Electron spin dynamics in the new halogen-bridged one-dimensional complex, Ni2(CH3CS2)4I studied by 1H NMR

We measured temperature and Larmor frequency(ω) dependences of the 1H NMR spin-lattice relaxation time T1 in solid Ni2(CH3CS2)4I which contains the one-dimensional(1-D) chain of -Ni-Ni-I-Ni-Ni-I- with no Peierls distortion. Almost temperature independent T1 values of ca. 180 ms observed at ω = 40.98 MHz and in the range of 90–300 K are attributable to the relaxation due to the fluctuation of antiferromagnetically coupled unpaired electron spin formed at each -X-Ni-Ni- unit in consistent with the 1-D Mott-Hubbard type structure. T1 in this temperature range showed the Larmor frequency dependence of ω12 explainable by rapid spin diffusion along the 1-D chain. Applying the Devreuxʹs treatment on the low-dimensional spin dynamics, the diffusion rate and activation energy for the 1-D hopping of electron spins were evaluated.