@article {CHEM:CHEM201504959, title = {Exploring Regioselective Bond Cleavage and Cross-Coupling Reactions using a Low-Valent Nickel Complex}, journal = {Chemistry {\textendash} A European Journal}, volume = {22}, number = {12}, year = {2016}, pages = {4070{\textendash}4077}, abstract = {Recently, esters have received much attention as transmetalation partners for cross-coupling reactions. Herein, we report a systematic study of the reactivity of a series of esters and thioesters with [{(dtbpe)Ni}2(μ-η2:η2-C6H6)] (dtbpe=1,2-bis(di-tert-butyl)phosphinoethane), which is a source of (dtbpe)nickel(0). Trifluoromethylthioesters were found to form η2-carbonyl complexes. In contrast, acetylthioesters underwent rapid Cacyl-S bond cleavage followed by decarbonylation to generate methylnickel complexes. This decarbonylation could be pushed backwards by the addition of CO, allowing for regeneration of the thioester. Most of the thioester complexes were found to undergo stoichiometric cross-coupling with phenylboronic acid to yield sulfides. While ethyl trifluoroacetate was also found to form an η2-carbonyl complex, phenyl esters were found to predominantly undergo Caryl-O bond cleavage to yield arylnickel complexes. These could also undergo transmetalation to yield biaryls. Attempts to render the reactions catalytic were hindered by ligand scrambling to yield nickel bis(acetate) complexes, the formation of which was supported by independent syntheses. Finally, 2-naphthyl acetate was also found to undergo clean Caryl-O bond cleavage, and although stoichiometric cross-coupling with phenylboronic acid proceeded with good yield, catalytic turnover has so far proven elusive.}, keywords = {CROSS-COUPLING, ELIMINATION, NICKEL, P ligands, SULFUR}, issn = {1521-3765}, doi = {10.1002/chem.201504959}, url = {http://dx.doi.org/10.1002/chem.201504959}, author = {Desnoyer, Addison N. and Friese, Florian W. and Chiu, Weiling and Drover, Marcus W. and Patrick, Brian O. and Love, Jennifer A.} } @article {ISI:000244896900002, title = {Sulfur K-edge XAS as a probe of sulfur-centered radical intermediates.}, journal = {J. Am. Chem. Soc.}, volume = {129}, number = {11}, year = {2007}, month = {mar}, pages = {3034{\textendash}5}, abstract = {Sulfur K-edge XAS is used in the identification and characterization of sulfur based radicals obtained from UV irradiated glutathione. Ground state and time-dependent DFT calculations are used to identify thiyl (RS center dot) and perthiyl (RSS center dot) radical species.}, keywords = {DFT, Free Radicals, Free Radicals: analysis, Free Radicals: chemistry, GLUTATHIONE, Glutathione: chemistry, Oxidation-Reduction, PHOTOCHEMISTRY, SPECTROMETRY, SPECTROPHOTOMETRY, Sulfhydryl Compounds, Sulfhydryl Compounds: chemistry, SULFUR, sulfur redox, Sulfur: chemistry, ULTRAVIOLET, X-Ray Emission, X-Ray Emission: methods, XAS}, issn = {0002-7863}, doi = {10.1021/ja0676760}, url = {http://www.ncbi.nlm.nih.gov/pubmed/17319664}, author = {Martin-Diaconescu, Vlad and Kennepohl, Pierre} } @article {4744, title = {2-Pyrrolythiones as monoanionic bidentate N,S-chelators: Synthesis and molecular structure of 2-pyrrolylthionato complexes of nickel(II), cobalt(III), and mercury(II)}, journal = {Inorganic Chemistry}, volume = {39}, number = {26}, year = {2000}, note = {ISI Document Delivery No.: 385TFTimes Cited: 35Cited Reference Count: 55}, month = {Dec}, pages = {6100-6106}, type = {Article}, abstract = {{The metal-chelating ability of 2-pyrrolylthiones is described. The readily available ligands di-2-pyrrolyl thione (6), 2-thioncetylpyrrole (10), and 2-thiobenzoylpyrrole (11) constitute examples of monoanionic ligands with N,S-donor atom sets, although di-2-pyrrolyl thione (6) could theoretically also achieve chelation through an N,N-donor set. A square planar Ni(II)) complex, 14, an octahedral Co(III) complex, 18, and a tetrahedral Hg(II) complex, 17, with the di-2-pyrrolyl thionato chelate have been prepared, and their structures have been characterized by H-1 NMR, UV-vis, MS, IR, elemental analysis, and single-crystal X-ray difraction. Crystal data for 14: C18H14N4N4-NiS2.0.28H(2)O, NiS2.0.28H(2)O, trigonal, R (3) over bar, a 18.467(1) Angstrom}, keywords = {BLUE COPPER PROTEINS, CHEMISTRY, CRYSTAL-STRUCTURE, CU(II), LIGANDS, PRECURSORS, SULFUR}, isbn = {0020-1669}, url = {://000166019200030}, author = {Bruckner, C. and Rettig, S. J. and Dolphin, D.} } @article {4655, title = {Tensor LEED analysis for the Cu(111)-(root x root 7)R19.1 degrees-S surface structure}, journal = {Surface Science}, volume = {441}, number = {2-3}, year = {1999}, note = {ISI Document Delivery No.: 253RWTimes Cited: 11Cited Reference Count: 36}, month = {Nov}, pages = {425-435}, type = {Article}, abstract = {A tensor LEED analysis is reported for the (root 7 x root 7)R19.1 degrees structure formed by S at the Cu(lll)surface. A new structural model is found which corresponds to a modified version of the copper sulphide overlayer model first proposed by Domange and Oudar. In that model, the topmost layer has 3/7 monolayer each of Cu and S atoms, but the modification involves one S atom per unit mesh moving down to displace a Cu atom from the second metal layer. Relaxations among the topmost Cu atoms result in one S atom being effectively three-fold coordinate while the other two are sixfold coordinate and 12-fold coordinate: the averaged S-Cu bond lengths are indicated to equal 2.19, 2.47 and 2.62 Angstrom respectively. Some discussion is included of factors that may influence this choice of surface structure. (C) 1999 Elsevier Science B.V. All rights reserved.}, keywords = {ADSORPTION, chemisorption, copper, ENERGY-ELECTRON-DIFFRACTION, LAYERS, low energy electron diffraction, LOW INDEX SINGLE CRYSTAL, METAL-SURFACES, MOLECULE, RAY STANDING-WAVE, RECONSTRUCTION, RU(0001), SUBSTRATE, SULFUR, sulphur, SURFACE, surface reconstruction}, isbn = {0039-6028}, url = {://000083570400024}, author = {Saidy, M. and Mitchell, K. A. R.} } @article {4657, title = {Tensor LEED analysis for the Ni(111)-(root 7 x root 7)R19.1 degrees-P surface structure: Comparison with other root 7 systems}, journal = {Surface and Interface Analysis}, volume = {28}, number = {1}, year = {1999}, note = {ISI Document Delivery No.: 234JZTimes Cited: 1Cited Reference Count: 36Asia-Pacific Surface and Interface Analysis Conference 1998 (APSIAC 98)NOV 30-DEC 04, 1998SINGAPORE, SINGAPORE}, month = {Aug}, pages = {84-91}, type = {Proceedings Paper}, abstract = {A crystallographic analysis is reported using low-energy electron diffraction (LEED) in the tensor LEED approach for the (root 7 x root 7)R19.1 degrees structure formed by 3/7 monolayer of phosphorus at the Ni(111) surface. This surface has a novel structure in which each phosphorus atom bonds to seven neighbouring Ni atoms, four in the top layer and three in the second layer, at an average distance close to 2.39 Angstrom. Formally this reconstruction involves three neighbouring Ni atoms in a triangular arrangement per unit mesh of the original unreconstructed surface being replaced by three phosphorus atoms. A discussion is included of the structural relaxations that occur in this surface as the demands of Ni-P bonding are balanced against those for Ni-Ni and P-P contributions. Comparisons are made with the root 7 reconstructions observed for related systems, including those for P/Rh(111), S/Pd(111) and S/Cu(111). Copyright (C) 1999 John Wiley \& Sons, Ltd.}, keywords = {(ROOT-3X-ROOT-3)R30-DEGREES, analysis, chemisorption, CRYSTALLOGRAPHIC, ENERGY-ELECTRON-DIFFRACTION, LEED, METAL-SURFACES, Ni, NI(111), P, RAY STANDING-WAVE, RECONSTRUCTION, RELAXATIONS, SUBSTRATE, SULFUR}, isbn = {0142-2421}, url = {://000082482200018}, author = {Saidy, M. and Zhou, M. Y. and Mitchell, K. A. R.} } @article {4385, title = {(13)CPMAS-NMR spectroscopy and chemical analysis of coarse woody debris in coastal forests of Vancouver Island}, journal = {Forest Ecology and Management}, volume = {111}, number = {1}, year = {1998}, note = {ISI Document Delivery No.: 137DZTimes Cited: 46Cited Reference Count: 52}, month = {Nov}, pages = {51-68}, type = {Article}, abstract = {The coastal forests of British Columbia have large accumulations of coarse woody debris, and information on this pool is considered essential in developing sustainable management practices. We characterized coarse woody debris (7-12 and >12 cm diameter) in forest chronosequences of four age classes located on the eastern and western sides of Vancouver Island. For three species (Douglas-fir (Pseudotsuga menziesii (Mirb.) France), western hemlock (Tsuga heterophylla (Raf.) Sarg), western red cedar (Thuja plicata Donn.)) and unidentified samples, increases in decay class (I to V, assigned in the field) were associated with decreasing density, and small increases in concentrations of C, N, and P. Sulfur concentrations (0.6-2.4 g/kg) were higher than those found elsewhere for wood and did not show any significant changes with decay class. C-13 nuclear magnetic resonance spectroscopy with cross polarization and magic-angle spinning (C-13-CPMAS-NMR) was used to analyze organic components in a subset of samples >12 cm. Logs up to decay class III generally showed little change in composition or a slight increase in polysaccharide C. After this, polysaccharide was lost more quickly and logs of decay class V were composed almost entirely of lignin, a pattern consistent with decay by brown-rot fungi. However, two samples of western red cedar decay class III and IV showed accumulation of polysaccharide, the pattern expected from white-rot fungi. The results of the density, chemical and NMR analysis indicate that for management purposes, a system with fewer decay classes would suffice. (C) 1998 Elsevier Science B.V.}, keywords = {BRITISH-COLUMBIA, brown-rot, chronosequence, COLORADO BLUE SPRUCE, cross polarization, CUO OXIDATION, DECOMPOSITION, DOUGLAS-FIR FORESTS, LIGNIN, NUCLEAR-MAGNETIC-RESONANCE, NUTRIENT CONTENT, SOLID-STATE NMR, SULFUR, WESTERN OREGON, white-rot, WHITE-ROT DECAY}, isbn = {0378-1127}, url = {://000076900700005}, author = {Preston, C. M. and Trofymow, J. A. and Niu, J. and Fyfe, C. A.} } @article {4061, title = {The structure of the Pd(111)-(root 7x root 7)R19.1 degrees-S surface: comparison with the corresponding P/Rh(111) surface}, journal = {Surface Science}, volume = {393}, number = {1-3}, year = {1997}, note = {ISI Document Delivery No.: YP959Times Cited: 15Cited Reference Count: 35}, month = {Dec}, pages = {L119-L125}, type = {Letter}, abstract = {The structure of the Pd(lll)-(root 7 x root 7)R19.1://000071333200009}, author = {Liu, W. and Mitchell, K. A. R. and Berndt, W.} } @article {2866, title = {LEED CRYSTALLOGRAPHIC STUDIES FOR THE RH(100)-P(2X2)-S AND RH(100)-C(2X2)-S SURFACE-STRUCTURES}, journal = {Surface Science}, volume = {281}, number = {1-2}, year = {1993}, note = {ISI Document Delivery No.: KH844Times Cited: 13Cited Reference Count: 40}, month = {Jan}, pages = {21-32}, type = {Article}, abstract = {New LEED intensity-versus-energy curves have been measured for the p(2 x 2) and c(2 x 2) surface structures formed by the chemisorption and annealing of H2S on to the (100) surface of rhodium, and the data analyzed with multiple scattering calculations to investigate structural details. Bucklings are indicated in the second metal layer of magnitudes 0.01 and 0.06 angstrom for the c(2 x 2) and p(2 x 2) surfaces respectively; for the latter structure the top layer metal atoms are laterally relaxed by around 0.05 angstrom. A surprising feature in the present work concerns the possibility that S is displaced laterally from the symmetrical centre site of 4-fold coordination, by around 0.27 angstrom, toward bridge sites. This shifting of S has a small, but definite, effect on the intensity curves of the higher order fractional beams. At this time, it does not appear as an artefact introduced by uncertainties in the direction of incidence, the second metal layer buckling or the surface Debye temperature.}, keywords = {chemisorption, ENERGY ELECTRON-DIFFRACTION, INDUCED RELAXATION, RECONSTRUCTION, RH(100), SULFUR}, isbn = {0039-6028}, url = {://A1993KH84400009}, author = {Liu, W. and Lou, J. R. and Mitchell, K. A. R.} } @article {7269, title = {HYDRIDO MERCAPTO AND BIS(MERCAPTO) DERIVATIVES OF RUTHENIUM(II) PHOSPHINE COMPLEXES}, journal = {Inorganic Chemistry}, volume = {31}, number = {22}, year = {1992}, note = {ISI Document Delivery No.: JV836Times Cited: 27Cited Reference Count: 42}, month = {Oct}, pages = {4601-4605}, type = {Article}, abstract = {{The complex cct-Ru(SH)2(CO)2(PPh3)2 (1), synthesized by treating THF solutions of RU(CO)2(PPh3)3 or cct-Ru(H)2(CO)2(PPh3)2 With H2S, crystallizes in the space group P1BAR (No. 2), with a = 10.3030 (6) angstrom}, keywords = {bis(diphenylphosphino)methane, CHEMISTRY, ELECTROCHEMICAL PARAMETRIZATION, H2S, HYDROGEN-SULFIDE, LIGANDS, MOLECULAR-STRUCTURE, RAY CRYSTAL-STRUCTURES, SULFUR}, isbn = {0020-1669}, url = {://A1992JV83600030}, author = {Jessop, P. G. and Lee, C. L. and Rastar, G. and James, Brian R. and Lock, C. J. L. and Faggiani, R.} } @article {7003, title = {NEAMPHINE, A SULFUR-CONTAINING AROMATIC HETEROCYCLE ISOLATED FROM THE MARINE SPONGE NEAMPHIUS-HUXLEYI}, journal = {Tetrahedron Letters}, volume = {32}, number = {24}, year = {1991}, note = {ISI Document Delivery No.: FN524Times Cited: 9Cited Reference Count: 17}, month = {Jun}, pages = {2707-2710}, type = {Article}, abstract = {The structure of neamphine (1), a cytotoxic metabolite of the marine sponge Neamphius huxleyi, has been solved by single crystal x-ray diffraction analysis. Neamphine (1) represents the first example, either from nature or synthesis, of the imidazo[4,5-e]-1,2-thiazine ring system.}, keywords = {ALKALOIDS, CYTOTOXIC, HETEROCYCLE, NITROGEN, SPONGE, SULFUR, TUNICATE}, isbn = {0040-4039}, url = {://A1991FN52400003}, author = {De Silva, E. D. and Racok, J. S. and Andersen, R. J. and Allen, T. M. and Brinen, L. S. and Clardy, J.} }