摘要
通过合成镨叶绿素 a(Pr-Chla)研究了稀土在叶绿素中的结合方式 .Pr-Chla的紫外可见光谱 (UV-Vis)、红外光谱 (FTIR)证实镨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 ,确定了Pr周围的近邻结构 .表明合成镨叶绿素 a具有双层夹心结构 .Pr( )夹于两个卟啉环之间 ,与上下卟啉环上共 8个 N原子配位 ,Pr— N键平均键长 0 .2 4 2
The Pr(Ⅲ) complex of Chlorophyll a was synthesized and characterized. The results of UV Vis and IR spectra indicate the coordination of Pr(Ⅲ) to the porphyrin rings. The special bands in Soret band region in MCD spectra shown a transition type of the sandwich structure porphyrin complexes. By extended X ray Absorption Fine Structure(XAFS) method, a double decker sandwich structure was well fitted, in which Pr is surrounded by eight nitrogen atoms from two porphyrin rings. Combining the MCD with EXAFS results, it is believed that the binding mode of Pr ion in chlorophyll a is a sandwich structure with the Pr—N bond length of average 0.242 nm.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2000年第3期331-334,共4页
Chemical Journal of Chinese Universities
基金
国家自然科学基金!(批准号 :2 980 5 0 0 3和 2 92 710 30 )
