4-Hydroxy-2,2,6,6-tetra­methyl­piperidinium trifluoro­acetate

Yan-Xue Chen; Mei-Ling Han; Yi Deng; Jin-Hui Yang

doi:10.1107/S1600536807066305

. 2007 Dec 18;64(Pt 1):o275. doi: 10.1107/S1600536807066305

4-Hydroxy-2,2,6,6-tetramethylpiperidinium trifluoroacetate

Yan-Xue Chen ^a, Mei-Ling Han ^a, Yi Deng ^b,^*, Jin-Hui Yang ^c

PMCID: PMC2915329 PMID: 21200840

Abstract

The title compound, C₉H₂₀NO⁺·C₂F₃O₂ ⁻, is an important intermediate in the synthesis of hindered light stabilizers. The piperidinium ring adopts a chair conformation with the hydroxyl group in an equatorial position. The crystal packing is stabilized by O—H⋯O and N—H⋯O hydrogen bonds. The CF₃ group is disordered over two positions with almost equal site occupancy factors.

Related literature

For general background, see: Borzatta & Carrozza (1991 ▶). For related structures, see: Nengfang et al. (2005 ▶).

Experimental

Crystal data

C₉H₂₀NO⁺·C₂F₃O₂ ⁻
M _r = 271.28
Orthorhombic,
a = 7.6204 (8) Å
b = 9.8939 (10) Å
c = 18.099 (2) Å
V = 1364.6 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 113 (2) K
0.22 × 0.20 × 0.16 mm

Data collection

Rigaku Saturn diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005 ▶) T _min = 0.974, T _max = 0.981
17989 measured reflections
2039 independent reflections
1993 reflections with I > 2σ(I)
R _int = 0.057

Refinement

R[F ² > 2σ(F ²)] = 0.057
wR(F ²) = 0.132
S = 1.23
2039 reflections
202 parameters
48 restraints
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997 ▶); molecular graphics: SHELXTL (Bruker, 1997 ▶); software used to prepare material for publication: CrystalStructure (Rigaku/MSC, 2005 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536807066305/bt2664sup1.cif

e-64-0o275-sup1.cif^{(18.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807066305/bt2664Isup2.hkl

e-64-0o275-Isup2.hkl^{(100.3KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1B⋯O2	0.92	1.88	2.786 (3)	169
N1—H1A⋯O1ⁱ	0.92	1.96	2.869 (3)	171
O1—H1⋯O3ⁱⁱ	0.84	1.85	2.682 (3)	171

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Symmetry codes: (i) Inline graphic ; (ii) .

supplementary crystallographic information

Comment

4-hydroxyl-2,2,6,6-tetramethylpiperidine is a very important intermediate in the synthesis of hindered light stabilizers (Borzatta & Carrozza, 1991; She et al., 2005). The piperidium ring adopts a chair conformation with the hydroxyl group in an equatorial position. The crystal packing is stabilized by O—H···O and N—H···O hydrogen bonds.

Experimental

An ethanol solution (10 ml) of 2,2,6,6-tetramethylpiperidin-4-ol (3.2 mmol, 0.5 g) was added dropwise to a stirred aqueous solution (6 ml) of trifluoroacetic acid (3.8 mmol, 0.43 g) at 293 K. Then the reaction mixture was filtered and the filtrate stood for about five days until colourless needle shaped crystals were obtained.