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21.
A hybrid macrocycle composed of two bipyridines and two dipyrrins gave biscobalt complexes of figure eight macrocycle conformation with κ2-carboxylate ligands and water ligands at the axial sites. The axial acetate ligands of the biscobalt complex are readily exchanged with carboxylates of α-hydroxyl acids and α-amino acids. The chiral center of the axial carboxylate ligands controls the helical handedness of the macrocycle as evidenced by a typical CD couplet at 550 nm. The substitution labile nature of the biscobalt complex plays a key role for helical chirality induction on the macrocycle upon co-ordination of chiral carboxylate anions. 相似文献
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Takeuchi Hiroshi Watanabe Ryosuke Enmi Jun-ichiro Egawa Toru Konaka Shigehiro 《Structural chemistry》1998,9(1):33-38
The molecular structure and conformation of methyl acrylate have been determined by analyzing the 1H NMR spectrum with 13C satellites of the molecules dissolved in the liquid crystal ZLI 1132. In the structural analysis, direct coupling constants have been corrected for molecular vibrations and converted to those in the r
structure. The correlation between reorientational motion and internal rotation has been taken into account by using the mean external potential described in terms of bond interaction tensors. The potential for the internal rotation about the
bond has been represented as V() = (V
1/2) (1 – cos ) + (V
2/2)(1 – cos 2), where is zero for the s-cis configuration, and the determined values of V
1 and V
2 are 2.7(1) and 8.4(13) kJ mol–1, respectively. The relative abundance of the s-cis conformer, 76(1)%, agrees with a gas-phase value, 67(11)%, determined by electron diffraction within experimental errors. 相似文献
24.
Treatment of o-bromophenoxide anion with sodium salts of active methylene compounds in the presence of copper(I) bromide in dioxane afforded benzofuran-2-one derivatives. The phenoxide group of o- and p-bromophenol activates the coupling reaction. 相似文献
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The green and effective oxidation of alcohols to carboxylic acids with molecular oxygen via biocatalytic reaction 总被引:1,自引:0,他引:1
Jun-ichiro Hirano 《Tetrahedron letters》2008,49(7):1217-1219
A clean and effective alcohol oxidizing system using three enzymes has been developed. Regeneration of NAD+ by NADH oxidase with molecular oxygen enabled to oxidize alcohols to carboxylic acids in good yield under mild conditions (25 °C, 1 atm). 相似文献
27.
A numerical scattering calculation method for defective gratings is proposed. This method is based on an integral equation method that computes a difference-field distribution, which is the difference between the scattering fields with and without the defect, and it is possible to simulate the arbitrary (finite) size and shape of a defect in the grating without any limitation. A calculation example is also presented to demonstrate the fast convergence and high accuracy of this method. 相似文献
28.
Hayashi M Ieda J Yamane Y Ohe J Takahashi YK Mitani S Maekawa S 《Physical review letters》2012,108(14):147202
The spinmotive force associated with a moving domain wall is observed directly in Permalloy nanowires using real time voltage measurements with proper subtraction of the electromotive force. Whereas the wall velocity exhibits nonlinear dependence on magnetic field, the generated voltage increases linearly with the field. We show that the sign of the voltage reverses when the wall propagation direction is altered. Numerical simulations explain quantitatively these features of spinmotive force and indicate that it scales with the field even in a field range where the wall motion is no longer associated with periodic angular rotation of the wall magnetization. 相似文献
29.
Allylindium reagents allylated azirines to give allylaziridines in good yields. The delivery of the allyl group was well regulated by the substituents at the C3-carbon of azirines. The cis-allylation with respect to the substituent was realized with azirines bearing a hydroxylmethyl or an acetoxymethyl group due to the chelation with allylindium reagents, whereas the trans-allylation was achieved with azirines substituted by a methyl, phenyl, or ester group owing to the steric repulsion. 相似文献
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