Laurence K. Thompson

Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada

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Publications (198)510.38 Total impact

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    ABSTRACT: Tri-topic pyridine bis-hydrazone ligands produce polynuclear complexes with Fe(II) and Fe(III) salts with varying nuclearity and metal ion oxidation states. Mononuclear, tetranuclear, hexanuclear, and nonanuclear examples are discussed using structural, magnetic and Mössbauer data. In one case, although X-ray data suggest a [3 × 3] Fe9 grid (space group P42/n), careful examination of the structure, in conjunction with magnetic and Mössbauer data, indicates an unusual situation where the corner and center sites are present at unit occupancy, whereas side site occupancy is ∼0.6.
    Inorganic Chemistry 04/2014; · 4.59 Impact Factor
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    ABSTRACT: Reactions of the copper(II)-gadolinium(III) 15-metallacrown-5 complex [GdCu5(Glyha)5(NO3)2(H2O)6](NO3) (Glyha(2-) = dianion of glycinehydroxamic acid) with different di/tricarboxylates (1,3-phthalate, 1,4-phthalate, biphenyl-4,4'-dicarboxylate, citrate) resulted in formation of different types of products: {[(GdCu5(Glyha)5(H2O)2)(GdCu5(Glyha)5(H2O)3)(1,3-bdc)3]·16H2O}n (1), {[(GdCu5(Glyha)5(H2O)3)2(1,4-bdc)2](1,4-bdc)·8H2O}n (2), {[(GdCu5(Glyha)5(H2O)4)2(1,4-bdc)3]·8H2O}n (3), [GdCu5(Glyha)5(Citr)(H2O)4]·7H2O (4), {[GdCu5(Glyha)5(H2O)5](μ2-CO3)[Cu(Fgg)]}·7H2O (5) and [Cu(Gly)2(H2O)]n (6) (where bdc(2-) is the corresponding phthalate (benzenedicarboxylate), Citr(3-) is citrate, Fgg(3-) is the trianion of [(N-formylaminoacetyl)amino]acetic acid and Gly(-) is glycinate). Complexes 1-5 contain the [GdCu5(Glyha)5](3+) cation. Complexes 2 and 3 possess the same composition but differ by the mode of p-phthalate coordination to the [GdCu5(Glyha)5](3+) unit. In compounds 1-3, metallacrown cations are linked by the corresponding phthalates in 1D, 1D and 2D polymers, respectively, whereas 4 and 5 are discrete molecules. Compound 5 is the product of a multistep reaction, which finally involves atmospheric CO2 capture. Hydrolysis of hydroxamate in this reaction is confirmed by isolation of a mononuclear copper glycine complex 6. The χMT vs T data for 1 were fitted using a model based on the Hamiltonian Ĥ (GdCu5) = -2J1(S1 × SGd + S2 × SGd + S3 × SGd + S4 × SGd + S5 × SGd) - 2J2(S1 × S2 + S2 × S3 + S3 × S4 + S4 × S1 + S5 × S1. The best fit corresponded to J1 = +0.60(2) cm(-1), J2 = -61.0(5) cm(-1) and zJ' = -0.035(4) cm(-1). Complex 1 is the first example of a 15-metallacrown-5 system, for which numerical values of exchange parameters have been reported. The isotherm for methanol absorption by compound 1 at 293 K was typical for microporous sorbents, whereas ethanol sorption was negligibly small.
    Inorganic Chemistry 01/2014; · 4.59 Impact Factor
  • Laurence K. Thompson, Louise N. Dawe
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    ABSTRACT: A survey of transition metal and lanthanide clusters involving polytopic hydrazone ligands in the range M3, M4, M6, M9, M12, and M16 will be discussed, with examples of chains, triangles and square [nxn] grids. Magnetic properties are interpreted using fully isotropic models in some cases, and approximations where spin state calculations exceed the computer's capacity to handle the enormous matrices involved. In the case of some Dyn complexes SMM (single molecule magnet) behavior is observed, with relaxation properties interpreted using field and temperature dependent AC measurements.
    Coordination Chemistry Reviews 01/2014; · 11.02 Impact Factor
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    ABSTRACT: Tetranuclear, dinuclear and chain complexes involving some polyfunctional hydrazone and thio-carbohydrazone-based ligands are discussed. Ni(II) and Mn(II) [2 × 2] grids form with μ2-S and μ2-O bridges respectively, and are antiferromagnetically coupled (J = −167(5), −3.59(2) cm−1 respectively). With the Fe(II) based system oxidation to Fe(III) occurs, and a μ2-Ohydrazone bridged dimer results, with antiferromagnetic exchange between the S = 5/2 spin centers (J = −22.5(2) cm−1). In the case of Cu(II) the diazine group acts as a μ2-N–N bridge between Cu(II) centers in two cases involving a tetranuclear and a chain complex. Non-orthogonal bridging through N–N and carboxylate bridges leads to antiferromagnetic exchange in the tetranuclear case (J = −32.7(7), −16.1(7) cm−1 respectively) and ferromagnetic exchange in the chain complex due to orthogonal N–N bridging (J = 3.3(1) cm−1).
    Polyhedron 01/2014; 68:94–102. · 2.05 Impact Factor
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    ABSTRACT: Self-assembly of the Ln(III) ions (Ln = Eu, Gd, Dy, Ho, Yb) into square [2 × 2] grid-like arrays has been readily effected using simple, symmetric ditopic ligands based on a carbohydrazone core. The metal ions are connected via single atom bridges (e.g., μ2-Ohydrazone, μ2-OH, μ2-OMe, μ2-1,1-N3(-), μ4-O), depending on reaction conditions. The Gd(III)4 examples exhibit intramolecular antiferromagnetic exchange (-J < 0.11 cm(-1)), and in one Dy(III)4 example, with a combination of μ2-1,1-N3(-), and μ4-O bridges linking adjacent metal ions, SMM behavior is observed. One thermally driven relaxation process is observed in the temperature range 10-25 K (τ0 = 6.5(1) × 10(-7) s, Ueff = 110(1) K) in the presence of an 1800 Oe external field, employed to suppress a second quantum based relaxation process. The extended group of Ln(III) ions which submit to this controlled self-assembly, typical of the transition metal ions, indicates the general applicability of this approach to the lanthanides. This occurs despite the anticipated limitations based on larger ionic radii and coordination numbers, and is an encouraging sign for extension to larger grids with appropriately chosen polytopic ligands.
    Inorganic Chemistry 05/2013; · 4.59 Impact Factor
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    ABSTRACT: The lanthanide coordination chemistry of a tri-functional vanillin-hydrazone-oxime ligand reveals a variety of different products, depending on reaction conditions, with mono-nuclear (Dy), dinuclear (Yb, Tm), tetranuclear (Gd) and hexanuclear (Gd, Tb, Dy) examples. The Ln6 (Ln = Gd, Dy, Tb) complexes form in the presence of both triethylamine and acetic acid, and have unique, flat hexanuclear structures built on a μ3-O bridged triangular core, with the six lanthanide ions bridged further through μ-acetate and μ-Ohydrazone connections in an expanded fused triangular array. Similar reaction conditions with Yb(iii) and Tm(iii) lead preferentially to dinuclear systems, while in the presence of a competitive benzoate ligand a rectangular Gd4 complex results. Variable temperature DC magnetic data for the Gd(iii) complexes reveal weak antiferromagnetic exchange. AC magnetic data on the other polynuclear complexes down to 2 K, both in the absence and presence of external bias fields, revealed no significant out of phase signals normally indicative of SMM behavior. However, the mononuclear Dy(iii) complex shows frequency dependent AC signals and maxima in the temperature range 2-20 K in the presence of an external bias field, indicative of SMM behaviour, with Ueff = 36(1) K, and τ0 = 4.4(2) × 10(-6) s.
    Dalton Transactions 04/2013; · 3.81 Impact Factor
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    Nicholas M Randell, Laurence K Thompson, Louise N Dawe
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    ABSTRACT: The title compound, C(16)H(16)N(2)O(4)·2CH(3)OH, is a hydrazone in an E geometric arrangement, with an inversion centre at the mid-point of the N-N bond. A symmetry-related pair of six-membered hydrogen-bonded rings [graph-set motif S(1) (1)(6)] are present for the terminal vanillin-imine moieties. Two lattice methanol solvent mol-ecules are present per formula unit (Z' = 1/2), which form hydrogen-bonded chains along [010] with two orientations due to disorder of the methanol H-atom.
    Acta Crystallographica Section E Structure Reports Online 09/2012; 68(Pt 9):o2711. · 0.35 Impact Factor
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    ABSTRACT: High nuclearity [Mn(10)M(2)] clusters have been achieved through a self-assembly approach where multiple coordinating functional groups are incorporated into one ligand. When the hydrazone group appended with an oxime function as a reactive intermediate is used, the attachment of a vanillin subunit creates a ligand (L4) with three coordinating groups, which in their own right lead to cluster assemblies. The trifunctional ligand L4 produces a series of self-assembled, mixed oxidation state (Mn(II)/Mn(III)) Mn(10)M(2) based clusters with an overall linear structure comprising two connected pentanuclear Mn(5) halves, which bind alkali metal cations (M = Li, Na, K, Rb, Cs) and H(3)O(+) in the vanillin (O(6)) end pockets, created by the assembly of three ligands around each Mn(5) subunit. Antiferromagnetic exchange dominates the spin coupling in the Mn(10) complexes, and surface studies on highly oriented pyrolytic graphite (HOPG) clearly show the arrangement of metal ions (Mn, Cs) in the Mn(10)Cs(2) linear cluster assembly.
    Inorganic Chemistry 03/2012; · 4.59 Impact Factor
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    ABSTRACT: Reactions between 2,6-diformyl-4-methylphenol (DFMF) and tris(hydroxymethyl) aminomethane (THMAM = H(3)L2) in the presence of copper(II) salts, CuX(2) (X = CH(3)CO(2)(-), BF(4)(-), ClO(4)(-), Cl(-), NO(3)(-)) and Ni(CH(3)CO(2))(2) or Ni(ClO(4))(2)/NaC(6)H(5)CO(2), sodium azide (NaN(3)), and triethylamine (TEA), in one pot self-assemble giving a coordination polymer consisting of repeating pentanuclear copper(II) clusters {[Cu(2)(H(5)L(2-))(μ-N(3))](2)[Cu(N(3))(4)]·2CH(3)OH}(n) (1) and hexanuclear Ni(II) complexes [Ni(6)(H(3)L1(-))(2)(HL2(2-))(2)(μ-N(3))(4)(CH(3)CO(2))(2)]·6C(3)H(7)NO·C(2)H(5)OH (2) and [Ni(6)(H(3)L1(-))(2)(HL2(2-))(2)(μ-N(3))(4)(C(6)H(5)CO(2))(2)]·3C(3)H(7)NO·3H(2)O·CH(3)OH (3). In 1, H(5)L(2-) and in 2 and 3 H(3)L1(-) and HL2(2-) represent doubly deprotonated, singly deprotonated, and doubly deprotonated Schiff-base ligands H(7)L and H(4)L1 and a tripodal ligand H(3)L2, respectively. 1 has a novel double-stranded ladder-like structure in which [Cu(N(3))(4)](2-) anions link single chains comprised of dinuclear cationic subunits [Cu(2)(H(5)L(2-))(μ-N(3))](+), forming a 3D structure of interconnected ladders through H bonding. Nickel(II) clusters 2 and 3 have very similar neutral hexanuclear cores in which six nickel(II) ions are bonded to two H(4)L1, two H(3)L2, four μ-azido, and two μ-CH(3)CO(2)(-)/μ-C(6)H(5)CO(2)(-) ligands. In each structure two terminal dinickel (Ni(2)) units are connected to the central dinickel unit through four doubly bridging end-on (EO) μ-azido and four triply bridging μ(3)-methoxy bridges organizing into hexanuclear units. In each terminal dinuclear unit two nickel centers are bridged through one μ-phenolate oxygen from H(3)L1(-), one μ(3)-methoxy oxygen from HL2(2-), and one μ-CH(3)CO(2)(-) (2)/μ-C(6)H(5)CO(2)(-) (3) ion. Bulk magnetization measurements on 1 show moderately strong antiferromagnetic coupling within the [Cu(2)] building block (J(1) = -113.5 cm(-1)). Bulk magnetization measurements on 2 and 3 demonstrate that the magnetic interactions are completely dominated by ferromagnetic coupling occurring between Ni(II) ions for all bridges with coupling constants (J(1), J(2), and J(3)) ranging from 2.10 to 14.56 cm(-1) (in the Ĥ = -J(1)(Ŝ(1)Ŝ(2)) - J(1)(Ŝ(2)Ŝ(3)) - J(2)(Ŝ(3)Ŝ(4)) - J(1)(Ŝ(4)Ŝ(5)) - J(1)(Ŝ(5)Ŝ(6)) - J(2)(Ŝ(1)Ŝ(6)) - J(3)(Ŝ(2)Ŝ(6)) - J(3)(Ŝ(2)Ŝ(5)) - J(3)(Ŝ(3)Ŝ(5)) convention).
    Inorganic Chemistry 03/2012; 51(5):3270-82. · 4.59 Impact Factor
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    ABSTRACT: Tritopic pyridinebis(hydrazone)-based ligands typically produce square M(9) [3 × 3] grid complexes with first-row transition-metal ions (e.g., M = Mn, Fe, Co, Cu, Zn), but with larger lanthanide ions, such coordination motifs are not produced, and instead linear trinuclear complexes appear to be a preferred option. The reaction of 2pomp [derived from pyridine-2,6-bis(hydrazone) and 2-acetylpyridine] with La(III), Gd(III), and Dy(III) salts produces helical linear trinuclear [Ln(3)(2pomp)(2)]-based complexes, where each metal ion occupies one of the three tridentate ligand pockets. Two ligands encompass the three metal ions, and internal connections between metal ions occur through μ-O(hydrazone) bridges. Coligands include benzoate, nitrate, and N,N-dimethylformamide. The linear Dy(III)(3) complex exhibits single-molecule magnet behavior, demonstrated through alternating-current susceptibility measurements. Slow thermal magnetic relaxation was detected in an external field of 1800 Oe, where quantum-tunneling effects were suppressed (U(eff) = 14 K).
    Inorganic Chemistry 12/2011; 51(2):1028-34. · 4.59 Impact Factor
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    ABSTRACT: The iron coordination chemistry of some polytopic hydrazone based ligands is examined. The complexes derive from a general self-assembly strategy, where ligand design can be used to devise specific polymetallic [n × n] grid architectures. However, as part of any complex equilibrium process, oligomeric entities can also occur, particularly when ligand tautomeric flexibility is considered, and examples of mononuclear, dinuclear, tetranuclear, and pentanuclear complexes have been observed within a related class of ligands. In addition, ligand site donor composition can lead to coordination spheres that stabilize both high spin Fe(II) and Fe(III) sites, with evidence for Fe(II) spin crossover. Structural and magnetic properties are examined, which reveal the presence of antiferromagnetic exchange in the polynuclear systems.
    Inorganic Chemistry 12/2011; 50(23):12141-54. · 4.59 Impact Factor
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    ABSTRACT: The coordination chemistry of a group of hydrazone-based ligands, modified with carboxylate and heterocyclic terminal donor groups, with MnII and CoII has been investigated. The multifunctional nature of the ligands allows coordinative flexibility based on the hydrazone core, which is well established to lead to spin-coupled polymetallic assemblies through μ-Ohydrazone bridging. Examples of dinuclear, tetranuclear and chain complexes are reported with hydrazone, carboxylate and triazole bridging. Spin exchange through the μ-O and μ-N,N bridging connections leads to antiferromagnetic exchange in most cases, except for the central subunit in the MnII4 chain complex, where small (< 90°) bridge angles result in contributing ferromagnetic interactions.
    Berichte der deutschen chemischen Gesellschaft 11/2011; 2011(32). · 2.94 Impact Factor
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    ABSTRACT: Two lanthanide tetrafluoro-p-phthalate (L(2-)) complexes, Ln(L)(1.5)·DMF·H(2)O (Ln = Pr(3+) (1), Nd(3+) (2)), were synthesized using pyridine as a base. The compounds were found to be isostructural, and the structure of 1 has been determined by single crystal X-ray diffraction (monoclinic, space group C2, a = 22.194(2) Å, b = 11.4347(12) Å, c = 11.7160(12) Å, β = 94.703(2)°, V = 2963.3(5) Å(3), Z = 4). The crystal structure of 1 consists of dinuclear Pr(3+) units, which are connected by tetrafluoro-p-phthalate, forming separate 2D polymeric layers. The Ln(3+) ions in the dinuclear Ln(2) units are linked by two μ-O atoms and by two bridging O-C-O groups. The structure is porous with DMF and water molecules located between layers. Non-coordinated DMF molecules occupy about 27% of the unit cell volume. A systematic analysis of reported structures of Ln(III) polymers with p-phthalate and its derivatives shows that the ca. known 60 structures can be divided into six possible structural types depending on the presence of certain structural motifs. The magnetic properties of compounds 1 and 2 were studied. The dependence of χ(M)T on T (where χ(M) is magnetic susceptibility per dinuclear lanthanide unit) for 1 and 2 was simulated using two different models, based on: (i) the Hamiltonian Ĥ = ΔĴ(z)(2)+ μ(B)g(J)HĴ, which utilises an axial splitting parameter Δ and temperature-independent paramagnetism (tip) and (ii) crystal field splitting. It was found that both models gave satisfactory fits, indicating that the Ln-Ln exchange interactions are small and the symmetry of the coordination environment is the main factor influencing the magnetic properties of these compounds.
    Dalton Transactions 09/2011; 40(41):10989-96. · 3.81 Impact Factor
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    ABSTRACT: Hydrazone ligands modified with benzothiazole and oxime groups produce spin-coupled tetra- (Mn, Ni, Cu), penta- (Co), and hexanuclear (Cu) self-assembled clusters.
    Dalton Transactions 03/2011; 40(17):4623-35. · 3.81 Impact Factor
  • Graham Bullock, Frederick W. Hartstock, Laurence K. Thompson
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    ABSTRACT: Mononuclear and binuclear copper(II) complexes of the potentially tetradentate binucleating ligands 1,4-di(3′-methyl-2′-pyridyl)aminophthalazine (PAP3Me) and 1,4-di(5′-methyl-2′-pyridyl)aminophthalazine (PAP5Me) are reported. In the case of the ligand 1,4-di(4′,6′-dimethyl-2′-pyridyl)aminophthalazine (PAP46DiMe) only binuclear derivatives were obtained. The mononuclear complexes, involving protonated ligand, result from the sensitivity of these ligands to mildly acidic conditions in aqueous solutions of certain copper salts. Binuclear, neutral ligand, complexes are also formed when the pH increases. Hydroxy bridged binuclear structures exist in all the binuclear complexes described with the exception of one acetate bridged derivative. Sub normal magnetic moments are observed for all the binuclear complexes (< 1.74 BM) indicating spin coupled systems with very low values (< 0.88 BM) for binuclear complexes of PAP46DiMe, indicating the possibility of strong antiferromagnetic exchange between the metal centres.
    Canadian Journal of Chemistry 02/2011; 61(1):57-62. · 0.96 Impact Factor
  • Liqin Chen, Laurence K. Thompson, John N. Bridson
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    ABSTRACT: The preparation and properties of the thioether–pyridazine macrocycle (L4; C16H20S6N4) containing two pyridazine subunits, and its Cu(II), Cu(II)Cu(I), and Cu(I) complexes are described. The ligand is characterized by 1H nuclear magnetic resonance and mass spectrometry, and the complexes by infrared, eleetronic spectra, and magnetism, and in some cases by X-ray crystallography. The complex [Cu2(L4)Cl4]x, (1) crystallized in the triclinic system, space group with a = 8.6204(8) Å, b = 9.850(1) Å, c = 8.348(1) Å, α = 111.46(1)°, β = 102.50(1)°, γ = 71.818(9)°, V = 622.6(1) Å3, and Z = 1 (R = 0.043, Rw = 0.042 for 1312 reflections). Two monodentate pyridazine rings in the same ligand bind to one trans square-planar copper centre (CuN2Cl2) with two sulfurs from each ligand binding to another trans square-planar copper centre (CuS2Cl2) to form a polynuclear chain. The complex [Cu(L4)Cl2] (3) crystallized in the triclinic system, space group with a = 11.001(1) Å, b = 12.888(2) Å, c = 8.704(1) Å, α = 102.89(1)°, β = 103.36(1)°,γ = 75.84(1)°, V = 1145.8(3) Å3 and Z = 2 (R = 0.056, Rw = 0.044 for 2059 reflections). A trans square-planar structure (CuN2Cl2) exists for 3 with monodentate pyridazines. [Cu(L4)(NO3)2] (4) crystallized in the orthorhombic system, space group P212121, with a = 15.148(2) Å, b = 15.562(3) Å, c = 11.064(1) Å, V = 2608.2(7) Å3 and Z = 4 (R = 0.039, Rw = 0.034 for 1864 reflections). Two monodentate pyridazine rings and two bidentate nitrates bind to a pseudo-octahedral copper(II) centre.
    Canadian Journal of Chemistry 02/2011; 71(7):1086-1093. · 0.96 Impact Factor
  • Canadian Journal of Chemistry 02/2011; 80(11):1568-1583. · 0.96 Impact Factor
  • Dorothy V. Bautista, John C. Dewan, Laurence K. Thompson
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    ABSTRACT: Mononuclear, binuclear, and trinuclear copper(II) complexes of the tetradentate ligands 1,4-di(2′-pyridyl) aminophthalazine (PAP) and 1,4-di(4′-methyl-2′-pyridyl) aminophthalazine (PAP4Me) and binuclear complexes of the tetradentate ligand 1,4-di(6′-methyl-2′-pyridyl) aminophthalazine (PAP6Me) are reported. In a series of binuclear carboxylate derivatives carboxylate bridges exist between copper centres in all cases and in some cases oxygen bridges (hydroxide or methoxide) are indicated. In all other polynuclear derivatives hydroxide bridges are anticipated on the basis of analytical, spectral, and magnetic data. The ligands exist as anionic groups in some binuclear carboxylate derivatives while in the other polynuclear systems neutral ligands are found. In reactions in aqueous solution protonated mononuclear derivatives are obtained for both PAP and PAP4Me in cases where solutions of the metal salts are inherently acidic, followed by polynuclear, neutral ligand complexes which form when the pH increases. Mononuclear protonated complexes are not obtained with PAP6Me, where steric factors may prevent the formation of such derivatives. Low magnetic moments (1.1–1.5 BM) are observed for most hydroxy bridged complexes while even lower values ( < 0.70 BM ) are observed for two binuclear complexes of PAP6Me, indicating the possibility of strong antiferromagnetic exchange between metal centres. A preliminary X-ray investigation of the complex [Cu2(PAP4Me)(OH)(NO3)2(H2O)2]NO3 indicates a triple bridged binuclear structure including a bidentate nitrate bridge and a hydroxide bridge with an oxygen bridge angle of 115.2°.
    Canadian Journal of Chemistry 02/2011; 60(20):2583-2593. · 0.96 Impact Factor
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    ABSTRACT: Binuclear, antiferromagnetically coupled, macrocyclic copper(II) complexes, [Cu2(C28H32N4O4)]•H2O (II) and [Cu2(C36H32N4O4)]•CH3CN•H2O (III), involving asymmetric ligands with two deprotonated amide, two azomethine nitrogen, and two phenoxide donors at the binuclear centre, have been synthesized and characterized by single-crystal X-ray diffraction and variable temperature magnetic studies. Complex II crystallizes in the monoclinic system, space group P21/n, with a = 16.4854(9) Å, b = 7.6005(13) Å, c = 21.1617(11) Å, β = 104.090(5)°, Z = 4, Rf = 0.068 for 2062 significant reflections. The two copper(II) centres have square planar N2O2 donor sets with two phenoxide oxygen atoms bridging the copper centres with a copper–copper separation of 2.898(2) Å. A long copper–oxygen (amide) contact (2.808(10) Å) forms a weak dimer association. Complex III crystallizes in the triclinic system, space group , with a = 8.7771(9) Å, b = 12.3983(16) Å, c = 15.7299(16) Å, α = 85.003(11)°, β = 84.574(8)°, γ = 76.838(10)°, Z = 2, Rf = 0.041 for 2966 significant reflections. The two copper(II) centres have distorted square-pyramidal geometry involving an N2O2 in plane donor set and two phenoxide oxygen bridges with a copper–copper separation of 3.018(1) Å. The fifth coordination site at each copper centre involves an amide oxygen from a neighbouring molecule (Cu(1)—O 2.371(4), Cu(2)—O 2.413(3) Å) in a staggered intermolecular array. Very strong antiferromagnetic exchange is observed in both cases (−2J = 689 ± 7 cm−1 (II), −2J = 816 ± 8 cm−1 (III)). Keywords: macrocycles, binuclear copper(II) complexes.
    Canadian Journal of Chemistry 02/2011; 67(4):662-670. · 0.96 Impact Factor
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    ABSTRACT: The ligand PTP (3,6-bis(2-pyridylthio)pyridazine) generates both hydroxo- and halogeno-bridged, square-pyramidal, binuclear copper(II) complexes ([Cu2(PTP)X4] (X = Cl (I), Br (II)); [Cu2(PTP)(OH)X3] (X = Cl (IV), Br (V)), which are antiferromagnetically coupled. The hydroxo-bridged derivatives are more strongly coupled than those with just halogen bridges and within each pair of complexes substantially increased spin exchange is observed for the bromo-derivatives (−2J = 130.5 ± 0.4 (I), 243.5 ± 0.3 (II), 294 ± 3 (IV), 326 ± 6 (V) cm−1). A related halogen-bridged derivative [Cu2(PAP46Me)Cl4] (III) (PAP46Me = 1,4-di(4,6-dimethyl-2-pyridylamino)phthalazine) exhibits much weaker spin exchange associated with the diminished superexchange capacity of the phthalazine bridge compared with pyridazine (−2J = 55 ± 0.1 cm−1). An X-ray study on [Cu2(PTP)Br4] reveals an asymmetric tribridged structure involving a pyridazine and two bromo-bridges with a copper–copper separation of 3.318(3) Å, one relatively short terminal copper–bromine bond (2.375(3), 2.398(3) Å), and a short and long copper–bromine bridging contact (2.380(3), 2.801(3); 2.414(3), 2.766(3) Å) per copper. The complex formed green crystals with a = 11.1042(18), b = 15.6554(10), c = 12.6058(14) Å, β = 113.485(11)°, P21/c, Z = 4, Rf = 0.045.
    Canadian Journal of Chemistry 02/2011; 66(2):348-354. · 0.96 Impact Factor

Publication Stats

781 Citations
510.38 Total Impact Points

Institutions

  • 1985–2014
    • Memorial University of Newfoundland
      • Department of Chemistry
      St. John's, Newfoundland and Labrador, Canada
  • 2009–2012
    • Salem State University
      Salem, Massachusetts, United States
  • 2011
    • National Academy of Sciences of Ukraine
      • L. V. Pisarzhevsky Institute of Physical Chemistry
      Kiev, Misto Kyyiv, Ukraine
  • 1999–2009
    • Drexel University
      • Department of Chemistry
      Philadelphia, PA, United States
  • 2005–2008
    • Florida Memorial University
      Little Canada, Minnesota, United States
    • La Salle University
      • Chemistry
      Philadelphia, Pennsylvania, United States
  • 2007
    • Kent State University
      • Department of Chemistry and Biochemistry
      Kent, OH, United States
  • 2006–2007
    • University of New Brunswick
      • Department of Chemistry
      Fredericton, New Brunswick, Canada
    • University of Victoria
      • Department of Chemistry
      Victoria, British Columbia, Canada
    • Universität Bern
      • Departement für Chemie und Biochemie
      Bern, BE, Switzerland
  • 2005–2006
    • Dalhousie University
      • Department of Chemistry
      Halifax, Nova Scotia, Canada
  • 2004
    • University of Ottawa
      • Department of Chemistry
      Ottawa, Ontario, Canada
    • The University of the West Indies, Trinidad and Tobago
      • Department of Chemistry
      Port-of-Spain, Port-of-Spain, Trinidad and Tobago
  • 2003
    • Mississippi State University
      • Department of Chemistry
      Starkville, MS, United States
  • 2000
    • University of Toronto
      • Department of Chemistry
      Toronto, Ontario, Canada
    • Friedrich-Alexander Universität Erlangen-Nürnberg
      • Department of Chemistry and Pharmacy
      Erlangen, Bavaria, Germany
  • 1986–1990
    • National Research Council Canada
      Ottawa, Ontario, Canada
  • 1988
    • Indian Association for the Cultivation of Science
      • Department of Inorganic Chemistry
      Calcutta, Bengal, India