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The title compound, C5H12NO2+·C2F3O2- or BET+·CF3COO- [BET is tri­methyl­glycine (betaine); IUPAC: 1-carboxy-N,N,N-tri­methyl­methanaminium inner salt], contains pairs of bet­ainium and tri­fluoro­acetate ions forming a dimer bridged by a strong hydrogen bond between the carboxyl and carboxyl­ate groups of the two ions. The molecular symmetry of the cation is close to Cs, with protonation occurring at the carboxy O atom positioned anti to the N atom. The tri­fluoro­acetate anions are disordered over two positions. In one, the conformation of the CF3 group is staggered with respect to the carboxyl­ate group, in the other, it is close to an eclipsed conformation. The sole hydrogen bond present in the structure is the strong O-H...O bond between the anion and the cation.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101004966/sk1468sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101004966/sk1468Isup2.hkl
Contains datablock I

CCDC reference: 167000

Comment top

Betaine (trimethylglycine) is a naturally occurring compound present in many biological systems, where it acts as a transmethylating agent in the synthesis of lipids and also as osmoprotector and osmoregulator. It can be obtained in large concentrations as a by-product of sugar processing. The betaine molecule is an inner salt (zwitterion) where the carboxylate and trimethylammonium groups carry a negative and positive charge, respectively. The molecule has a large proton affinity and can be easily combined with even weak acids to form 1:1 and 2:1 betainium salts. Several adducts of betaine with inorganic salts, e.g. KBr, have also been synthesized. Betaine can act as a chelating agent, via the carboxy group, of many d- and f- metals. Several betaine salts and adducts exhibit low-temperature phase transitions associated with ferroelectric, antiferroelectric and ferroelastic behaviour as well as commensurate and incommensurate superstructures (Shildkamp & Spilker, 1984; Haussühl 1984, 1988). The betaine compound known as BCCD (betaine calcium chloride dihydrate) has been much studied, because it exhibits a series of phase transitions chained in a `devil stair' sequence (Almeida et al., 1992). Other compounds attracting much attention are the isostructural ferroelectric betaine phosphite and antiferroelectric betaine phosphate which form solid solutions over an extended composition range (Andrade et al., 1999; Banys et al., 2000). The crystal structures of betaine hydrate (Mak, 1990) and its salts of hydrogen chloride (Fisher et al., 1970; Mak & Chen, 1990), phosphoric (Shildkamp & Spilker, 1984), sulfuric (Ratajczak et al., 1994), arsenic (Shildkamp et al., 1984), boric (Zobetz et Preisinger, 1989), telluric (Ilczysczyn et al., 1992), maleic (Ilczysczyn et al., 1995), nitric (Baran, Drozd, Glowiak et al., 1995), selenic (Baran, Drozd, Lis et al., 1995; Baran et al., 1997), and selenous acids (Paixão et al., 1997) are reported in the October 2000 release of the Cambridge Structural Database (Allen & Kennard, 1993).

Very recently the crystal structures of anhydrous betaine (Viertorinne et al., 1999), betainium trichloroacetate (Baran et al., 2000), perchlorate (Matos Beja et al., 2000) and betaine-betainium hydrogen oxalate hydrate (Rodrigues et al., 2001a) have been reported. In the trichloroacetate salt two reversible low-temperature phase transitions at 177 and 187 K were resolved in both DSC and temperature-dependent FT—IR measurements, one of them having been also detected by powder diffraction. Furthermore, the FT—IR data suggest that a further transition below 100 K possibly exists (Baran et al., 2000).

The present work represents an effort to find other compounds of N-methylated glycine derivatives which may feature similar interesting physical properties. Motivated by the results reported on betainium trichloroacetate, we have decided to synthesize and investigate the structure and physical properties of the trifluoroacetate salts. The trifluoroacetic acid is a very strong carboxylic acid due to the charge withdrawing effect of the F atoms on the Cα atom. Its dissociation constant is K = 0.66 mol dm-3 (Strehlow & Hildebrandt, 1990), as determined by Raman spectroscopy. Phase transitions at low temperature on crystalline trifluoroacetic acid tetrahydrate itself have been discovered on undeuterated and deuterated samples (Mootz & Schilling, 1992). Thus, betainium trifluoroacetate is expected to be a good candidate to exhibit phase transitions and, possibly, superstructures at low temperature. We have already determined the crystal structures of sarcosinium trifluoroacetate (Rodrigues et al., 2000) and dimethylglycinium trifluoroacetate (Rodrigues et al., 2001b). Further studies of these trifluoroacetate salts including dielectric measurements, DSC calorimetry, low-temperature X-ray diffraction and spectroscopic measurements will be reported elsewhere. \sch

The title compound, (I), contains a protonated betaine molecule counterbalanced by a disordered trifluoroacetate anion (Fig. 1). The ionization states of both betaine and TFA acid molecules were determined from the localization of the H atom bonded to the carboxyl group of betaine, which was clearly seen on a difference Fourier map, but could also be inferred from an inspection of the C–O bond distances. These are highly asymmetric [1.193 (2), 1.299 (2) Å], corresponding to a well ordered carboxylic acid group. It is interesting to note that protonation occurs at the carboxy O atom which is in anti position with respect to the N atom. In a recently reported ab-initio study of betainium dimer complexes (Zhu et al., 2000), protonation at the anti-position of an isolated betaine molecule was found to be more stable by 16.2 kJ mol-1 than at the syn- position. For the betainium/NH3 complex, protonation at the anti-position is 12.1 kJ mol-1 lower in energy than at the syn-position, the anti- and syn- isomers being separated by a transition state with an energy barrier of 17.2 kJ mol-1.

Previous studies have shown that the betaine molecule has some degree of conformational flexibility depending on the crystalline environment. However, in the title compound the symmetry does not deviate much from the ideal Cs symmetry of an isolated molecule. The main carboxy skeleton of the protonated betaine molecule is planar within 0.002 (2) Å. The methyl groups C3 and C4 are placed in almost symmetrical positions with respect to the least-squares plane passing through the molecule backbone. Atoms N and C5 are not strictly coplanar with the carboxyl group, they deviate from the least-squares plane by 0.076 (3) and 0.143 (5) Å, respectively. The small displacements arise from a small rotation of the carboxyl and trimethylammonium groups around bonds C1–C2 and C2–N of -2.7 (3)° and 3.07 (16)°, respectively, as shown by inspection of the appropriate torsion angles. These twist angles are comparable with those of betaine monohydrate, in the anhydrous crystalline form the molecule has a perfect, crystallographic imposed, Cs symmetry (Viertorinne et al., 1999). Larger twist angles, exceeding 20° for the carboxyl and 7° for the trimethylammonium group were found in other betainium compounds (Matos Beja et al., 2000, Rodrigues et al., 2001a). The N–C2–C1 angle [116.12 (13)°] is larger than the expected tetrahedral angle of 109.5°, a feature also observed in other betainium compounds as well as in the neutral molecule.

The trifluoroacetate anions are disordered in two positions with an occupancy ratio 0.62 (2):0.38 (2). The two disordered ions are related by a rotation of the CF3 group by 18 (2)° and a counter-rotation of the carboxylate group around the central C6—C7 bond by -25 (2)°. In the majoritary fraction the conformation of the CF3 group is staggered, whereas in the minority fraction one of the F atoms almost eclipses the carboxylate group, as can be seen by an inspection of the torsion angles. In both cases the anion establishes a strong hydrogen bond with the carboxylate group of the same neighbour betainium cation, as shown in Fig.1, with O1···O3a and O1···O3b distances of 2.565 (8) and 2.488 (14) Å. It is not unusual for the trifluoroacetate anion to be disordered over two rotational conformers, and such a disorder also occurs in the structure of perdeuterated trifluoroacetic acid tetrahydrate. However, when the carboxylate group is engaged in strong hydrogen bonding such as in the present case, this disorder usually affects the CF3 groups only, the carboxylate group remaining undisordered, anchored by the hydrogen bonds. It is an interesting feature of the title compound that interconversion between the two rotamers is accomplished by a concerted rotation of the carboxylate and CF3 groups. In the trichloroacetate compound the anions are also found to be disordered and such disorder was found to play a major role in the phase transitions occurring at low temperature (Baran et al., 2000) Therefore, similar phase transitions are likely to occur in the trifluoroacetate salt as well. In the closely related compounds sarcosinium and dimethylglycinium trifluoroacetate the anions were not found to be disordered as a whole, although the anisotropy of the displacement tensors of the fluorine atoms pointed to some minor static disorder of the CF3 groups or that these groups are rotating undergoing small angular oscillations around the single C–C bond at room temperature. It should be remarked that although the C6—C7 bond length [1.529 (2) Å] is longer than the average for a Csp3—Csp2 bond, it is nevertheless within the range of values normally found in trifluoroacetate salts (Lundgren, 1978).

The packing diagram of the structure is shown in Fig. 2. The sole hydrogen bond present in the structure is the strong bond linking the betainium-trifluoroacetate dimers. Inspection of the intermolecular distances shows that there are no C···O close contacts with appropriate geometry to be classified as weak hydrogen bonds. As usual, the F atoms are not actively engaged in hydrogen bonding and no relevant short contacts involving these atoms were found in the structure. This is in agreement with a recent study based on a statistical survey of the Cambridge Structural Database (Dunitz & Taylor, 1997) which shows that the neutral F atom seldom participates in hydrogen bonding, in contrast with the the fluorine anion, which often acts as a hydrogen-bond acceptor.

Experimental top

Small colourless crystals of block form were obtained after one day evaporation of the solution obtained from adding an excess of trifluoroacetic acid (Aldrich, 99%) directly to pure betaine (1 g) as purchased from Aldrich (98%). A suitable crystal was selected and checked by photographic methods before the data collection.

Refinement top

All H atoms could be located on a difference Fourier map; those bonded to C atoms where placed at idealized positions and refined as riding using suitable AFIX instructions with SHELXL97 (Sheldrick, 1997) defaults. The H atom attached to the betaine carboxyl group involved in the intra-dimer hydrogen bond was freely refined isotropically. The anisotropic displacement parameters of the F atoms were restrained with a DELU instruction.

Examination of the crystal structure with PLATON (Spek, 2001) showed that there are no solvent-accessible voids in the crystal lattice. All calculations were performed on a Pentium 350 MHz PC running LINUX.

Computing details top

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: HELENA (Spek, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. ORTEPII (Johnson, 1976) plot of the title compound. Displacement ellipsoids are drawn at the 50% level and H atoms are shown as spheres of arbitrary radii.
[Figure 2] Fig. 2. Packing diagram viewed along the a axis.
N,N,N-trimethylglycinium-trifluoroacetate top
Crystal data top
C5H12NO2+·CF3COOF(000) = 480
Mr = 231.18Dx = 1.474 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 6.088 (2) ÅCell parameters from 25 reflections
b = 11.9486 (15) Åθ = 7.8–15.2°
c = 15.022 (12) ŵ = 0.15 mm1
β = 107.54 (4)°T = 293 K
V = 1041.9 (9) Å3Block, colourless
Z = 40.33 × 0.27 × 0.25 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
Rint = 0.039
Radiation source: fine-focus sealed tubeθmax = 27.5°, θmin = 3.3°
Graphite monochromatorh = 07
profile data from ω–2θ scansk = 150
2588 measured reflectionsl = 1918
2371 independent reflections3 standard reflections every 180 min
1735 reflections with I > 2σ(I) intensity decay: 4.7%
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.039H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.124 w = 1/[σ2(Fo2) + (0.0514P)2 + 0.3392P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max < 0.001
2371 reflectionsΔρmax = 0.17 e Å3
190 parametersΔρmin = 0.14 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.017 (4)
Crystal data top
C5H12NO2+·CF3COOV = 1041.9 (9) Å3
Mr = 231.18Z = 4
Monoclinic, P21/cMo Kα radiation
a = 6.088 (2) ŵ = 0.15 mm1
b = 11.9486 (15) ÅT = 293 K
c = 15.022 (12) Å0.33 × 0.27 × 0.25 mm
β = 107.54 (4)°
Data collection top
Enraf-Nonius CAD-4
diffractometer
Rint = 0.039
2588 measured reflections3 standard reflections every 180 min
2371 independent reflections intensity decay: 4.7%
1735 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0390 restraints
wR(F2) = 0.124H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.17 e Å3
2371 reflectionsΔρmin = 0.14 e Å3
190 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
O10.7099 (3)0.39062 (14)0.44445 (9)0.0793 (5)
H10.825 (6)0.347 (3)0.442 (2)0.133 (12)*
O20.6053 (2)0.38061 (13)0.29024 (9)0.0703 (4)
N0.2194 (2)0.52732 (11)0.27730 (9)0.0445 (3)
C10.5768 (3)0.41307 (14)0.36106 (11)0.0489 (4)
C20.3822 (3)0.48786 (14)0.36801 (11)0.0485 (4)
H2A0.29410.44780.40190.058*
H2B0.44860.55300.40480.058*
C30.0897 (3)0.43145 (18)0.22151 (15)0.0660 (5)
H3A0.01540.45910.16450.099*
H3B0.00510.39330.25700.099*
H3C0.19620.38040.20730.099*
C40.3431 (3)0.59090 (17)0.22133 (14)0.0647 (5)
H4A0.44320.54110.20160.097*
H4B0.43270.64950.25890.097*
H4C0.23310.62290.16750.097*
C50.0511 (3)0.60441 (19)0.30180 (16)0.0752 (6)
H5A0.13220.66720.33630.113*
H5B0.02650.56490.33920.113*
H5C0.05990.63030.24560.113*
F1a1.5739 (16)0.1694 (12)0.5607 (8)0.110 (3)0.62 (2)
F2a1.3904 (11)0.1425 (8)0.4209 (3)0.0824 (16)0.62 (2)
F3a1.2744 (14)0.0628 (5)0.5219 (7)0.114 (2)0.62 (2)
O3a1.0577 (14)0.2750 (7)0.4355 (5)0.0640 (15)0.62 (2)
O4a1.2429 (19)0.2941 (9)0.5881 (6)0.0689 (18)0.62 (2)
F1b1.544 (3)0.1448 (18)0.5731 (10)0.106 (5)0.38 (2)
F2b1.422 (3)0.1724 (17)0.4250 (8)0.126 (5)0.38 (2)
F3b1.2699 (16)0.0581 (9)0.4947 (14)0.110 (4)0.38 (2)
O3b1.011 (3)0.2491 (16)0.4463 (13)0.092 (4)0.38 (2)
O4b1.265 (3)0.3219 (16)0.5678 (15)0.083 (4)0.38 (2)
C61.2036 (3)0.25327 (13)0.50964 (11)0.0474 (4)
C71.3635 (3)0.15712 (16)0.50288 (12)0.0574 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0819 (10)0.0983 (11)0.0488 (7)0.0471 (9)0.0066 (7)0.0008 (7)
O20.0706 (8)0.0911 (10)0.0524 (7)0.0304 (7)0.0233 (6)0.0019 (7)
N0.0386 (6)0.0481 (7)0.0454 (7)0.0038 (5)0.0105 (5)0.0024 (6)
C10.0511 (9)0.0503 (9)0.0457 (8)0.0089 (7)0.0152 (7)0.0022 (7)
C20.0523 (9)0.0539 (9)0.0411 (8)0.0118 (7)0.0167 (7)0.0010 (7)
C30.0510 (10)0.0711 (12)0.0729 (12)0.0134 (9)0.0143 (9)0.0209 (10)
C40.0656 (11)0.0643 (11)0.0601 (11)0.0038 (9)0.0129 (9)0.0214 (9)
C50.0570 (11)0.0818 (14)0.0808 (14)0.0304 (10)0.0119 (10)0.0149 (11)
F1a0.053 (2)0.136 (6)0.119 (6)0.032 (3)0.006 (3)0.021 (4)
F2a0.094 (2)0.106 (3)0.0506 (19)0.042 (2)0.026 (2)0.0074 (14)
F3a0.181 (6)0.048 (3)0.145 (4)0.027 (2)0.099 (4)0.027 (3)
O3a0.056 (3)0.078 (3)0.0521 (19)0.024 (2)0.0081 (19)0.010 (2)
O4a0.070 (4)0.080 (4)0.0531 (19)0.020 (3)0.0138 (17)0.016 (2)
F1b0.107 (10)0.121 (8)0.062 (3)0.075 (8)0.019 (4)0.006 (4)
F2b0.155 (8)0.126 (8)0.145 (8)0.011 (5)0.115 (7)0.018 (4)
F3b0.087 (4)0.056 (4)0.178 (9)0.014 (3)0.024 (5)0.041 (5)
O3b0.063 (6)0.082 (7)0.101 (8)0.030 (5)0.020 (4)0.046 (5)
O4b0.062 (3)0.088 (8)0.098 (10)0.012 (5)0.023 (6)0.052 (6)
C60.0481 (8)0.0447 (8)0.0482 (9)0.0053 (7)0.0125 (7)0.0027 (7)
C70.0591 (10)0.0619 (11)0.0491 (9)0.0168 (8)0.0132 (8)0.0015 (8)
Geometric parameters (Å, º) top
O1—C11.298 (2)C4—H4C0.9600
O1—H10.88 (4)C5—H5A0.9600
O2—C11.193 (2)C5—H5B0.9600
N—C41.495 (2)C5—H5C0.9600
N—C31.496 (2)F1a—C71.321 (9)
N—C21.499 (2)F2a—C71.302 (5)
N—C51.504 (2)F3a—C71.319 (6)
C1—C21.512 (2)O3a—C61.225 (8)
C2—H2A0.9700O4a—C61.231 (9)
C2—H2B0.9700F1b—C71.281 (13)
C3—H3A0.9600F2b—C71.334 (12)
C3—H3B0.9600F3b—C71.303 (10)
C3—H3C0.9600O3b—C61.268 (14)
C4—H4A0.9600O4b—C61.174 (16)
C4—H4B0.9600C6—C71.529 (2)
C1—O1—H1110 (2)H5B—C5—H5C109.5
C4—N—C3110.15 (15)O4b—C6—O3a120.6 (11)
C4—N—C2111.33 (13)O4b—C6—O4a23.7 (10)
C3—N—C2111.17 (14)O3a—C6—O4a131.7 (6)
C4—N—C5108.82 (15)O4b—C6—O3b126.8 (11)
C3—N—C5108.82 (15)O3a—C6—O3b22.1 (12)
C2—N—C5106.43 (14)O4a—C6—O3b127.1 (8)
O2—C1—O1125.25 (16)O4b—C6—C7120.6 (10)
O2—C1—C2125.51 (16)O3a—C6—C7113.6 (4)
O1—C1—C2109.23 (14)O4a—C6—C7114.7 (5)
N—C2—C1116.12 (13)O3b—C6—C7112.6 (6)
N—C2—H2A108.3F3b—C7—F1b102.4 (10)
C1—C2—H2A108.3F3b—C7—F2a88.0 (8)
N—C2—H2B108.3F1b—C7—F2a116.2 (8)
C1—C2—H2B108.3F3b—C7—F1a118.2 (7)
H2A—C2—H2B107.4F1b—C7—F1a18.4 (14)
N—C3—H3A109.5F2a—C7—F1a105.3 (6)
N—C3—H3B109.5F3b—C7—F2b105.5 (9)
H3A—C3—H3B109.5F1b—C7—F2b110.4 (10)
N—C3—H3C109.5F2a—C7—F2b17.5 (10)
H3A—C3—H3C109.5F1a—C7—F2b95.7 (8)
H3B—C3—H3C109.5F3b—C7—F3a17.7 (9)
N—C4—H4A109.5F1b—C7—F3a91.7 (11)
N—C4—H4B109.5F2a—C7—F3a105.5 (5)
H4A—C4—H4B109.5F1a—C7—F3a109.5 (7)
N—C4—H4C109.5F2b—C7—F3a122.9 (8)
H4A—C4—H4C109.5F3b—C7—C6114.8 (5)
H4B—C4—H4C109.5F1b—C7—C6115.9 (8)
N—C5—H5A109.5F2a—C7—C6115.3 (3)
N—C5—H5B109.5F1a—C7—C6112.5 (6)
H5A—C5—H5B109.5F2b—C7—C6107.4 (6)
N—C5—H5C109.5F3a—C7—C6108.4 (4)
H5A—C5—H5C109.5
C4—N—C2—C158.52 (19)O4a—C6—C7—F2a153.8 (9)
C3—N—C2—C164.70 (19)O3b—C6—C7—F2a50.8 (17)
C5—N—C2—C1176.96 (16)O4b—C6—C7—F1a7.1 (17)
O2—C1—C2—N2.7 (3)O3a—C6—C7—F1a147.6 (9)
O1—C1—C2—N176.60 (15)O4a—C6—C7—F1a33.0 (11)
O4b—C6—C7—F3b132 (2)O3b—C6—C7—F1a171.6 (18)
O3a—C6—C7—F3b73.4 (12)O4b—C6—C7—F2b111 (2)
O4a—C6—C7—F3b106.0 (14)O3a—C6—C7—F2b43.5 (11)
O3b—C6—C7—F3b49 (2)O4a—C6—C7—F2b137.0 (13)
O4b—C6—C7—F1b13 (2)O3b—C6—C7—F2b68 (2)
O3a—C6—C7—F1b167.4 (14)O4b—C6—C7—F3a114.1 (16)
O4a—C6—C7—F1b13.1 (16)O3a—C6—C7—F3a91.2 (7)
O3b—C6—C7—F1b169 (2)O4a—C6—C7—F3a88.2 (9)
O4b—C6—C7—F2a127.9 (16)O3b—C6—C7—F3a67.2 (17)
O3a—C6—C7—F2a26.8 (7)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O3a0.88 (4)1.68 (4)2.565 (8)175 (3)
O1—H1···O3b0.88 (4)1.62 (4)2.488 (14)168 (3)

Experimental details

Crystal data
Chemical formulaC5H12NO2+·CF3COO
Mr231.18
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)6.088 (2), 11.9486 (15), 15.022 (12)
β (°) 107.54 (4)
V3)1041.9 (9)
Z4
Radiation typeMo Kα
µ (mm1)0.15
Crystal size (mm)0.33 × 0.27 × 0.25
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2588, 2371, 1735
Rint0.039
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.124, 1.03
No. of reflections2371
No. of parameters190
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.17, 0.14

Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, HELENA (Spek, 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEPII (Johnson, 1976), SHELXL97.

Selected geometric parameters (Å, º) top
O1—C11.298 (2)C6—C71.529 (2)
O2—C11.193 (2)
N—C2—C1116.12 (13)
C4—N—C2—C158.52 (19)C5—N—C2—C1176.96 (16)
C3—N—C2—C164.70 (19)O2—C1—C2—N2.7 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O3a0.88 (4)1.68 (4)2.565 (8)175 (3)
O1—H1···O3b0.88 (4)1.62 (4)2.488 (14)168 (3)
 

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