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[溶液中色素各聚集形式的光谱发光特性]

[Spectral-luminescent properties of separate aggregated forms of pigments in solutions].

作者信息

Zen'kevich E I, Kochubeev G A, Losev A P, Gurinovich G P

出版信息

Mol Biol (Mosk). 1978 Sep-Oct;12(5):1002-11.

PMID:739987
Abstract

The aggregated forms of protochlorophyll a (PChl), 4-vinyl-protochlorophyll a (4VPChl) and chlorophyll a (Chl) in binar mixtures of dioxane-water was investigated. The aggregates are oligomer particles of pigment molecules having considerable degrees of fluorescence polarisation which points to their ordered structure. Two types of fluorescent associates I and II have been discovered. By its electronic spectrum I is similar to the molecular pigment but has smaller quantum yield B congruent to 10(-2) and the lifetime of fluorescence tau congruent to 3--4.10(-9) sec. Associates of type I spontaneously transform into associates of type II which have narrower bands of electronic spectrum than the monomer, very low B congruent to 10(-3)--10(-4) and tau congruent to 2--4.10(-10) sec. In contrast with the decreasing of B and the band intensities in CD spectrum conditioned by rotational strength increase by factor of 100 under transformation from I to II. It follows from these data that the antibatic connection possibly exists between excitation deactivation in associates and their optical activity. From data on splitting the associate CD spectra of type I and II the excitation interaction energy V12 congruent to 75 cm-1 was estimated. The reasons of increasing of rotational strength under transformation from I to II and the overturn of the sign dependence of bands in CD spectrum in some cases are discussed.

摘要

研究了二氧六环 - 水二元混合物中原叶绿素a(PChl)、4 - 乙烯基原叶绿素a(4VPChl)和叶绿素a(Chl)的聚集形式。这些聚集体是具有相当程度荧光偏振的色素分子的寡聚体颗粒,这表明它们具有有序结构。发现了两种类型的荧光缔合体I和II。通过其电子光谱,I与分子色素相似,但具有较小的量子产率B≈10⁻²,荧光寿命τ≈3 - 4×10⁻⁹秒。I型缔合体自发转化为II型缔合体,II型缔合体的电子光谱带比单体更窄,B非常低,约为10⁻³ - 10⁻⁴,τ约为2 - 4×10⁻¹⁰秒。与从I型到II型转变时由于旋转强度增加100倍导致的圆二色光谱(CD)中B和谱带强度降低相反。从这些数据可以推断,缔合体中的激发失活与其光学活性之间可能存在反位连接。根据I型和II型缔合体CD光谱的分裂数据,估计激发相互作用能V12≈75厘米⁻¹。讨论了从I型到II型转变时旋转强度增加以及某些情况下CD光谱中谱带符号依赖性反转的原因。

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