A Variable Temperature X-ray Diffraction Investigation of [PPN+][S4N5−]: Supramolecular Interactions Governing an Order/Disorder Transformation and the First High Resolution X-ray Structure of the Anion

Molecules

René T. Boeré¹  Tracey L. Roemmele¹ 

[1]Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB T1K 3M4, Canada

[2] E-Mails:

关键词: sulfur-nitride;    crystal structure;    disorder modelling;    DFT calculations;   

DOI  :  10.3390/molecules19021956

来源: mdpi

【 摘 要 】

The title salt, triphenyl(P,P,P-triphenylphosphineimidato-κN)-phosphorus(1+) 1,3,5,7-tetrathia(1,5-S^IV)-2,4,6,8,9-pentaazabicyclo[3.3.1]nona-1,4,6,7-tetraene(1−), CAS [48236-06-2], prepared by the literature method, is found by crystallography to be a 1:1 CH₃CN solvate. Disorder exists for the N atoms of the anion. A VT crystal structure study was conducted at 100 K, 120 K, 140 K, 172 K, 200 K, 240 K and 280 K. The 100 K structure is superior, with only 10% of a second anion position oppositely-oriented w.r.t the diad axis of point group 2mm. At 120 K, an adjacent two-site disorder is encountered, but at higher temperatures three-site disorder with both opposite and adjacent placements of S₄N₅⁻ ions is required w.r.t. the primary component. At 240 and especially 280 K, the anion nitrogen atoms appear fully scrambled amongst the six possible sites on the edges of an S₄ tetrahedron with 83.3% occupancy for each. The PPN⁺ geometry does not show strong cation-cation interactions. However, there are numerous supramolecular contacts corresponding mostly to non-classical H-bonds between PPN⁺ ions and S₄N₅⁻ as well as CH₃CN. The geometry of the anion is corroborated from B3LYP/6-311++G(3df) DFT calculations, and the infra-red spectrum was assigned with excellent agreement between experimental and calculated frequencies.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.