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41.
The standard enthalpy of formation, δfHo, of2 II CH has been determined at converged levels of ab initio electronic structure theory, including high order coupled cluster and full configuration interaction benchmarks. The atomic Gaussian basis sets employed include the (aug)-cc-p(C)VXZ family with X = 3, 4, 5 and 6. Extrapolations to the complete one-particle basis set and the full configuration interaction limits, where appropriate, have been performed to reduce remaining computational errors. Additional improvements in the enthalpy of formation of 2II CH were achieved by appending the valence-only treatment with core-valence correlation, relativistic effects including spin-orbit correlation, and the diagonal Born-Oppenheimer correction. The recommended values for δfHo 0 and δAf H o 298 of 2II CH are 592.48+0.47 ?0.56 kJ mol?1 and 595.93 +0.47 ?0.56 kJ mol?1, respectively. 相似文献
42.
Natasha J. Lundin Dr. Penny J. Walsh Dr. Sarah L. Howell Dr. Allan G. Blackman Prof. Keith C. Gordon Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(36):11573-11583
The ligands 11‐cyanodipyrido[3,2‐a:2′,3′‐c]phenazine and 2‐(11‐dipyrido[3,2‐a:2′,3′‐c]phenazine)‐5‐phenyl‐1,3,4‐oxadiazole have been coordinated to ReI, CuI, RuII and IrIII metal centres. Single‐crystal X‐ray analyses were performed on fac‐chlorotricarbonyl(11‐cyanodipyrido[3,2‐a:2′,3′‐c]phenazine)rhenium (C22H9ClN5O3Re, a=6.509(5), b=12.403(5), c=13.907(5) Å, α=96.88(5), β=92.41(5), γ=92.13(5)°, triclinic, P , Z=2) and bis‐2,2′‐bipyridyl(2‐(11‐dipyrido[3,2‐a:2′,3′‐c]phenazine)‐5‐phenyl‐1,3,4‐oxadiazole)ruthenium triflate ? 2 CH3CN (C52H36F6N12O8RuS2, a=10.601(5), b=12.420(5), c=20.066(5) Å, α=92.846(5), β=96.493(5), γ=103.720(5)°, triclinic, P , Z=2). The ground‐ and excited‐state properties of the ligands and complexes have been investigated with a range of techniques, including electrochemistry, absorption and emission spectroscopy, spectroelectrochemistry and excited‐state lifetime studies. Spectroscopic, time‐resolved and DFT studies reveal that the ligand‐centred (LC) transitions and their resultant excited states play an important role in the photophysical properties of the complexes. Evidence for the presence of lower‐lying metal‐to‐ligand charge‐transfer transitions is obtained from resonance Raman spectroscopy, but nanosecond transient Raman experiments suggest that once excited, the 3LC state is populated. 相似文献
43.
Haack T Haack K Diederich WE Blackman B Roy S Pusuluri S Georg GI 《The Journal of organic chemistry》2005,70(19):7592-7604
[reaction: see text] Two formal total syntheses of the (-)-salicylihalamides, based on chiral pool approaches, are reported. D-glucose and L-rhamnose were used to prepare advanced intermediates 23 and 54, which can be converted in three or four steps, respectively, to the target compounds. The synthesis of 23 from a known D-glucose-derivative was accomplished in 12 steps and 17% overall yield, and the synthesis of 54 from a known L-rhamnose-derivative was done in nine steps and 6% overall yield. A key step in the synthesis was a ring-closing metathesis reaction to prepare the macrocyclic ring system. It was demonstrated that the phenolic protecting group was critical for inducing the preferential formation of the desired E isomer. It was further shown that the protecting group at the C13 hydroxyl group had no significant influence on the E:Z ratio during the ring-closing metathesis reaction. 相似文献
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Described is a bioorthogonal reaction that proceeds with unusually fast reaction rates without need for catalysis: the cycloaddition of s-tetrazine and trans-cyclooctene derivatives. The reactions tolerate a broad range of functionality and proceed in high yield in organic solvents, water, cell media, or cell lysate. The rate of the ligation between trans-cyclooctene and 3,6-di-(2-pyridyl)-s-tetrazine is very rapid (k2 2000 M-1 s-1). This fast reactivity enables protein modification at low concentration. 相似文献
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Boudalis AK Aston RE Smith SJ Mirams RE Riley MJ Schenk G Blackman AG Hanton LR Gahan LR 《Dalton transactions (Cambridge, England : 2003)》2007,(44):5132-5139
The ligand, 2-((2-hydroxy-5-methyl-3-((pyridin-2-ylmethylamino)methyl)benzyl)(2-hydroxybenzyl)amino)acetic acid (H(3)HPBA), which contains a donor atom set that mimics that of the active site of purple acid phosphatase is described. Reaction of H(3)HPBA with iron(III) or iron(II) salts results in formation of the tetranuclear complex, [Fe(4)(HPBA)(2)(OAc)(2)(mu-O)(mu-OH)(OH(2))(2)]ClO(4) x 5H(2)O. X-Ray structural analysis reveals the cation consists of four iron(III) ions, two HPBA(3-) ligands, two bridging acetate ligands, a bridging oxide ion and a bridging hydroxide ion. Each binucleating HPBA(3-) ligand coordinates two structurally distinct hexacoordinate iron(III) ions. The two metal ions coordinated to a HPBA(3-) ligand are linked to the two iron(III) metal ions of a second, similar binuclear unit by intramolecular oxide and hydroxide bridging moieties to form a tetramer. The complex has been further characterised by elemental analysis, mass spectrometry, UV-vis and MCD spectroscopy, X-ray crystallography, magnetic susceptibility measurements and variable-temperature M?ssbauer spectroscopy. 相似文献