143 results for Nicholson, Brian K.

  • An electron-deficient triosmium cluster containing the thianthrene ligand: Synthesis, structure and reactivity of [Os₃(CO)₉(μ3-η2-C₁₂H₇S₂)(μ-H)]

    Raha, Arun K.; Hassan, Mohammad R.; Kabir, Shariff E.; Karim, Md. Manzurul; Nicholson, Brian K.; Sharmin, Ayesha; Salassa, Luca; Rosenberg, Edward (2008)

    Journal article
    University of Waikato

    Reaction of [Os₃(CO)₁₀(CH₃CN)₂] with thianthrene at 80 °C leads to the nonacarbonyl dihydride compound [Os₃(CO)₉(μ-3,4-η²-C₁₂H₆S₂)(μ-H)₂] (1) and the 46-electron monohydride compound [Os₃(CO)₉(μ₃-η²-C₁₂H₇S₂)(μ-H)] (2). Compound 2 reacts reversibly with CO to give the CO adduct [Os₃(CO)₁₀(μ-η²-C₁₂H₇S₂)(μ-H)] (3) whereas with PPh₃ it gives the addition product [Os₃(CO)₉)(PPh₃)(μ-η²-C₁₂H₇S₂)(μ-H)] (4) as well as the substitution product 1,2-[Os₃(CO)₁₀ ((PPh₃)₂] (5) Compound 2 represents a unique example of an electron-deficient triosmium cluster in which the thianthrene ring is bound to cluster by coordination of the sulfur lone pair and a three-center-two-electron bond with the C(2) carbon which bridges the same edge of the triangle as the hydride. Electrochemical and DFT studies which elucidate the electronic properties of 2 are reported.

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  • Transition-metal carbonyl derivatives of the germanes. Part 13. Preparation, spectroscopic properties, and the crystal and molecular structure of bis[µ-carbonyl-bis(tricarbonylcobaltio)(Co–Co)]germanium (4Co–Ge), [Ge{Co₂(CO)₇}₂]; a new type of group 4–tetracobalt species

    Gerlach, Robert F.; Mackay, Kenneth M.; Nicholson, Brian K.; Robinson, Ward T. (1981)

    Journal article
    University of Waikato

    Reaction between Gel₄ and [Co(CO)₄]⁻ or between GeH₄ and [Co₂(CO)₈] gives [Ge{Co₂(CO)₇}₂](1). The crystal and molecular structure of (1) has been obtained by X-ray methods. Crystals are triclinic, with a= 10.396(2), b= 16.495(3), c= 12.879(2)Å, α= 90.33(2), β= 97.68(2), γ= 95.03(2)°, space group P1, and Z= 4. The structure was solved by direct methods and refined by least-squares techniques to R= 0.056 for 2 852 reflections [I 5σ(l)]. The molecule exhibits approximate C₂ symmetry with the Ge atom bridging the Co–Co bonds of two Co₂(CO)₇ units. The Ge bridge is unsymmetric with unequal Ge–Co bond lengths (average 2.38, 2.34 Å); the corresponding µ-CO in each unit is asymmetrically disposed in the opposite sense. Infrared and mass spectral data for [Ge{Co₂(CO)₇}₂] are also discussed.

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  • A study of zinc complexes of the metalloligand [Pt₂(μ-S)₂(PPh₃)₄] of the type [Pt₂(μ-S)₂(PPh₃)₄ZnL]⁺ (L = bidentate chelating ligand)

    Henderson, William; Robertson, Scott H.; Nicholson, Brian K. (2013)

    Journal article
    University of Waikato

    Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with zinc acetate and an ancillary chelating ligand L (HL = 8-hydroxyquinoline, 8-tosylaminoquinoline or maltol) with added trimethylamine in methanol give new cationic platinum–zinc sulfide aggregates [Pt₂(μ-S)₂(PPh₃)₄ZnL]+, isolated as their BF4− salts. The complexes were characterized by NMR spectroscopy, ESI mass spectrometry, microelemental analysis, and an X-ray structure determination of the tosylamidoquinoline derivative [Pt₂(μ-S)₂(PPh₃)₄Zn(TAQ)]BF₄, which showed a distorted tetrahedral coordination geometry at zinc. Additional examples, containing picolinate, dithiocarbamate, or dithiophosphinate ligands were also synthesized and partly characterized in order to demonstrate a wider range of available derivatives.

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  • Immobilization of [Pt₂(μ-S)₂(PPh₃)₄] on polymeric supports by sulfide alkylation and phosphine exchange reactions

    Ujam, Oguejiofo Theophilus; Devey, Kyle; Henderson, William; Nicholson, Brian K.; Mucalo, Michael R.; Decker, Corry; Hor, T.S. Andy (2013)

    Journal article
    University of Waikato

    The immobilization of the dinuclear platinum(II) sulfido complex [Pt₂(μ-S)₂ (PPh₃)₄] on solid supports has been investigated. Reaction with haloalkyl functionalized polymers [Merrifield's resin (chloromethylated polystyrene), chloropropyl silica, chloropropyl controlled pore glass, and bromopropyl polysiloxane] gives complexes immobilized through alkylation of one of the sulfide ligands, forming a μ-thiolate ligand acting as an anchor to the polymer support, akin to well-established reactions of [Pt₂(μ-S)₂(PPh₃)₄] with molecular alkylating agents. The model complex [Pt₂(μ-S)(μ-SCH₂SiMe₃)(PPh₃)₄]PF₆ was prepared as the first molecular silicon-containing derivative of [Pt₂(μ-S)₂(PPh₃)₄] and was fully characterized by NMR spectroscopy, electrospray ionization-mass spectrometry, and single-crystal X-ray diffraction. Immobilization of [Pt₂(μ-S)₂(PPh₃)₄] by phosphine exchange reactions was also achieved using commercial polystyrene-grafted triphenylphosphine or a new immobilized phosphine [derived by sequential functionalization of Merrifield's resin with a polyether amine and then Ph₂PCH₂OH].

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  • Cycloaurated gold(III) complexes with monoanionic thiourea ligands

    Smith, Tiffany Sharee; Henderson, William; Nicholson, Brian K. (2013-11)

    Journal article
    University of Waikato

    Using a simple one-pot procedure, reaction of cycloaurated gold(III) dihalide complexes [LAuCl₂] (L = 2-benzylpyridyl, 2-anilinopyridyl) with trisubstituted thioureas PhNHC(S)NR₂ (R = Me, Cy) and Me3N in methanol, followed by addition of excess NaBPh₄ gave the salts [Lau{SC(-NR₂)NPh}]⁺BPH₄⁻ containing N,S-chelated thiourea monoanion ligands. The compounds were obtained in good yields, and were characterised by ESI MS, elemental microanalysis and in two cases by X-ray structure determinations. The series of complexes was extended by additional microscale reactions of LAuCl₂ complexes (L = 2-benzylpyridyl, 2-anilinopyridyl, 2-benzoylpyridyl or picolinamide) with a wide range of trisubstituted thioureas, with products identified by ESI MS.

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  • Syntheses and molecular structures of some compounds containing many-atom chains end-capped by tricobalt carbonyl clusters

    Bruce, Michael I.; Zaitseva, Natasha N.; Nicholson, Brian K.; Skelton, Brian W.; White, Allan H. (2008)

    Journal article
    University of Waikato

    Several complexes containing Co₃ carbonyl clusters end-capping carbon chains of various lengths are described. Pd(0)/Cu(I)-catalysed reactions between {Co₃{μ₃-C(Ctriple bond; length of mdashC)₂Au(PPh₃)}(μ-dppm)(CO)₇ and I(Ctriple bond; length of mdashC)₂SiMe₃ or FcCtriple bond; length of mdashCI gave {Co₃{μ₃-C(Ctriple bond; length of mdashC)xR}(μ-dppm)(CO)₇ [x = 4, R = SiMe₃3; x = 3, R = Fc 8]; treatment of 3 with NaOMe and AuCl(PPh₃) gave 4 [x = 4, R = Au(PPh3)]. Related preparations of Co₃{μ₃-C(Ctriple bond; length of mdashC)₂[Ru(PP)Cp′]}(μ-dppm)n(CO)9−2n [PP = (PPh₃)₂, Cp’ = Cp, n = 1, 5; PP = dppe, Cp′ = Cp∗, n = 1, 6; 0, 7] are also described. Syntheses of bis-cluster complexes {Co₃(μ-dppm)(CO)₇}₂(μ-Cx) (x = 14, 12; 16, 9; 18, 11; 26, 10) – the latter being the longest cluster-capped Cx chains so far described – and the mercury-bridged compounds Hg{(Ctriple bond; length of mdashC)xC[Co₃(μ-dppm)(CO)₇]}₂ (x = 1, 13; 2, 14) are reported. The molecular structures of 7, 12, 13 and 14, as well as of Co₃(μ₃-CCtriple bond; length of mdashCSiMe₃)(μ-dppm)(CO)₆(PPh₃) (15) and Co₃{μ₃-CC(O)OEt}(μ-dppm)(CO)₇ (16), are reported.

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  • Preparation and structures of several complexes containing carbon-rich ligands attached to polynuclear metal carbonyls

    Bruce, Michael I.; Gaudio, Maryka; Melino, Giovanni; Zaitseva, Natasha N.; Nicholson, Brian K.; Skelton, Brian W.; White, Allan H. (2008)

    Journal article
    University of Waikato

    Several new gold-containing cluster complexes have been prepared from the reactions of gold alkynyl complexes, L n M-C x -Au(PPh₃), (x = 3, 4, 6) with Ru₃(CO)₁₀(NCMe)₂. The bis-cluster complex 1,4-{AuRu₃(CO)₉(PPh₃)(μ₃-C₂)}₂C₆H₄ was obtained from Ru₃(CO)₁₀(NCMe)₂ and 1,4-{(Ph₃P)Au(C≡C)}₂C₆H₄. The complexes Ru₃(μ-H){μ₃-C₂C≡C[Ru(PP)Cp′]}(CO)₉ [PP = (PPh₃)₂, Cp′ = Cp; PP = dppe, Cp′ = Cp*] were also obtained as minor by-products and synthesised independently from Ru(C≡CC≡CH)(PP)Cp′. A reaction between Co₃{μ₃-CC≡CC≡CAu(PPh₃)}(μ-dppm)(CO)₇ and Ru₃(CO)₁₂ afforded {(Ph₃P)(OC)₉AuRu₃}C≡CC≡CC{Co₃(μ-dppm)(CO)₇} 7. Related complexes AuRu₃{μ₃-C₂C≡[M(CO)₂Tp]}(CO)₉(PPh₃) (M = Mo 8, W 9) were obtained from {Tp(OC)₂M}≡CC≡C{Au(PPh₃)}, while the mixed metal cluster complexes MoM₂(C₂Me)(CO)₈Tp (M = Ru 13, Fe 14) were obtained from M(≡CC≡CSiMe₃)(CO)₂Tp (M = Mo, W) with Fe₂(CO)₉ and Ru₃(CO)₁₂, respectively. Reactions of the Mo carbyne complex with Co₂(LL)(CO)₆ [LL = (CO)₂, μ-dppm] or nickelocene afforded complexes 15–17 in which Co₂ and Ni₂ fragments, respectively, had coordinated to the C≡C triple bond. XRD structural determinations of 7, 8, 14, 16 and {Tp(OC)₂W}≡CC≡CC≡{Co₃(μ-dppm)(CO)₇} (18-W) are reported.

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  • A re-investigation of arsenoacetic acid, (AsCH₂COOH)n

    Nicholson, Brian K.; Wilson, Peter S.; Nancekivell, Adelle (2013)

    Journal article
    University of Waikato

    Detailed spectroscopic data have been obtained for arsonoacetic acid, As(CH₂COOH)O₃H₂, and its barium and sodium salts. The X-ray crystal structure of the free acid is isomorphous with phosphonoacetic acid. Reduction gave the As(I) compound arsenoacetic acid, (AsCH₂COOH)n which was shown by ESI-MS to contain cyclic species based on As–As bonds, with n mainly 3–6. The X-ray crystal structure of the hexamer was determined as the pyridine solvate and shown to have a hexacyclic As₆ ring in a puckered chair conformation, with –CH₂COOH groups in equatorial sites, each H-bonded to a pyridine molecule in the lattice.

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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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  • Rubidium-templated bowl-shaped isopolyoxoantimonates [RbH₁₁˗ₓ(RSb)₁₄O₃₄]ₓ˗ derived from arylstibonic acids

    Nicholson, Brian K.; Clark, Christopher J.; Jameson, Geoffrey B.; Telfer, Shane G. (2013)

    Journal article
    University of Waikato

    Arylstibonic acids, RSbO₃H₂ (R = p-MeC₆H₄- or p-ClC₆H₄-) when neutralised in the presence of Rb⁺ give isopolyoxometalates derived from [RbH₁₁(RSb) ₁₄O₃₄]. The X-ray crystal structures of four examples were determined and all gave the same basic framework with a bowl-shaped Sb14 polyhedron cradling the Rb⁺ in an 11-coordinate embrace. All were further linked into chains in the lattice by an intermolecular interaction involving a second Rb⁺, coordinated to three O atoms of one polyoxometalate and to an aryl group of an adjacent unit via an η⁶ interaction. One example has the same basic structure but with one framework O atom replaced by a Br.

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  • Syntheses and Structural Studies of Several Group 8 Metal Complexes Derived from 1,3-Butadiyne

    Bruce, Michael I.; Cole, Marcus L.; Costuas, Karine; Ellis, Benjamin G.; Kramarczuk, Kathy A.; Lapinte, Claude; Nicholson, Brian K.; Perkins, Gary J.; Skelton, Brian W.; White, Allan H.; Zaitseva, Natasha N. (2013)

    Journal article
    University of Waikato

    As part of an extensive investigation into the chemistry of complexes containing metal-ligand centers linked by chains of C(sp) atoms, the preparation, characterization, and single-crystal X-ray diffraction molecular structure determinations of four complexes {MLn}-C≡CC≡C-{M’L’m} [MLn = Ru(dppe)Cp*, M’L’m = Fe(dppp)Cp* (1), Ru(dppe)Cp* (2), MLn = M’L’m = Os(PPh₃)₂Cp (3)], and {Cp*(dppe)Ru}C≡CC≡C{trans-RuCl(dppe) ₂} (4), in which the alternating C(sp)–C(sp) bonds have values between 1.375 and 1.40 Å (single) and between 1.20 and 1.259 Å (triple), respectively, are described. In addition, a structure determination of Ru₃(μ-H){μ3-C2C≡C[Ru(PPh₃)₂Cp]}(CO)₉ (5) shows that the C2 fragment attached to the HRu3 cluster shows the expected lengthening [to 1.311(7) Å] and bending at the two carbon atoms [to 152.6(6) and 157.6(5)°] (resulting from back-bonding from the Ru3 cluster into the C≡C π* orbitals) compared with the essentially linear Ru–CC– moiety [C≡C 1.222(6) Å, angles at C of 178.0(5), 172.3(6)°].

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  • Some Ruthenium Derivatives of Penta-1,4-diyn-3-one

    Bruce, Michael I.; Burgun, Alexandre; Fox, Mark A.; Jevric, Martyn; Low, Paul J.; Nicholson, Brian K.; Parker, Christian R.; Skelton, Brian W.; White, Allan H.; Zaitseva, Natasha N. (2013)

    Journal article
    University of Waikato

    The reaction between Ru(C≡CH)(dppe)Cp* (1) and oxalyl chloride affords ({Ru(dppe)Cp*}C≡C)₂CO (2) in 72% yield. Methylation (MeOTf) of 2 occurs first on the carbonyl oxygen, affording [({Ru(dppe)Cp*}C≡C)2C(OMe)]OTf ([3]OTf). A second methylation of [3]⁺ on the alkynyl Cβ proceeds slowly, affording [{Cp*(dppe)Ru}CCMeC(OMe)CC{Ru(dppe)Cp*}][OTf]₂ ([4][OTf]₂), whereas protonation of [3]+ occurs readily to give crystallographically characterized [{Cp*(dppe)Ru}CCHC(OMe)CC{Ru(dppe)Cp*}][OTf]₂ ([5][OTf]₂). The molecular structures of [3]OTf and [5][OTf]2 suggest that polarization by the CO group results in significant contributions from the alkynyl-allenylidene or alkynyl-carbyne mesomers, respectively. Reaction of 2 in refluxing MeOH containing [NH4]PF6 results in partial methanolysis to give Ru{C≡CC(O)CH═CH(OMe)}(dppe)Cp* (6). Knövenagel condensation of 2 with CH₂(CN)₂ affords {[Ru(dppe)Cp*]C≡C}₂C═C(CN) ₂ (7). The related asymmetric complex {Cp*(dppe)Ru}C≡C[C═C(CN)₂]C≡CC≡C{Ru(dppe)Cp*} (8) was obtained from the reaction between Ru{C≡CC(CN)═C(CN)₂}(dppe)Cp* and lithiated Ru(C≡CC≡CH)(dppe)Cp*. Single-crystal structural determinations of 2, [3]OTf, [5][OTf]₂, 6, 7, and 8 are reported, together with a supporting computational study of relevant electronic structures.

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  • A zwitterionic monoalkylated derivative of [Pt₂(μ-S)₂(PPh₃)₄] from 1,3-propanesultone

    Ujam, Oguejiofo Theophilus; Henderson, William; Nicholson, Brian K. (2013)

    Journal article
    University of Waikato

    Reaction of dinuclear platinum(II) sulfido complex [Pt₂(μ-S)₂(PPh₃)₄] with 1,3-propanesultone gives the novel zwitterionic monoalkylated thiolate complex [Pt₂(μ-S){μ-S(CH₂)₃SO₃}•(PPh₃)₄], which was characterized by NMR spectroscopy, electrospray ionisation mass spectrometry, and a single crystal X-ray structure determination. Crystals are monoclinic, space group P2(1)/c with unit cell dimensions a = 16.8957(3) Å, b = 15.5031(3) Å, c = 28.0121(5) Å, β = 99.780(1)°, for Z = 4.

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  • Crystal structure models for the Aldaramide Units of Poly(pentaramides)

    Hinton, Michael R.; Nicholson, Brian K.; Manley-Harris, Merilyn; Hardcastle, Kenneth I.; Kiely, Donald E. (2013)

    Journal article
    University of Waikato

    The X-ray crystal structures of seven structurally related diamides, N,N′-dihexyl- and N,N′-dimethylglutaramide, N,N′-dimethylxylaramide, N,N′-dimethyl-l-arabinaramide, N,N′-dimethylribaramide monohydrate, 2,3,4-tri-O-acetyl-N,N′-dimethylxylaramide, and 2,3,4-tri-O-acetyl-N,N′-dimethyl-l-arabinaramide, were determined. These diamides were chosen as solid-state conformational models for the diamido repeating units of the corresponding polyamides. Solid-state conformations of the two N,N-dialkyglutaramides, with no pendant groups, were compared to those of their stereochemically different trihydroxy derivatives N,N′-dimethylxylaramide, l-arabinaramide and ribaramide, and the two aforementioned tri-O-acetylpentaramides.

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  • Isopolyoxometalates derived from arylstibonic acids with "reverse-Keggin ion" structures based on [M(RSb) ₁₂O ₂₈] cores, M = Co(ii) or Zn(ii).

    Nicholson, Brian K.; Clark, Christopher J.; Telfer, Shane G.; Groutso, Tania (2012)

    Journal article
    University of Waikato

    The preparations and structures are described of four new polyoxostibonates, [Co(p-MeC ₆H ₄Sb) ₁₂O ₂₈{Co(H ₂O) ₃} ₄]Cl ₂₋ 6H ₂O, [Co(p-ClC ₆H ₄Sb)₁₂O ₂₈{Co(H ₂O) ₃} ₄]Cl₂₋ 22H ₂O, (PhCH ₂NMe ₃) ₂[Zn(p-ClC ₆H ₄Sb) ₁₂O ₂₈Zn ₄Cl₂•₅₄ Br ₁•₄₆]•8MeCN•H ₂O and [BaCoH ₄(p-MeC ₆H ₄Sb)O ₂₈] •5H₂O. Each of these has a framework of 12 (RSb) groups linked by 28 O atoms, with one transition metal ion in a tetrahedral site in the centre. Other metal ions are coordinated to the polyhedral faces. Three of the complexes have the ε Keggin ion geometry, while the fourth is a δ isomer.

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  • Synthesis and structure of a dimeric, anionic thioglycolate derivative of manganese carbonyl

    Dai, Yuan; Nicholson, Brian K. (2012)

    Journal article
    University of Waikato

    The thioglycolate anion reacts with BrMn(CO)5 to form a dimeric complex with bridging sulfur atoms of formula [Mn ₂(thioglycolate) ₂ (CO) ₆] ²⁻. This was isolated as the Et ₃NH ⁺ salt and fully characterized for comparison with the previously reported thiosalicylate analogue.

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  • Platinum(II) complexes containing the 3,3-dimethylglutarimidate ligand

    Nair, Ashwin Gopalan; Ujam, Oguejiofo Theophilus; Lane, Joseph R.; Henderson, William; Nicholson, Brian K. (2012)

    Journal article
    University of Waikato

    Reaction of cis-[PtCl ₂(PPh ₃) ₂] with excess 3,3-dimethylglutarimide (dmgH) and sodium chloride in refluxing methanol gives the mono-imidate complex cis-[PtCl(dmg)(PPh ₃) ₂], which was structurally characterized. The plane of the imidate ligand is approximately perpendicular to the platinum coordination plane which, coupled with restricted rotation about the Pt-N bond, results in inequivalent methyl groups and CH2 protons of the dmg ligand in the room temperature ¹H NMR spectrum. These observations were corroborated by a theoretical study using density functional theory methods. The analogous bromide complex cis-[PtBr(dmg)(PPh ₃) ₂] can be prepared by replacing NaCl with NaBr in the reaction mixture.

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  • A novel structural rearrangement reaction of dialkylated derivatives of [Pt ₂ (μ-S) ₂ (PPh ₃) ₄] involving Pt-C bond formation

    Ujam, Oguejiofo Theophilus; Devoy, Sarah M.; Henderson, William; Nicholson, Brian K.; Hor, T.S. Andy (2012)

    Journal article
    University of Waikato

    Reaction of [Pt ₂ (μ-S) ₂ (PPh ₃) ₄] with the dialkylating agents ClCH ₂ C(O)CH ₂ Cl or ClCH ₂ C(NNHC(O)NH ₂)CH ₂ Cl gives the dicationic di-μ-thiolate complexes [Pt ₂ {μ-SCH ₂ C(O)CH ₂ S)(PPh ₃) ₄] ²⁺ or [Pt ₂ {μ-SCH ₂ C(NNHC(O)NH ₂)CH ₂ S} (PPh ₃) ₄] ²⁺, isolated as BPh ₄ ⁻ salts and characterised by ESI mass spectrometry, NMR spectroscopy and single-crystal X-ray crystallography. Treatment of the complex [Pt 2{μ-SCH 2C(O)CH 2S)(PPh₃) ₄] ²⁺, which contains a [6.6.4] bicyclic system, with hydroxide ions results in deprotonation of a CH 2 group and rearrangement of the resulting monocation, giving [Pt ₂ (μ-SCH ₂ C(O)CHS}(PPh ₃) ₄] ⁺, isolated as its PF ₆ ⁻ salt. An X-ray structure determination shows the complex to have a novel rearranged [6.5.5] bicyclic system containing a Pt-S-Pt-S-C five-membered ring with a Pt-C bond. The alkyl ligand has a high trans-influence, manifest in a long trans Pt-P bond and small 1J(PtP) coupling constant to the trans PPh 3 ligand. Reaction of [Pt ₂ (μ-S) ₂ (PPh ₃) ₄] with the 2,4-dinitrophenylhydrazone derivative of 1,3-dichloroacetone leads to the closely related complex [Pt ₂ {μ-SCH ₂ C(NNHAr)CHS} (PPh ₃) ₃Cl] [Ar = C ₆H ₃ (NO ₂) ₂] in which a PPh ₃ ligand is substituted by a chloride.

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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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  • An orthomanganation route to 2-substituted derivatives of N-methyl-1,8-naphthalimide

    Nicholson, Brian K.; Crosby, Paul M.; Maunsell, Kieran R.; Wyllie, Megan J. (2012)

    Journal article
    University of Waikato

    N-methyl naphthalimide can be readily cyclomanganated at the 2-position, directed by the adjacent amide O atom. Di-cyclomanganation also occurs readily to attach Mn(CO)₄ groups at both 2, 7 positions. An X-ray structure determination of the mono-substituted example confirmed the five-membered metallocyclic ring. Cleavage of the Mn–C bond by HgCl₂ or ICl generates 2-substituted HgCl or I derivatives respectively. Reaction of the mono-cyclomanganated N-methyl naphthalimide with phenylacetylene gives an (η⁵-cyclohexadienyl)Mn(CO)₃ complex where the cyclohexadienyl ring has formed by two PhCCH adding in a formal [2 + 2 + 2] process across the C(1)–C(2) bond of the naphthalimide, breaking the aromaticity of the naphthalene ring as shown by a single crystal structure determination.

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