Synthesis and Characterization of RE-Chlorophyll-a Complexes (RE=La, Ce, Eu and Y)

RE chlorophyll a complexes (RE=La, Ce, Eu and Y) were synthesized in acetone solution. The UV Vis and FTIR spectra of RE chlorophyll a, chlorophyll a and pheophytin a as well as MCD spectra of chlorophyll a, pheophytin a and La chlorophyll a were studied. Results show that Soret band splits, Q y(0→0) blue shifts, and the other Q band disappearance occurred in the UV Vis spectra of the RE chlorophyll a complexes. The FTIR spectra of the RE chlorophyll a complexes are similar to that of chlorophyll a, but are distinct from that of pheophytin a. These phenomena indicate that La 3+ , Ce 3+ , Eu 3+ , and Y 3+ coordinate to the porphyrin rings of pheophytin, and RE chlorophyll a complexes are formed. MCD spectrum of La chlorophyll a shows the special bands in Soret band region, which indicated that La chlorophyll a are sandwich structure porphyrin complexes.