3-Oxocyclo­butane­carboxylic acid: hydrogen bonding in a small-ring γ-keto acid

Efthimiopoulos, G.; Thompson, H.W.; Lalancette, R.A.

doi:10.1107/S1600536809003961

organic compounds

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doi:10.1107/S1600536809003961

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3-Oxocyclobutanecarboxylic acid: hydrogen bonding in a small-ring γ-keto acid

Georgia Efthimiopoulos,^a Hugh W. Thompson ^a and Roger A. Lalancette ^a ^*

^aCarl A. Olson Memorial Laboratories, Department of Chemistry, Rutgers University, Newark, NJ 07102, USA
^*Correspondence e-mail: rogerlal@andromeda.rutgers.edu

(Received 21 January 2009; accepted 2 February 2009; online 11 February 2009)

The title ketocarboxylic acid, C₅H₆O₃, is the smallest carboxycyclanone to have its crystal structure determined. It adopts a chiral conformation, by rotation of its carboxyl O atoms away from the plane of skeletal symmetry that passes through the carboxyl carbon and both atoms of the ketone carbonyl. The four-membered ring is non-planar, with a shallow fold of 14.3 (1)° along a line connecting the two α-carbons of the ketone group. In the crystal, the molecules are linked by centrosymmetric hydrogen-bond pairing of ordered carboxylic acid groups [O⋯O = 2.6392 (12) Å and O—H⋯O = 175.74 (15)°], yielding two different sets of dimers, related by by a 2₁ screw axis in c, in the cell. A C—H⋯O interaction is also present.

Related literature

For related structures, see: Barcon et al. (1999 ); Borthwick (1980 ); Harata et al. (1977 ); Malak et al. (2006 ); Meiboom & Snyder (1967 ); Pigou & Schiesser (1988 ). For hydrogen bonding, see: Steiner (1997 ).

Experimental

Crystal data

C₅H₆O₃
M_r = 114.10
Monoclinic, P 2₁ /c
a = 8.8858 (19) Å
b = 5.3631 (12) Å
c = 11.625 (3) Å
β = 106.899 (4)°
V = 530.1 (2) Å³
Z = 4
Cu Kα radiation
μ = 1.03 mm⁻¹
T = 100 (2) K
0.48 × 0.20 × 0.15 mm

Data collection

Bruker SMART CCD APEXII area-detector diffractometer
Absorption correction: numerical (SADABS; Sheldrick, 2008 ) T_min = 0.638, T_max = 0.861
3854 measured reflections
906 independent reflections
891 reflections with I > 2σ(I)
R_int = 0.019

Refinement

R[F² > 2σ(F²)] = 0.029
wR(F²) = 0.070
S = 1.06
906 reflections
77 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3⋯O2ⁱ	0.885 (18)	1.756 (18)	2.6392 (12)	175.74 (15)
C1—H1⋯O1ⁱⁱ	1.00	2.45	3.1003 (15)	122
Symmetry codes: (i) -x+1, -y+1, -z+1; (ii) $[-x, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

Data collection: APEX2 (Bruker, 2006 ); cell refinement: SAINT (Bruker, 2005 ); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809003961/fl2232sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809003961/fl2232Isup2.hkl

checkCIF report

Comment top

Our study of crystalline ketocarboxylic acids explores their five known hydrogen-bonding modes. The most frequently encountered overall is carboxyl pairing, but acid-to-ketone catemers constitute a sizable minority of cases, followed by the three remaining, rarely observed patterns, consisting of acid-to-acid catemers, internal H-bonds and carboxyl-to-ketone dimers. Of significant interest is the behavior of keto acids in the smallest size range, where aggregation influences other than H-bonding are minimized. These may offer insights into the minimum requirements for specific aggregation modes. Among simple C₃—C₅ monocarboxyketones, only the (dimeric) crystal structure of pyruvic acid (Harata et al., 1977) has been reported to date, while 3-oxocyclopentanecarboxylic acid (Malak et al., 2006), a catemer, is the sole published example of a C₆ keto acid.

Fig. 1 depicts the asymmetric unit for the title compound, (I), and its conformation. Although (I) is inherently symmetric, the carboxyl is rotated away from alignment along the central plane of skeletal symmetry, producing a chiral conformation; the O2—C5—C1—C4 torsion angle = 78.70 (14) Å. As is normal in cyclobutanes, the ring is not planar but flexed to ease the eclipsing strain that arises when the torsional angles for substituents on adjacent carbons approach zero. This nonplanarity in (I) may be envisioned as the result of folding the ring along a line connecting C2 to C4; the ketone and carboxyl halves of the ring lie in planes at a mutual dihedral angle of 14.3 (1)°. Because of the presence of the ketone, this dihedral is significantly smaller than those typically seen in cyclobutanes containing only sp³ carbons, which range from 19.1° in trans-pinononic acid (Barcon et al., 1999) to 35° in cyclobutane itself (Meiboom & Snyder, 1967). When any four-sided figure departs from planarity, the internal angles are no longer constrained to an average of 90°, but may approach zero. Because of the shallowness of the fold in (I), the average of all four internal ring angles is 89.63 (18)°, with the carbonyl, where the hybridization strain is greatest, having an angle of 92.88 (9)°. Presumably due to packing interactions, the internal ring angles at C2 and C4 differ slightly, with values of 88.37 (9) and 87.33 (9)°, respectively. The dihedral angle between the carboxyl and ketone planes (O2—O3—C1—C5 versus O1—C2—C3—C4) is 69.40 (5)°.

Although disorder-averaging of C—O bond lengths and C—C—O angles is common in dimeric carboxyls, these lengths and angles are not significantly averaged in (I), but conform to values typical of highly ordered cases (Borthwick, 1980).

In contrast to its next-higher ring-homolog (Malak et al., 2006), compound (I) aggregates as standard carboxyl dimers. Fig. 2 illustrates the packing of the chosen cell with the centrosymmetrically hydrogen-bonded pairs of asymmetric units. These appear in two orientations, centered at 1/2,1/2,1/2 and at 1/2,0,0.

Within the 2.6 Å range we standardly survey for C—H···O packing interactions (Steiner, 1997), a single close intermolecular contact was found, involving the ketone (Table 1).

Related literature top

For related structures, see: Barcon et al. (1999); Borthwick (1980); Harata et al. (1977); Malak et al. (2006); Meiboom & Snyder (1967); Pigou & Schiesser (1988). For hydrogen bonding, see: Steiner (1997).

Experimental top

Compound (I) was synthesized in low yield by the method of Pigou & Schiesser (1988); when the final extract failed to crystallize spontaneously on concentration, (I) was isolated by sublimation. Recrystallization from hexane-ether provided material suitable for X-ray, mp 342 K. The solid-state (KBr) infrared spectrum of (I) features widely separated carbonyl peaks for strained ketone and carboxyl dimer, at 1786 & 1696 cm^-1, respectively. In CHCl₃ solution, where dimers predominate, the separation is nearly identical, although the peaks are somewhat shifted, at 1797 & 1709 cm^-1.

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The asymmetric unit for (I). Displacement ellipsoids are drawn at the 40% probability level.
	Fig. 2. A partial packing diagram, illustrating the centrosymmetric pairing of the asymmetric units, with dimers centered at 1/2,1/2,1/2 and at 1/2,0,0 of the chosen cell. Displacement ellipsoids are drawn at the 40% probability level.

3-Oxocyclobutanecarboxylic acid top

Crystal data top

C₅H₆O₃	F(000) = 240
M_r = 114.10	D_x = 1.430 Mg m⁻³
Monoclinic, P2₁/c	Melting point: 342 K
Hall symbol: -P 2ybc	Cu Kα radiation, λ = 1.54178 Å
a = 8.8858 (19) Å	Cell parameters from 3724 reflections
b = 5.3631 (12) Å	θ = 4.0–66.7°
c = 11.625 (3) Å	µ = 1.03 mm⁻¹
β = 106.899 (4)°	T = 100 K
V = 530.1 (2) Å³	Parallelepiped, colourless
Z = 4	0.48 × 0.20 × 0.15 mm

Data collection top

Bruker SMART CCD APEXII area-detector diffractometer	906 independent reflections
Radiation source: fine-focus sealed tube	891 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.019
ϕ and ω scans	θ_max = 66.7°, θ_min = 5.2°
Absorption correction: numerical (SADABS; Sheldrick, 2008)	h = −10→10
T_min = 0.638, T_max = 0.861	k = −5→6
3854 measured reflections	l = −13→13

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.029	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.070	w = 1/[σ²(F_o²) + (0.0304P)² + 0.27P] where P = (F_o² + 2F_c²)/3
S = 1.06	(Δ/σ)_max < 0.001
906 reflections	Δρ_max = 0.25 e Å⁻³
77 parameters	Δρ_min = −0.17 e Å⁻³
0 restraints	Extinction correction: SHELXTL (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0140 (13)

Crystal data top

C₅H₆O₃	V = 530.1 (2) Å³
M_r = 114.10	Z = 4
Monoclinic, P2₁/c	Cu Kα radiation
a = 8.8858 (19) Å	µ = 1.03 mm⁻¹
b = 5.3631 (12) Å	T = 100 K
c = 11.625 (3) Å	0.48 × 0.20 × 0.15 mm
β = 106.899 (4)°

Data collection top

Bruker SMART CCD APEXII area-detector diffractometer	906 independent reflections
Absorption correction: numerical (SADABS; Sheldrick, 2008)	891 reflections with I > 2σ(I)
T_min = 0.638, T_max = 0.861	R_int = 0.019
3854 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.029	0 restraints
wR(F²) = 0.070	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	Δρ_max = 0.25 e Å⁻³
906 reflections	Δρ_min = −0.17 e Å⁻³
77 parameters

Special details top

Experimental. crystal mounted on a Cryoloop using Paratone-N

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

	x	y	z	U_iso*/U_eq
O1	0.11919 (10)	0.09994 (19)	0.84099 (8)	0.0276 (3)
C1	0.20439 (13)	0.4459 (2)	0.63057 (10)	0.0164 (3)
H1	0.1194	0.5695	0.5949	0.020*
O2	0.42464 (10)	0.29447 (16)	0.57144 (8)	0.0226 (3)
C2	0.13692 (14)	0.1810 (2)	0.63346 (11)	0.0190 (3)
H2A	0.0251	0.1641	0.5863	0.023*
H2B	0.2016	0.0472	0.6132	0.023*
O3	0.35444 (10)	0.69510 (15)	0.53889 (8)	0.0197 (3)
H3	0.4319 (19)	0.696 (3)	0.5052 (14)	0.030*
C3	0.16234 (13)	0.2142 (2)	0.76737 (11)	0.0187 (3)
C4	0.25515 (14)	0.4542 (2)	0.77165 (11)	0.0204 (3)
H4A	0.3698	0.4359	0.8096	0.024*
H4B	0.2126	0.5984	0.8053	0.024*
C5	0.33761 (13)	0.4681 (2)	0.57643 (10)	0.0158 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0220 (5)	0.0380 (6)	0.0232 (5)	−0.0043 (4)	0.0075 (4)	0.0098 (4)
C1	0.0165 (6)	0.0169 (6)	0.0165 (6)	0.0006 (4)	0.0056 (4)	0.0008 (5)
O2	0.0221 (5)	0.0194 (5)	0.0304 (5)	0.0050 (4)	0.0140 (4)	0.0079 (4)
C2	0.0194 (6)	0.0187 (7)	0.0206 (6)	−0.0032 (5)	0.0085 (5)	−0.0026 (5)
O3	0.0222 (5)	0.0155 (5)	0.0254 (5)	0.0003 (3)	0.0132 (4)	0.0021 (3)
C3	0.0135 (6)	0.0229 (7)	0.0198 (6)	0.0018 (5)	0.0049 (4)	0.0033 (5)
C4	0.0208 (6)	0.0253 (7)	0.0162 (6)	−0.0041 (5)	0.0071 (5)	−0.0035 (5)
C5	0.0165 (6)	0.0168 (6)	0.0132 (5)	−0.0004 (5)	0.0028 (4)	0.0006 (4)

Geometric parameters (Å, º) top

O1—C3	1.2024 (15)	C2—H2A	0.9900
C1—C5	1.4983 (16)	C2—H2B	0.9900
C1—C2	1.5458 (17)	O3—C5	1.3164 (15)
C1—C4	1.5701 (16)	O3—H3	0.885 (18)
C1—H1	1.0000	C3—C4	1.5217 (17)
O2—C5	1.2225 (15)	C4—H4A	0.9900
C2—C3	1.5171 (17)	C4—H4B	0.9900

C5—C1—C2	116.17 (10)	O1—C3—C2	133.43 (12)
C5—C1—C4	114.48 (9)	O1—C3—C4	133.61 (12)
C2—C1—C4	89.94 (9)	C2—C3—C4	92.88 (9)
C5—C1—H1	111.5	C3—C4—C1	87.33 (9)
C2—C1—H1	111.5	C3—C4—H4A	114.1
C4—C1—H1	111.5	C1—C4—H4A	114.1
C3—C2—C1	88.37 (9)	C3—C4—H4B	114.1
C3—C2—H2A	113.9	C1—C4—H4B	114.1
C1—C2—H2A	113.9	H4A—C4—H4B	111.3
C3—C2—H2B	113.9	O2—C5—O3	123.66 (11)
C1—C2—H2B	113.9	O2—C5—C1	123.18 (11)
H2A—C2—H2B	111.1	O3—C5—C1	113.12 (10)
C5—O3—H3	109.3 (10)

C5—C1—C2—C3	126.54 (10)	C5—C1—C4—C3	−128.00 (10)
C4—C1—C2—C3	9.07 (8)	C2—C1—C4—C3	−9.05 (8)
C1—C2—C3—O1	167.67 (14)	C2—C1—C5—O2	−24.15 (16)
C1—C2—C3—C4	−9.38 (9)	C4—C1—C5—O2	78.70 (14)
O1—C3—C4—C1	−167.80 (14)	C2—C1—C5—O3	158.11 (10)
C2—C3—C4—C1	9.24 (9)	C4—C1—C5—O3	−99.04 (12)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2ⁱ	0.885 (18)	1.756 (18)	2.6392 (12)	175.74 (15)
C1—H1···O1ⁱⁱ	1.00	2.45	3.1003 (15)	122

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x, y+1/2, −z+3/2.

Experimental details

Crystal data
Chemical formula	C₅H₆O₃
M_r	114.10
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	8.8858 (19), 5.3631 (12), 11.625 (3)
β (°)	106.899 (4)
V (Å³)	530.1 (2)
Z	4
Radiation type	Cu Kα
µ (mm⁻¹)	1.03
Crystal size (mm)	0.48 × 0.20 × 0.15

Data collection
Diffractometer	Bruker SMART CCD APEXII area-detector diffractometer
Absorption correction	Numerical (SADABS; Sheldrick, 2008)
T_min, T_max	0.638, 0.861
No. of measured, independent and observed [I > 2σ(I)] reflections	3854, 906, 891
R_int	0.019
(sin θ/λ)_max (Å⁻¹)	0.596

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.029, 0.070, 1.06
No. of reflections	906
No. of parameters	77
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.25, −0.17

Computer programs: APEX2 (Bruker, 2006), SAINT (Bruker, 2006), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2ⁱ	0.885 (18)	1.756 (18)	2.6392 (12)	175.74 (15)
C1—H1···O1ⁱⁱ	1.00	2.45	3.1003 (15)	122

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x, y+1/2, −z+3/2.

Acknowledgements

The authors gratefully acknowledge support in the form of NSF-CRIF grant No. 0443538. EG and HWT express their gratitude to Sanofi-Aventis for a grant in support of undergraduate research in organic synthesis. HWT also thanks Professor Gree Loober Spoog for helpful discussions.

References

Barcon, A., Brunskill, A. P. J., Thompson, H. W. & Lalancette, R. A. (1999). Acta Cryst. C55, 1899–1902. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Borthwick, P. W. (1980). Acta Cryst. B36, 628–632. CrossRef CAS IUCr Journals Web of Science Google Scholar
Bruker (2005). SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2006). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Harata, K., Sakabe, N. & Tanaka, J. (1977). Acta Cryst. B33, 210–212. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Malak, M. H., Baker, D., Brunskill, A. P. J., Thompson, H. W. & Lalancette, R. A. (2006). Acta Cryst. C62, o669–o670. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Meiboom, S. & Snyder, L. C. (1967). J. Am. Chem. Soc. 89, 1038–1039. CrossRef Web of Science Google Scholar
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Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
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CRYSTALLOGRAPHIC
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Volume 65| Part 3| March 2009| Page o492

doi:10.1107/S1600536809003961

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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

3-Oxo­cyclo­butane­carboxylic acid: hydrogen bonding in a small-ring γ-keto acid

Related literature

Experimental

Crystal data

Data collection

Refinement

Supporting information

Acknowledgements

References

organic compounds

3-Oxocyclobutanecarboxylic acid: hydrogen bonding in a small-ring γ-keto acid