**Kazuha Sakaguchi, Biao Zhou \*, Yuki Idobata, Hajime Kamebuchi and Akiko Kobayashi**

Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-Ku, Tokyo 156-8550, Japan; sakakazu0309@gmail.com (K.S.); 6sided.currencystone@ezweb.ne.jp (Y.I.); hkame@chs.nihon-u.ac.jp (H.K.); akoba@chs.nihon-u.ac.jp (A.K.) **\*** Correspondence: zhou@chs.nihon-u.ac.jp; Tel.: +81-3-5317-9364

Received: 13 October 2020; Accepted: 3 November 2020; Published: 4 November 2020

**Abstract:** In order to develop new types of single-component molecular conductors with novel electronic structures and physical properties, the neutral gold dithiolate complex with an etdt (= ethylenedithiotetrathiafulvalenedithiolate) ligand, [Au(etdt)2] was prepared. However, unlike the reported single-component molecular metals, the neutral gold complex [Au(etdt)2]·THF (**2**) contains a solvent molecule of tetrahydrofuran (THF). The crystals of **2** form a two-dimensional conducting layer structure, which are separated by the terminal ethylene groups and THF molecules. The fairly high room-temperature conductivity of 0.2 S/cm and semiconducting behavior with a low activation energy of 0.1 eV of **2**, is consistent with the result of the density functional theory band structure calculations. The observed non-magnetic behavior of **2** is caused from the dimeric structure of [Au(etdt)2] molecules.

**Keywords:** single-component molecular conductors; extended-TTF dithiolate ligands; gold dithiolate complexes
