Self-assembly and alterable relaxivity of an organic cation-encapsulated gadolinium-containing polyoxometalate.
A new amphiphilic molecule bearing poly(ethylene oxide) (PEO) and quaternary ammonium group, was designed and synthesized to encapsulate paramagnetic Gd(III)-containing polyoxometalate (Gd-POM) through electrostatic interaction for obtaining a water-soluble organic-inorganic hybrid building block based on POM. The yielding organic cation-encapsulated Gd-POM (OCEP-Gd) complex exhibited water-solubility and amphiphility, leading to the spontaneous self-assembly into a regular vesicular structure with PEO chains towards water phase and POM units locating at the middle. The vesicular aggregate which has a regular monolayer structure, was further studied by means of dynamic light scattering, transmission electron microscopy, and X-ray diffraction. Due to the synergy of different building units, the self-assembly of the complexes was demonstrated to be efficient to adjust the ability of Gd-POM to accelerate relaxation of water-proton, which results from the paramagnetic property of Gd-POM, to a large extent. The present work provides a new methodology to obtain water-soluble hybrid building blocks based on POM, which may generate more hybrid self-assembly structures in aqueous solution and further direct POM-based materials towards biomedical applications.
State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, 130012, P.R. China.
Yinglin
Y
Wang
Shengyan
S
Zhou
Daliang
D
Kong
Haishan
H
Yang
Wenqiang
W
Chai
Ulrich
U
Kortz
Lixin
L
Wu
D002412:Cations / Q000737:chemistry; D003287:Contrast Media / Q000737:chemistry; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry; D005682:Gadolinium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D055672:Static Electricity; D017973:Tungsten Compounds / Q000737:chemistry*; D014867:Water; D014961:X-Ray Diffraction; D000099294:Polyoxometalates
D002412:Cations; D003287:Contrast Media; D056831:Coordination Complexes; D005682:Gadolinium; D017973:Tungsten Compounds; D014867:Water; C102296:polyoxometalate I; D000099294:Polyoxometalates