(3R*,4R*)-3-Iso­propyl-4-phenyl­azetidin-2-one at 150 K

The title compound, C₁₂H₁₅NO, crystallized in the centrosymmetric space group C2/c with one mol­ecule as the asymmetric unit. There is a single conventional N—H...O hydrogen bond, with a donor–acceptor distance of 2.912 (1) Å, which forms an R(8) cyclic dimer about a center of symmetry. There is a single significant intermolecular C—H...O interaction, which also forms an R(8) cyclic dimer about a center of symmetry. Taken together, these interactions form chains propagating along [110]. Structural comparisons are made with another β-­lactam, (1′R*,3R*,4S*)-3-(1′-hydroxy­ethyl)-4-phenylazet­id­in-2-one.

S1. Comment

This report is one of a series on hydrogen bonding and C—H···O interactions in organic solids. The title compound, (I), crystallized in the centrosymmetric space group C2/c with one molecule as the asymmetric unit. The refined molecule and the labeling scheme are given in Fig. 1. A single hydrogen bond and a single significant intermolecular C—H···O interaction (Taylor & Kennard, 1982; Steiner & Desiraju, 1998) are present in this structure. The geometric parameters of these are given in Table 2. The results of basic first- and second-level graph-set analysis (Bernstein et al., 1995) involving these interactions, labelled a and b for this purpose in the order of their appearance in Table 2, are given in Table 3. A t the first level, each of the two interactions forms a cyclic dimer, R₂²(8), about a center of symmetry. The second-level chain propagates along [110]. Each molecule is linked by these interactions directly to two others. The resulting chains of molecules fall into two sets, with one comprising molecules of space-group symmetry types 1, 3, 5 and 7, and the other, symmetry types 2, 4, 6, and 8. The packing diagram, Fig. 2, shows a portion of a chain, in which by symmetry all four- and six-membered best-fit ring planes are, respectively, parallel. \sch

The four-membered ring (N1/C2—C4) of (I) is only roughly planar, the maximum deviation of any of its atoms from the best-fit plane describing them being 0.023 (1) Å, while the average deviation is 0.020 (2) Å. In contrast, the four-membered ring N1/C2—C4 (present labeling) of the quite similar molecule (1'R*,3R*,4S*)-3-(1'-hydroxyethyl)-4-phenylazetidin-2-one (hereafter, HEPA) determined at room temperature (Burnett et al., 1985) is very nearly planar, with corresponding deviations 0.004 (2) and 0.003 (1) Å, respectively. In (I) and HEPA the maximum deviations of ring atoms form the best-fit planes of the four-membered ring and phenyl ring in (I) is 69.6 (1); in HEPA, 72.7°. Also, in (I), the dihedral angle between phenyl rings not required by symmetry to be parallel is 48.3 (1)°. These features are apparent in the packing diagram, Fig. 2. In both (I) and HEPA, the angular sum at C2 is 360° within less than 1 s.u. in each study, establishing the absence of pyramidal character at C2 in these molecules.

Selected bond distances and angles of (I) are given in Table 1. A l l distances and angles fall within normal limits. For comparisons with (I), HEPA appears to be quite satisfactory, though the temperature difference must be noted. For the N1/C2—C4 rings, perhaps the most interesting molecular feature, there is very good agreement in both (intra-ring) distances and angles: upon ordering the two sets of four distances and four angles by magnitude, corresponding distances and angles occur in precisely the same order in (I) and HEPA. Moreover, the mean differences between corresponding distances and angles in the four-membered rings of these two molecules are 0.010 Å and 0.3°, while the s.u.'s are 0.001 Å and 0.1° for (I) and 0.003 Å and 0.2° for HEPA. In (I), the closest intermolecular approaches, excluding pairs of atoms involved in the hydrogen bonding or the tabulated C—H···O interaction, are between C2 and H1ⁱ (i = 3/2 − x, 1/2 − y, 1 − z) and fall short of the corresponding Bondi (1964) van der Waals radius sum by 0.06 Å.

S2. Experimental

(I) was obtained as an off-white crystalline powder from a sample in Dr D. J. Hart's chemical collection. A solution of this material in ether produced suitable crystals upon slow evaporation at room temperature. A synthesis is described by Burnett et al. (1986).

Computing details

Data collection: COLLECT (Nonius, 1999); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS86 (Sheldrick, 1985); program(s) used to refine structure: TEXSAN (Molecular Structure Corporation, 1995); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: TEXSAN and PLATON (Spek, 1990).

Figures

	Fig. 1. ORTEPII (Johnson, 1976) drawing of (I), showing the labeling scheme. Displacement ellipsoids are drawn for 50% probability for all non-H atoms; spheres of arbitrary small radius depict H atoms.
	Fig. 2. ORTEPII (Johnson, 1976) packing diagram of (I) viewed down the b axis. Displacement ellipsoids are drawn for 50% probability for all non-H atoms; spheres of arbitrary small radius depict H atoms. Hydrogen bonds are represented by dashes, C—H···O interactions by dotted lines.

(I)

Crystal data

C12H15NO	F(000) = 816
Mr = 189.26	Dx = 1.225 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 14.7505 (9) Å	Cell parameters from 5017 reflections
b = 5.7579 (3) Å	θ = 2.5–27.5°
c = 24.941 (2) Å	µ = 0.08 mm^−1
β = 104.358 (3)°	T = 150 K
V = 2052.1 (2) Å^3	Cut plate, colorless
Z = 8	0.38 × 0.35 × 0.06 mm

Data collection

Nonius KappaCCD diffractometer	1896 reflections with I > 2.00σI
Radiation source: X-ray tube	Rint = 0.026
Graphite monochromator	θmax = 27.5°
ω scans with κ offsets	h = 0→19
5017 measured reflections	k = 0→7
2274 independent reflections	l = −32→31

Refinement

Refinement on F^2	131 parameters
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.042	Weighting scheme based on measured s.u.'s 1/[σ^2cs + (0.010I)^2]
wR(F^2) = 0.088	(Δ/σ)max = 0.001
S = 1.95	Δρmax = 0.28 e Å^−3
2274 reflections	Δρmin = −0.26 e Å^−3

Special details

Experimental. The Laue group assignment, the systematic absences and the centrosymmetry indicated by the intensity statistics led to assignment of the space group as C2/c (No. 15); since refinement proceeded well, it was adopted. Fourier difference methods were used to locate initial H atom positions and all the H atoms were refined. Refined C—H distances ranged from 0.94 (1) to 1.01 (1) Å, with mean value 0.98 (2) Å; their U_iso values ranged from 0.9 to 1.5 times the U_eq values of the attached C atoms. The H atoms, excepting H1 on N1, were then made canonical, with C—H = 0.98 Å and U_iso = 1.2 × U_eq of the attached C atom. In the later stages of refinement the extinction coefficient was predicted to be negative, so was not included in the model. The maximum peak in the final difference map occurs ~0.7 Å from C3 and 0.8 Å from C2, the maximum negative peak ~0.6 Å from C4.

Geometry. Table of Least-Squares Planes ——————————

————– Plane number 1 —————

Atoms Defining Plane Distance e.s.d. N1 (1) 0.0208 0.0010 C2 (1) −0.0228 0.0011 C3 (1) 0.0174 0.0010 C4 (1) −0.0195 0.0011

Mean deviation from plane is 0.0201 angstroms Chi-squared: 1614.5

————– Plane number 2 —————

Atoms Defining Plane Distance e.s.d. N1 (1) 0.0000 C2 (1) 0.0000 C3 (1) 0.0000

Additional Atoms Distance C4 (1) 0.0863

Mean deviation from plane is 0.0000 angstroms Chi-squared: 0.0

Dihedral angles between least-squares planes plane plane angle 2 1 177.54

————– Plane number 3 —————

Atoms Defining Plane Distance e.s.d. N1 (1) 0.0000 C2 (1) 0.0000 C4 (1) 0.0000

Additional Atoms Distance C3 (1) −0.0901

Mean deviation from plane is 0.0000 angstroms Chi-squared: 0.0

Dihedral angles between least-squares planes plane plane angle 3 1 177.43 3 2 3.39

————– Plane number 4 —————

Atoms Defining Plane Distance e.s.d. N1 (1) 0.0000 C3 (1) 0.0000 C4 (1) 0.0000

Additional Atoms Distance C2 (1) 0.0763

Mean deviation from plane is 0.0000 angstroms Chi-squared: 0.0

Dihedral angles between least-squares planes plane plane angle 4 1 178.00 4 2 4.45 4 3 3.27

————– Plane number 5 —————

Atoms Defining Plane Distance e.s.d. C2 (1) 0.0000 C3 (1) 0.0000 C4 (1) 0.0000

Additional Atoms Distance N1 (1) −0.0736

Mean deviation from plane is 0.0000 angstroms Chi-squared: 0.0

Dihedral angles between least-squares planes plane plane angle 5 1 178.07 5 2 3.14 5 3 4.49 5 4 2.88

————– Plane number 6 —————

Atoms Defining Plane Distance e.s.d. C8 (1) −0.0037 0.0009 C9 (1) −0.0008 0.0010 C10 (1) 0.0058 0.0010 C11 (1) −0.0045 0.0010 C12 (1) −0.0005 0.0010 C13 (1) 0.0050 0.0009

Mean deviation from plane is 0.0034 angstroms Chi-squared: 102.9

Dihedral angles between least-squares planes plane plane angle 6 1 110.38 6 2 70.62 6 3 72.06 6 4 68.98 6 5 67.85

————– Plane number 7 —————

Atoms Defining Plane Distance e.s.d. C8 (2) 0.0037 0.0009 C9 (2) 0.0008 0.0010 C10 (2) −0.0058 0.0010 C11 (2) 0.0045 0.0010 C12 (2) 0.0005 0.0010 C13 (2) −0.0050 0.0009

Mean deviation from plane is 0.0034 angstroms Chi-squared: 102.9

Dihedral angles between least-squares planes plane plane angle 7 1 80.80 7 2 98.55 7 3 101.61 7 4 99.88 7 5 97.34 7 6 48.31

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.87910 (5)	0.2001 (1)	0.50009 (3)	0.0313 (2)
N1	0.77489 (7)	0.4964 (2)	0.46092 (4)	0.0266 (3)
C2	0.85478 (7)	0.3726 (2)	0.47157 (5)	0.0230 (3)
C3	0.89852 (7)	0.5274 (2)	0.43507 (4)	0.0208 (3)
C4	0.80078 (7)	0.6567 (2)	0.42141 (5)	0.0224 (3)
C5	0.93459 (7)	0.4136 (2)	0.38913 (5)	0.0221 (3)
C6	0.97190 (8)	0.5957 (2)	0.35574 (5)	0.0302 (3)
C7	1.01075 (8)	0.2369 (2)	0.41319 (5)	0.0329 (4)
C8	0.73939 (7)	0.6457 (2)	0.36348 (5)	0.0204 (3)
C9	0.73679 (7)	0.8322 (2)	0.32743 (5)	0.0259 (3)
C10	0.68042 (8)	0.8270 (2)	0.27411 (5)	0.0283 (3)
C11	0.62459 (7)	0.6358 (2)	0.25584 (5)	0.0276 (3)
C12	0.62679 (7)	0.4490 (2)	0.29104 (5)	0.0266 (3)
C13	0.68382 (7)	0.4534 (2)	0.34422 (5)	0.0234 (3)
H1	0.7210 (8)	0.465 (2)	0.4691 (5)	0.041 (4)*
H3	0.9471	0.6263	0.4580	0.025*
H4	0.8070	0.8163	0.4355	0.027*
H5	0.8824	0.3322	0.3642	0.026*
H6B	0.9217	0.7043	0.3390	0.036*
H6C	1.0234	0.6809	0.3802	0.036*
H6A	0.9946	0.5191	0.3265	0.036*
H7A	1.0308	0.1598	0.3830	0.039*
H7B	1.0643	0.3163	0.4374	0.039*
H7C	0.9861	0.1209	0.4346	0.039*
H9	0.7756	0.9693	0.3401	0.031*
H10	0.6800	0.9589	0.2492	0.034*
H11	0.5838	0.6326	0.2183	0.033*
H12	0.5877	0.3126	0.2782	0.032*
H13	0.6851	0.3193	0.3686	0.028*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0274 (4)	0.0359 (5)	0.0316 (5)	0.0029 (4)	0.0090 (4)	0.0126 (4)
N1	0.0234 (5)	0.0345 (6)	0.0250 (6)	0.0037 (4)	0.0120 (4)	0.0067 (4)
C2	0.0219 (5)	0.0280 (6)	0.0188 (6)	−0.0017 (5)	0.0049 (5)	−0.0012 (5)
C3	0.0193 (5)	0.0218 (6)	0.0214 (6)	−0.0024 (4)	0.0051 (5)	−0.0006 (5)
C4	0.0255 (6)	0.0203 (6)	0.0233 (6)	0.0001 (5)	0.0097 (5)	−0.0001 (5)
C5	0.0198 (5)	0.0244 (6)	0.0225 (6)	−0.0036 (5)	0.0061 (5)	−0.0028 (5)
C6	0.0298 (6)	0.0339 (7)	0.0307 (7)	−0.0047 (5)	0.0144 (6)	−0.0012 (5)
C7	0.0310 (6)	0.0346 (7)	0.0350 (8)	0.0054 (5)	0.0119 (6)	−0.0029 (6)
C8	0.0182 (5)	0.0207 (6)	0.0244 (6)	0.0037 (4)	0.0093 (5)	0.0003 (4)
C9	0.0241 (6)	0.0207 (6)	0.0335 (7)	−0.0007 (5)	0.0085 (5)	0.0023 (5)
C10	0.0273 (6)	0.0284 (7)	0.0299 (7)	0.0038 (5)	0.0081 (5)	0.0086 (5)
C11	0.0214 (6)	0.0357 (7)	0.0258 (7)	0.0042 (5)	0.0059 (5)	0.0020 (5)
C12	0.0216 (5)	0.0269 (6)	0.0320 (7)	−0.0024 (5)	0.0080 (5)	−0.0028 (5)
C13	0.0216 (5)	0.0223 (6)	0.0285 (7)	0.0012 (5)	0.0105 (5)	0.0044 (5)

Geometric parameters (Å, º)

O1—C2	1.222 (1)	C6—H6A	0.98
N1—C2	1.346 (1)	C7—H7A	0.98
N1—C4	1.468 (1)	C7—H7B	0.98
N1—H1	0.89 (1)	C7—H7C	0.98
C2—C3	1.527 (1)	C8—C9	1.395 (1)
C3—C4	1.583 (1)	C8—C13	1.390 (1)
C3—C5	1.526 (1)	C9—C10	1.383 (2)
C3—H3	0.98	C9—H9	0.98
C4—C8	1.504 (2)	C10—C11	1.382 (2)
C4—H4	0.98	C10—H10	0.98
C5—C6	1.524 (1)	C11—C12	1.384 (2)
C5—C7	1.524 (2)	C11—H11	0.98
C5—H5	0.98	C12—C13	1.384 (2)
C6—H6B	0.98	C12—H12	0.98
C6—H6C	0.98	C13—H13	0.98
C2—N1—C4	96.01 (8)	H6B—C6—H6C	109.5
C2—N1—H1	129.6 (8)	H6B—C6—H6A	109.5
C4—N1—H1	132.8 (8)	H6C—C6—H6A	109.5
O1—C2—N1	131.40 (9)	C5—C7—H7A	109.5
O1—C2—C3	135.63 (9)	C5—C7—H7B	109.5
N1—C2—C3	92.97 (8)	C5—C7—H7C	109.5
C2—C3—C4	84.60 (7)	H7A—C7—H7B	109.5
C2—C3—C5	118.33 (9)	H7A—C7—H7C	109.5
C2—C3—H3	110.3	H7B—C7—H7C	109.5
C4—C3—C5	120.59 (9)	C4—C8—C9	120.02 (9)
C4—C3—H3	110.3	C4—C8—C13	121.90 (9)
C5—C3—H3	110.3	C9—C8—C13	118.1 (1)
N1—C4—C3	86.24 (7)	C8—C9—C10	121.1 (1)
N1—C4—C8	115.04 (8)	C8—C9—H9	119.4
N1—C4—H4	111.4	C10—C9—H9	119.4
C3—C4—C8	119.09 (8)	C9—C10—C11	120.1 (1)
C3—C4—H4	111.4	C9—C10—H10	120.0
C8—C4—H4	111.4	C11—C10—H10	120.0
C3—C5—C6	110.81 (8)	C10—C11—C12	119.4 (1)
C3—C5—C7	110.57 (9)	C10—C11—H11	120.3
C3—C5—H5	108.4	C12—C11—H11	120.3
C6—C5—C7	110.10 (8)	C11—C12—C13	120.5 (1)
C6—C5—H5	108.4	C11—C12—H12	119.8
C7—C5—H5	108.4	C13—C12—H12	119.8
C5—C6—H6B	109.5	C8—C13—C12	120.8 (1)
C5—C6—H6C	109.5	C8—C13—H13	119.6
C5—C6—H6A	109.5	C12—C13—H13	119.6
O1—C2—N1—C4	−176.2 (1)	C3—C2—N1—C4	3.39 (8)
O1—C2—C3—C4	176.5 (1)	C3—C4—C8—C9	−100.3 (1)
O1—C2—C3—C5	54.5 (2)	C3—C4—C8—C13	79.9 (1)
N1—C2—C3—C4	−3.14 (8)	C4—C3—C5—C6	76.4 (1)
N1—C2—C3—C5	−125.1 (1)	C4—C3—C5—C7	−161.21 (9)
N1—C4—C3—C2	2.88 (7)	C4—C8—C9—C10	−179.52 (9)
N1—C4—C3—C5	122.7 (1)	C4—C8—C13—C12	178.94 (9)
N1—C4—C8—C9	159.48 (9)	C5—C3—C4—C8	6.1 (1)
N1—C4—C8—C13	−20.3 (1)	C8—C9—C10—C11	0.7 (2)
C2—N1—C4—C3	−3.27 (8)	C8—C13—C12—C11	0.5 (1)
C2—N1—C4—C8	117.20 (9)	C9—C8—C13—C12	−0.8 (1)
C2—C3—C4—C8	−113.79 (9)	C9—C10—C11—C12	−1.0 (2)
C2—C3—C5—C6	177.64 (9)	C10—C9—C8—C13	0.2 (1)
C2—C3—C5—C7	−60.0 (1)	C10—C11—C12—C13	0.4 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1^i	0.89 (1)	2.06 (1)	2.912 (1)	161
C3—H3···O1^ii	0.98	2.71	3.634 (1)	158

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