Phthalocyanine-modified surfactant-encapsulated polyoxometalate and its self-assembly in solution

Firstly, a novel functional double-chain cationic surfactant was designed and prepared in this study. Zinc phthalocyanine (ZnPc) was bonded onto the dodecyl (11-hydroxy-undecyl) dimethylammonium bromide (DHDA), obtaining the novel surfactant ZnPc-O-DHDA. Then, the surfactant-encapsulated polyoxometalate (POM) complex (ZnPc-O-DHDA/PW12) was prepared by using the double-phase co-precipitation method, through ion replacement with the Keggin-type polyoxometalate H3PW12O40 (PW12) The composition and structure of the complex were characterized using FT-IR, (HNMR)-H-1 and elemental analysis (EA). ZnPc-O-DHDA has a good absorption and emission spectral performance in the visible region. When ZnPc-O-DHDA combined with PW12 to form a complex, and its Q-band fluorescence emission was enhanced because of the increased singlet-triplet energy gap of ZnPc. Thermogravimetric analysis (TGA) and EA data indicated the ratio of ZnPc-O-DHDA and PW12 in the complex was 2.8:1. ZnPc-O-DHDA/PW12 can self-assemble in DMSO/H2O (v:v = 4:1) solvent to form a spherical structure with a size of about 500 nm. The resulting aggregates could be successfully transferred into water to produce pellets of about 50 nm, while transferred into ethanol to produce small cubes of about 150 nm. The successful synthesis of this functional surfactant ZnPc-O-DHDA and its POM complex provide a new approach for the further design and preparation of functional POM aggregates.