Racemic tricarbon­yl[7-meth­oxy-2-(η6-phen­yl)chromane]­chromium(0)

Gohain, M.; Muller, T.J.; Bezuidenhoudt, B.C.B.

doi:10.1107/S1600536811008683

metal-organic compounds

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ISSN: 2056-9890

Volume 67| Part 4| April 2011| Pages m438-m439

doi:10.1107/S1600536811008683

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Racemic tricarbonyl[7-methoxy-2-(η⁶-phenyl)chromane]chromium(0)

Mukut Gohain,^a Theunis J. Muller ^a ^* and Barend C. B. Bezuidenhoudt ^a

^aDepartment of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa
^*Correspondence e-mail: muller.theunis@gmail.com

(Received 19 February 2011; accepted 7 March 2011; online 12 March 2011)

In the title compound, [Cr(C₁₆H₁₆O₂)(CO)₃], the Cr⁰ atom of the Cr(CO)₃ unit is coordinated to the phenyl ring of the flavan ligand in an η⁶ mode, with a normal arene-to-metal distance. The Cr(CO)₃ unit exhibits a three-legged piano-stool conformation, while the dihydropyran ring displays a distorted envelope configuration. The phenyl ring is twisted away from the fused ring system by 25.5 (2)°. The methoxy group is almost coplanar with the phenyl ring [C_Me—O—C_ar—C_ar torsion angle = 8.46 (2)°]. The crystal packing is stabilized by intermolecular C—H⋯O interactions.

Related literature

For similar structures, see: van Tonder et al. (2010a ,b ) and for other related structures, see: van Tonder et al. (2009a ,b ). For the synthesis of the title compound, see: Müller et al. (1999 ) and for the sythesis of 7-methoxyflavan-4-one, see: Sato et al. (2006 ). For standard bond lengths, see: Allen et al. (1987 ). For the importance of flavonoids in biological investigations, see: Rice-Evans & Packer (2003 ). For the use of tricarbonyl(arene)chromium complexes in regioselective organic synthesis, see: Muschalek et al. (2007 ).

Experimental

Crystal data

[Cr(C₁₆H₁₆O₂)(CO)₃]
M_r = 376.32
Monoclinic, P 2₁ /c
a = 9.7703 (5) Å
b = 19.1820 (9) Å
c = 8.8049 (4) Å
β = 97.494 (2)°
V = 1636.07 (14) Å³
Z = 4
Mo Kα radiation
μ = 0.73 mm⁻¹
T = 100 K
0.34 × 0.23 × 0.08 mm

Data collection

Bruker X8 APEXII 4K KappaCCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ) T_min = 0.818, T_max = 0.942
29057 measured reflections
4069 independent reflections
3526 reflections with I > 2σ(I)
R_int = 0.033

Refinement

R[F² > 2σ(F²)] = 0.034
wR(F²) = 0.090
S = 1.00
4069 reflections
222 parameters
H-atom parameters constrained
Δρ_max = 0.73 e Å⁻³
Δρ_min = −0.52 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4′—H4′⋯O2ⁱ	0.93	2.54	3.459 (2)	169
C2′—H2′⋯O4ⁱⁱ	0.93	2.46	3.153 (2)	132
C1—H1C⋯O4ⁱⁱⁱ	0.96	2.57	3.314 (2)	134
Symmetry codes: (i) $[-x, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[x, -y-{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (iii) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT-Plus (Bruker, 2008); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenberg & Putz, 2005 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811008683/hp2002sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811008683/hp2002Isup2.hkl

checkCIF report

Comment top

The title compound, [Cr(CO)₃(C₁₆H₁₆O₂)] forms part of a series of chromium(0) complexes of the type [Cr(flav)(CO)₃] (flav = flavan, flavone or isoflavone ligand) (van Tonder et al., 2009a,b and 2010a,b). Our interest in this type of chromium(0) complexes is partly due to regioselective organic syntesis (Muschalek et al., 2007) and to the general biological activity of flavanoids (Rice-Evans & Packer, 2003).

The title compound crystalized in the monoclinic space group P2(1)/c, with Z = 4. For the title compound the molecular structure displays the Cr(CO)₃ moiety complexed to the flavone C-ring, exhibiting the known three-legged piano-stool conformation. All bond distances and angles are within range (Allen et al., 1987). The distance between the Cr⁰ atom and the centroid of the A-η⁶-coordinated phenyl ring is 1.7119 (3) Å. The plane through C1'-C6' (r.m.s =0.0038 fitted atoms C1'-C6') of the phenyl ring is at an angle of 42.762 (43) ° to the plane formed between C4—C10 and O1 (r.m.s = 0.00824 fitted atoms C4, C5, C6, C7, C8, C9, C10 and O1). The dihydropyran ring displays a distored envelope configuration by displacement of atoms C2 and C3 from the fused ring system plane, with distances of 0.105 (2) 0.618 (2) Å respectively. The methoxy group at the C7 position is nearley coplanar to the plane created by the fused ring system. The methoxy forme a dihedral angle of -8.464 (23) ° between C1—O2—C7—C6. The molecules form chains through intermolecular C4—H4···O2ⁱ, C2—H2···O4ⁱⁱ and C1—H1C···O4ⁱⁱⁱ hydrogen interactions (Table 1).

Related literature top

For similar structures, see: van Tonder et al. (2010a,b) and for other related structures, see: van Tonder et al. (2009a,b). For the synthesis of the title compound, see: Müller et al. (1999) and for the sythesis of 7-methoxyflavan-4-one, see: Sato et al. (2006). For standard bond lengths, see: Allen et al. (1987). For the importance of flavonoids in biological investigations, see: Rice-Evans & Packer (2003). For the use of tricarbonyl(arene)chromium complexes in regioselective organic synthesis, see: Muschalek et al. (2007).

Experimental top

7-methoxyflavan-4-one was synthesized as described by Sato et al. (2006). 7-Methoxyflavan-4-one (1.00 g; 3.9 mmol), 10% Pd/C (0.10 g), 3 M H₂SO₄ (aq) (1 ml), ethanol (30 ml). Purification by means of flash column-chromatography yielded 7-methoxyflavan (0.67 g; 70.6%) as a colourless oil as described by Sato et al. (2006) R_f 0.65 (hexane:DCM:ethyl acetate; 50:50:1); ¹H NMR (600 MHz, CDCl₃) δ 7.44–7.41 (m, H-2' and H-6', 2H), 7.40–7.37 (m, H-3' and H-5', 2H), 7.34–7.31 (m, H-4', 1H), 6.99–6.97 (m, H-5, 1H), 6.50–6.47 (m, H-6 and H-8, 2H), 5.05 (dd, J = 10.19, 2.37 Hz, H-2 1H), 3.77 (s,-OCH₃, 3H), 2.92 (ddd, J = 16.08, 10.92, 6.02 Hz, H-4(a) 1H), 2.74 (ddd, J = 16.08, 5.12, 3.40 Hz, H-4(e) 1H), 2.22–2.18 (m, H-3 1H), 2.11–2.04 (m, H-3 1H); ¹³C NMR (151 MHz, CDCl₃) δ p.p.m. 24.47 (C-4), 30.19 (C-3), 55.38 (–OCH₃), 77.98 (C-2),101.71 (C-6/8), 107.54 (C-6/8), 114.01, 126.11, 127.93, 128.61, 130.05, 141.79, 155.91, 159.23.

Preparation of the title compound was based on a method described by Müller et al. (1999). A solution of 7-methoxyflavan (0.27 g, 1.1 mmol) and Cr(CO)₆ (0.25 g, 1.1 mmol, 1 eq) in butylether:THF (9:1; 25 ml) was degassed with argon, using standard Schlenk techniques, and refluxed (70 hr) under an oxygen free atmosphere. The reaction mixture was cooled to room temperature and evaporated in vacuo. Purification through flash column-chromotography yielded the title compound (0.10 g; 24%) as a yellow solid. Recrystallization from hexane:dichloromethane (6:1) yielded yellow plate like crystals suitable for X-ray analysis.

R_f 0.30 (hexane:ethyl acetate; 3:5); Mp 145–147 °C IR ν(CO) = 1952, 1894 and 1844 cm^-1;¹H NMR (600 MHz, CDCl₃) δ 6.96 (d, J = 8.3 Hz, 1H), 6.49 (dd, J = 8.3, 2.5 Hz, 1H), 6.48 (d, J = 2.5 Hz, 1H), 5.56 (d, J = 6.2 Hz, 1H), 5.43–5.41 (m, 1H), 5.37–5.32 (m, 3H), 4.67 (dd, J = 10.4, 2.3 Hz, 1H), 3.77 (s, 3H), 2.94–2.87 (m, 1H), 2.76 (m, 1H), 2.25 (m, 1H), 1.99 (m, 1H). ¹³C NMR (151 MHz, CDCl₃) δ p.p.m. 232.53, 159.27, 155.02, 129.85, 113.31, 111.38, 108.09, 101.51, 92.22, 91.62, 91.49, 91.22, 90.68, 75.37, 55.37, 29.89, 24.11.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT-Plus (Bruker, 2008); data reduction: SAINT-Plus (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenberg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

Fig. 1. Diamond representation of the title compound, showing the numbering scheme and displacement ellipsoids (50% probability).

tricarbonyl[7-methoxy-2-(η⁶-phenyl)chromane]chromium(0) top

Crystal data top

[Cr(C₁₆H₁₆O₂)(CO)₃]	F(000) = 776
M_r = 376.32	D_x = 1.528 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.7703 (5) Å	Cell parameters from 9920 reflections
b = 19.1820 (9) Å	θ = 3.0–28.2°
c = 8.8049 (4) Å	µ = 0.73 mm⁻¹
β = 97.494 (2)°	T = 100 K
V = 1636.07 (14) Å³	Plate, yellow
Z = 4	0.34 × 0.23 × 0.08 mm

Data collection top

Bruker X8 APEXII 4K KappaCCD diffractometer	4069 independent reflections
Graphite monochromator	3526 reflections with I > 2σ(I)
Detector resolution: 8.5 pixels mm^-1	R_int = 0.033
ϕ and ω scans	θ_max = 28.3°, θ_min = 3.1°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −13→9
T_min = 0.818, T_max = 0.942	k = −25→25
29057 measured reflections	l = −11→11

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.090	H-atom parameters constrained
S = 1.00	w = 1/[σ²(F_o²) + (0.0434P)² + 1.6967P] where P = (F_o² + 2F_c²)/3
4069 reflections	(Δ/σ)_max = 0.015
222 parameters	Δρ_max = 0.73 e Å⁻³
0 restraints	Δρ_min = −0.52 e Å⁻³

Crystal data top

[Cr(C₁₆H₁₆O₂)(CO)₃]	V = 1636.07 (14) Å³
M_r = 376.32	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 9.7703 (5) Å	µ = 0.73 mm⁻¹
b = 19.1820 (9) Å	T = 100 K
c = 8.8049 (4) Å	0.34 × 0.23 × 0.08 mm
β = 97.494 (2)°

Data collection top

Bruker X8 APEXII 4K KappaCCD diffractometer	4069 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2008)	3526 reflections with I > 2σ(I)
T_min = 0.818, T_max = 0.942	R_int = 0.033
29057 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.034	0 restraints
wR(F²) = 0.090	H-atom parameters constrained
S = 1.00	Δρ_max = 0.73 e Å⁻³
4069 reflections	Δρ_min = −0.52 e Å⁻³
222 parameters

Special details top

Experimental. The intensity data was collected on a Bruker X8 ApexII 4 K Kappa CCD diffractometer using an exposure time of 15 s/frame. A total of 1821 frames were collected with a frame width of 0.5° covering up to θ = 28.18° with 99.7% completeness accomplished.

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
C1	0.3380 (2)	0.29331 (9)	0.6478 (2)	0.0208 (4)
H1A	0.291	0.2854	0.7355	0.031*
H1B	0.3066	0.3363	0.5995	0.031*
H1C	0.4356	0.2959	0.6798	0.031*
C1'	0.17467 (19)	−0.11113 (9)	0.36846 (19)	0.0178 (3)
C2	0.28858 (19)	−0.07158 (9)	0.4658 (2)	0.0190 (3)
H2	0.3777	−0.0837	0.4332	0.023*
C2'	0.19981 (19)	−0.17979 (9)	0.3254 (2)	0.0196 (3)
H2'	0.2859	−0.1997	0.355	0.023*
C3'	0.0952 (2)	−0.21918 (9)	0.2369 (2)	0.0213 (4)
H3'	0.1123	−0.265	0.2106	0.026*
C3	0.29216 (19)	−0.08786 (9)	0.6350 (2)	0.0202 (4)
H3A	0.3106	−0.1371	0.6528	0.024*
H3B	0.2034	−0.0771	0.6676	0.024*
C4'	−0.03356 (19)	−0.18914 (10)	0.1893 (2)	0.0219 (4)
H4'	−0.1018	−0.2147	0.1301	0.026*
C4	0.40480 (18)	−0.04451 (8)	0.72666 (19)	0.0167 (3)
H4A	0.4003	−0.0501	0.8354	0.02*
H4B	0.4948	−0.0602	0.7056	0.02*
C5	0.43124 (17)	0.08604 (9)	0.77979 (19)	0.0159 (3)
H5	0.4782	0.0757	0.8759	0.019*
C5'	−0.05972 (19)	−0.11962 (10)	0.2316 (2)	0.0220 (4)
H5'	−0.1454	−0.0995	0.2003	0.026*
C6	0.41013 (17)	0.15570 (9)	0.73907 (19)	0.0159 (3)
H6	0.4428	0.1912	0.8062	0.019*
C6'	0.04282 (19)	−0.08107 (9)	0.3203 (2)	0.0197 (3)
H6'	0.0248	−0.0355	0.348	0.024*
C7	0.33885 (17)	0.17112 (9)	0.59536 (19)	0.0159 (3)
C7'	0.20844 (19)	−0.03456 (9)	0.0866 (2)	0.0210 (2)
C8	0.29047 (18)	0.11775 (9)	0.49617 (19)	0.0176 (3)
H8	0.2422	0.1281	0.4007	0.021*
C8'	0.26596 (17)	−0.16022 (8)	0.02184 (19)	0.0168 (3)
C9	0.31439 (18)	0.04906 (9)	0.53999 (19)	0.0163 (3)
C9'	0.02989 (18)	−0.11148 (9)	−0.0765 (2)	0.0185 (3)
C10	0.38501 (17)	0.03117 (8)	0.68272 (19)	0.0148 (3)
O1	0.25988 (15)	0.00078 (6)	0.43410 (14)	0.0232 (3)
O2	0.30939 (14)	0.23734 (6)	0.54184 (14)	0.0210 (3)
O3	0.26044 (13)	0.01758 (6)	0.06402 (15)	0.0210 (2)
O4	0.35317 (13)	−0.18513 (7)	−0.03763 (15)	0.0218 (3)
O5	−0.02741 (14)	−0.10672 (8)	−0.19953 (15)	0.0280 (3)
Cr1	0.12859 (3)	−0.120499 (13)	0.11540 (3)	0.01295 (8)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0271 (9)	0.0133 (8)	0.0223 (9)	−0.0016 (6)	0.0046 (7)	−0.0035 (6)
C1'	0.0238 (9)	0.0148 (8)	0.0143 (8)	−0.0025 (6)	0.0010 (6)	0.0018 (6)
C2	0.0226 (8)	0.0155 (8)	0.0185 (8)	−0.0028 (6)	0.0008 (7)	0.0002 (6)
C2'	0.0249 (9)	0.0141 (8)	0.0184 (8)	−0.0011 (6)	−0.0022 (7)	0.0037 (6)
C3'	0.0295 (10)	0.0125 (7)	0.0214 (9)	−0.0055 (7)	0.0017 (7)	0.0026 (6)
C3	0.0240 (9)	0.0170 (8)	0.0189 (8)	−0.0025 (7)	0.0007 (7)	0.0026 (6)
C4'	0.0204 (9)	0.0238 (9)	0.0215 (8)	−0.0092 (7)	0.0030 (7)	0.0029 (7)
C4	0.0190 (8)	0.0152 (8)	0.0149 (7)	0.0005 (6)	−0.0017 (6)	0.0014 (6)
C5	0.0134 (7)	0.0194 (8)	0.0145 (7)	−0.0003 (6)	−0.0003 (6)	0.0010 (6)
C5'	0.0157 (8)	0.0282 (9)	0.0231 (9)	−0.0005 (7)	0.0062 (7)	0.0040 (7)
C6	0.0146 (8)	0.0168 (8)	0.0160 (8)	−0.0024 (6)	0.0013 (6)	−0.0034 (6)
C6'	0.0243 (9)	0.0188 (8)	0.0170 (8)	0.0011 (7)	0.0072 (7)	−0.0003 (6)
C7	0.0168 (8)	0.0143 (7)	0.0169 (8)	0.0001 (6)	0.0029 (6)	0.0005 (6)
C7'	0.0240 (5)	0.0159 (4)	0.0236 (5)	−0.0015 (4)	0.0056 (4)	0.0004 (4)
C8	0.0218 (8)	0.0169 (8)	0.0130 (7)	−0.0012 (6)	−0.0016 (6)	0.0016 (6)
C8'	0.0179 (8)	0.0128 (7)	0.0184 (8)	−0.0028 (6)	−0.0019 (6)	−0.0013 (6)
C9	0.0215 (8)	0.0140 (7)	0.0134 (7)	−0.0029 (6)	0.0019 (6)	−0.0017 (6)
C9'	0.0143 (8)	0.0202 (8)	0.0213 (8)	0.0005 (6)	0.0036 (6)	−0.0005 (6)
C10	0.0134 (7)	0.0159 (7)	0.0151 (7)	0.0004 (6)	0.0025 (6)	0.0016 (6)
O1	0.0419 (8)	0.0117 (6)	0.0135 (6)	−0.0046 (5)	−0.0057 (5)	0.0009 (4)
O2	0.0314 (7)	0.0122 (6)	0.0177 (6)	0.0000 (5)	−0.0027 (5)	0.0002 (5)
O3	0.0240 (5)	0.0159 (4)	0.0236 (5)	−0.0015 (4)	0.0056 (4)	0.0004 (4)
O4	0.0190 (6)	0.0206 (6)	0.0258 (7)	0.0003 (5)	0.0032 (5)	−0.0063 (5)
O5	0.0236 (7)	0.0394 (8)	0.0195 (7)	0.0032 (6)	−0.0032 (5)	0.0001 (6)
Cr1	0.01308 (14)	0.01116 (13)	0.01423 (14)	−0.00064 (9)	0.00033 (9)	−0.00028 (9)

Geometric parameters (Å, º) top

C1—O2	1.426 (2)	C4—H4A	0.97
C1—H1A	0.96	C4—H4B	0.97
C1—H1B	0.96	C5—C6	1.392 (2)
C1—H1C	0.96	C5—C10	1.393 (2)
C1'—C2'	1.401 (2)	C5—H5	0.93
C1'—C6'	1.424 (3)	C5'—C6'	1.399 (3)
C1'—C2	1.517 (2)	C5'—Cr1	2.2187 (18)
C1'—Cr1	2.2221 (17)	C5'—H5'	0.93
C2—O1	1.436 (2)	C6—C7	1.394 (2)
C2—C3	1.518 (2)	C6—H6	0.93
C2—H2	0.98	C6'—Cr1	2.2188 (17)
C2'—C3'	1.419 (2)	C6'—H6'	0.93
C2'—Cr1	2.2044 (17)	C7—O2	1.372 (2)
C2'—H2'	0.93	C7—C8	1.388 (2)
C3'—C4'	1.397 (3)	C7'—O3	1.151 (2)
C3'—Cr1	2.2194 (17)	C7'—Cr1	1.8552 (18)
C3'—H3'	0.93	C8—C9	1.384 (2)
C3—C4	1.524 (2)	C8—H8	0.93
C3—H3A	0.97	C8'—O4	1.160 (2)
C3—H3B	0.97	C8'—Cr1	1.8300 (18)
C4'—C5'	1.417 (3)	C9—O1	1.3716 (19)
C4'—Cr1	2.2216 (17)	C9—C10	1.395 (2)
C4'—H4'	0.93	C9'—O5	1.156 (2)
C4—C10	1.508 (2)	C9'—Cr1	1.8413 (18)

O2—C1—H1A	109.5	C5'—C6'—C1'	120.42 (16)
O2—C1—H1B	109.5	C5'—C6'—Cr1	71.62 (10)
H1A—C1—H1B	109.5	C1'—C6'—Cr1	71.42 (10)
O2—C1—H1C	109.5	C5'—C6'—H6'	119.8
H1A—C1—H1C	109.5	C1'—C6'—H6'	119.8
H1B—C1—H1C	109.5	Cr1—C6'—H6'	129.6
C2'—C1'—C6'	118.91 (16)	O2—C7—C8	115.32 (14)
C2'—C1'—C2	118.79 (16)	O2—C7—C6	124.44 (15)
C6'—C1'—C2	122.29 (15)	C8—C7—C6	120.24 (15)
C2'—C1'—Cr1	70.86 (10)	O3—C7'—Cr1	177.22 (16)
C6'—C1'—Cr1	71.16 (10)	C9—C8—C7	119.69 (15)
C2—C1'—Cr1	130.16 (12)	C9—C8—H8	120.2
O1—C2—C1'	105.27 (14)	C7—C8—H8	120.2
O1—C2—C3	111.62 (14)	O4—C8'—Cr1	179.72 (16)
C1'—C2—C3	111.90 (14)	O1—C9—C8	114.63 (14)
O1—C2—H2	109.3	O1—C9—C10	123.27 (15)
C1'—C2—H2	109.3	C8—C9—C10	122.07 (15)
C3—C2—H2	109.3	O5—C9'—Cr1	177.22 (16)
C1'—C2'—C3'	120.66 (17)	C5—C10—C9	116.69 (15)
C1'—C2'—Cr1	72.24 (10)	C5—C10—C4	123.31 (15)
C3'—C2'—Cr1	71.86 (10)	C9—C10—C4	119.97 (15)
C1'—C2'—H2'	119.7	C9—O1—C2	118.15 (13)
C3'—C2'—H2'	119.7	C7—O2—C1	117.25 (13)
Cr1—C2'—H2'	128.5	C8'—Cr1—C9'	87.31 (8)
C4'—C3'—C2'	120.04 (17)	C8'—Cr1—C7'	87.84 (8)
C4'—C3'—Cr1	71.75 (10)	C9'—Cr1—C7'	88.31 (8)
C2'—C3'—Cr1	70.71 (10)	C8'—Cr1—C2'	89.59 (7)
C4'—C3'—H3'	120	C9'—Cr1—C2'	152.67 (7)
C2'—C3'—H3'	120	C7'—Cr1—C2'	118.72 (7)
Cr1—C3'—H3'	130.1	C8'—Cr1—C5'	155.74 (7)
C2—C3—C4	109.27 (14)	C9'—Cr1—C5'	93.20 (7)
C2—C3—H3A	109.8	C7'—Cr1—C5'	116.42 (8)
C4—C3—H3A	109.8	C2'—Cr1—C5'	78.89 (7)
C2—C3—H3B	109.8	C8'—Cr1—C6'	152.24 (7)
C4—C3—H3B	109.8	C9'—Cr1—C6'	120.40 (7)
H3A—C3—H3B	108.3	C7'—Cr1—C6'	91.05 (7)
C3'—C4'—C5'	119.71 (16)	C2'—Cr1—C6'	66.76 (7)
C3'—C4'—Cr1	71.57 (10)	C5'—Cr1—C6'	36.75 (7)
C5'—C4'—Cr1	71.28 (10)	C8'—Cr1—C3'	91.40 (7)
C3'—C4'—H4'	120.1	C9'—Cr1—C3'	115.48 (7)
C5'—C4'—H4'	120.1	C7'—Cr1—C3'	156.15 (8)
Cr1—C4'—H4'	129.4	C2'—Cr1—C3'	37.43 (6)
C10—C4—C3	109.26 (13)	C5'—Cr1—C3'	66.50 (7)
C10—C4—H4A	109.8	C6'—Cr1—C3'	78.69 (7)
C3—C4—H4A	109.8	C8'—Cr1—C1'	114.87 (7)
C10—C4—H4B	109.8	C9'—Cr1—C1'	157.81 (7)
C3—C4—H4B	109.8	C7'—Cr1—C1'	91.79 (7)
H4A—C4—H4B	108.3	C2'—Cr1—C1'	36.90 (6)
C6—C5—C10	122.81 (15)	C5'—Cr1—C1'	66.97 (7)
C6—C5—H5	118.6	C6'—Cr1—C1'	37.42 (7)
C10—C5—H5	118.6	C3'—Cr1—C1'	66.98 (6)
C6'—C5'—C4'	120.25 (17)	C8'—Cr1—C4'	118.55 (7)
C6'—C5'—Cr1	71.63 (10)	C9'—Cr1—C4'	90.93 (7)
C4'—C5'—Cr1	71.51 (10)	C7'—Cr1—C4'	153.54 (8)
C6'—C5'—H5'	119.9	C2'—Cr1—C4'	66.91 (7)
C4'—C5'—H5'	119.9	C5'—Cr1—C4'	37.21 (7)
Cr1—C5'—H5'	129.4	C6'—Cr1—C4'	66.71 (7)
C5—C6—C7	118.50 (15)	C3'—Cr1—C4'	36.68 (7)
C5—C6—H6	120.8	C1'—Cr1—C4'	79.24 (7)
C7—C6—H6	120.8

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4′—H4′···O2ⁱ	0.93	2.54	3.459 (2)	169
C2′—H2′···O4ⁱⁱ	0.93	2.46	3.153 (2)	132
C1—H1C···O4ⁱⁱⁱ	0.96	2.57	3.314 (2)	134

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

Experimental details

Crystal data
Chemical formula	[Cr(C₁₆H₁₆O₂)(CO)₃]
M_r	376.32
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	9.7703 (5), 19.1820 (9), 8.8049 (4)
β (°)	97.494 (2)
V (Å³)	1636.07 (14)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.73
Crystal size (mm)	0.34 × 0.23 × 0.08

Data collection
Diffractometer	Bruker X8 APEXII 4K KappaCCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2008)
T_min, T_max	0.818, 0.942
No. of measured, independent and observed [I > 2σ(I)] reflections	29057, 4069, 3526
R_int	0.033
(sin θ/λ)_max (Å⁻¹)	0.668

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.034, 0.090, 1.00
No. of reflections	4069
No. of parameters	222
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.73, −0.52

Computer programs: APEX2 (Bruker, 2008), SAINT-Plus (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenberg & Putz, 2005), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C4'—H4'···O2ⁱ	0.93	2.54	3.459 (2)	169
C2'—H2'···O4ⁱⁱ	0.93	2.46	3.153 (2)	132
C1—H1C···O4ⁱⁱⁱ	0.96	2.57	3.314 (2)	134

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

Acknowledgements

The University of the Free State and Sasol Ltd are gratefully acknowledged for financial support and Johannes van Tonder for the NMR data and help with the synthesis of the title compound. Special thanks are due to Prof Andreas Roodt.

References

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CrossRef Web of Science Google Scholar
Brandenberg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Bruker (2008). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838. CrossRef CAS IUCr Journals Google Scholar
Müller, T. J. J., Ansorge, M. & Polburn, K. (1999). J. Organomet. Chem. 578, 252–259. Google Scholar
Muschalek, B., Weidner, I. & Butenschön, H. (2007). J. Organomet. Chem. 692, 2415–2424. Web of Science CrossRef CAS Google Scholar
Rice-Evans, C. A. & Packer, L. (2003). Flavonoids in Health and Disease, Vol. 578, 2nd ed., pp. 252–259. New York: Marcel Dekker Inc. Google Scholar
Sato, S., Hiroe, K., Kumazawa, T. & Jun-ichi, O. (2006). Carbohydr. Res. 341, 1091–1095. Web of Science CrossRef PubMed CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Tonder, J. H. van, Bezuidenhoudt, B. C. B. & Janse van Rensburg, J. M. (2009a). Acta Cryst. E65, m1343. Web of Science CrossRef IUCr Journals Google Scholar
Tonder, J. H. van, Bezuidenhoudt, B. C. B. & Janse van Rensburg, J. M. (2009b). Acta Cryst. E65, m1346. Web of Science CrossRef IUCr Journals Google Scholar
Tonder, J. H. van, Bezuidenhoudt, B. C. B. & Janse van Rensburg, J. M. (2010a). Acta Cryst. E66, m907–m908. Web of Science CSD CrossRef IUCr Journals Google Scholar
Tonder, J. H. van, Bezuidenhoudt, B. C. B. & Janse van Rensburg, J. M. (2010b). Acta Cryst. E66, m1086. Web of Science CSD CrossRef IUCr Journals Google Scholar