A low-temperature phase of bis(tetrabutylammonium) octa-μ₃-chlorido-hexachlorido-octahedro-hexatungstate

Abstract

The title compound, (C(16)H(36)N)(2)[W(6)Cl(14)], undergoes a reversible phase transition at 268 (1) K. The structure at 150 and 200 K has monoclinic (P2(1)/c) symmetry. Both crystallographically independent tungsten chloride cluster anions sit on crystallographic inversion centers [symmetry codes: (-x, -y + 1, -z) and (-x + 1, -y + 2, -z)]. Two previous studies at room temperature describe the structure in the space group P2(1)/n with a unit-cell volume approximately half the size of the low-temperature unit cell [Zietlow, Schaefer et al. (1986). Inorg. Chem. 25, 2195-2198; Venkataraman et al. (1999). Inorg. Chem. 38, 828-830]. The unit cells of the room- and low-temperature polymorphs are closely related. The hydrocarbon chain of one of the tetrabutylammonium cations is disordered at both 150 and 200 K.

Reentrant structural and optical properties of organic–inorganic hybrid metal cluster compound ((n-C4H9)4N)2[Mo6Bri8Bra6]

“…This is because their high-temperature phases are generally associated with the freedom of rotational and reorientational motions of the alkylammonium cations [24,25]. In MC-based compounds, a phase transition of (TBA) 2 [W 6 Cl i 8 Cl a 6 ], similar to the present study, has already been reported by Johnston et al [26]. This study reveals that (TBA) ], but are not completely identical.…”

“…This is indicative of an enhancement in the luminescence efficiency along with the structural transition. There have been a few studies that have investigated the phase transitions and crystallographic polymorphs of MC-based compounds [26]. Therefore, this study is the first to discover the reentrancy of the phase transition and improvement of the optical property by the crystal structure change in the MC-based compound system; meanwhile this study still remained some structure and property investigations such as temperature-variable measurements of powder XRD and photoluminescence quantum yield, and those will be vital to further understand the present phenomena.…”

Luminescent coordination polymers based on Ca2+ and octahedral cluster anions [{M6Cli8}Cla6]2− (M = Mo, W): synthesis and thermal stability studies

“…Table S2, ESI †). 36,37,39,41 Apart from ionic bonding, the structures of 1 and 2 are supported by an extensive network of hydrogen bonds (Fig. 1) and 4 are close to the analogous distances in these complexes.…”