128 results for Boyd, Peter, Journal article

  • Extending the Range of Neutral N-Donor Ligands Available for Metal Catalysts: N-[1-Alkylpyridin-4(1H)-ylidene]amides in Palladium-Catalyzed Cross-Coupling Reactions

    Boyd, Peter; Wright, Leonard; Zafar, MN (2011-09)

    Journal article
    The University of Auckland Library

    N-[1-Alkylpyridin-4(1H)-ylidene]amides (PYAs) are a new class of easily prepared, neutral N-donor ligands that share some features in common with N-heterocyclic carbenes. They are strongly electron-donating toward metal centers, and a palladium(II) complex of one of these ligands has been shown to successfully catalyze both the Heck-Mizoroki and Suzuki-Miyaura cross-coupling reactions.

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  • Potential antitumor agents. 62. Structure-activity relationships for tricyclic compounds related to the colon tumor active drug 9-oxo-9H-xanthene-4-acetic acid

    Rewcastle, Gordon; Atwell, Graham; Palmer, Brian; Boyd, Peter; Baguley, Bruce; Denny, William (1991)

    Journal article
    The University of Auckland Library

    A series of tricyclic analogues of 9-oxo-9H-xanthene-4-acetic acid have been prepared and evaluated for their ability to cause hemorrhagic necrosis in subcutaneously implanted colon 38 tumors in mice, in an effort to extend the structure - activity relationships for this series. As was found previously with analogues of flavone-8-acetic acid (FAA) (Atwell et al. Anti-Cancer Drug Des. 1989, 4, 161), all electronic modifications of the XAA nucleus led to severe decreases or complete abolition of activity, suggesting narrow structure - activity relationships. Dipole moments for many of the compounds were computed, and the degree to which the molecular dipole moment lay out of the plane of the aromatic part of these molecules was found to be determined largely by the contributions from the acetic acid moiety relative to that from the tricyclic ring system. There did not appear to be any general relationship between the magnitude of the dipole moment and activity. However, for compounds containing the 9-carbonyl functionality, the orientation of the dipole vector may be of significance. In all compounds possessing an ether group peri to the acetic acid side chain, there was a close approach (ca. 2.4 Å) between this and the side chain OH.

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  • Novel coordination in the first tellurium porphyrin complex: Synthesis and crystal structure of [Te(ttp)Cl-2]

    Grubisha, DS; Guzei, IA; Al-Salim, N; Boyd, Peter; Brothers, Penelope; Woo, LK (2001)

    Journal article
    The University of Auckland Library

    Despite the wealth of fundamental and applied research on porphyrin complexes of the metallic elements, non-metal porphyrin complexes have been much less extensively studied.[1] Porphyrin complexes of the groups 13 ± 15 elements are well-established, but as yet no porphyrin complex of any group 16 element is known. ...

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  • SYNTHESIS AND ELECTRONIC CHARACTERIZATION OF DISCRETE BUCKMINSTERFULLERIDE SALTS - C-60(2-) AND C-60(3-)

    BHYRAPPA, P; PAUL, P; STINCHCOMBE, J; Boyd, Peter; REED, CA (1993-11-17)

    Journal article
    The University of Auckland Library

    Exceptional ball-to-ball interactions between fulleride ions are the basis of superconductivity in alkali-metal-doped c60 and of ferromagnetismZ in [TDAE] [C,]. It is therefore of fundamental...

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  • Supramolecular fullerene-porphyrin chemistry. Fullerene complexation by metalated "jaws porphyrin" hosts

    Sun, D; Tham, FS; Reed, CA; Chaker, L; Boyd, Peter (2002)

    Journal article
    The University of Auckland Library

    Porphyrins and fullerenes are spontaneously attracted to each other. This new supramolecular recognition element is explored in discrete, soluble, coordinatively linked porphyrin and metalloporphyrin climers, Jawlike clefts in these bis-porphyrins ar

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  • SYNTHESIS, STRUCTURE AND MAGNETIC-PROPERTIES OF A LINEAR TRIMANGANESE(III,II,III) COMPLEX BRIDGED WITH A (MU-HYDROXO)BIS(MU-ACETATO) UNIT

    KITAJIMA, N; OSAWA, M; IMAI, S; FUJISAWA, K; MOROOKA, Y; HEERWEGH, K; REED, CA; Boyd, Peter (1994-10-12)

    Journal article
    The University of Auckland Library

    A mixed valence trinuclear manganese(II,III,II) complex [Mn3(admtrz)6(OH)2(DMF)2(H2O)2]2(ClO4)10·2(admtrz)·3H2O (1), (admtrz=4-amino-3,5-dimethyl-1,2,4-triazole) with hydroxo and 1,2,4-triazole as bridging ligands has been isolated, and characterized by X-ray crystallography and magnetic susceptibility measurements. In each cation structure, the central Mn(III) ion lies on an inversion center and is bridged to each of the external Mn(II) ions by one OH− anion and two admtrz ligands. Each external Mn(II) ion completes its octahedral surroundings with one admtrz, one DMF and one H2O molecule. Complex 1 exhibits weak antiferromagnetic coupling. Analysis of variable temperature magnetic susceptibility data (4–300 K) according to a Heisenberg model yields a J value of −4.47 cm−1.

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  • BUCKMINSTERFULLERIDE(1-) SALTS - SYNTHESIS, EPR, AND THE JAHN-TELLER DISTORTION OF C-60-

    STINCHCOMBE, J; PENICAUD, A; BHYRAPPA, P; Boyd, Peter; REED, CA (1993-06-16)

    Journal article
    The University of Auckland Library

    Synthetic methods are reported for the isolation of a number of buckminsterfulleride(1-) salts. Counterions include cobaltocenium ion, Na(dibenzo-18-crown-6)+, and bis(N-methylimidazole)(tetraphenylporphinato)tin(IV)2+. The EPR spectrum of C60- in frozen solution shows two unusual features. First, there is a counterion-dependent anisotropy observed at low temperatures. This is ascribed to an ellipsoidal distortion induced by ion pairing. It is consistent with, but not directly ascribable to, a static Jahn-Teller distortion. Second, there are two components to the high-temperature spectrum: the broad essentially Isotropic, major signal and a narrower "spike". The narrower signal is ascribed to thermal population of a low-lying excited state, a natural consequence of the distortion that splits the 2T1u state into closely spaced 2E and 2A states. In contrast to intuition and to ab initio calculations, the 2E state is lowest in most systems studied to date.

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  • Role of phosphine ligands in gold cluster chemistry. Relativistic SCF calculations on Au2 and Au2(PH3)2

    Schwerdtfeger, P; Boyd, Peter (1992)

    Journal article
    The University of Auckland Library

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  • Potential building blocks for molecular ferromagnets: [Mn12O12(O2CPh)16(H2O)4] with a S = 14 ground state

    Boyd, Peter; Li, Q; Vincent, JB; Folting, K; Chang, HR; Streib, WE; Huffman, JC; Christou, G; Hendrickson, DN (1988)

    Journal article
    The University of Auckland Library

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  • SYNTHETIC, STRUCTURAL, AND THEORETICAL-STUDIES ON THE ELECTRON-DEFICIENT CUBANES (RC5H4)4TI4S4, (RC5H4)4V4S4, AND [(RC5H4)4V4S4]+

    DARKWA, J; LOCKEMEYER, JR; Boyd, Peter; RAUCHFUSS, TB; RHEINGOLD, AL (1988-01-06)

    Journal article
    The University of Auckland Library

    Treatment of (MeCp),V,S4 with PBu, gives the electron-deficient (56e) cubane (MeCp),V4S4 (1). Desulfurization of a 1:l mixture of (MeCp),V,S, and Cp2V2S4 gave a mixture of ring-substituted cubanes (MeCp),,Cp,V4S4 ( x = 1-4) while (MeCp),V,S, and Cp2V react to give exclusively (MeCp),Cp2V4S4. Compound 1 has a triplet ( S = 1) ground state, exhibits Curie-Weiss magnetic behavior, and has a well-resolved isotropically shifted 'H NMR spectrum. Cyclic voltammetry (vs Ag/AgCl) established the following redox series: 1+/1 (772 mV), 1/1- (176 mV), and 1-/1*- (-1281 mV). The salt [l](BF,) was prepared by the reaction of 1 and Ph3CBF4. The diamagnetic 52e cubanes (RCp),Ti4S4 (R = Me (2), i-Pr) were prepared from (RCp)TiCI,(THF), and (Me,Si),S. The compounds 1, [1](BF4), and 2 were characterized by single-crystal X-ray diffraction. Compound 1 crystallized in the cubic space group P43n with a = 16.551 ( 3 ) A with Z = 6; 671 unique reflecti_ons were processed to a final R ( F ) = 5.31 (R,(F) = 5.80). Compound [1](BF4) crystallized in the tetragonal space group I4 with a = 10.600 (3) A and c = 12.600 ( 3 ) A with Z = 2; 463 unique reflections were processed to a final R = 6.40 (R,(F) = 6.55). Compound 2 crystallized i n the orthorhombic space group Cmca with a = 1.412 (5), b = 17.293 (6), c = 24.503 ( 9 ) %, with Z = 8; 558 unique reflections were processed to give R = 10.5 (R,(F) = 12.6). 1 and [1]+ are extremely similar structurally; no bond distances differ by more than 0.03 A. The structure of 2 revealed two sets of Ti-Ti distances, four distances of 3.00 %, and two of 2.93 A. Electronic structure calculations of Cp4V4S4 and [Cp4V4S4]+ were performed by the scattered wave-Xa method. The ground-state configuration for the Cp4V4S4 metal bonding orbitals is a,2e4t22. The t2 orbital is predicted to be nonbonding, consistent with the structural results. The bonding i n 1, 1+, and 2 is discussed i n light of recent results from other laboratories

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  • BIS-BENZIMIDAZOLE-APPENDED BINUCLEATING PORPHYRIN LIGANDS - SYNTHESIS, CHARACTERIZATION, AND X-RAY STRUCTURE

    LARSEN, NG; Boyd, Peter; RODGERS, SJ; WUENSCHELL, GE; KOCH, CA; RASMUSSEN, S; TATE, JR; ERLER, BS; REED, CA (1986-10-29)

    Journal article
    The University of Auckland Library

    The synthesis and characterization of some new binucleating tetraarylporphyrin ligands is reported. The potentially most useful example is α,α,5,15-bis[N-(2-methylbenzimidazolyl)acetamidophenyl]-α, α,10,20-bis(pivalamidophenyl)porphine (8). The ligands have two appended benzimidazole arms which are designed to chelate a second metal directly above the porphyrin. The synthetic methodology for obtaining both the 5,15 (i.e., trans) and the 5,10 (i.e., cis) bis-appended ligand from an α, α, α, α,5,10,15,20 tetra-functionalized starting material is described in detail. A key design feature of the ligand system is amenability to single-crystal X-ray structure determination and this is demonstrated with an X-ray structure of a copper(II) complex. Crystal data for CuC74H66N12O4·1.5(diethyl ether)·toluene are the following: monoclinic, C2/c, a = 31.240 (4) Å, b = 16.769 (5) Å, c = 35.199 (4) Å, β = 121.4 (1)°; R = 0.0823, Rw = 0.0826. H bonding between the benzimidazole moieties and the pivalamido pickets is seen to determine the structural disposition of the appendages lying above the porphyrin ring. Iron(III) porphyrin complexes of these new ligands exist in a hydroxo monomer form as well as the familiar μ-oxo dimer form.

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  • Relativistic effects in gold chemistry. 3. Gold(I) complexes

    Schwerdtfeger, P; Boyd, Peter; Burrell, AK; Robinson, WT; Taylor, MJ (1990)

    Journal article
    The University of Auckland Library

    Geometry-optimized Hartree-Fock (HF) calculations have been carried out for the ground-state properties of linear two-coordinated gold(1) complexes, AuLC (L = H, F, CI, Br, I, CN, SCN, CH3, and PH3+), and for AuCH3, AuPH3, AuPH3+, AuCN, and AuSCN by us ing multielectron adjusted nonrelativistic and relativistic pseudopotentials for the gold atom. Configuration interaction calculations have been performed for the gold(]) halide complexes. The relativistic effects in the Au-L bond are analyzed, and the differences from the corresponding Cu-L and Ag-L bonds are explained. The preference of coordination number 2 in Au(1) is strengthened by relativistic effects. I n contrast to singly bonded AuL species ( J . C h e m . P h y s . 1989, 91, 1762), 5d and 6p contributions to t h e Au-L bond are important in Au(1) complexes. The magnitude of these effects is dependent on the elec- tronegativity of the ligand. Relativistic effects increase gold Sd contributions in the Au-L bond, as expected from the relativistic expansion of the A u Sd orbital and the relativistic contraction of the Au 6 s orbital. I n contrast to the diatomics, no significant relativistic bond destabilization was found for the complex halides. Large relativistic bond stabilizations were obtained for A u ( P H ~ ) ~ + and for Au(CN); ( 8 7 and 39 kJ mol-' per Au-L bond at the H F level, respectively), which account for their high stability compared to the analogous copper or silver compounds. The unusually large negative "CI nuclear quadrupole coupling constant in AuCIY compared with CuCIY and AgCI2- is caused by relativistic effects. Relativistic difference density plots are shown for AuH2-, AuFT, and Au(CN)<. AuSCN and Au(SCN)Y are predicted to have a bent Au-S-C conformation. Since structural data on Au(SCN)Y were not available, we have synthesized [ A s P ~ ~ ] A u ( S C N ) ~ and analyzed this compound by infrared and Raman spectroscopy and have determined its structure by single-crystal X-ray diffraction. These studies confirm the calculated nonlinear Au-S-C arrangement of t h e Au(SCN)Y ion.

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  • An SCV-MS-Xα study of the bonding and nuclear quadrupole coupling in oxygen compounds of the halogens

    Bowmaker, Graham; Boyd, Peter (1989)

    Journal article
    The University of Auckland Library

    SCF-MS-Xα calculations of the electronic structure of the oxy-halogen compounds Cl2O, ClO, ClO2, ClO2−, ClO3−, ClO4−, BrO, BrO2, BrO3−, IO3−, and IO4− have been used to investigate the bonding and nuclear quadrupole coupling in these molecules and ions. The halogen d orbital participation in the bonding increases with increasing oxidation number of the halogen atom in the molecule or ion. The inclusion of the halogen d orbitais results in an increase in the principal component of the halogen electric field gradient tensor, but only in some cases this result in improved agreement between the calculated and observed halogen nuclear quadrupole coupling constants. In other cases better agreement is obtained for calculations involving the halogen p orbitais only in the valence shell. Thus the results do not provide unambiguous evidence for the involvement of halogen d orbitais in the bonding. In the case of the ClO3− and BrO3− ions for which 17O quadrupole coupling constants have been reported, the Xα values have been calculated. Agreement between the calculated and observed values is much poorer than for the halogen coupling constants. The results of the calculations have also been used to investigate some of the approximations made in the Townes and Dailey method of analysis of nuclear quadrupole coupling data.

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  • Valence trapping in mixed-valence MnIIMnIII complexes of a macrocyclic binucleating ligand

    Chang, HR; Larsen, SK; Boyd, Peter; Pierpont, CG; Hendrickson, DN (1988)

    Journal article
    The University of Auckland Library

    The electronic structures of two mixed-valence MnMn complexes, [LMnClBr]·HO (2) and [LMnBr]·1/2CHCl (3), and the Mn complex LMnCl (4) are probed. The L ligand is the dianion of the Schiff base condensation of 2 mol of 1,3-diaminopropane and 2 mol of 2,6-diformyl-4-tert-butylphenol. The X-ray structure of complex 4 has been determined by using direct methods to give discrepancy factors of R = 0.0501 and R = 0.0697 for 1884 observed (|F| > 6.0σ|F|) reflections. Complex 4 crystallizes in the triclinic space group P1 with one molecule in a unit cell with dimensions a = 7.270 (1) Å, b = 9.457 (2) Å, c = 12.316 (2) Å, α = 108.36 (1)°, β = 94.92 (1)°, and γ = 99.58 (1)°. The observed and calculated densities are 1.39 (2) and 1.41 g cm, respectively. The L ligand in LMnCl is essentially planar, with the Mn ions displaced by 0.69 Å on either side of the ligand plane. The Mn⋯Mn distance is 3.168 (3) Å. The X-ray structure of complex 2 has been determined by using direct methods to give R = 0.0711 and R = 0.0974 for 1732 observed (|F| > 6.0σ|F|) reflections. Complex 2 crystallizes in the monoclinic space group C2/c with 8 molecules in a unit cell with dimensions a = 21.064 (7) Å, b = 13.559 (4) Å, c = 27.652 (6) Å, and β = 105.51 (2)°. The observed and calculated densities are 1.38 (2) and 1.34 g cm. The structural results for [LMnClBr]·HO show that this complex is valence trapped. The Mn ion has an average Mn-O length of 1.936 (10) Å, while the Mn ion exhibits Mn-O lengths of 2.129 (10) and 2.386 (11) Å. The Mn ion is coordinated axially to two halide ions and is 0.15 Å out of the ligand-atom plane. The Mn ion is displaced 1.25 A from the ligand-atom plane on the opposite side and interacts with one of the halide ions coordinated to the Mn ion. Electrochemical results are presented for LMnX (X = Cl or Br) to show that these complexes have two one-electron oxidation waves at ca. +0.6 and ca. +1.2 V vs NHE. Variable-temperature magnetic susceptibility data are fit to give magnetic exchange parameters of +0.24, -2, and -1 cm for complexes 4, 2, and 3, respectively. Similar EPR data are found for the two mixed-valence complexes. At 7.5 K a glass of 3 gives an X-band spectrum with a broad g = 2 signal and apparent fine structure signals at g = 29.0, 7.4, 5.4, and 4.1. A combination of Orbach relaxation processes involving low-lying spin states and modulation of the g, g values for the ground doublet by strain effects on the magnitude of the isotropic exchange and/or single-ion zero-field splitting are suggested as the origin of the absence of resolution of manganese hyperfine structure in the g = 2 signal. Relatively weak antiferromagnetic interactions are seen for the five known binuclear MnMn complexes, whereas, strong antiferromagnetic interactions are found for the five known binuclear MnMn complexes. The possible causes of this difference in magnitude of exchange interactions are discussed.

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  • An SCF-Xα scattered wave study of the electronic structure and iron quadrupole splitting in the [Fe(MoS4)Cl2]2− ion

    Boyd, Peter (1987-07)

    Journal article
    The University of Auckland Library

    Spin restricted and spin polarised SCF MS-Xα calculations have been performed to investigate the electronic structure and iron nuclear quadrupole coupling tensor of the [Fe(MoS4)Cl2]2− dianion. It is found that both the spin restricted and spin polarised models predict a ground state quintet (S = 2) in agreement with that observed experimentally with similar overall charge distributions. However the calculated quadrupole coupling tensor varies in magnitude and sign between the two calculations. The spin polarised calculation gives values of the quadrupole coupling tensor that agree well both in magnitude, sign, and direction with those reported from single crystal Mössbauer spectroscopy. The principal direction of the electric field gradient tensor is found to be sensitive to the relative occupations of the iron dz2 and dx2-y2 orbitals (which are mixed under C2V symmetry).

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  • SPIN SPIN INTERACTIONS IN POLYNUCLEAR NICKEL(II) COMPLEXES - A LOW-TEMPERATURE SUSCEPTIBILITY AND MAGNETIZATION STUDY OF THE CUBANE TETRANUCLEAR COMPLEX NI4(II)(CYCLOHEXANE-R-1,C-3,C-5-TRIAMINE)4(MU-OH)4(NO3)4.7H2O

    Boyd, Peter; MARTIN, RL; SCHWARZENBACH, G (1988-01-01)

    Journal article
    The University of Auckland Library

    The bulk magnetic susceptibility of the complex Ni4(chta)4(μ-OH)4(NO3)4.7H2O ( chta = cyclohexane-r-1,c-3,c-5-triamine) has been measured over the temperature range from 1.9 to 300 K at a field of 1 T. The observed data were fitted by a Heisenberg exchange model for the susceptibility of a cubane [Ni4II(μ-OH)4]4+ cluster with a single exchange interaction J between each pair of NiII ions for a single ion g value 2.20 and an antiferromagnetic spin-spin coupling parameter 2J = -1.14 cm-1. The bulk magnetization measured at fields of 1 to 5 T in the temperature range from 5 to 1.9 K differed from that calculated from the simple Heisenberg model above. Several possibilities were examined for this deviation including intercluster interactions, single ion zero-field splitting and differing exchange coupling constants between nickel(II) ions in the cluster. This last model was successful in describing the complete set of magnetic data. A comparison with other known oxygen-bridged nickel(II) cubane clusters shows a change from antiferromagnetic to ferromagnetic coupling as the Ni-O-Ni bond angle decreases. It appears that the cubane cluster studied here is in a region very close to the crossover from antiferromagnetic to ferromagnetic coupling between the nickel ions.

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  • Crystal, molecular, and electronic structure of [Ta2Cl 4(μ-Cl)4(PMe3)4]: A metal-metal single bond between eight-co-ordinate tantalum atoms

    Boyd, Peter; Jones, TC; Nielson, AJ; Rickard, CEF (1984)

    Journal article
    The University of Auckland Library

    The crystal structure of the title complex shows an MCl4M bridge across a weak Ta–Ta interaction and eight-fold co-ordination about each metal centre; an electronic structure calculation supports the existence of a σ metal–metal bond.

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  • Electrochemical and ESR studies of the redox reactions of nickel(II), palladium(II), and platinum(II) complexes of 1,2-diphenyl-1,2-ethenedithiolate(2-)-S,S′

    Bowmaker, Graham; Boyd, Peter; Campbell, GK (1983)

    Journal article
    The University of Auckland Library

    The electron spin resonance (ESR) spectra of the one-electron-reduction products of the 1,2-diphenyl- 1,2-ethenedithiolate complexes M(Ph2C2S2)2 (M = Ni, Pd, Pt) support the view that these reductions are mainly ligand based. Dc cyclic voltammetric studies of the above complexes also show an apparently quasi-reversible oxidation process in each case. ESR studies indicate that several species with slightly differing g values are formed in this process under the longer time scale of controlled-potential electrolysis. The 1,2-diphenyl-l,2-ethenedithiolate(2-)-SS' complexes M(dpe)(Ph2C,S2) (M = Ni(II), Pd(II), Pt(I1); dpe = 1,2-bis(diphenylphosphino)ethane) and M(PPh3)2(PhzCzSz) (M = Pd(I1)) were prepared, as described by previous workers, by ligand substitution reactions between the metal dithiolene complexes and the appropriate phosphine ligand. Ni(dpe)(Ph,C2S,) undergoes a reversible one-electron reduction to the corresponding nickel(1) complex and a reversible one-electron oxidation to give a long-lived species that is characterized by ESR spectroscopy as a complex of the previously unknown dithioketyl (PhzC2Sz)-.. The palladium and platinum 1,2-diphenyl-l,2-ethenedithiolate(2-)-S,S'complexes do not undergo reversible reduction but like the above nickel complex undergo reversible oxidation to give dithioketyl complexes.

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  • SCF-MS-Xα study of the bonding and nuclear quadrupole coupling in trihalide ions XY2 - (X = I, Br or Cl; Y = I, Br, Cl or F) and xenon difluoride

    Bowmaker, Graham; Boyd, Peter; Sorrenson, RJ (1984)

    Journal article
    The University of Auckland Library

    SCF-MS-Xα calculations have been carried out on the trihalide ions I–3, IBr–2, ICl–2, Br–3, BrCl–2 and Cl–3 and on XeF2. The nuclear quadrupole coupling constants calculated from the Xα wavefunctions agree well with experimentally determined values. In the case of the X–3 ions (X = Cl, Br or I) calculations have been carried out for unsymmetrical structures as well as for symmetrical D∞h structures, and it is found that the experimentally observed dependence of the quadrupole coupling constants on geometry is well reproduced by the Xα calculations. For D∞h I–3 the valence σ wavefunctions are very similar to those of the three-centre four-electron bonding scheme originally proposed by Pimentel. The bonding involves the valence p orbitals almost exclusively, s and d orbitals being involved to only a limited extent. The unbalanced p-orbital populations calculated for these species from the Xα wavefunctions agree reasonably well with those obtained from nuclear quadrupole coupling data using the Townes and Dailey equations, but systematic differences are observed, particularly for the central halogen atoms. Analysis of the various contributions to the Xα calculated electric field gradients shows that most of the approximations involved in the derivation of the Townes and Dailey equations are justified. However, it is shown that a slight contraction of the π atomic orbitals on the central halogen atoms results in a larger field gradient and quadrupole coupling constant at this atom. This has the consequence that the unbalanced p-orbital populations calculated for the central halogen atoms from the Townes and Dailey equations are systematically too high. Similar calculations have been carried out for the IF–2 ion, which has recently been identified by matrix-isolation infrared spectroscopy. In this case the I 5d orbitals become involved to a greater extent in the bonding, so that the I orbital populations are midway between those expected for the delocalized three-centre four-electron bonding scheme involving p orbitals only and a localized bonding scheme involving pd hybridization on iodine.

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  • Corrole as a binucleating ligand: Preparation, molecular structure and density functional theory study of diboron corroles

    Albrett, AM; Conradie, J; Boyd, Peter; Clark, George; Ghosh, A; Brothers, Penelope (2008)

    Journal article
    The University of Auckland Library

    The reactions of BF3 center dot OEt2 with four triaryl corroles (H3Cor) give the complexes [(B2OF2)(Cor)]- in which the corrole acts as a binucleating ligand. The new complexes were fully characterized, including an X-ray crystal structure of the triphenylcorrole complex. Density functional theory calculations support the observation that the boron atoms coordinate in two dipyrromethene sites in a cisoid geometry on one face of the macrocycle rather than in the alternative dipyrromethene/bipyrrole sites. The UV-visible spectra are insensitive to the corrole substituents, consistent with the lack of low-lying orbitals associated with the coordinated boron atoms.

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