A Semiconductor or A One‐Dimensional Metal and Superconductor through Tellurium π Stacking

Controlled Synthesis of Polyions of Heavy Main-Group Elements in Ionic Liquids

“…A variety of homoatomic polycations of group 15 or 16 elements has been synthesized in ILs [26,27,31,99,101,102,103,104] and several influencing reaction parameters were deduced.…”

“…Apart from Te 4 2+ , which proves a dominance in Lewis-acidic AlCl 3 -containing ILs similar to Bi 5 3+ , several other tellurium polycations (Figure 5) were accessed in ILs [26,27,31,101,102,103]. Thereby, the utilization of an IL as reaction medium can lead to extraordinary properties of the reaction product as the following example demonstrates: Te 4 [Bi 0.67 Cl 4 ] obtained from a gas-phase transport reaction is an conventional semiconductor.…”

“…Thereby, the utilization of an IL as reaction medium can lead to extraordinary properties of the reaction product as the following example demonstrates: Te 4 [Bi 0.67 Cl 4 ] obtained from a gas-phase transport reaction is an conventional semiconductor. However, the closely related Te 4 [Bi 0.74 Cl 4 ], obtained from an IL-based low-temperature synthesis, proved to be a one-dimensional metal and type-I superconductor [31]. …”

“…In the system Te–Bi–Cl, three different ternary compounds (and polycations) can be synthesized under identical conditions in the Lewis-acidic IL [BMIm]Cl· n AlCl 3 ( n = 1.3–1.5): the aforementioned Te 4 [Bi 0.74 Cl 4 ] [31] as well as the closely related semiconductors Te 4 [Bi 6 Cl 20 ] [26] and Te 8 [Bi 4 Cl 14 ] [26]. The distinctive directing parameter of these room temperature reactions has proven to be the ratio of the starting materials: If elemental tellurium, TeCl 4 , and BiCl 3 are utilized in a proportion according to the respective composition, each compound is yielded as phase-pure product.…”

“…Owing to the distinctive physicochemical properties of ILs (wide liquidus range, high redox and thermal stability, negligible vapor pressure, and tunable polarity) and their advantages over organic solvents, classic melts, or solid state reactions, their applications include separation techniques [7,8,9], lubrication [10], electrodeposition [11], acting as electrolytes in photovoltaic devices (e.g., solar cells) [12,13,14], catalysis for clean technology [15,16,17,18], polymerization processes [19], crystal engineering of a wide range of inorganic substances [20,21,22,23,24,25], and syntheses of new inorganic materials in general [23,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51]. Recently, several comprehensive reviews on syntheses of inorganic compounds in ILs have been published by Taubert [52], Feldmann [28], Dehnen [51], Janiak [42,53], Scrosati and Passerini [48], Morris [54], Mudring [55], Prechtl [56], Zhu [57], Dai [58], and Ruck [23,27,59] among others.…”