Competition between electron-correlation in Ni(III) and electron-lattice interaction in Pd(II)-Pd(IV) in mixed-metal MX-chain, Ni1−xPdx(chxn)2Br3

The electrical conductivities, IR, XPS and resonance Raman spectra of a series of Ni-Pd mixed-metal MX-chain compounds, Ni1−xPdx(chxn)2Br3 have been measured in order to investigate the competition between the electron-correlation in Ni(III) and the electron-lattice interaction in Pd(II)-Pd(IV) states. In these compounds, at x=0.4, the activation energy in electrical conductivity is minimized. And at x=0.4 or below, the vN-H does not split, while at x with larger than 0.5, vN-H shows triplet. This result suggests that the Pd(II)-Pd(IV) mixed-valence states are effectively influenced by Ni(III) states, approaching toward the Pd(III) states.