Crystal structure of (4R,5S,6R)-6-azido-5-benz­yloxy-3,3,4-tri­fluoro­azepan-1-ium 2,2,2-tri­fluoro­acetate from synchrotron data

Acta Crystallographica Section E: Crystallographic Communications

Patel, A.R.¹  Liu, F.¹  Bhadbhade, M.M.² 

[1] Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia;Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, 2052 NSW, Australia

关键词: CRYSTAL STRUCTURE;    AZEPANE;    FLUORINATION;    FLUORINE GAUCHE EFFECT;    HYDROGEN BONDING;   

DOI  :  10.1107/S2056989015019416

学科分类：数学（综合）

来源: International Union of Crystallography

【 摘 要 】

The structure of the title compound, C15H16F6N4O3, was determined using synchrotron radiation on an extremely small crystal (0.015 × 0.01 × 0.01 mm). Although the diffraction was weak, leading to high residuals and a poor data-to-parameter ratio, the data allowed ready solution and refinement to reveal the entire structure. The solid-state structure is in accordance with the absolute configuration assigned based on that of the known starting material. The compound comprises a highly substituted seven-membered N-heterocyclic cation and a tri­fluoro­methane­sulfonate counter-anion. The title compound crystallizes with two independent cations (A and B) and anions (C and D) in the asymmetric unit. Two geminal F atoms, a single F atom, a benzyl ether and an azide group are substituted on consecutive C atoms between the NH2 and CH2 units of the azepan-1-ium ring system. The seven-membered rings adopt different conformations with the principal differences occurring in the CF2CHFCH2 segments of the ring systems. The geminal F atoms on the quaternary C atom exhibit essentially identical bond angles [109 (2) and 106 (2)°] in the two independent mol­ecules. The two mol­ecules associate as a dimeric unit via two C—H⋯F inter­actions. An extensive series of N—H⋯O, N—H⋯F, C—H⋯O, C—H⋯N, C—H⋯F and C—H⋯π contacts generate a three-dimensional network with cations and anions linked into ABCD repeat columns along a.

【 授权许可】

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