Metal Valence and Spin Structures in 1-D Ni-Pd Mixed-Metal Complexes, [Ni_<1-x>Pd_xBr(chxn)_2](NO_3)_2(0.00&le;x&le;1.00), Studied by ^<13>C NMR and ESR Measurements

^<13>C solid-state NMR and ESR spectra were observed in [Ni_<1-x>Pd_xBr(chxn)_2] (NO_3)_2 (0.00&le;x&le;1.00 ; chxn : 1R, 2R-diamonocyclohexane), where the antiferromagnetically coupled paramagnetic-Br-Ni^<3+>-Br-Ni^<3+>-Br-chains are formed at x=0.00, while the mixed-valence-Br-Pd^<2+>-Br-Pd^<4+>-Br-state is formed at x=1.00. The ^<13>C NMR signals at C_α coordinating to Ni atoms in mixed-metal complexes afforded the marked decrease of intensity with increasing x from 0.00. This result seems to be attributed to the effect of the strong spin fluctuation on paramagnetic Ni^<3+> sites, and was supported by ESR spectrum measurement.