Dye-polyoxometalate composite films: self-assembly, thermal and photochemical properties.
A series of dye-polyoxometalate composite films were prepared by alternately depositing cationic dye molecules and anionic polyoxometalates such as Keggin-type [BW(12)O(40)](5-) and the sandwich complex [Co(4)(H(2)O)(2)(PW(9)O(34))(2)](10-)via layer-by-layer (LbL) self-assembly method. These cationic dye molecules (MB, AA, TH, BB3, BCB and NB) are heterocyclic planar and rigid phenothiazine and phenoxazine dye molecules with different substituting groups in the side chains. The self-assembly of the films was studied by UV-vis and IR spectra. The results show that the substituting groups of dye molecules such as NH(2) and CH(2)CH(3) have influence on the self-assembly properties. The continuous and regular growth of the films was also dependent upon hydrogen bonding (NHO) formed between the amino groups of dye molecules and oxygen atoms of POMs as well as electrostatic interactions. The investigation of thermal and photochemical treatments of the composite films is also presented. The thermal stability experiments indicate that the composite films of TH with two NH(2) substitute groups and NB with more pi-conjugated system exhibit high thermal stability, whereas the sunlight irradiation results indicate that the composite films of TH have good photochemical stability.
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, The Chinese Academy of Sciences, Fuzhou 350002, China. rcao@fjirsm.ac.cn
Shuiying
S
Gao
Rong
R
Cao
Chunpeng
C
Yang
D004396:Coloring Agents / Q000737:chemistry*; D010777:Photochemistry; D013696:Temperature; D017973:Tungsten Compounds / Q000737:chemistry*; D000099294:Polyoxometalates
D004396:Coloring Agents; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates