Preparation And Characterization Of Dawson Type Polyoxometalate/Fluorene-based Hybrid Materials

In recent years, the research of organic-inorganic hybrid materials have been developed rapidly. Four new covalently linked organic-polyoxometalate hybrid materials were synthesized. A series of hybrid Langmuir-Blodgett films were prepared. The structure and properties of four new hybrids were characterized by NMR, IR, UV-vis, PL, CV, AFM and so on.Chapter I:IntroductionThe species and application of organic-inorganic hybrid materials and development of Langmuir-Blodgett films technique were introduced. An overview includes the properties and structure of polyoxometalates, the properties and application of fluorene and porphyrin, the type of the covalently connected ways between the organic composite and polyoxometalate composite, the synthesis and functionalization of organic-polyoxometalate hybrid materials combined by phosphorus-oxygen bond. Finally, the research purposes and the work plans were presented.Chapter II:Preparation and characterization of covalently linked fluorene/Dawson-type polyoxometalate hybrid materials.The organic component,7-ethynyl-2-fluorenylphosphonic acid (F), was synthesized staring from fluorene by halogenating and Pd-catalyzed coupling reactions. The hybrid compound (Bu4N)6[a-P2W17O61(P(O)C13H8C=CH)](FD) was synthesized by F and K10[α-P2W17O61](D) in acid condition with tetrabutylammonium bromide acting as phase transfer catalyst. The luminescence spectra indicated POM quenched partial fluorescence possibly due to the POM as a good electron acceptor. The hybrid LB film of FD was prepared and characterized. The FD could form stable LB film and the LB film of FD displayed good conductivity.Chapter HI:Postfunctionalization of covalently linked ethynyl fluoren and ethynyl benzene/Dawson-type polyoxometalate hybrid materials by Pd-catalyzed coupling reactionThree new organic-polyoxometalate covalently linked hybrids (F’-FD, Zn-TPP-FD and C16-F’-OD) were synthesized by Pd-catalyzed coupling reaction from the hybrid precursor FD and (Bu4N)6[a-P2W17O61(P(O)C6H5C=CH)](OD), reacted with2-bromofluorene (F’), tetraphenyl Zn-porphyrin (Zn-TPP),2-bromo-9,9-dihexadecylfluorene (C16-F’), respectively. The LB films of F’-FD, Zn-TPP-FD and C16-F’-OD were prepared and characterized. The photoluminescence spectra showed that the fluorescence intensity of F’-FD, Zn-TPP-FD and C16-F’-OD are much lower than FD and OD. The LB films of F’-FD, Zn-TPP-FD and C16-F’-OD showed good conductivity.