In-situ high-pressure study of the ordered phase of ethyl propionate

Ethyl propionate, C₅H₁₀O₂ (m.p. 199 K), has been in-situ pressure-frozen and its structure determined at 1.34, 1.98 and 2.45 GPa. The crystal structure of the new high-pressure phase (denoted β) is different from phase α obtained by lowering the temperature. The freezing pressure of ethyl propionate at 296 K is 1.03 GPa. The molecule assumes an extended chain s-trans–trans–trans conformation, only slightly distorted from planarity. The closest intermolecular contacts in both phases are formed between carbonyl O and methyl H atoms; however, the ethyl-group H atoms in phase β form no contacts shorter than 2.58 Å. A considerable molecular volume difference of 24.2 ų between phases α and β can be rationalized in terms of degrees of freedom of molecules arranged into closely packed structures: the three degrees of freedom allowed for rearrangements of molecules confined to planar sheets in phase α, but are not sufficient for obtaining a densely packed pattern.

Computing details

For all compounds, data collection: CrysAlis (Oxford Diffraction, 2003); cell refinement: CrysAlis (Oxford Diffraction, 2003); data reduction: CrysAlis (Oxford Diffraction, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1990); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

(ethylpropionate1) ethyl propionate

Crystal data

C5H10O2	Dx = 1.300 Mg m^−3
Mr = 102.13	Melting point: 198 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 4.9347 (10) Å	Cell parameters from 1085 reflections
b = 9.4163 (19) Å	θ = 3.6–27.3°
c = 11.321 (2) Å	µ = 0.10 mm^−1
β = 97.39 (3)°	T = 293 K
V = 521.70 (18) Å^3	Cylinder, colourless
Z = 4	0.36 × 0.28 × 0.15 mm
F(000) = 224

Data collection

Kuma KM4CCD κ geometry diffractometer	316 independent reflections
Radiation source: fine-focus sealed tube	259 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.142
ω scans	θmax = 27.3°, θmin = 3.6°
Absorption correction: analytical Katrusiak, A. (2003). REDSHADE - Program for correcting reflections intensities for DAC absorption, gasket shadowing and sample crystal absorption. Adam Mickiewicz University, Poznań. Katrusiak, A. (2004). Z. Kristallogr. 219, 461-467	h = −6→6
Tmin = 0.68, Tmax = 0.96	k = −5→5
1838 measured reflections	l = −13→13

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.099	H-atom parameters constrained
wR(F^2) = 0.270	w = 1/[σ^2(Fo^2) + (0.1734P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.25	(Δ/σ)max < 0.001
316 reflections	Δρmax = 0.15 e Å^−3
60 parameters	Δρmin = −0.16 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.22 (11)

Special details

Experimental. High-pressure measurement at 1.34 GPa.

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 (Ų)

	x	y	z	Uiso*/Ueq
O2	0.2180 (7)	0.6154 (7)	0.3982 (3)	0.054 (5)
O1	−0.0305 (8)	0.7862 (8)	0.3083 (3)	0.072 (4)
C3	−0.2673 (14)	0.8538 (13)	0.5166 (7)	0.076 (7)
H3A	−0.3068	0.8661	0.5968	0.115*
H3B	−0.4294	0.8232	0.4671	0.115*
H3C	−0.2062	0.9423	0.4873	0.115*
C2	−0.0525 (11)	0.7463 (11)	0.5145 (5)	0.051 (6)
H2A	−0.1181	0.6576	0.5439	0.061*
H2B	0.1048	0.7754	0.5695	0.061*
C1	0.0386 (11)	0.7196 (12)	0.3971 (5)	0.045 (2)*
C4	0.3291 (12)	0.5829 (10)	0.2907 (5)	0.059 (5)
H4A	0.4110	0.6674	0.2614	0.070*
H4B	0.1844	0.5512	0.2303	0.070*
C5	0.5350 (10)	0.4719 (14)	0.3134 (5)	0.055 (6)
H5A	0.6090	0.4504	0.2411	0.082*
H5B	0.4529	0.3881	0.3416	0.082*
H5C	0.6789	0.5041	0.3725	0.082*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.059 (3)	0.068 (16)	0.039 (4)	0.011 (3)	0.019 (2)	0.002 (2)
O1	0.077 (3)	0.090 (13)	0.054 (3)	0.029 (4)	0.025 (2)	0.022 (3)
C3	0.057 (4)	0.11 (2)	0.069 (6)	0.008 (5)	0.033 (3)	0.007 (5)
C2	0.062 (4)	0.05 (2)	0.044 (4)	0.016 (5)	0.019 (3)	0.013 (4)
C4	0.063 (4)	0.08 (2)	0.034 (4)	−0.005 (5)	0.025 (3)	−0.011 (3)
C5	0.053 (4)	0.06 (2)	0.060 (4)	0.010 (4)	0.024 (3)	−0.002 (4)

Geometric parameters (Å, º)

O2—C1	1.320 (11)	C3—C2	1.468 (12)
O2—C4	1.431 (6)	C2—C1	1.479 (8)
O1—C1	1.197 (9)	C4—C5	1.457 (12)
C1—O2—C4	118.8 (5)	O1—C1—C2	125.4 (9)
C3—C2—C1	115.8 (6)	O2—C1—C2	113.5 (6)
O1—C1—O2	121.0 (6)	O2—C4—C5	109.7 (5)
C4—O2—C1—O1	−0.1 (12)	C3—C2—C1—O2	−175.6 (8)
C4—O2—C1—C2	−177.7 (6)	C1—O2—C4—C5	176.2 (7)
C3—C2—C1—O1	6.9 (13)

(ethylpropionate2) ethyl propionate

Crystal data

C5H10O2	Dx = 1.319 Mg m^−3
Mr = 102.13	Melting point: 198 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 4.8917 (10) Å	Cell parameters from 1777 reflections
b = 9.3649 (19) Å	θ = 2.8–24.8°
c = 11.318 (2) Å	µ = 0.10 mm^−1
β = 97.24 (3)°	T = 293 K
V = 514.35 (18) Å^3	Cylinder, colourless
Z = 4	0.36 × 0.28 × 0.14 mm
F(000) = 224

Data collection

Kuma KM4CCD κ geometry diffractometer	283 independent reflections
Radiation source: fine-focus sealed tube	264 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.059
ω scans	θmax = 24.8°, θmin = 2.8°
Absorption correction: analytical Katrusiak, A. (2003). REDSHADE - Program for correcting reflections intensities for DAC absorption, gasket shadowing and sample crystal absorption. Adam Mickiewicz University, Poznań. Katrusiak, A. (2004). Z. Kristallogr. 219, 461-467	h = −5→5
Tmin = 0.67, Tmax = 0.97	k = −6→6
2054 measured reflections	l = −11→11

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.054	H-atom parameters constrained
wR(F^2) = 0.107	w = 1/[σ^2(Fo^2) + (0.048P)^2 + 0.3823P] where P = (Fo^2 + 2Fc^2)/3
S = 1.20	(Δ/σ)max < 0.001
283 reflections	Δρmax = 0.12 e Å^−3
71 parameters	Δρmin = −0.10 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.02 (2)

Special details

Experimental. High-pressure measurement at 1.98 GPa.

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 (Ų)

	x	y	z	Uiso*/Ueq
O2	0.2191 (5)	0.6138 (4)	0.3997 (2)	0.0326 (16)
O1	−0.0346 (6)	0.7876 (5)	0.3074 (3)	0.048 (2)
C3	−0.2739 (8)	0.8572 (9)	0.5161 (4)	0.038 (3)
H3A	−0.3184	0.8660	0.5960	0.057*
H3B	−0.4306	0.8207	0.4655	0.057*
H3C	−0.2250	0.9491	0.4877	0.057*
C2	−0.0575 (8)	0.7443 (6)	0.5151 (3)	0.037 (3)
H2A	0.0998	0.7702	0.5720	0.045*
H2B	−0.1300	0.6550	0.5413	0.045*
C1	0.0381 (8)	0.7217 (7)	0.3969 (4)	0.028 (3)
C4	0.3324 (7)	0.5843 (6)	0.2900 (3)	0.030 (2)
H4A	0.4151	0.6699	0.2618	0.036*
H4B	0.1880	0.5524	0.2291	0.036*
C5	0.5431 (7)	0.4714 (7)	0.3152 (3)	0.029 (2)
H5A	0.6354	0.4584	0.2459	0.044*
H5B	0.4614	0.3828	0.3349	0.044*
H5C	0.6738	0.5019	0.3808	0.044*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0383 (15)	0.037 (6)	0.023 (3)	0.0107 (19)	0.0080 (11)	0.0023 (11)
O1	0.0511 (18)	0.067 (8)	0.030 (4)	0.024 (2)	0.0143 (14)	0.0162 (18)
C3	0.038 (2)	0.033 (12)	0.045 (4)	0.004 (3)	0.0144 (18)	−0.0010 (19)
C2	0.041 (2)	0.049 (13)	0.023 (5)	0.008 (3)	0.0097 (17)	−0.0027 (17)
C1	0.0259 (18)	0.031 (12)	0.027 (4)	−0.008 (3)	0.0015 (15)	0.000 (2)
C4	0.0325 (19)	0.031 (10)	0.027 (4)	0.008 (3)	0.0061 (15)	0.0010 (17)
C5	0.031 (2)	0.020 (10)	0.039 (4)	0.003 (2)	0.0094 (16)	−0.0028 (17)

Geometric parameters (Å, º)

O2—C1	1.341 (6)	C3—C2	1.497 (7)
O2—C4	1.449 (4)	C2—C1	1.486 (6)
O1—C1	1.202 (6)	C4—C5	1.479 (7)
C1—O2—C4	116.5 (3)	O1—C1—C2	126.3 (6)
C1—C2—C3	114.2 (4)	O2—C1—C2	111.6 (4)
O1—C1—O2	122.1 (4)	O2—C4—C5	107.7 (3)
C4—O2—C1—O1	2.6 (6)	C3—C2—C1—O2	−176.2 (4)
C4—O2—C1—C2	−178.4 (3)	C1—O2—C4—C5	175.1 (4)
C3—C2—C1—O1	2.7 (7)

(ethylpropionate3) ethyl propionate

Crystal data

C5H10O2	Dx = 1.346 Mg m^−3
Mr = 102.13	Melting point: 198 K
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 4.8455 (10) Å	Cell parameters from 1559 reflections
b = 9.3249 (19) Å	θ = 2.9–25.0°
c = 11.251 (2) Å	µ = 0.10 mm^−1
β = 97.52 (3)°	T = 293 K
V = 504.00 (18) Å^3	Cylinder, colourless
Z = 4	0.36 × 0.28 × 0.13 mm
F(000) = 224

Data collection

Kuma KM4CCD κ geometry diffractometer	299 independent reflections
Radiation source: fine-focus sealed tube	268 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.047
ω scans	θmax = 25.0°, θmin = 2.9°
Absorption correction: analytical Katrusiak, A. (2003). REDSHADE - Program for correcting reflections intensities for DAC absorption, gasket shadowing and sample crystal absorption. Adam Mickiewicz University, Poznań. Katrusiak, A. (2004). Z. Kristallogr. 219, 461-467	h = −5→5
Tmin = 0.68, Tmax = 0.97	k = −6→6
2119 measured reflections	l = −11→11

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.048	H-atom parameters constrained
wR(F^2) = 0.119	w = 1/[σ^2(Fo^2) + (0.0645P)^2 + 0.3573P] where P = (Fo^2 + 2Fc^2)/3
S = 1.14	(Δ/σ)max < 0.001
299 reflections	Δρmax = 0.13 e Å^−3
71 parameters	Δρmin = −0.14 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.04 (3)

Special details

Experimental. High-pressure measurement at 2.45 GPa.

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 (Ų)

	x	y	z	Uiso*/Ueq
O2	0.2203 (5)	0.6135 (4)	0.3999 (2)	0.0334 (14)
O1	−0.0367 (6)	0.7880 (5)	0.3066 (3)	0.0480 (19)
C3	−0.2768 (8)	0.8585 (8)	0.5162 (4)	0.039 (2)
H3A	−0.3290	0.8666	0.5954	0.058*
H3B	−0.4342	0.8271	0.4617	0.058*
H3C	−0.2154	0.9501	0.4910	0.058*
C2	−0.0585 (7)	0.7448 (6)	0.5156 (3)	0.0369 (19)
H2A	0.1008	0.7710	0.5729	0.044*
H2B	−0.1318	0.6553	0.5422	0.044*
C1	0.0373 (8)	0.7212 (7)	0.3967 (4)	0.032 (2)
C4	0.3332 (7)	0.5842 (5)	0.2896 (3)	0.032 (2)
H4A	0.4162	0.6703	0.2614	0.038*
H4B	0.1866	0.5524	0.2283	0.038*
C5	0.5464 (7)	0.4708 (7)	0.3147 (3)	0.034 (2)
H5A	0.6387	0.4548	0.2454	0.051*
H5B	0.4622	0.3831	0.3365	0.051*
H5C	0.6794	0.5027	0.3802	0.051*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O2	0.0365 (15)	0.041 (5)	0.025 (3)	0.0102 (17)	0.0101 (11)	0.0022 (10)
O1	0.0512 (18)	0.060 (7)	0.036 (3)	0.025 (2)	0.0150 (15)	0.0168 (16)
C3	0.037 (2)	0.033 (9)	0.050 (4)	0.003 (3)	0.0155 (18)	−0.0031 (19)
C2	0.041 (2)	0.044 (8)	0.027 (4)	0.006 (3)	0.0109 (17)	−0.0009 (17)
C1	0.0270 (19)	0.041 (10)	0.028 (5)	−0.007 (3)	0.0043 (16)	0.001 (2)
C4	0.0333 (18)	0.036 (9)	0.027 (4)	0.004 (2)	0.0087 (16)	−0.0004 (15)
C5	0.029 (2)	0.038 (9)	0.037 (4)	0.005 (2)	0.0091 (15)	−0.0014 (17)

Geometric parameters (Å, º)

O2—C1	1.337 (6)	C3—C2	1.498 (7)
O2—C4	1.445 (4)	C2—C1	1.489 (6)
O1—C1	1.204 (6)	C4—C5	1.479 (7)
C1—O2—C4	116.3 (3)	O1—C1—C2	125.9 (5)
C1—C2—C3	114.4 (4)	O2—C1—C2	111.8 (4)
O1—C1—O2	122.3 (4)	O2—C4—C5	107.7 (3)
C4—O2—C1—O1	2.1 (6)	C3—C2—C1—O2	−176.6 (4)
C4—O2—C1—C2	−178.2 (3)	C1—O2—C4—C5	175.3 (4)
C3—C2—C1—O1	3.1 (7)