142 results for Nicholson, Brian K., Journal article

  • New ruthenium carbonyl clusters containing unusual 5-sulfido-, 4-benzyne-, and thianthrene-derived ligands: Insertion of ruthenium into the thianthrene ring by C-S activation

    Hassan, Mohammad R.; Kabir, Shariff E.; Nicholson, Brian K.; Nordlander, Ebbe; Uddin, Md. Nazim (2007-07-01)

    Journal article
    University of Waikato

    Treatment of [Ru3(CO)12] with thianthrene in refluxing toluene afforded [( 4-S)Ru4( -CO)2(CO)9( 4- 2-C6H4)] (1), [( 5-S)Ru6( -CO)2(CO)15( - 3-C12H8S)] (2), and [( 5-S)Ru5( -CO)2(CO)11( - 3-C12H8S)( 4- 2-C6H4)] (3) in 18%, 8%, and 16% yields, respectively. Thermolysis of 2 in refluxing heptane gave compounds 1 and 3. A similar thermolysis of 3 in refluxing toluene gave 1 in 90% yield. Treatment of 3 with neat MeCN afforded the labile compound [( 5-S)Ru5( -CO)2(CO)10( - 3-C12H8S)( 4- 2-C6H4)(MeCN)] (4) in 73% yield. The reaction of 4 with P(OMe)3 gave the substitution product [( 5-S)Ru5( -CO)2(CO)10( - 3-C12H8S)( 4- 2-C6H4){P(OMe)3}] (5) in 52% yield. Compounds 1-4 have been structurally characterized. Compound 1 contains a 4-capping sulfido and a 4- 2-benzyne ligand, whereas 3, 4, and 5 contain 5-sulfido and 4- 2-benzyne ligands. The latter three compounds provide rare examples of 5-sulfido and metal-assisted opening of the thianthrene ligand on polynuclear centers. In compounds 1, 3, and 4 the 4- 2-benzyne ligand is perpendicular to the Ru4 face of the clusters and represents a previously uncharacterized bonding mode for benzyne.

    View record details
  • β-Cyclomanganated 1,5-diphenylpenta-1,4-dien-3-ones and their reactions with alkynes: routes to η5-pyranyl--- and η5-oxocycloheptadienyl---Mn(CO)3 complexes

    Tully, Warren; Main, Lyndsay; Nicholson, Brian K. (2001-08-01)

    Journal article
    University of Waikato

    1,5-Diphenylpenta-1,4-dien-3-ones (4) are cyclometalated with benzylpentacarbonylmanganese to form [[1-phenyl-2-((E)-3-phenylprop-2-en-1-oyl-κO)]ethenyl-κC1]tetracarbonylmanganese derivatives (5). Coupling of 5 with alkynes in some cases gives [4-phenyl-2-(2-phenylethenyl)pyranyl-η5]tricarbonylmanganese complexes (6) analogous to those previously reported for β-manganated chalcones, but in other cases an alternative cyclisation pathway subsequent to insertion of alkyne into the C---Mn bond leads to [6-oxo-4,7-diphenylcyclohepta-1,4-dienyl-1,2,3,4,5-η]tricarbonylmanganese complexes (7). The X-ray crystal structure determination is reported for one such compound, [6-oxo-2,4,7-triphenylcyclohepta-1,4-dienyl-1,2,3,4,5-η]tricarbonylmanganese (7a), derived from 1,5-diphenylpenta-1,4-dien-3-one and phenylacetylene. The 7-phenyl group is found to occupy the endo position, and a mechanism involving Mn-mediated aryl migration is suggested to explain this stereochemistry. The reaction of 7a with ammonium cerium(IV) nitrate gives a low yield of 2-nitro-3,5,7-triphenylcyclohepta-2,4,6-trien-1-one (9), whose structure was established by X-ray crystal structure analysis. The pyranyl complexes (6) provide the corresponding pyrylium triiodide salts (8) when demetalated with iodine.

    View record details
  • 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.

    View record details
  • Cluster Chemistry : XVII.Radical ion-initiated synthesis of ruthenium cluster carbonyls containing tertiary phosphines, phosphites, arsines, SbPh₃, or isocyanides

    Bruce, Michael I.; Matisons, Janis G.; Nicholson, Brian K. (1983)

    Journal article
    University of Waikato

    The syntheses of over sixty known and new derivatives of Ru₃(CO)₁₂ and H₄Ru₄(CO)₁₂ by substitution reactions initiated by sodium diphenylketyl are described. The range of ligands studied includes isocyanides, tertiary phosphines and phosphites, tertiary arsines and SbPh₃. The reactions are characterised by high degrees of specificity and conversion: under mild conditions up to four ligands can be introduced. Comparisons with the corresponding thermally induced reactions are made in several cases. The reactions provide routes to mixed ligand derivatives of the cluster carbonyls, although account of relative Lewis base strengths of the ligands may have to be taken. Possible mechanisms of these reactions are discussed briefly, as are the IR ν (CO) spectra of the Ru₃ (CO)12-nLn complexes.

    View record details
  • Preparation and the crystal and molecular structure of [Net₄][Ge{Co₂(CO)₇}{Co₂(CO)₆[HgCo(CO)₄]}]: an anion containing a mercury-bridged cobalt–cobalt bond

    Duffy, D. Neil; Mackay, Kenneth M.; Nicholson, Brian K.; Robinson, Ward T. (1981)

    Journal article
    University of Waikato

    The title compound has been isolated from the reaction of Gel4 with Na[Co(CO)₄] in the presence of Hg and has been characterised by X-ray analysis. Crystals are triclinic, a= 12.065(1), b= 17.334(2), c= 9.222(1)Å, α= 95.17(3), β= 82.72(3), γ= 96.95(3)°, space group P , and Z= 2. The structure has been solved by direct methods and refined to R= 0.049 for 3 136 reflections [I 5σ(I)]. The anion contains a common Ge atom bridging the Co–Co bonds both of a Co₂(CO)₇ unit and of a Co₂(CO)₆ unit which is also bridged by a HgCo(CO)₄ group.

    View record details
  • Transition metal carbonyl derivatives of the germanes: XIV. Studies of mixed cobalt carbonyl/manganese carbonyl substituted germanes including [(CO)₅MnGeCo₃(CO)₉], μ₃-(pentacarbonylmanganesegermylidyne)cyclotris(tricarbonylcobalt)(3Co---Co)

    Christie, Judy A.; Duffy, D. Neil; Mackay, Kenneth M.; Nicholson, Brian K. (1982)

    Journal article
    University of Waikato

    [Mn(CO)₅GeH₃] reacts smoothly with Co₂(CO)₈ to form the [(CO)₅MnGeCo₃(CO)₉], which is also produced by the reaction of Mn(CO)₅⁻ with [(CO)₄CoGeCo₃(CO)₉]. [Mn(CO)₅GeMeH₂] similarly reacts with Co₂(CO)₈ to give [{Mn(CO)₅} {Co₂(CO)₇}GeMe]. The products were characterised spectroscopically and the ESR spectrum of the radical ion of the title compound is presented.

    View record details
  • Anionic germanium polycobalt carbonyl clusters. Part 3. Preparation and structures of [Net₄][Ge₂Co₇(CO)₂₁] and [Net₄][Ge{Co₇(CO)₂₀}]; two large clusters incorporating tetrahedral GeCo₃ units

    Duffy, D. Neil; Mackay, Kenneth M.; Nicholson, Brian K.; Thomson, Ralph A. (1982)

    Journal article
    University of Waikato

    Reactions of the [Ge{Co₅(CO)₁₆}]⁻ cluster have given rise to two new germanium–polycobalt cluster anions, characterised as their Net₄⁺ salts by X-ray crystallography. The complex [NEt₄][Ge₂Co₇(CO)₂₁](1a) forms triclinic crystals, space group P , with a= 13.085(2), b= 19.712(7). c= 12.220(8)Å, α= 109.10(3), β= 92.60(2), γ= 129.32(3)°, and Z= 2. The structure was solved by direct methods and refined to R=R′= 0.046 for 2 076 reflections with l > 3σ(l). The anion (1) consists of two –GeCo₃(CO)₉ units bonded mutually trans about a trigonal planar Co(CO)₃ group, giving idealised C3v, symmetry. For [Net₄][Ge{Co₇(CO)₂₀}](2a). crystals are monoclinic, space group P21/c, with a= l2.761(7), b= 18.415(3), c= 17.675(4)Å, β= 102.91(3)°, and Z= 4. The structure was refined to R= 0.077, R′= 0.074, for 1 123 reflections with I > 2σ(I). The anion (2) is a derivative of the C3v structure of [Co₄(CO)₁₂] with the axial carbonyl ligand of one basal cobalt replaced by a –GeCo₃-(CO)₉⁻ fragment. The Co4 tetrahedron is disordered.

    View record details
  • Anionic germanium polycobalt carbonyl clusters. Part 2. Preparation and structure of [Net₄][Ge{Co₅(CO)₁₆}], a cluster which contains five-co-ordinate germanium

    Croft, Rex A.; Duffy, D. Neil; Nicholson, Brian K. (1982)

    Journal article
    University of Waikato

    Addition of [Co(CO)₄]⁻ to [Ge{Co₄(CO)n}](n= 16, 14, or 13) under mild conditions gives good yields of [Ge{Co₅(CO)₁₆}]⁻. This forms crystals with Net₄⁺ which are orthorhombic, space group Pn2₁ a with a= 12.014(1), b= 36.938(4), c= 15.249(2), and Z= 8. The crystal structure was solved by direct methods and refined, with some difficulty due to pseudo-symmetry, to R= 0.088, R′= 0.081, for 1 590 unique reflections with F² > 2σ(F²). The anion has a GeCo₅ metal skeleton consisting of a GeCo₂ triangle and a GeCo₃ tetrahedron sharing a common apex at Ge. The five Ge–Co bond lengths vary from 2.33 to 2.51 Å. Three of the CO ligands on the GeCo₃ unit bridge the three Co–Co bonds, with two terminal CO groups on each Co atom. On the GeCo₂ moiety there are six terminal and one bridging carbonyls.

    View record details
  • 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.

    View record details
  • 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.

    View record details
  • Reactivity, structure and electrospray mass spectrometry of pentafluoro- and pentachloro-phenoxy-substituted cyclotriphosphazenes

    Depree, Craig V.; Ainscough, Eric W.; Brodie, Andrew M.; Burrell, Anthony K.; Lensink, Cornelis; Nicholson, Brian K. (2000-09-01)

    Journal article
    University of Waikato

    The reaction of N3P3Cl6 with the sodium salts of pentachloro- and pentafluorophenol, has been investigated. In contrast to the non-geminal substitution typified by other RO− nucleophiles, the regiochemistry of the reaction of C6X5O− (X=Cl and F) with N3P3Cl6 is dominated by geminal substitution. The reaction of C6Cl5O− with N3P3Cl6 in refluxing tetrahydrofuran yielded gem-N3P3Cl2(OC6Cl5)4 (1) as the major product. The fully substituted derivative N3P3(OC6Cl5)6 (2) was attained in low yield from reaction in refluxing diglyme. In contrast, the reaction of C6F5O− with N3P3Cl6 in refluxing tetrahydrofuran yielded the fully substituted product N3P3(OC6F5)6 (3) after approximately 4 h. 31P NMR spectral results suggest the C6F5O− ion may be attacking in a 'random' fashion at low degrees of substitution, which is largely replaced by an electronic geminal-directing effect at tetrasubstitution. Single crystal X-ray crystallographic analyses have been carried out on compounds 1 and 3. Electrospray mass spectrometry has been evaluated as a general technique for characterizing cyclotriphosphazenes, N3P3R6. If R=OEt or OPh, good positive ion spectra are observed but, in contrast, if R is more strongly electron withdrawing (Cl, C6Cl5O or C6F5O) negative ion spectra are obtained.

    View record details
  • Reversible pyranyl complex formation and the mechanism of rearrangement to (η5-6-oxocycloheptadienyl)Mn(CO)3 complexes in the reaction of β-cyclomanganated 1,5-diarylpenta-1,4-dien-3-ones and alkynes; the crystal structure of [2,4-diphenyl-6-(2-phenylethenyl)pyranyl-η5]tricarbonylmanganese

    Mace, Wade; Main, Lyndsay; Nicholson, Brian K. (2005-07-01)

    Journal article
    University of Waikato

    1-Phenyl-2-[(E)-3-phenylprop-2-en-1-oyl-κO]ethenyl-κC1]tetracarbonylmanganese (1a) reacts with PhCCH in CCl4 at room temperature to form [2,4-diphenyl-6-(2-phenylethenyl)pyranyl-η5]tricarbonylmanganese (2a), whose X-ray crystal structure is reported to complement that of its isomer [6-oxo-2,4,7-triphenylcyclohepta-1,4-dienyl-1,2,3,4,5-η]tricarbonylmanganese (3a), previously obtained from the reaction under reflux; but for 1a and PhCCPh the pyranyl complex cannot be isolated before rearrangement to the 3a analogue occurs. More forcing reaction conditions for 1a with Me3SiCCH and for [1-(2-trifluoromethylphenyl)-2-[(E)-3-(2-trifluoromethylphenyl)prop-2-en-1-oyl-κO]ethenyl-κC1]tetracarbonylmanganese (1b) with Me3SiCCH and PhCCH give new analogues of 3a where previously only 2a analogues had been isolated. The reaction in CCl4 under reflux of PhCCH and the β-deuterio analogue of 1a, [1-phenyl-2-[(E)-3-phenylprop-2-en-1-oyl-3d-κO]ethenyl-κC1]tetracarbonylmanganese, gave deuteriated 3a with exo-D at the α-carbon, C7. This is inconsistent with the Mn-mediated Ph migration mechanism originally proposed to accommodate the endo position of Ph in 3a, and instead it implicates a cyclopropyl carbonyl-addition intermediate or a cyclopropyl acyl-substitution transition state in the key rearrangement step for 2a → 3a.

    View record details
  • New complexes with M-Si-O or M-Si-S linkages (M = Fe or Co)

    McIndoe, J. Scott; Nicholson, Brian K. (2002-01-01)

    Journal article
    University of Waikato

    Ph2XSiFe(CO)2Cp [X = p-tolylS (1a), MeO (1b)] and Ph[2-MeOC6H4]XSiFe(CO)2Cp [X = Cl (2a), OMe (2b)] have been fully characterised, including X-ray crystal structure determinations for 1a, 1b and 2a. None of the examples showed any tendency for migration of the X groups from silicon to iron, with elimination of silylene. However very ready loss of the X groups was seen in the electrospray mass spectra, suggesting formation of the cationic silylene-iron complex ions is favoured. This was especially so for 2a and 2b, where intramolecular stabilisation of the silicon centre from the 2-OMe group is possible.The stable siloxane O[SiPh2{Co(CO)4}]2 was also characterised; the X-ray crystal structure analysis shows a Si-O-Si bond angle of 153°.

    View record details
  • Characterisation of the first authenticated organomercury hydroxide, 4-Me₂NC₆H₄HgOH

    Nicholson, Brian K.; Whitley, Sam K. (2004-01-01)

    Journal article
    University of Waikato

    4-Me₂NC₆H₄HgOH was prepared from 4-Me₂NC₆H₄HgOAc. Full characterisation showed that it crystallises as discrete molecules, the first example of a true organomercury hydroxide in the solid state. The structures of 4-Me₂NC₆H₄HgOAc and (4-Me₂NC₆H₄)₂Hg are also discussed. 4-Me₂NC₆H₄HgOH has been characterised spectroscopically and crystallographically as a true organomercury hydroxide.

    View record details
  • Isonitrile substitution reactions of Co₄(μ₄-SiR)₂(CO)₁₁ clusters and the structure of Co₄(μ₄-SiC₆H₄OMe)₂(CO)₇(XyNC)₄

    Evans, Cameron; Nicholson, Brian K. (2003-01-01)

    Journal article
    University of Waikato

    The substitution of carbonyl ligands by isonitriles on Co₄(μ₄-SiC₆H₄R)₂(CO)₁₁ (R=H, OMe, NMe₂) clusters has been examined. The reactions could be monitored by electrospray ionisation mass spectrometry, identifying the substituted products as either protonated [M+H]⁺ (R=NMe₂) or oxidised [M]⁺ (R=H, OMe) ions. Evidence for substitution of up to nine carbonyl ligands was found and the structure of tetra-substituted example, Co₄(μ₄-SiC₆H₄OMe)₂(CO)₇(XyNC)₄, was determined.

    View record details
  • Alkynyl and poly-ynyl derivatives of carbon-tricobalt clusters

    Antonova, Alla B.; Bruce, Michael I.; Humphrey, Paul A.; Gaudio, Maryka; Nicholson, Brian K.; Scoleri, Nancy; Skelton, Brian W.; White, Allan H.; Zaitseva, Natasha N. (2006-04-01)

    Journal article
    University of Waikato

    A series of alkynyl-tricobalt carbonyl clusters, Co₃(μ₃-CnR)(μ-dppm)(CO)₇ [R = But, Ph, C₆H₄I, C₆H₄C≡CPh, SiMe₃, Fc, Au(PPh₃)] containing three, five or seven carbons in the chain, have been prepared by elimination of phosphine–gold(I) halides in reactions between Co₃(μ₃-CBr)(μ-dppm)(CO)₇ and Au(C≡CR)(PPh₃) or between Co₃{μ₃-CC≡CAu(PR₃)} (μ-dppm)(CO)₇ (R = Ph, tol) and IC≡CR′ (R′ = SiMe₃, Fc). The use of poly-substituted arenes or ferrocenes has enabled preparation of the complexes 1,4-{(OC)₇(μ-dppm)Co₃ (μ₃-CC≡C)}₂C₆H₃X-5 (X = H, Br), 1,3,5-{(OC)₇(μ-dppm)Co₃(μ₃-CC≡C)}₃C₆H₃ and 1,1′-{(OC)₇(μ-dppm)Co₃ (μ₃-CC≡C)}₂Fc′ [Fc′ = Fe(η-C₅H₄-)₂]. The X-ray determined molecular structures of 12 of the complexes are reported.

    View record details
  • Indenols, indenones and (arylcyclohexadienyl)Mn(CO)3 π-complexes from the thermally promoted reactions of alkynes with ortho-Mn(CO)4 aryl ketone, amide, ester and aldehyde derivatives

    Robinson, Nicholas P.; Depree, Gary J.; de Wit, Rene W.; Main, Lyndsay; Nicholson, Brian K. (2005-08-01)

    Journal article
    University of Waikato

    Thermally promoted reactions of a range of alkynes with the orthomanganated acetophenone (η2-2-acetylphenyl)Mn(CO)4 generally give 1H-inden-1-ols in good yield; effects of substituents and solvent on these reactions are reported, along with the crystal structure of 1-methyl-2,3-diphenyl-1H-inden-1-ol. The corresponding orthomanganated benzophenone similarly gives the indenol with diphenylacetylene but by exception, orthomanganated 3-acetylthiophene with phenylacetylene reacts via triple alkyne insertion and cyclisation, shown by crystal structure determination of the π-complex product [(1,2,3,4,5-η)-2-(3-acetylthien-2-yl)-1,3,5-triphenylcyclohexadienyl]tricarbonylmanganese. Corresponding orthomanganated derivatives of N,N-dimethylbenzamide, methyl 3,4,5-trimethoxybenzoate and 4-dimethylaminobenzaldehyde all give indenones with diphenylacetylene, but with (excess) acetylene only the aldehyde gives an indenone, the amide and ester giving instead [(1,2,3,4,5-η)-6-arylcyclohexadienyl]Mn(CO)3 complexes. 1H NMR analysis of these complexes shows H at C6 to be on the same face of the cyclohexadienyl ring as Mn(CO)3 (endo-6-H; exo 6-aryl) as expected from three successive syn additions of alkyne at metallated carbon followed by intramolecular syn addition of alkene in the final cyclisation stage.

    View record details
  • A structural, spectroscopic and theoretical study of the triphenylphosphine chalcogenide complexes of tungsten carbonyl, [W(XPPh3)(CO)5], X=O, S, Se

    Cook, Julian B.; Nicholson, Brian K.; Smith, Derek W. (2004-02-01)

    Journal article
    University of Waikato

    The series [W(XPPh3)(CO)5], X=O, S, Se has been structurally determined by X-ray crystallography and fully characterised spectroscopically to provide data for comparing the bonding of the Ph3PX ligands to the metal. The P-X-W angles are 134.3°, 113.2° and 109.2°, respectively, for X=O, S, Se. The bonding has been analysed using EHMO calculations which suggest that lower P-X-W angles depend on the relative importance of σ-bonding, which in turn depends on the chalcogen in the order X=Se > S > O. The effect is enhanced by lower energies of the metal σ and π orbital energies.

    View record details
  • Manganese carbonyl-mediated reactions of azabutadienes with phenylacetylene, methyl acrylate and other unsaturated molecules

    Mace, Wade; Main, Lyndsay; Nicholson, Brian K.; van de Pas, Daniel J. (2004-08-01)

    Journal article
    University of Waikato

    Reaction of PhCH₂Mn(CO)₅ with l,4-di-aryl-1-aza-1,3-butadienes gave substituted pyrrolinonyl rings which were η⁴-coordinated to a Mn(CO)₃ group. These are formed by intramolecular CO insertion into a (non-isolated) cyclomanganated intermediate, followed by cyclisation. Other unsaturated reagents (PhC≡CH, CH2=CHCOOMe, PhNCO) gave products arising from insertion of these, including a structurally characterised tri-aryl-η⁵-azacyclohexadienyl-Mn(CO)₃ complex from the reaction with the alkyne. PhCH₂Mn(CO)₅ reacts with l,4-di-aryl-1-aza-1,3-butadienes in the presence of unsaturated substrates to give products based on a cyclomanganated intermediate.

    View record details
  • An X-ray absorption spectroscopic study at the mercury LIII edge on phenylmercury(II) oxygen species

    Jackson, Wendy J.; Moen, Arild; Nicholson, Brian K.; Nicholson, David G.; Porter, Keith A. (2000-01-01)

    Journal article
    University of Waikato

    The X-ray absorption spectra of the reference and model compounds HgCl2, PhHgCl, PhHgOAc and [(PhHg)2OH][BF4].H2O have been analysed in both the XANES and EXAFS regions, and the technique was extended to determine the structures of (PhHg)2O, PhHgOH, and the basic salts PhHgOH.PhHgNO3 and PhHgOH.(PhHg)2SO4, which were previously structurally uncharacterised. Results indicate that (PhHg)2O is a molecular species with Hg-O-Hg 135°, while PhHgOH contains the [(PhHg)2OH]+ cation and is better formulated as [(PhHg)2OH]OH. The same cation is also featured in the two basic salts. Electrospray mass spectral studies of PhHgOH in aqueous solutions show that [PhHgOH2]+, [(PhHg)2OH]+ and [(PhHg)3O]+ co-exist in solution in a pH-dependent equilibrium.

    View record details