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Nickel(II) meso‐Hydroxyporphyrin Complexes Revisited: Palladium‐Catalysed Synthesis,Electronic Structures of Derived Oxy Radicals,and Oxidative Coupling to a Dioxoporphodimethene Dyad 下载免费PDF全文
Dr. Louisa J. Esdaile Dr. Llew Rintoul Mean See Goh Khalissa Merahi Dr. Nathalie Parizel Dr. R. Mark Wellard Dr. Sylvie Choua Prof. Dennis P. Arnold 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(10):3430-3446
We report the synthesis and characterisation of new examples of meso‐hydroxynickel(II) porphyrins with 5,15‐diphenyl and 10‐phenyl‐5,15‐diphenyl/diaryl substitution. The OH group was introduced by using carbonate or hydroxide as nucleophile by using palladium/phosphine catalysis. The NiPor?OHs exist in solution in equilibrium with the corresponding oxy radicals NiPor?O.. The 15‐phenyl group stabilises the radicals, so that the 1H NMR spectra of {NiPor?OH} are extremely broad due to chemical exchange with the paramagnetic species. The radical concentration for the diphenylporphyrin analogue is only 1 %, and its NMR line‐broadening was able to be studied by variable‐temperature NMR spectroscopy. The EPR signals of NiPor?O. are consistent with somewhat delocalised porphyrinyloxy radicals, and the spin distributions calculated by using density functional theory match the EPR and NMR spectroscopic observations. Nickel(II) meso‐hydroxy‐10,20‐diphenylporphyrin was oxidatively coupled to a dioxo‐terminated porphodimethene dyad, the strongly red‐shifted electronic spectrum of which was successfully modelled by using time‐dependent DFT calculations. 相似文献
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Kee Sung Han Seong-Soo Kim Ki Hyeok Kang Byoung Jean Mean Heon Hwa Choi Oc Hee Han Moohee Lee 《Electrochemistry communications》2009,11(2):466-468
195Pt nuclear magnetic resonance (NMR) was employed to study the influence of Nafion ionomers (NIs), a common ingredient used as a proton conducting mediator and binder in a membrane-electrode-assembly (MEA) for proton exchange membrane fuel cells, on the local density of states at the Fermi surface (EF-LDOS) of Pt/C catalysts. NIs were observed to increase the surface EF-LDOS of Pt particles, thereby altering of the catalytic properties of metal particles. This correlates well with the reduction of fuel oxidation rates. Thus, ionomers decreasing the surface EF-LDOS of Pt particles would be desirable. In addition, a new concept to interpret the surface EF-LDOS was introduced and validated. 相似文献
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Corrigendum: Nickel(II) meso‐Hydroxyporphyrin Complexes Revisited: Palladium‐Catalysed Synthesis,Electronic Structures of Derived Oxy Radicals,and Oxidative Coupling to a Dioxoporphodimethene Dyad 下载免费PDF全文
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The derivatized cyclotetrachromotropylene host forms complexes of 1:1 host to guest stoichiometry with tetraalkylammonium cations and amino acids whereas complexes of 1:2 host to guest stoichiometry are formed with mono and diprotonated amines in an aqueous solution. Both electrostatic and hydrophobic interactions are involved in the complexation. 相似文献
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T. K. Park B. J. Mean K. H. Lee S. W. Seo K. S. Han D. H. Kim Moohee Lee H. S. Lee H. B. Kim W. C. Lee Joung-Sook Cho 《Physica C: Superconductivity and its Applications》1999,320(3-4):245-252
We have prepared Zn-substituted YBa2Cu3−xZnxO7 (YBCO, x=0.0–0.09) and performed 63,65Cu nuclear quadrupole resonance (NQR) measurements for the plane site at 300 and 100 K as a function of Zn concentration. The substitutional effects are observed in resonant frequencies and linewidths of spectra, and relaxation times as well as in the superconducting transition temperature. The spin–lattice relaxation rate 1/T1 is reduced for the higher Zn concentration and the reduction is more significant at 100 K. The ratio of 63,65Cu spin–lattice relaxation rates suggests that a magnetic contribution due to the antiferromagnetic spin fluctuation becomes weak as the Zn concentration increases. These effects confirm that the antiferromagnetic spin fluctuation of Cu 3d spins is suppressed by the Zn substitution due to the absence of local moment at the zinc site. 相似文献
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Mean 《Fresenius' Journal of Analytical Chemistry》1887,26(1):642
Ohne Zusammenfassung 相似文献
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Kihyeok Kang Byoung-Jean Mean Sung Hoon Kim Moohee Lee Ae Ran Lim 《Journal of Physics and Chemistry of Solids》2012,73(4):545-549
87Rb and 39K nuclear magnetic resonance (NMR) spectra of RbKSO4 single crystals were measured at room temperature. 87Rb central line has the angular dependences of second-order quadrupolar shifts. From these results, the quadrupole coupling constant and the asymmetry parameter were determined at room temperature. In addition, the spin–lattice relaxation rate, 1/T1, and the spin–spin relaxation rate, 1/T2, were measured as a function of temperature. The values of 1/T1 for the 87Rb and 39K nuclei were found to increase with increasing temperature, and 1/T1 was determined to be proportional to Tn. Therefore, for the 87Rb and 39K nuclei, Raman processes with n=2 are more significantly in nuclear quadrupole relaxation than direct processes. 相似文献
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