摘要
在甲醇和醋酸体系中合成得到翠绿色的叶绿素镧配合物,研究了它和叶绿素a、脱镁叶绿素a的紫外可见光谱,并首次研究了它们的磁园二色性谱(MCD谱)。叶绿素镧的UV-Vis谱和MCD谱与叶绿素a的相似,但是与脱镁叶绿素a有明显的区别,从而证明了镧离子已配位到叶绿素的卟啉环上.并形成了金属叶绿索镧的配合物。三者的变温MCD谱均含有C项的贡献,对于c项的来源,初步推测为体系中产生的自由基,这有待于EPR谱和更宽温度范围的MCD研究来确认。此外,由MCD谱推断叶绿素镧与叶绿素a具有相似的单层结构。
La(Ⅲ)-chlorophyll-a was synthesized in mixed solution of methanol and acetic acid.The room temperature UV-Vis and variable temperature MCD spectraof La(Ⅲ)-chlorophyll-a,chlorophyll-a and pheophytin-a were studied in tetrahy-dro-2-methylfuran solvent.The UV-Vis and MCD spectra of La (Ⅲ)-chlorophy-aare very similar to those of chlorophyll-a,but different from those of pheophytin-a.This shows that porphyrin ring of pheophytin-a is coordinated to La(Ⅲ)ion,andgives new complex.All variable temperature MCD spectra show the present ofFaraday C term,which may be contributed by the cation radicals. This need to befurther verified by EPR spectra.In addition,La(Ⅲ)-chlorophyll-a may have simi-lar monoporphyrin structure with chlorophyll-a from their similar MCD spectra.
出处
《北京大学学报（自然科学版）》
CAS
CSCD
北大核心
1996年第2期182-187,共6页
Acta Scientiarum Naturalium Universitatis Pekinensis
基金
国家自然科学基金
国家科委攀登计划
稀土材料化学及应用国家重点实验室资助项目
