通过合成镧叶绿素a(La-Chla),研究稀土在叶绿素中的赋存状态.La-Chla的紫外可见光谱(UV-vis)、红外光谱(FT-IR)证实,镧离子已配位到叶绿素a的卟啉环上.其磁圆二色谱(MCD)在Soret带具有双层夹心卟啉结构的特征结构.通过扩展X射线吸收精细结构谱(EXAFS),采用双层夹心结构模型拟合,确定La周围的近邻结构,取得满意结果.表明合成镧叶绿素a具有双层夹心结构.La夹于两个卟啉环之间,与上下卟啉环上共八个N原子配位,La—N平均键长0.261nm. La-Chla was used to study the occurrence of rare earth elements in chlorophyll.La-Chla UV-vis and FT-IR spectra confirmed that lanthanum ions coordinated to chlorophyll a porphyrin ring.The magnetic circular dichroism (MCD) has a double-layered sandwich porphyrin structure in Soret band.Through the extension of the X-ray absorption fine structure (EXAFS), the double-layer sandwich model fitting, The results show that the lanthanum chlorophyll a has a double-layer sandwich structure, and La is sandwiched between two porphyrin rings and coordinated with eight N atoms on the upper and lower porphyrin rings. La-N The average bond length 0.261nm.