Metallic behaviour and molecular motions in a 1-D -Pt-Pt-I- type complex, Pt2(CH3CS2)4I, studied by solid-state 13C and 1H NMR

13C and 1H NMR measurements were performed on Pt2(CH3CS2)4I in which a metallic phase was reported above ca. 300 K. CS2 carbon signals gave the Knight shift with the line-broadening above ca. 300 K. In a range of 200-350 K, the 1H T1 showed that the distribution of two kinds of twist orientations in CS2 skeletons is not static but dynamic, where the jump between the two orientations was shown to take place between highly asymmetric potential wells. The transition from semiconducting to metallic phases is attributable to the Pt valence transition with a dynamic twisting motion of the ligand.