2004 Fiscal Year Final Research Report Summary
Synthesis and New Reactivity of Nano-scale Conjugated Transition Metal Molecules
| Project/Area Number |
14350476
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Synthetic chemistry
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| Research Institution | Osaka University |
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Principal Investigator |
MASHIMA Kazushi Osaka University, Graduate School of Engineering Science, Professor, 基礎工学研究科, 教授 (70159143)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGATA Tsuneaki Osaka University, Graduate School of Engineering Science, Research Associate, 基礎工学研究科, 助手 (70166594)
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| Project Period (FY) |
2002 – 2004
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| Keywords | nanoscale / Cluster / Tetranuclear Complexes / Trinuclear complex / Oxidative Reaction / Conjugated system / Addition Reaction |
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| Research Abstract |
The construction of one-dimensional, covalently bonded metal strings has attracted much interest in view of fundamental bonding nature as well as promising applications as extensive electronic and optoelectronic materials. Two major synthetic approaches to these compounds have been conducted by (a)using polydentate ligands such as oligo-α-pyridylamido ligands or by (b)partial oxidation of d^8 square-planar complexes to form metal-metal bonds (e.g. platinum blue). Our effort has been focused on aligning transition metals by using a tridentate ligand 6-diphenylphosphino-2-pyridonate (pyphos), in which three different elements, P,N, and O, were linearly laid out by the rigid pyridone framework and could act as coordination sites for arrangement of more than two kinds of transition metals in linear manner. And we have demonstrated linear hetelometallic clusters containing both group VI and group X metals by use of the quadruply-bounded dimolybdenum(II) complex, Mo_2(pyphos)_4 (1)as a core
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part of metal strings such as Mo_2Pd_2Cl_2(pyphos)_4 (2)We have prepared linearly aligned tetranuclear complexes bearing the Rh-Mo-Mo-Rh array and their unique oxidative reaction. We found that rhodium metals at both axial positions of the Mo_2 cluster 1 electronically communicated through the Mo_2 core and, as a result, oxidative reaction Rh(I)/Rh(II) induced the formation of metal-metal bonds.
The formation of a metal-nanowire, of which four transition metals are linearly bounded through three metal-metal bonds, was accomplished by oxidation of each Rh(I) atom of 4a by two equiv of (Cp_2Fe)PF_6 to afford [Mo_2Rh_2(Cl)_2(^tBuNC)_4(pyphos)_4](PF_6)_2 (5)accompanied by the formation of two Mo-Rh(II) single bonds and the reduction of bond order of the Mo-Mo moiety.
Treatment of Pd_2Cl_2(CNC_6H_3Me_2-2,6)_4 (6)and Mo_2(O_2CCF_3)_4 (7)in dichloromethane afforded an infinite zigzag chain {[Pd_2Cl_2(CNC_6H_3Me_2-2,6)_4][Mo_2(O_2CCF_3)_4]}_n (8), where two metal-metal bonded dinuclear Pd-Pd and Mo-Mo units were bridged by chloro atoms. The Mo-Mo distance (2.1312(3) Å of 8 is significantly elongated compared to that of 7 (2.090(4)) Å) and lies in the range of that of the quadruple Mo-Mo bonded complexes. Such the elongation might be attributed to the axial donation of the chloro atoms of the Pd-Pd unit to the Mo-Mo moiety. Less
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