| Research Abstract |
The aim of this project is to produce new molecular devices of photoconduction on the basis of electron-proton cooperation in hydrogen-bonded charge-transfer compounds the electron-proton transer. The subject of this project has been performed using three main systems as follows :
(1) Control of the 1-D electronic state by introduction of the strong H-bonds in halogen-bridged metal complexes, {[MA2X2]Y2}, M=Pt, Pd, and Ni, X=Cl, Br, and I, Y : caunter anions, A : ligands.
(2) extended conjugated quinhydrones : 1,5-dihalo-2,6-naphthoquinhydrones.(ref.8)
(3) Creation of new molecular functions on the basis of the electron-proton cooperation in [M(H_2DAG)(HDAG)]TCNQ (M=Ni, Pd, Pt).
In (1), a new material has been synthesized by introduction of the strong inter-chain H-bonds. By detailed analysis of the newly synthesized complexes, the possibility to find a new type of the superconductivity might be considered to increase.
From the experimental results of these materials, it has been elucidated that the coexistence of the inter- and intra-molecular charge-transfer with inter-molecular H bonds leads to the auto-charge ceparation of charge-transfer excitons, which can be utilized as a new type of photo-sensitive copy mechanism.
In (3) systems, [M(H2DAG)(HDAG)]TCNQ (M=Ni, Pd, Pt, and H2DAG : diaminoglyoxime) single crystals have been investigated by optical, vibrational and XPS measurements in details. The results indicate that the dz2 electronic state of the metal (M) chain and the *-electronic state of acceptor (TCNQ) stack closely correlate through the intra-H-bonds in ligands (HDAG and H2DAG) and the interchain H-bonds. This gives the strongly temperature-dependent mixed-valence state of metals, which is quite consistent with the prediction from molecular orbital analysis of a model material. These results unquestionably indicate a promising of our proposal of creation of novel H-bonded molecular systems.
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