(2Z)-3-(5-Hydroxy-4-oxo-4H-chromen-3-yl)acrylonitrile

The title compound, C₁₂H₇NO₃, consists of a chromone moiety substituted in position 3 with an acrylonitrile group in a Z configuration. The two planar groups are twisted with respect to one another. The only significant hydrogen bond in the structure is an intra­molecular O—H...O bond. π–π contacts connecting aromatic groups and C—H...O inter­molecular weak inter­actions lead to a supramolecular layer arrangement.

S1. Comment

Organic and organic inorganic hybrid layered crystals have received significant attention, due to their restricted space for reactions or molecular recognition, as well as their chemical and physical properties (Clearfield, 1988; Lee et al., 2003). Recently, robust organic layered structures of 1-naphtylmethyl ammonium n-alkanoates, with adjustable interlayer distances, have been reported (Sada et al., 2004). It is not easy to construct robust structures with weak intermolecular interactions, and only a few examples have ever been reported, e.g. an organic clay mimic based on the two-dimensional array of calixarene derivatives (Coleman et al., 1988) and laminated crystalline materials of N,N-dialkylammonium salts of 1,3,5-benzenetricarboxylic acid (Melendez et al., 1996; Melendez & Zaworotko, 1997; Krishnamonhan et al., 1997; Biradha et al., 1998; Zaworotko, 2001). Taking into account that supramolecular construction may be achieved not only with strong hydrogen bonds such as O—H···O and N—H···O, but also with C—H···O bonds, rationalization of the packing observed can be useful for the recognition of supramolecular synthons of importance in crystal engineering (Desiraju, 1996).

Recently, some authors have reported that hydrocarbons are weak H-atom donors. However, addition of electron-withdrawing groups strengthens them to the point where their interaction energies with H-atom acceptors could lie within the range of conventional hydrogen bonds. The cyano group, among other functional groups, has been described as an electron-withdrawing agent that imparts sufficient acidity to the CH group to allow hydrogen bonding (Scheiner et al., 2001; Cabaleiro-Lago et al., 2000; Desiraju, 1996). On the other hand, the chromone system (4H-1-benzopyran-4-one) has received attention because of the possibility that the heterocyclic moiety may present some aromatic character (Polly & Taylor, 1999), and also because many chromone derivatives show interesting biological properties, including antitumour activity in vivo (Valenti et al., 1996; Rajski & Williams, 1998) and phosphatase inhibition (Shim et al., 2003). Moreover, some heteroarylacrylonitriles have also shown cytotoxic activities (Saczewsky et al., 2004). Therefore, the combination of acrylonitrile and chromone moieties in one single molecule gives the possibility of achieving novel bioactive compounds. However, there are no reports to date dealing with the synthesis of chromone attached to an acrylonitrile framework. Rewording OK?

The structure of the title compound (I), was initially assigned by NMR spectroscopy. In order to confirm its double-bond geometry, as well as to obtain more detailed information on its structural conformation, the X-ray structure determination of (I) (Fig. 1) has been carried out and the results are presented here. The planar geometry of the benzopyran ring system supports the observation regarding the aromatic character of chromone reported previously for the benzopyrane ring (Polly et al., 1999; Rybarczyk-Pirek & Nawrot-Modranka, 2004), that there is an elongation of the C6—C9 bond and a decrease of the valence angle because atom C9 is engaged in a formal C═O bond. On the other hand, the shortest bond length and the largest angle are observed for atom C7.

Similar variations of the geometric parameters have been reported also for other compounds (Thinagar et al., 2003; Wallet & Gaydou, 1992; Adams et al., 1991). These distances can be compared with the typical aromatic bond length of 1.384 (13) Å (Allen et al., 1987). Both rings are planar to within 0.02 (1) Å of the maximum deviation. The planar acrylonitrile moiety (atoms C10, C11, C12 and N1) is twisted around C8—C10 with respect to the chromone system, subtending a dihedral angle of 38.1 Å; such an arrangement of these two groups reduces the possibility of resonance between them.

The packing of (I) is stabilized by extensive C—H···O intermolecular weak interactions. The structure presents a strong intramolecular hydrogen bond connecting atoms H1 and O3 (Table 1). In addition, a C—H···O hydrogen bond (Table 1) generates chains along [010] (Figs. 2 and 3). The only other significant intermolecular interactions are the π–π contacts which govern the stacking of aromatic groups along the [100] direction. Symmetry-related moieties at (1 − x, 2 − y, −z) and (2 − x, 2 − y, −z) extend parallel to each other at a graphitic distance of 3.45 (1) Å and a slippage angle of less than 20°, defining well connected? columns which run parallel to a.

S2. Experimental

Triphenylphosphoranylideneacetonitrile (0.5 g) was added to a solution of 5-hydroxy-4-oxo-4H-1-benzopyran-3-carboxaldehyde (5-hydroxy-3-formylchromone) (0.3 g) in toluene (50 ml) and the resulting solution was heated under reflux for 2 h, yielding a mixture of the two geometrical isomers. This mixture was chromatographed on silica gel (hexane–ethyl acetate–acetone, 4:1:0.01) to afford pure Z and E compounds. The title compound (60% yield) was crystallized as pale-yellow needles by adding hexane over an ethyl acetate solution of the compound until opalescence. Analysis: calculated for C₁₂H₇NO₃: C 67.6, H 3.3, N 6.6%; found: C 67.0, H 3.0, N 6.9%.

S3. Refinement

All H atoms were located from difference maps and then treated as riding, with O—H distances of 0.82 Å and U_iso(H) = 1.5U_eq(O), and C—H distances of 0.93 Å and U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SMART; data reduction: SAINT-Plus NT (Bruker, 2002); program(s) used to solve structure: XS in SHELXTL-NT (Bruker, 2002); program(s) used to refine structure: XL in SHELXTL-NT; molecular graphics: XP in SHELXTL-PC (Sheldrick, 1994); software used to prepare material for publication: SHELXTL-NT.

Figures

	Fig. 1. A view of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. A packing view of (I), showing the formation of a chain along [010]. [Symmetry codes: (A) x, y, z; (B) x, 1 + y, z; (C) 1 − x, −1/2 + y, 1/2 − z; (D) 1 − x, 1/2 + y, 1/2 − z; (E) 1 − x, 3/2 + y, 1/2 − z.]
	Fig. 3. A stereo packing view of (I), showing the [010] chains.

(2Z)-3-(5-hydroxy-4-oxo-4H-chromen-3-yl)acrylonitrile

Crystal data

C12H7NO3	F(000) = 440
Mr = 213.19	Dx = 1.460 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 999 reflections
a = 7.2251 (11) Å	θ = 2.5–26.2°
b = 11.1930 (17) Å	µ = 0.11 mm^−1
c = 12.2219 (18) Å	T = 293 K
β = 101.099 (2)°	Polyhedron, colourless
V = 969.9 (3) Å^3	0.35 × 0.30 × 0.25 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	1494 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.041
Graphite monochromator	θmax = 27.9°, θmin = 2.5°
ϕ and ω scans	h = −9→9
6913 measured reflections	k = −14→14
2172 independent reflections	l = −15→15

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.113	H-atom parameters constrained
S = 0.99	w = 1/[σ^2(Fo^2) + (0.0638P)^2] where P = (Fo^2 + 2Fc^2)/3
2172 reflections	(Δ/σ)max < 0.001
146 parameters	Δρmax = 0.17 e Å^−3
0 restraints	Δρmin = −0.20 e Å^−3

Special details

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
C1	0.21236 (17)	0.11441 (11)	0.08159 (11)	0.0452 (3)
C2	0.15267 (18)	0.21046 (12)	0.01397 (11)	0.0526 (4)
H2	0.1258	0.2826	0.0453	0.063*
C3	0.13249 (19)	0.20019 (13)	−0.09990 (11)	0.0557 (4)
H3	0.0918	0.2659	−0.1446	0.067*
C4	0.17134 (19)	0.09451 (13)	−0.14926 (11)	0.0540 (4)
H4	0.1561	0.0879	−0.2263	0.065*
C5	0.23328 (16)	−0.00066 (11)	−0.08071 (10)	0.0430 (3)
C6	0.25632 (14)	0.00497 (10)	0.03493 (9)	0.0403 (3)
C7	0.32552 (19)	−0.20164 (12)	−0.06960 (11)	0.0498 (3)
H7	0.3483	−0.2712	−0.1064	0.060*
C8	0.34848 (17)	−0.20640 (11)	0.04215 (10)	0.0430 (3)
C9	0.32047 (16)	−0.09831 (11)	0.10284 (10)	0.0414 (3)
C10	0.40502 (19)	−0.31420 (12)	0.10657 (11)	0.0529 (4)
H10	0.4858	−0.3034	0.1749	0.063*
C11	0.3552 (2)	−0.42569 (13)	0.07951 (11)	0.0561 (4)
H11	0.4054	−0.4860	0.1287	0.067*
C12	0.2296 (2)	−0.45883 (12)	−0.02024 (13)	0.0548 (4)
N1	0.1298 (2)	−0.48676 (12)	−0.09987 (12)	0.0747 (4)
O1	0.22579 (16)	0.12602 (9)	0.19233 (7)	0.0636 (3)
H1	0.2614	0.0627	0.2231	0.095*
O2	0.27246 (13)	−0.10473 (8)	−0.13224 (7)	0.0530 (3)
O3	0.34752 (13)	−0.09620 (8)	0.20650 (7)	0.0567 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0420 (7)	0.0461 (8)	0.0469 (7)	−0.0055 (5)	0.0069 (6)	−0.0054 (6)
C2	0.0519 (8)	0.0417 (7)	0.0654 (9)	−0.0012 (6)	0.0140 (7)	−0.0013 (6)
C3	0.0538 (8)	0.0471 (8)	0.0659 (9)	0.0010 (6)	0.0112 (7)	0.0145 (7)
C4	0.0570 (8)	0.0597 (9)	0.0449 (8)	−0.0007 (7)	0.0086 (6)	0.0088 (6)
C5	0.0434 (7)	0.0437 (7)	0.0425 (7)	−0.0030 (6)	0.0097 (5)	−0.0015 (5)
C6	0.0352 (6)	0.0435 (7)	0.0417 (7)	−0.0049 (5)	0.0064 (5)	−0.0006 (5)
C7	0.0571 (8)	0.0435 (7)	0.0502 (8)	0.0021 (6)	0.0142 (6)	−0.0026 (6)
C8	0.0402 (7)	0.0465 (8)	0.0419 (7)	0.0010 (5)	0.0068 (5)	−0.0002 (5)
C9	0.0361 (6)	0.0490 (8)	0.0388 (7)	−0.0029 (5)	0.0063 (5)	−0.0017 (5)
C10	0.0532 (8)	0.0561 (9)	0.0479 (8)	0.0087 (7)	0.0058 (6)	0.0021 (6)
C11	0.0641 (9)	0.0489 (9)	0.0562 (9)	0.0114 (7)	0.0136 (7)	0.0083 (6)
C12	0.0668 (9)	0.0426 (8)	0.0600 (9)	0.0019 (7)	0.0244 (8)	0.0030 (7)
N1	0.0940 (10)	0.0646 (9)	0.0662 (9)	−0.0126 (8)	0.0175 (8)	−0.0039 (7)
O1	0.0860 (7)	0.0547 (6)	0.0491 (6)	0.0028 (5)	0.0108 (5)	−0.0114 (4)
O2	0.0697 (6)	0.0505 (6)	0.0396 (5)	0.0032 (5)	0.0129 (4)	0.0009 (4)
O3	0.0674 (6)	0.0624 (6)	0.0383 (5)	0.0065 (5)	0.0052 (4)	−0.0005 (4)

Geometric parameters (Å, º)

C1—O1	1.3445 (15)	C7—O2	1.3404 (16)
C1—C2	1.3739 (18)	C7—C8	1.3448 (17)
C1—C6	1.4129 (17)	C7—H7	0.9300
C2—C3	1.3760 (17)	C8—C9	1.4535 (18)
C2—H2	0.9300	C8—C10	1.4556 (18)
C3—C4	1.381 (2)	C9—O3	1.2444 (14)
C3—H3	0.9300	C10—C11	1.323 (2)
C4—C5	1.3758 (18)	C10—H10	0.9300
C4—H4	0.9300	C11—C12	1.422 (2)
C5—O2	1.3792 (15)	C11—H11	0.9300
C5—C6	1.3923 (17)	C12—N1	1.1379 (18)
C6—C9	1.4464 (17)	O1—H1	0.8200
O1—C1—C2	118.91 (12)	O2—C7—C8	125.31 (12)
O1—C1—C6	120.79 (11)	O2—C7—H7	117.3
C2—C1—C6	120.30 (12)	C8—C7—H7	117.3
C1—C2—C3	120.20 (13)	C7—C8—C9	118.89 (12)
C1—C2—H2	119.9	C7—C8—C10	123.31 (12)
C3—C2—H2	119.9	C9—C8—C10	117.78 (11)
C2—C3—C4	121.50 (13)	O3—C9—C6	122.63 (11)
C2—C3—H3	119.2	O3—C9—C8	121.69 (11)
C4—C3—H3	119.2	C6—C9—C8	115.67 (11)
C5—C4—C3	117.83 (13)	C11—C10—C8	127.75 (13)
C5—C4—H4	121.1	C11—C10—H10	116.1
C3—C4—H4	121.1	C8—C10—H10	116.1
C4—C5—O2	116.56 (12)	C10—C11—C12	123.95 (13)
C4—C5—C6	122.98 (12)	C10—C11—H11	118.0
O2—C5—C6	120.46 (11)	C12—C11—H11	118.0
C5—C6—C1	117.18 (11)	N1—C12—C11	179.17 (16)
C5—C6—C9	120.58 (11)	C1—O1—H1	109.5
C1—C6—C9	122.23 (11)	C7—O2—C5	118.94 (10)
O1—C1—C2—C3	−178.17 (11)	C5—C6—C9—O3	178.11 (11)
C6—C1—C2—C3	1.00 (19)	C1—C6—C9—O3	−2.67 (18)
C1—C2—C3—C4	−0.1 (2)	C5—C6—C9—C8	−2.97 (16)
C2—C3—C4—C5	−0.7 (2)	C1—C6—C9—C8	176.25 (10)
C3—C4—C5—O2	−179.48 (11)	C7—C8—C9—O3	−176.91 (11)
C3—C4—C5—C6	0.6 (2)	C10—C8—C9—O3	1.57 (18)
C4—C5—C6—C1	0.23 (18)	C7—C8—C9—C6	4.16 (17)
O2—C5—C6—C1	−179.66 (10)	C10—C8—C9—C6	−177.36 (10)
C4—C5—C6—C9	179.49 (11)	C7—C8—C10—C11	−37.1 (2)
O2—C5—C6—C9	−0.41 (17)	C9—C8—C10—C11	144.50 (14)
O1—C1—C6—C5	178.11 (11)	C8—C10—C11—C12	−1.5 (2)
C2—C1—C6—C5	−1.04 (17)	C10—C11—C12—N1	166 (11)
O1—C1—C6—C9	−1.14 (18)	C8—C7—O2—C5	−1.47 (19)
C2—C1—C6—C9	179.71 (10)	C4—C5—O2—C7	−177.18 (11)
O2—C7—C8—C9	−2.10 (19)	C6—C5—O2—C7	2.72 (17)
O2—C7—C8—C10	179.51 (12)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O3	0.82	1.91	2.6327 (14)	147
C10—H10···O1^i	0.93	2.51	3.3286 (17)	147

Symmetry code: (i) −x+1, y−1/2, −z+1/2.