Co-Investigator(Kenkyū-buntansha) |
NARUKE Haruo Tokyo Institute of Technology, Chem. Resources Lab., Associate Professor (40237623)
OZEKI Tomoji Tokyo Institute of Technology, Grad. School Sci. & Eng., Associate Professor (60214136)
ISHIKAWA Eri Chubu Univ., Dept. Appl Chem., Associate Professor (90323831)
ITOH Takeru Tokai Univ., Dept. Chem., Assistant Professor (50376935)
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Research Abstract |
Since we found the spin-frustrated (VO)_3^<6+>-triangle sandwiched by two diamagnetic α-B-[XW_9O_<33>]^<9-> (X=Sb^<III> and Bi^<III>) ligands in [(VO)_3(SbW_9O_<33>)_2]^<12-> and [(VO)_3(BiW_9O_<33>)_2]^<12-> as a simple model of the magnetization (involving Dzyaloshinsky-Moriya interaction) between pure quantum states S=1/2 and S=3/2 in 2004, we have clarified the magnetochemistry of a variety of the spin rings embedded in polyoxometalates for understanding the quantum hysteresis of spin rings at molecular level, as well as the self-assembly mechanism for establishing a methodology of molecular design of these novel polyoxometalates. The results constitute a basis for establishment of the polyoxometalate-based electronic/magnetic devices: (1) Details of photochemically controlled self-assembly to superclusters such as nano-rings, -ball, -ellipsoids, -egg, -chains, and -tubes have been clarified together with their structure chemistry, which enable us successfully to design of a variety of nano-sized polyoxometalate super clusters. (2) Molecular magnetisms (magnitudes of J and Δ, and their origins) of spin hexagon, spin prism, and rhombic spin tetragon have been clarified by designing the model compounds such as [(CuCl)_6(AsW_9O_<33>)_2]^<12->, [Mn_6(H_2O)_2(AsW_9O_<34>)_2(AsW_6O_<26>)]^<17->, and [Cu_4(GeW_9O_<34>)_2]^<12->14H_2O, which provide quantum tunneling, quantum hysteresis, anisotropy at zero field, and point-dipole approximation in magnetization experiments. (3) The near infra-red light-induced photoconductivity of Mo-blue giant clusters is found, and a significance of the coordination of aqua ligands on the molecular surface in photoconduction is pointed out.
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