This paper reports the CD and UV spectra of the β- cdx inclusions of α- naphthylamine, β- naphthylamine, α- naphthylacetic acid and according to KAJTAR sector rule the Cotton effect and g factor give the orientation of guest molecules in β- cdx, correlates the CD spectra the orientation of guest molecules in β- cdx and the quantum calculating for the electric moment of transition.
Studied the influence of temperature, pH, Ca2+, boron and congo red on circular dichroism of konjac glucomannan,the results showed that it brought a new cotton effect when in high pH, the rest mainly brought out the changes on absorptionintensity in different extent.
When chloroform was used as solvent and the concentration was 65wt%,the handedness of the two helicoidal structures was left handed (positive Cotton effect),but when dioxane or THF was used with the same concentration,a reversed handedness was observed.
The monoclonal antibodies specific for meso_tetra (α,α,α,α-0-phenylacetyl benzene) porphyrin cause a large shift of the Soret band of meso_tetra (α,α,α,α-0-phenylacetyl benzene) porphyrin to a larger wavelength and great induced Cotton effects (ICD) on meso_tetra (α,α,α,α-0-phenylacetyl benzene) porphyrin.
Using the Kronig-Kramers formula in crystal and the approximation of a Gaussian CD band, the specific rotatory powers of NYAB crystal in the Z direction were evaluated from the parameters of its Cotton effects.
CD (circular dichroisin ) spectra of neodymium yttrium aluminum borate (NYAB) crystal were measured over a wavelength range of 300￣800nm with a CARY model 61 CD spectropolarimeter at room temperature under constant nitrogen flush. The parameters of Cotton effects were given.
The specific optical rotations of products 2c, 2d and 2e were also comparable to those inliterature. The enantiomeric excess(e. e) value were determined to be no less than 95 % on a L - 4 - hydroxyproline - bonded high - performance ligand exchange column.
The positions and intensities of the Cotton effects in CD spectra of the MP-2 peptide and its retro-analogue in various solvents are almost indistinguishable.
Nearly all substances give biphasic extrinsic Cotton effects.
Besides a simple correction for the different densities of the solvent and the solution a systematic error has to be taken into consideration, which results from a reflection in the sample cell and may erroneously be taken for Cotton effects.
Bidentate complexes of dimolybdenum tetraacetate with 1,3-diaxial diols show Cotton effects around 490-540 nm (CD band I), 400-440 nm (II), 350-380 nm (III), 320 nm (IV) and 280 nm (V).
It seems that from the Cotton effects for cyclic 1,3-diols the absolute configurations or conformations can be obtained.
In this paper, the ORD and sector projection of 6 synthetic γ-lactone intermediates of Qinghaosu(Arteannuin) are reported. By-using ketone octant rule, lactone chirality rule and lactone sector rule, the predicted cotton effects of these compounds coincided with the result of determination and so the absolute configurations were assigned.
This paper deals with the determination of the A,B ring configuration of artean-
青蒿酸甲酯4环氧化所得的化合物5和6经三氟化硼重排生成的7及其表异构物8在圆二色谱294nm 附近分别出现负的和正的 Cotton 效应.因而推定青蒿酸的 A,B 环为顺式稠合.用双氢青蒿酸甲酯也得到相同的 CD 结果.
A new bicyclo[9.3.0]tetradecane diterpenoid (dolabellane) lactone 3 was isolated from soft coral qunzhuchong (Clavularia sp.). Its partial structure was determinated by spectral analysis and hydrogenation reaction. X-ray analysis established the complete molecular structure of 3 and the relative cofiguration. Finally, according to the negative Cotton effect of n→π CD band of α,β-unsaturated δ-lactone in 252 nm, the absolute configuration was assigned.