Novel tellurium containing fulvalene-type electron donors, triselenatellurafulvalene (TSTeF) and diselenaditellurafulvalene (DSDTeF) are synthesized by an efficient two- or three-stage procedure. They behave as superior electron donors to give highly conductive charge-transfer (CT) complexes with TCNQ. TSTeF–TCNQ shows a high conductivity of 2000 S cm−1 at room temperature and is metallic down to 85 K, where a metal–insulator (MI) transition takes place. In contrast, the conductivity of DSDTeF–TCNQ is 1400 S cm−1 at room temperature and monotonously increases down to 4.2 K without any MI transition. An X-ray structural analysis shows that TSTeF–TCNQ is crystallographically isostructural with TTF–TCNQ comprising typical one-dimensional donor and acceptor columns. On the other hand, the crystal structure of DSDTeF–TCNQ is characterized
by quasi one-dimensional donor stacks with side-by-side intercolumnar interactions through Te–Se contacts, which stabilize the metallic state at low temperature.
新型
碲化物包含富瓦烯类电子供体三
硒化
碲富瓦烯(TSTeF)和二
硒化二
碲富瓦烯(D
SDTeF),可通过高效的两步或三步合成工艺合成。它们作为优异的电子供体,与TCNQ形成高导电性的电荷转移(CT)复合物。TSTeF-TCNQ在室温下表现出2000 S cm-1的高导电性,在85 K以下为
金属态,在此温度下发生
金属-绝缘体(MI)转变。相比之下,D
SDTeF-TCNQ在室温下的导电性为1400 S cm-1,在4.2 K以下单调增加,没有发生MI转变。X射线结构分析显示,TSTeF-TCNQ与
TTF-TCNQ在晶体结构上具有同构性,包含典型的一维供体和受体柱。另一方面,D
SDTeF-TCNQ的晶体结构特征是准一维供体堆叠,通过Te-Se接触形成并排的柱间相互作用,从而在低温下稳定
金属态。