水素結合と電子状態 The H-bonds and the Electronic States
In this report, the cooperation of electron and proton in organic-inorganic hybrid systems is discussed.<BR>Particularly, the experimental results of the X-ray diffraction measurements on the 1-D metallic charge-transfer crystal of [Pd (H<SUB>2-x</SUB>EDAG) (HEDAG) ] TCNQ (EDAG=ethylenediaminoglyoxime, x=ca. 0.7) were focused. Below the metal-insulator (M-I) phase transition (180 K), commensurate superlattice reflections were observed with a period of c<SUP>*</SUP>/2, c<SUP>*</SUP>/3, and c<SUP>*</SUP>/12 along the 1-D axis, <I>c</I>. The full X-ray diffraction analyses of temperature-dependent reflections ignoring the superlattice spots show remarkable anomalies of the temperature factors below 180 K for several atoms which associate with the intermolecular H-bonds between donor-molecules. This is a result of cooperation between the order-disorder transition of the 1-D H-bond intermolecular superlattice and the M-I transition of the 1-D electronic state in TCNQ acceptor stacks. These experimental results support a model of purely 1-D metallic hole-conduction introduced by partial deprotonation of H-bonds in the ligands of [Pd (H<SUB>2-x</SUB>EDAG) (HEDAG) ] .
日本結晶学会誌 40(1), 83-89, 1998-02-28
The Crystallographic Society of Japan