Crystal structure of bis(triphenylphosphonium) hexabromadigallate(II) in the correct space group: conformational complexity in a heteroethan
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Date
2016
Authors
Marasco, Olivia N. J. M.
Wolny, Sydney K.
Knott, Jackson P.
Stuart, Daniel
Roemmele, Tracey L.
Boeré, René T.
Journal Title
Journal ISSN
Volume Title
Publisher
Cogent OA
Abstract
The crystal structure of [Ph3PH]2[Ga2Br6], previously described as having a disordered anion in the space group R̄ 3, has been re-determined in the correct space group P̄ 3, where it is fully ordered. Interestingly, two-thirds of the [Ga2Br6]2− dianions have an intermediate conformation with a Br–Ga–Ga–Br torsion angle of 36.91 (1)°, while the remaining is staggered as required from adopting a site with inversion symmetry. In the lattice, [Ph3PH]+ ions lie along the same threefold axes as the dianions and are oriented such that the P–H bond is directed towards a gallium atom. The phosphonium ions lie back-to-back and interact with relatively strong T-interactions between phenyl rings on adjacent cations. DFT calculations at the B3LYP/6–311+G(fd,) level have been used to determine the barriers to rotation in [Ga2X6]2− ions. For X = Cl and X = Br, the barriers are found to be very small, with values of 4.3 and 5.1 kJ mol−1 for the two halogens.
Description
Sherpa Romeo green journal. Open access article. Creative Commons Attribution 4.0 License (CC-BY) applies
Keywords
Hexahallodigallate , Sextuple phenyl embrace , Single bond rotation , Conformation , X-ray crystal structure , Density functional theory calculations
Citation
Marasaco, O. N. J. M., Wolny, S. K., Knott, J. P., Stuart, D., Roemmele, T. L. & Boeré, R. T. (2016). Crystal structure of bis(triphenylphosphonium) hexabromodigallate(II) in the correct space group: Conformational complexity in a heteroethan. Cogent Chemistry, 2, 1273065. https://doi.org/10.1080/23312009.2016.1273065