukaemia cells, whereas the parent phosphonic acids are inactive.

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  • Isolation and crystallographic characterization of solvate- and anion-stabilized PCP pincer complexes of palladium(II)

    Neo, Kian Eang; Huynh, Han Vinh; Koh, Lip Lin; Henderson, William; Hor, T.S. Andy (2008)

    Journal article
    University of Waikato

    Pincer PCP-Pd(II) complex [PdCl(PCP)] (1) (PCP = −CH(CH₂CH₂PPh₂)₂) reacts with AgNO₃ to give [Pd(NO₃)(PCP)] (2). Similar reaction with AgBF₄ gives the aqua complex [Pd(OH₂)(PCP)][BF₄] (3) and the dinuclear complex [{Pd(PCP)}₂(μ-Cl)][BF₄] (4) with singly bridging chloro ligand. All new complexes were characterized by NMR spectroscopy, ESI-MS and single-crystal X-ray diffraction. Complex 1 and the triflate complex [Pd(OTf)(PCP)] (5) are active towards Suzuki–Miyaura coupling between aryl bromides and phenyl boronic acid.

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  • Synthesis and characterisation of ferrocenyl-phosphonic and -arsonic

    Alley, Steven R.; Henderson, William (2001)

    Journal article
    University of Waikato

    The ferrocene-derived acids FcCH₂CH₂E(O)(OH)₂ [4, E=P; 10, E=As; Fc=Fe(η₅-C₅H₅)(η⁵-C₅H₄)] have been synthesized by the reaction of FcCH₂CH₂Br with either P(OEt)₃ followed by hydrolysis, or with sodium arsenite followed by acidification. Reaction of FcCH₂OH with (EtO)₂P(O)Na gave FcP(O)(OEt)(OH), which was converted to FcCH₂P(O)(OH)₂ (3) by silyl ester hydrolysis using Me₃SiBr–Et₃N followed by aqueous work-up. Similarly, the known phosphonic acid FcP(O)(OH)₂and the new derivatives 1,1′-Fc′[P(O)(OH)₂]₂ [Fc′=Fe(η⁵-C₅H₄)₂] and 1,1′-Fc′[CH₂P(O)(OH)₂]₂(7) have been synthesized via their corresponding esters. X-ray crystal structure determinations have been carried out on 3 and 7, and the hydrogen-bonding networks discussed. Electrospray mass spectrometry has been employed in the characterization of the various acids. Phosphonic acids give the expected [M–H]− ions and their fragmentation at elevated cone voltages has been found to be dependent on the acid. FcP(O)(OH)₂ fragments to [C₅H₄PO₂H]−, but in contrast Fc(CH₂)nP(O)(OH)₂ (n=1, 2) give Fe{η⁵-C₅H₄(CH₂)nP(O)O₂]− ions, which are proposed to have an intramolecular interaction between the Fe atom and the phosphonate group. In contrast, arsonic acid (10), together with PhAs(O)(OH)₂for comparison, undergo facile alkylation (in methanol or ethanol solvent), and at elevated cone voltages (e.g. >60 V) undergo carbon–arsenic bond cleavage giving [CpFeAs(O)(OR)O]− (R=H, Me, Et) and ultimately [AsO₂]− ions.

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  • Dinuclear platinum(II) complexes containing ferrocenylalkyl–thiolate and –selenolate ligands

    Devoy, Sarah M.; Henderson, William; Nicholson, Brian K. (2013)

    Journal article
    University of Waikato

    Alkylation reactions of [Pt₂(μ-S)₂(PPh₃)₄] with haloalkylferrocenes FcCH₂Cl, Fc(CH₂)₆Br and Fc(CH₂)₁₁Br [Fc = (η⁵-C₅H₅)Fe(η⁵-C₅H₄)] gave the cationic μ-thiolate complexes [Pt₂(μ-S){μ-S(CH₂)nFc}(PPh₃)₄]⁺ (n = 1, 6, 11), isolated as PF₆⁻ and/or BPh₄⁻ salts, and characterised by ESI mass spectrometry, NMR spectroscopy, microelemental analysis, and by an X-ray structure determination on [Pt₂(μ-S){μ-SCH₂Fc}(PPh₃)₄]PF₆. The complex contains the typical folded {Pt₂(μ-S)₂} core with an axial ferrocenylmethylthiolate ligand. The corresponding selenolate complex [Pt₂ (μ-Se){μ-SeCH₂Fc}(PPh₃)₄]⁺ was similarly obtained by alkylation of [Pt₂(μ-Se)₂ (PPh₃)₄] with FcCH₂Cl, and isolated as PF₆⁻ and BPh₄⁻ salts. The attempted liberation of FcCH₂SH from [Pt₂(μ-S){μ-SCH₂Fc}(PPh₃)₄]+ using Na₂S was not successful.

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  • Dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate complexes

    Henderson, William; Nicholson, Brian K.; Oliver, Allen G.; Rickard, Clifton E.F. (2001-04-01)

    Journal article
    University of Waikato

    Reactions of the chloride-bridged dimers [LMCl(μ-Cl)]₂ (M=Rh, Ir; L=Cp*=η⁵-C₅Me₅; M=Ru, L=η⁶-p-cymene) with two mole equivalents of thiosalicylic acid (HSC₆H₄CO₂H, H₂tsal) and excess base gives the dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate complexes [LM(tsal)]₂. Reaction of the complex [Cp*RhCl₂(PPh₂)] with one equivalent of H₂tsal and triethylamine in dichloromethane gives a mixture of the dimer [Cp*Rh(tsal)]₂ and the phosphine complex [Cp*Rh(tsal)(PPh₃)]; upon recrystallisation, pure dimer is obtained. A single-crystal X-ray diffraction study on the rhodium and ruthenium dimers reveals the expected thiolate-bridged M₂(μ-S)₂ unit. Electrospray mass spectrometry (ESMS) is a useful technique in studying the chemistry of the thiosalicylate complexes, all complexes giving strong [M+H]⁺ ions. With added thiosalicylic acid, cations of the type [(LM)₂(Htsal)₃]⁺ were detected in the mass spectra.

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  • Ligand functionalization, reactivity, and transformation at the selenide centers of [Pt₂(μ-Se)₂(PPh₃)₄] with organic halides

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

    Journal article
    University of Waikato

    The selenium centers of [Pt₂(μ-Se)₂(PPh₃)₄] are subject to electrophilic attack from various organic halides. Reactions with MeI, n-BuCl, α,α⁶-dichloro-p-xylene, and α,α⁶-dichloro-o-xylene give [Pt₂(μ-Se)(μ-SeMe)(PPh₃)₄]⁺, [Pt₂(μ-Se)(μ-SeBu)(PPh₃)₄]⁺, [Pt₂(μ-Se)(μ-SeCH₂C₆H₄CH₂Cl)(PPh₃)₄]⁺, and [Pt₂(μ-SeCH₂C₆H₄CH₂Se)(PPh₃)₄]²⁺, respectively, preserving the dinuclear core and giving rise to new selenium-derivatized ligand complexes. Reaction with oxalyl chloride gives [Pt(η²-Se₂C₂O₂-Se,Se⁶)(PPh₃)₂], leading to the disintegration of the core to a mononuclear complex supported by a new chelating selenium donor ligand. Reactions with malonyl chloride and succinyl chloride give [(COCH₂COCl)Se]₂ and [(COCH₂CH₂COCl)Se]₂ respectively, leading to complex disintegration and liberation of new selenium materials. The crystal structures of the aggregates [Pt₂(μ-Se)(μ-SeMe)(PPh₃)₄][PF₆], [Pt₂(μ₃-Se)₂(PPh₃)₄(CH₂C₆H₄CH₂)][PF₆]₁.₂₅[Cl]₀.₇₅, and [Pt(η²-Se₂C₂O₂-Se,Se⁶)(PPh₃)₂] are described. The potential of using [Pt₂(μ-Se)₂(PPh₃)₄] as a source for metal-assisted synthesis of new and unusual organoselenium compounds is discussed.

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  • New ferrocene-derived hydroxymethylphosphines: FcP(CH₂OH)₂ [Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄)] and the dppf analogue 1,1′-Fc′[P(CH₂OH)₂]₂ [Fc′=Fe(η⁵-C₅H₄)₂]

    Alley, Steven R.; Henderson, William (2001)

    Journal article
    University of Waikato

    Reactions of the ferrocene-phosphines FcPH₂ and 1,1′-Fc′(PH₂)₂ with excess formaldehyde gives the new hydroxymethylphosphines FcP(CH₂OH)₂ 1 and 1,1′-Fc′[P(CH₂OH)₂]₂ 2, respectively. Phosphine 1 is an air-stable crystalline solid, whereas 2 is isolated as an oil. Reaction of 1 with H₂O₂, S₈ or Se gives the chalcogenide derivatives FcP(E)(CH₂OH)₂ (E=O, S or Se), whilst reaction of 2 with S8 gives 1,1′-Fc′[P(S)(CH₂OH)₂]₂, which were fully characterised. Phosphine 1 was also characterised by an X-ray crystal structure determination.

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  • Dinuclear PCP pincer complexes from Lewis acidic [Pd(OTf)(PCP)] and basic [Pd(4-Spy)(PCP)] (OTf = triflate; 4-Spy = 4-pyridinethiolate; PCP = –CH(CH₂CH₂PPh₂)₂)

    Neo, Kian Eang; Huynh, Han Vinh; Koh, Lip Lin; Henderson, William; Hor, T.S. Andy (2007)

    Journal article
    University of Waikato

    The Lewis acidic pincer with a labile triflate ligand, viz. [Pd(OTf)(PCP)] (PCP = –CH(CH₂CH₂PPh₂)₂) 1 was prepared from [PdCl(PCP)] with AgOTf. It reacts readily with neutral bidentate ligands [L = 4,4 -bipyridine (4,4 -bpy) and 1,1 -bis(diphenylphosphino)ferrocene (dppf)] to give dinuclear PCP pincers [{Pd(PCP)}₂(μ-L)][OTf]₂ (L = 4,4 -bpy, 2; dppf, 3). [PdCl(PCP)] also reacts with 4-mercaptopyridine in the presence of KOH to give a Lewis basic pincer with a free pyridine functional group [Pd(4-Spy)(PCP)] 4. Its metalloligand character is exemplified by the isolation of an asymmetric dinuclear double-pincer complex [{Pd(PCP)}₂(μ-4-Spy)][PF₆] 6 bridged by an ambidentate pyridinethiolato ligand. Complexes 1, 2, 3, 4 and 6 have been characterized by single-crystal X-ray diffraction analyses.

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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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  • Synthesis and crystal structure of the first complex containing a chelating selenourea dianion ligand

    Nicholson, Brian K.; Henderson, William; Dinger, Maarten B. (2003-11-01)

    Journal article
    University of Waikato

    Reaction of N,N′-diphenylselenourea, PhNHC(Se)NHPh, with cis-[PtCl2(PPh3)2] and triethylamine in hot methanol gives the first example of a selenourea dianion complex, [Pt{SeC(=NPh)NPh}(PPh3)2] isolated as a yellow solid in high yield. The structure of the complex was determined by X-ray crystallography and found to be similar to the related thiourea dianion complex [Pt{SC(=NPh)NPh}(PPh3)2], with a Pt---Se---C---N four-membered ring. The antitumour activity (P388 murine leukaemia cells) of the selenourea dianion complex was determined, together with a small selection of related platinum(II)-thiourea dianion complexes (prepared by an analogous method) for comparison. The complex [Pt{SC(=NMe)NMe}(PPh3)2] showed high activity [IC50 1.0 μM], with the other complexes showing moderate to low activity.

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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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