The ORD,CD and UV spectra of sulphides derived from carvone

The ord and cd spectra of aromatic and aliphatic sulphides derived from carvone are compared with the spectra of dicarvone sulphide and related compounds. The spectra are discussed in relation to the structure of the molecules, as evidenced by the nmr spectrum, and correlated with the electronic transitions involved.

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ORD-, CD- und UV-Spektren von Sulfiden des Carvons

Zusammenfassung Die CD- und ORD-Spektren aromatischer und aliphatischer Sulfide von Carvon werden mit Spektren von Dicarvonsulfid und verwandten Verbindungen verglichen. Die Spektren werden in bezug auf Molekülstrukturen, die durch NMR-Spektren bewiesen wurden, diskutiert und mit den betreffenden Elektronenübergängen in Wechselbeziehung gebracht.

     

Application Of Fluorescamine Xiv1. Determination Of Optical Purity Of A Small Amount Of Amino Acids By The Fluorescamine Method

Abstract

A new simple and fast micro method has been established to determine the optical purity of a small amount of amino acids (0.1–1 μg/ml). The amino acids react readily with fluorescamine to form pyrrolinone-type chromophores, which show strong CD bands at 400–300 nm and much larger optical rotation than the free amino acids in the visible spectral range.     

铜(Ⅱ)离子与神经红蛋白的相互作用

利用紫外可见吸收光谱、荧光光谱、同步荧光光谱及圆二色(CD)光谱研究了铜髤离子与神经红蛋白(NGB)的相互作用。结果表明,Cu2+离子使NGB在280nm处的紫外吸收增强,说明Cu2+与NGB发生了相互作用;Cu2+使NGB内源性荧光发生猝灭,其猝灭机制为静态猝灭;同步荧光光谱表明,Cu2+使色氨酸微环境的疏水性有所降低,Cu2+对NGB的作用位点更接近于色氨酸;CD光谱显示Cu2+没有引起NGB二级结构明显的变化。     

稀土离子与牛血Cu(Zn)-SOD的作用

采用ESR、CD谱和荧光光谱研究了pH=6.3时六次甲基四胺-HCl缓冲溶液中LaCl_3和TbCl_3与Cu(Zn)-SOD的配位作用和结构。Cu(Zn)-SOD可增强Tb~(3+)的荧光发射,Tb~(3+)与Cu(Zn)-SOD有多个配位位置,其中有2个强结合位点,La~(3+)与Tb~(3+)可竞争Cu(Zn)…SOD上相同结合位点,77K下La~(3+)与Tb~(3+)使Cu(Zn)-SOD的Cu~(2+)活性中心的配位环境由菱形对称结构向轴对称结构转变,使Cu(Zn)-SOD的局部结构变松散,但对SOD酶活性基本无影响,表明稀土离子主要与酶蛋白分子中的酸性氨基酸羧基配位,对酶蛋白二级结构仅产生微弱扰动,对活性中心空间结构影响较小,基本不影响Cu(Zn)-SOD酶活性。     

Synthesis and characterization of chiral enantiopure bis-chromanones: a Baylis-Hillman approach

Enantiopure bis-chromanones were prepared from (S)-Binol and bromo esters via a Baylis-Hillman approach. Chiroptical studies indicate that the two-naphthyl units of the chromanone system are non-coplanar.     

Darstellung und spektroskopische Eigenschaften von Nitridophthalocyaninatorhenium(V)

Preparation and Spectroscopical Properties of Nitridophthalocyaninatorhenium(V) Nitridophthalocyaninatorhenium(V) ([ReNPc^2?]) is prepared by the reaction of dirheniumheptoxide with ammoniumiodide in molten 1,2-dicyano-benzene. The diamagnetic complex is chemically und thermically extremely stable. In the Uv-vis spectra the typical π-π*-transitions of the Pc^2? ligand are observed. Extra bands in the solid state spectrum are due to strong excitonic coupling of ca. 2.8 kK. In the resonance Raman spectra the intensity of the Re≡N stretching vibration (v(Re≡N)) at 969 cm^?1 is selectively enhanced by laser excitations above 19.0 kK. v(Re≡N) is a dominant m.i.r. absorption at 976 cm^?1.     

Osmium(II)-Phthalocyanine: Darstellung und Eigenschaften von Di(acido)phthalocyaninatoosmaten(II)

Osmium(II) Phthalocyanines: Preparation and Properties of Di(acido)phthalocyaninatoosmates(II) “H[Os(X)₂Pc^2?]” (X = Br, Cl) reacts in basic medium or in the melt with (ⁿBu₄N)X forming less stable, diamagnetic, darkgreen (ⁿBu₄N)₂[Os(X)₂Pc^2?]. Similar dicyano and diimidazolido(Im) complexes are formed by the reaction of “H[Os(Cl)₂Pc^2?]” with excess ligand in the presence of [BH₄]^?. The cyclic voltammograms show up to three quasireversible redoxprocesses: E_1/2(I) = 0.13 V (X = CN), ?0.03 V (Im), ?0.13 V (Br) resp. ?0.18 V (Cl) is metal directed (Os^II/III), E_1/2(II) = 0.69 V (Cl), 0.71 V (Br), 0.83 V (CN), 1.02 V (Im) is ligand directed (Pc^2?/?) and E_1/2(III) = 1.17 V (Cl) resp. 1.23 V (Br) is again metal directed (Os^III/IV). Between the typical “B” (～16.2 kK) and “Q” (～29.4 kK), “N regions” (～34.1 kK) up to seven strong “extra bands” of the phthalocyanine dianion (Pc^2?) are observed in the uv-vis spectrum. Within the row CN > Im > Br > Cl, most of the bands are shifted slightly, the “extra bands” considerably more to lower energy in correlation with E_1/2(I). The vibrational spectra are typical for the Pc^2? ligand with D_4h symmetry. M.i.r. bands at 514, 909, 1 173 and 1 331 cm^?1 are specific for hexa-coordinated low spin Os^II phthalocyanines. In the resonance Raman (r.r.) spectra polarized, depolarized or anomalously polarized deformation and stretching vibrations of the Pc^2? ligand will be selectively enhanced, if the excitation frequency coincides with “extra bands”. With excitation at ～19.5 kK the intensity of the symmetrical Os? X stretching vibration at 295 cm^?1 (X = Cl), 252 cm^?1 (X = Im) and 181 cm^?1 (X = Br) is r.r. enhanced, too. The asymmetrical Os? X stretching vibration is observed in the f.i.r. spectrum at 345 cm^?1 (X = CN), 274 cm^?1 (X = Cl), 261 cm^?1 (X = Im) and 200 cm^?1 (X = Br).     

Reaction of myrtenal with dimethylamide of chloroacetic acid under the conditions of Darzens reaction

3-[2-(6,6-Dimethylbicyclo[3.1.1]hept-2-en-2-yl)]-2-dimethylcarbamoyloxirane and the dimethylamide of 2-chloro-3-[2-(6,6-dimethylbicyclo[3.1.1]hept-2-en-2-yl)]-3-(dimethyl-carbamidomethyloxy)propionic acid were obtained by the reaction of myrtenal with dimethylamide of chloroacetic acid in the presence of NaH. The structures of the compounds obtained were confirmed by NMR, IR, UV, and CD spectroscopy and mass-spectrometry.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 944–945, May, 1995.The authors express their gratitude to I. Kh. Rizvanov who recorded the mass spectrum of compound5.This work was financially supported by the Russian Foundation for Basic Research (Project No. 94-03-09586).     

牛血红蛋白与双十二烷基二甲基溴化铵相互作用的光谱研究(英文)

运用荧光光谱、紫外-可见吸收光谱和圆二色谱法研究了双十二烷基二甲基溴化铵(DDAB)与牛血红蛋白(Hb)的相互作用。从紫外-可见吸收光谱观察到,随着DDAB的浓度增大,Hb在406nm处的特征吸收峰强度下降,且峰位蓝移,说明DDAB导致血红素辅基微观环境变化。由荧光光谱研究可以得出随着DDAB的浓度增大,Hb在340nm处的荧光强度逐渐增强,说明导致色氨酸荧光淬灭的血红素辅基与色氨酸的距离增大。由Scatchard方程计算了不同温度下该反应的表观结合常数、结合位点数及结合热力学参数,热力学参数的变化表明DDAB与Hb之间以疏水作用力为主。圆二色谱的研究进一步表明DDAB使Hb产生轻微的二级结构改变,α-螺旋含量增加.     

Density Functional Study of Tetraphenylporphyrin Long-Range Exciton Coupling

The performance of time-dependent density functional theory (TDDFT) for calculations of long-range exciton circular dichroism (CD) is investigated. Tetraphenylporphyrin (TPP) is used as a representative of a class of strongly absorbing chromophores for which exciton CD with chromophore separations of 50 Å and even beyond has been observed experimentally. A dimer model for TPP is set up to reproduce long-range exciton CD previously observed for a brevetoxin derivative. The calculated CD intensity is consistent with TPP separations of over 40 Å. It is found that a hybrid functional with fully long-range corrected range-separated exchange performs best for full TDDFT calculations of the dimer. The range-separation parameter is optimally tuned for TPP, resulting in a good quality TPP absorption spectrum and small DFT delocalization error (measured by the curvature of the energy calculated as a function of fractional electron numbers). Calculated TDDFT data for the absorption spectra of TPP are also used as input for a ‘matrix method’ (MM) model of the exciton CD. For long-range exciton CD, comparison of MM spectra with full TDDFT CD spectra for the dimer shows that the matrix method is capable of producing very accurate results. A MM spectrum obtained from TPP absorption data calculated with the nonhybrid Becke88–Perdew86 (BP) functional is shown to match the experimental brevetoxin spectrum ‘best’, but for the wrong reasons.