パラジウムおよび白金の二次元π共役ジチオレン錯体ポリマーの研究

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 西原 寛, 東京大学教授 佃 達哉, 東京大学准教授 廣瀬 靖, 東京大学教授 塩谷 光彦, 東京大学教授 大越 慎一University of Tokyo(東京大学

Redox Control and High Conductivity of Nickel Bis(dithiolene) Complex π‑Nanosheet: A Potential Organic Two-Dimensional Topological Insulator

A bulk material comprising stacked nanosheets of nickel bis­(dithiolene) complexes is investigated. The average oxidation number is −3/4 for each complex unit in the as-prepared sample; oxidation or reduction respectively can change this to 0 or −1. Refined electrical conductivity measurement, involving a single microflake sample being subjected to the van der Pauw method under scanning electron microscopy control, reveals a conductivity of 1.6 × 10² S cm^–1, which is remarkably high for a coordination polymeric material. Conductivity is also noted to modulate with the change of oxidation state. Theoretical calculation and photoelectron emission spectroscopy reveal the stacked nanosheets to have a metallic nature. This work provides a foothold for the development of the first organic-based two-dimensional topological insulator, which will require the precise control of the oxidation state in the single-layer nickel bisdithiolene complex nanosheet (cf. Liu, F. et al. <i>Nano Lett.</i> <b>2013</b>, <i>13</i>, 2842)