Development of Energy Conversion Materials Based on Efficient Synthesis of Multimetallic Metal-Bis(dithiolene) Complexes

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K13626
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Nanomaterials chemistry
• Research Institution: Osaka Institute of Technology (2017-2018); Kyoto University (2016)
• Principal Investigator: Murata Michihisa 大阪工業大学, 工学部, 准教授 (30447932)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: エネルギー変換材料 / 環境発電 / 構造有機化学 / 金属錯体 / 有機π電子系

Outline of Final Research Achievements

One-dimensional (1D) polymers that consist of π-conjugated metal-bis(dithiolene) units have received significant attention on account of their unique properties, which include high conductivity, and due to their potential use in organic thermoelectric materials. Although a 1D metal-bis(dithiolene) polymer with tetrathiooxalate (tto) ligands has shown high thermoelectric performance, examples of such 1D conductive polymers remain limited. In this study, we have developed an improved method for the synthesis of structurally well-defined multimetallic gold-bis(dithiolene) complexes, which led to the formation of 1D rod-shaped and 2D starburst structures as potential precursors for molecular conductors. We further prepared π-conjugated bridging units, which contained cyanoethyl-protected thiol groups, by Pd-catalyzed cross coupling reactions as air-stable precursors. These precursors were subsequently converted into metal-coordinating polymers, which exhibit thermoelectric properties.

Free Research Field

有機化学

Academic Significance and Societal Importance of the Research Achievements

本研究では、π共役ジクロロ金錯体を末端ユニットとして用いる手法により，従来な合成困難な一次元ロッド型および二次元スターバースト型の二核および三核金ジチオレン錯体をアニオン性錯体として効率的かつ簡便な単離操作で得られることを示した。さらに，シアノエチル基で保護されたモノマー前駆体を用いる簡便な錯体の合成法を検討し，一次元π共役ニッケル錯体の溶液プロセスにより作製した薄膜が熱電特性を示すことを明らかにした。一次元π共役ニッケル錯体は、金属を介して拡張されたπ軌道に基づき、固体中での分子間π-π相互作用の増大が考えられ、フレキシブル熱電変換素子のための半導体材料の開発につながる知見が得られた。