Racemic tricarbon­yl(η6-7-meth­oxy­flavan)chromium(0)

Tonder, J.H. van; Bezuidenhoudt, B.C.B.; Janse van Rensburg, J.M.

doi:10.1107/S1600536810024992

metal-organic compounds

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ISSN: 2056-9890

Volume 66| Part 8| August 2010| Pages m907-m908

https://doi.org/10.1107/S1600536810024992

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Racemic tricarbonyl(η⁶-7-methoxyflavan)chromium(0)

Johannes. H. van Tonder,^a Barend C. B. Bezuidenhoudt ^a ^* and J. Marthinus Janse van Rensburg ^b

^aDepartment of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa, and ^bOrganic Chemistry, Department of Chemisry, Lund University, PO Box 124, S-221 00, Lund, Sweden
^*Correspondence e-mail: bezuidbc.sci@ufs.ac.za

(Received 15 February 2010; accepted 25 June 2010; online 10 July 2010)

In the title compound [systematic name: tricarbonyl(η⁶-7-methoxy-2-phenyl-3,4-dihydro-2H-1-benzopyran)chromium(0)], [Cr(C₁₆H₁₆O₂)(CO)₃], the Cr(CO)₃ unit is coordinated by the phenylene ring of the flavan ligand, exhibiting a three-legged piano-stool conformation, with a point to plane distance of 1.750 (1) Å. The phenyl ring is twisted away from the fused ring system by 36.49 (5)° (r.m.s. deviation = 0.027 Å; fitted atoms are the C₆ ring and the attached fused-ring C and O atoms). The dihydropyran ring displays a distorted envelope configuration by displacement of the phenyl-bearing and the adjacent ring C atoms from the fused-ring system plane by 0.356 (2) and 0.402 (2) Å, respectively.

Related literature

7-Methoxyflavan was synthesized via hydrogenation from 7-methoxyflavanone, as described by Sato et al. (2006 ). For coordination of 7-methoxyflavan to chromium, see: Müller et al. (1999 ). For the importance of flavonoids in biological investigations, see: Rice-Evans & Packer (2003 ). For Cr(CO)₃ coordination to the phenylene ring of a flavanone compound, see: Dominique et al. (1999 ). For comparison bond distances, see: Allen et al. (1987 ). For related structures, see: van Tonder et al. (2009a ,b ). 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 = 9.8422 (2) Å
b = 12.3850 (3) Å
c = 15.0146 (3) Å
β = 115.171 (1)°
V = 1656.42 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.72 mm⁻¹
T = 173 K
0.41 × 0.34 × 0.24 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ) T_min = 0.757, T_max = 0.847
12982 measured reflections
3985 independent reflections
3224 reflections with I > 2σ(I)
R_int = 0.030

Refinement

R[F² > 2σ(F²)] = 0.030
wR(F²) = 0.085
S = 1.07
3985 reflections
227 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.40 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus and XPREP (Bruker, 2004); program(s) used to solve structure: SIR97 (Altomare et al., 1999 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536810024992/zb2005sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810024992/zb2005Isup2.hkl

checkCIF report

Comment top

The title compound, (I), [Cr(C₁₆H₁₆O₂)(CO)₃], where (C₁₆H₁₆O₂) = 7-methoxyflavan, has been examined due to the general biological activity of flavanoids (Rice-Evans & Packer, 2003) and the use of tricarbonyl(arene)chromium complexes in regioselective organic synthesis (Muschalek et al., 2007).

As with the tricarbonyl(η⁶-flavanone)chromium(0) complex reported by Dominique et al. (1999), the Cr(CO)₃ unit of the title compound is coordinated by the phenylene ring of the flavanoid backbone (Fig.1). The chromium metal centre is displaced by 1.750 (1) Å from the A-η⁶-coordinated arene ring centre. The dihydropyran ring displays a distorted envelope configuration by displacement of atoms C2 and C3 from the fused ring system plane, with distances of 0.356 (2) and 0.402 (2) Å respectively (r.m.s. of fitted atoms C4, C10, C5, C6, C7, C8, C9 and O5 = 0.027 °). Further molecular disorder is displayed by the phenyl ring twist away from the fused ring system plane, by 36.49 (5)°.

The molecular packing displays two types of soft intermolecular contacts, this between O2···H8 [2.682 (1) Å] forming a O2···H8—C8 angle of 152.5 (1)° and O1···H6 [2.459 (1) Å] forming a O1···H6—C6 angle of 125.9 (1)° (Fig.2).

Related literature top

7-Methoxyflavan was synthesized via hydrogenation from 7-methoxyflavanone, as described by Sato et al. (2006). For coordination of 7-methoxyflavan to chromium, see: Müller et al. (1999). The importance of flavonoids in biological investigations is described in Rice-Evans & Packer (2003). For Cr(CO)₃ coordination to the phenylene ring of a flavanone compound, see: Dominique et al. (1999). For comparison bond distances, see: Allen et al. (1987). For related structures, see: van Tonder et al. (2009a,b). For the use of tricarbonyl(arene)chromium complexes in regioselective organic synthesis, see: Muschalek et al. (2007).

Experimental top

7-Methoxyflavan was synthesised via H₂SO₄ catalyzed hydrogenation (5 bar) over 10% Pd/C from 7-methoxyflavanone, 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), EtOH (30 ml). Purification by means of flash column-chromatography yielded 7-methoxyflavan (0.67 g; 70.6%) as a colourless oil.

R_f 0.65 (H:DCM:EtOAc; 50:50:1); ¹H NMR (600 MHz, CDCl₃) δ ppm 7.44 – 7.41 (2H, m, H-2' and H-6'), 7.40 – 7.37 (2H, m, H-3' and H-5'), 7.34 – 7.31 (1H, m, H-4'), 6.99 – 6.97 (1H, m, H-5), 6.50 – 6.47 (2H, m, H-6 and H-8), 5.05 (1H, dd, J = 2.37, 10.19 Hz, H-2), 3.77 (3H, s, -OCH₃), 2.92 (1H, ddd, J = 6.02, 10.92, 16.08 Hz, H-4(a)), 2.74 (1H, ddd, J = 3.40, 5.12, 16.08 Hz, H-4(e)), 2.22 – 2.18 (1H, m, H-3), 2.11– 2.04 (1H, m, H-3); ¹³C NMR (600 MHz, CDCl3) δ ppm 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, 155.91, 159.23

Preparation of the title compound, tricarbonyl(A-η⁶-7-methoxyflavane)chromium(0), was based on a method described by Müller et al. (1999). A solution of 7-Methoxyflavane (0.27 g, 1.1 mmol) and Cr(CO)₆ (0.25 g, 1.1 mmol: 1 eq.) in Bu₂O:THF (9:1; 10 ml per 100 mg Cr(CO)₆ was degassed with argon, using standard Schlenk techniques, and refluxed (48 h) under an oxygen free atmosphere. The reaction mixture was cooled to room temperature and the solvent evaporated in vacuo. Purification through flash column-chromatography yielded tricarbonyl(A-η⁶-7-methoxyflavane)chromium(0) (0.07 g; 16.6.0%) as a yellow solid. Recrystallization from diethyl ether yielded yellow cuboidal crystals.

R_f 0.23 (Hexane: Acetone; 8:2); Mp 148.4 °C; Note: A, B and C-ring labelling refers to the benzene, phenyl and dihydropyrane rings respectively. ¹H NMR (600 MHz, CDCl₃) δ ppm 7.49 (2H, d, J = 7.15 Hz, H-2' and H-6'), 7.41 (2H, dd, J = 7.15, 8.66 Hz, H-3' and H-5'), 7.39 – 7.35 (1H, m, H-4'), 5.65 (1H, d, J = 6.61 Hz, H-5), 5.15 (1H, s, H-8), 4.90 – 4.86 (2H, m, H-2 and H-6), 3.72 (3H, s, -OCH₃), 2.93 (1H, ddd, J = 4.89, 12.43, 15.65 Hz, H-4(a)), 2.54 (1H, dd, J = 4.14, 15.65 Hz, H-4(e)), 2.31 (1H, ddd, J = 4.14, 12.43, 13.68 Hz, H-3(a)), 2.13 (1H, dd, J = 4.89, 13.68 Hz, H-3(e)); ¹³C NMR (600 MHz, CDCl₃) δ ppm 25.52 (C-4), 29.52 (C-3), 55.86 (-OCH₃), 68.31 (C-8), 74.42 (C-2/6), 80.56 (C-2/6), 89.11, 94.55 (C-5), 126.61, 128.83, 128.89, 139.62, 140.30, 143.33, 234.44 (-Cr(CO)3); MS m/z 376 (M+, 13.0), 344 (0.2), 320 (0.1), 292 (70.7), 277 (0.2), 256 (0.1), 240 (5.8), 225 (0.5), 209 (0.3), 188 (100.0), 173 (0.4), 146 (10.0), 137 (2.1), 121 (2.0), 104 (5.1).

Structure description top

7-Methoxyflavan was synthesized via hydrogenation from 7-methoxyflavanone, as described by Sato et al. (2006). For coordination of 7-methoxyflavan to chromium, see: Müller et al. (1999). The importance of flavonoids in biological investigations is described in Rice-Evans & Packer (2003). For Cr(CO)₃ coordination to the phenylene ring of a flavanone compound, see: Dominique et al. (1999). For comparison bond distances, see: Allen et al. (1987). For related structures, see: van Tonder et al. (2009a,b). For the use of tricarbonyl(arene)chromium complexes in regioselective organic synthesis, see: Muschalek et al. (2007).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-Plus (Bruker, 2004); data reduction: SAINT-Plus and XPREP (Bruker, 2004); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

	Fig. 1. A view of (I) showing the atom-numbering scheme with displacement ellipsoids at the 30% probability level.
	Fig. 2. Indication of molecular packing in the unit-cell. Symmetry operators 1) x; y; z. 2) 1 - x; 0.5 + y; 1.5 - z.

tricarbonyl(η⁶-7-methoxy-2-phenyl-3,4-dihydro-2H- 1-benzopyran)chromium(0) top

Crystal data top

[Cr(C₁₆H₁₆O₂)(CO)₃]	F(000) = 776
M_r = 376.32	D_x = 1.509 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 5285 reflections
a = 9.8422 (2) Å	θ = 2.2–28.3°
b = 12.3850 (3) Å	µ = 0.72 mm⁻¹
c = 15.0146 (3) Å	T = 173 K
β = 115.171 (1)°	Prism, yellow
V = 1656.42 (6) Å³	0.41 × 0.34 × 0.24 mm
Z = 4

Data collection top

Bruker APEXII CCD diffractometer	3224 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.030
Absorption correction: multi-scan (Bruker, 2004)	θ_max = 28°, θ_min = 2.2°
T_min = 0.757, T_max = 0.847	h = −11→12
12982 measured reflections	k = −16→16
3985 independent reflections	l = −19→19

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.030	w = 1/[σ²(F_o²) + (0.0444P)² + 0.0884P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.085	(Δ/σ)_max = 0.001
S = 1.07	Δρ_max = 0.25 e Å⁻³
3985 reflections	Δρ_min = −0.40 e Å⁻³
227 parameters

Crystal data top

[Cr(C₁₆H₁₆O₂)(CO)₃]	V = 1656.42 (6) Å³
M_r = 376.32	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 9.8422 (2) Å	µ = 0.72 mm⁻¹
b = 12.3850 (3) Å	T = 173 K
c = 15.0146 (3) Å	0.41 × 0.34 × 0.24 mm
β = 115.171 (1)°

Data collection top

Bruker APEXII CCD diffractometer	3985 independent reflections
Absorption correction: multi-scan (Bruker, 2004)	3224 reflections with I > 2σ(I)
T_min = 0.757, T_max = 0.847	R_int = 0.030
12982 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.030	0 restraints
wR(F²) = 0.085	H-atom parameters constrained
S = 1.07	Δρ_max = 0.25 e Å⁻³
3985 reflections	Δρ_min = −0.40 e Å⁻³
227 parameters

Special details top

Experimental. The intensity data was collected on a Bruker Apex II CCD diffractometer using a frame width of 0.5° covering up to θ = 28° with 100 % completeness accomplished.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1'	1.01976 (18)	0.59116 (14)	0.84890 (12)	0.0260 (3)
C2'	0.9566 (2)	0.69062 (15)	0.85055 (13)	0.0325 (4)
H2'	0.8506	0.6988	0.8213	0.039*
C2	0.92726 (18)	0.49179 (14)	0.80339 (12)	0.0268 (4)
H2	0.9703	0.4553	0.7618	0.032*
C3'	1.0487 (2)	0.77884 (16)	0.89526 (14)	0.0385 (4)
H3'	1.0052	0.8471	0.8958	0.046*
C3	0.92236 (18)	0.41073 (13)	0.87814 (12)	0.0276 (4)
H3A	0.8755	0.4443	0.9181	0.033*
H3B	1.0257	0.3886	0.923	0.033*
C4	0.83175 (18)	0.31200 (14)	0.82448 (12)	0.0272 (4)
H4A	0.8908	0.2687	0.798	0.033*
H4B	0.8107	0.2663	0.8713	0.033*
C4'	1.2029 (2)	0.76723 (16)	0.93867 (13)	0.0380 (4)
H4'	1.2654	0.8272	0.9696	0.046*
C5'	1.2657 (2)	0.66846 (16)	0.93694 (13)	0.0360 (4)
H5'	1.3717	0.6603	0.967	0.043*
C5	0.56441 (18)	0.27492 (13)	0.69612 (12)	0.0260 (4)
H5	0.5723	0.2037	0.7214	0.031*
C6	0.43161 (18)	0.30503 (13)	0.61485 (12)	0.0263 (3)
H6	0.3532	0.2541	0.5842	0.032*
C6'	1.17553 (18)	0.58135 (15)	0.89185 (12)	0.0295 (4)
H6'	1.2201	0.5138	0.89	0.035*
C7	0.41667 (18)	0.41122 (13)	0.57975 (11)	0.0247 (3)
C8	0.53223 (18)	0.48677 (13)	0.62755 (12)	0.0251 (3)
H8	0.5183	0.5606	0.6085	0.03*
C9	0.66817 (17)	0.45213 (14)	0.70352 (12)	0.0242 (3)
C10	0.68615 (17)	0.34612 (13)	0.74146 (12)	0.0237 (3)
C11	0.56076 (19)	0.50205 (13)	0.85013 (13)	0.0269 (4)
C12	0.42375 (19)	0.32289 (14)	0.82151 (13)	0.0295 (4)
C13	0.29284 (19)	0.48252 (14)	0.70530 (13)	0.0298 (4)
C71	0.17072 (19)	0.37892 (16)	0.45371 (13)	0.0335 (4)
H71A	0.2029	0.3181	0.4255	0.05*
H71B	0.0894	0.4179	0.401	0.05*
H71C	0.1349	0.3518	0.5013	0.05*
O1	0.61634 (16)	0.55726 (10)	0.91861 (10)	0.0436 (4)
O2	0.39278 (16)	0.26735 (12)	0.87217 (10)	0.0486 (4)
O3	0.17872 (15)	0.52563 (12)	0.67906 (11)	0.0482 (4)
O5	0.77684 (12)	0.52853 (9)	0.73998 (9)	0.0305 (3)
O7	0.29490 (12)	0.45045 (10)	0.50235 (8)	0.0303 (3)
Cr	0.47389 (3)	0.413031 (19)	0.743218 (18)	0.01990 (9)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1'	0.0229 (8)	0.0363 (9)	0.0193 (8)	−0.0040 (7)	0.0096 (7)	0.0017 (7)
C2'	0.0282 (9)	0.0401 (10)	0.0317 (10)	−0.0012 (8)	0.0152 (8)	0.0017 (8)
C2	0.0198 (8)	0.0364 (9)	0.0228 (8)	−0.0006 (7)	0.0077 (7)	0.0013 (7)
C3'	0.0494 (11)	0.0344 (10)	0.0391 (11)	−0.0015 (9)	0.0259 (10)	0.0000 (8)
C3	0.0239 (8)	0.0319 (9)	0.0230 (8)	0.0030 (7)	0.0062 (7)	0.0046 (7)
C4	0.0241 (8)	0.0281 (8)	0.0265 (9)	0.0044 (7)	0.0079 (7)	0.0039 (7)
C4'	0.0444 (11)	0.0425 (11)	0.0286 (10)	−0.0176 (9)	0.0170 (9)	−0.0023 (8)
C5'	0.0278 (9)	0.0524 (12)	0.0263 (9)	−0.0110 (9)	0.0100 (8)	0.0034 (8)
C5	0.0286 (8)	0.0203 (8)	0.0280 (9)	0.0025 (7)	0.0110 (7)	−0.0027 (6)
C6	0.0261 (8)	0.0254 (8)	0.0256 (8)	−0.0011 (7)	0.0092 (7)	−0.0063 (7)
C6'	0.0248 (8)	0.0389 (10)	0.0247 (9)	−0.0013 (7)	0.0105 (7)	0.0037 (7)
C7	0.0209 (8)	0.0331 (9)	0.0195 (8)	0.0020 (7)	0.0081 (6)	0.0009 (7)
C8	0.0243 (8)	0.0279 (8)	0.0232 (8)	−0.0002 (7)	0.0102 (7)	0.0061 (7)
C9	0.0211 (8)	0.0306 (8)	0.0216 (8)	−0.0023 (7)	0.0098 (7)	0.0017 (7)
C10	0.0229 (8)	0.0258 (8)	0.0227 (8)	0.0021 (6)	0.0101 (7)	−0.0003 (6)
C11	0.0281 (9)	0.0203 (8)	0.0292 (9)	0.0040 (7)	0.0090 (7)	0.0041 (7)
C12	0.0291 (9)	0.0308 (9)	0.0269 (9)	−0.0074 (7)	0.0104 (7)	−0.0030 (7)
C13	0.0274 (9)	0.0331 (9)	0.0280 (9)	−0.0003 (7)	0.0108 (7)	−0.0054 (7)
C71	0.0206 (8)	0.0466 (11)	0.0286 (9)	−0.0041 (8)	0.0058 (7)	0.0003 (8)
O1	0.0546 (9)	0.0264 (6)	0.0327 (7)	0.0063 (6)	0.0020 (7)	−0.0075 (6)
O2	0.0537 (9)	0.0537 (9)	0.0381 (8)	−0.0232 (7)	0.0195 (7)	0.0062 (7)
O3	0.0302 (7)	0.0592 (9)	0.0495 (9)	0.0148 (7)	0.0115 (7)	−0.0084 (7)
O5	0.0203 (6)	0.0333 (7)	0.0295 (6)	−0.0058 (5)	0.0024 (5)	0.0110 (5)
O7	0.0231 (6)	0.0369 (7)	0.0243 (6)	−0.0018 (5)	0.0037 (5)	0.0050 (5)
Cr	0.02079 (14)	0.01811 (14)	0.02113 (14)	−0.00032 (10)	0.00923 (11)	0.00022 (10)

Geometric parameters (Å, º) top

C1'—C2'	1.385 (3)	C6—C7	1.401 (2)
C1'—C6'	1.393 (2)	C6—Cr	2.2350 (16)
C1'—C2	1.510 (2)	C6—H6	0.95
C2'—C3'	1.396 (3)	C6'—H6'	0.95
C2'—H2'	0.95	C7—O7	1.3558 (19)
C2—O5	1.4513 (19)	C7—C8	1.411 (2)
C2—C3	1.522 (2)	C7—Cr	2.2729 (16)
C2—H2	1	C8—C9	1.406 (2)
C3'—C4'	1.381 (3)	C8—Cr	2.2424 (16)
C3'—H3'	0.95	C8—H8	0.95
C3—C4	1.526 (2)	C9—O5	1.3568 (19)
C3—H3A	0.99	C9—C10	1.412 (2)
C3—H3B	0.99	C9—Cr	2.2838 (16)
C4—C10	1.505 (2)	C10—Cr	2.2580 (16)
C4—H4A	0.99	C11—O1	1.160 (2)
C4—H4B	0.99	C11—Cr	1.8319 (17)
C4'—C5'	1.375 (3)	C12—O2	1.159 (2)
C4'—H4'	0.95	C12—Cr	1.8344 (18)
C5'—C6'	1.378 (2)	C13—O3	1.151 (2)
C5'—H5'	0.95	C13—Cr	1.8376 (18)
C5—C6	1.407 (2)	C71—O7	1.433 (2)
C5—C10	1.408 (2)	C71—H71A	0.98
C5—Cr	2.1808 (16)	C71—H71B	0.98
C5—H5	0.95	C71—H71C	0.98

C2'—C1'—C6'	118.91 (16)	O5—C9—C8	115.42 (14)
C2'—C1'—C2	122.96 (15)	O5—C9—C10	122.93 (14)
C6'—C1'—C2	118.12 (15)	C8—C9—C10	121.58 (15)
C1'—C2'—C3'	120.00 (16)	O5—C9—Cr	130.27 (11)
C1'—C2'—H2'	120	C8—C9—Cr	70.31 (9)
C3'—C2'—H2'	120	C10—C9—Cr	70.90 (9)
O5—C2—C1'	106.96 (13)	C5—C10—C9	116.89 (14)
O5—C2—C3	110.32 (13)	C5—C10—C4	122.62 (14)
C1'—C2—C3	113.95 (14)	C9—C10—C4	120.46 (14)
O5—C2—H2	108.5	C5—C10—Cr	68.55 (9)
C1'—C2—H2	108.5	C9—C10—Cr	72.88 (9)
C3—C2—H2	108.5	C4—C10—Cr	130.77 (11)
C4'—C3'—C2'	120.27 (18)	O1—C11—Cr	179.12 (15)
C4'—C3'—H3'	119.9	O2—C12—Cr	178.82 (16)
C2'—C3'—H3'	119.9	O3—C13—Cr	178.24 (16)
C2—C3—C4	109.51 (14)	O7—C71—H71A	109.5
C2—C3—H3A	109.8	O7—C71—H71B	109.5
C4—C3—H3A	109.8	H71A—C71—H71B	109.5
C2—C3—H3B	109.8	O7—C71—H71C	109.5
C4—C3—H3B	109.8	H71A—C71—H71C	109.5
H3A—C3—H3B	108.2	H71B—C71—H71C	109.5
C10—C4—C3	110.43 (13)	C9—O5—C2	117.07 (12)
C10—C4—H4A	109.6	C7—O7—C71	117.83 (13)
C3—C4—H4A	109.6	C11—Cr—C12	87.55 (7)
C10—C4—H4B	109.6	C11—Cr—C13	91.11 (7)
C3—C4—H4B	109.6	C12—Cr—C13	89.65 (8)
H4A—C4—H4B	108.1	C11—Cr—C5	130.80 (7)
C5'—C4'—C3'	119.72 (18)	C12—Cr—C5	89.36 (7)
C5'—C4'—H4'	120.1	C13—Cr—C5	137.98 (7)
C3'—C4'—H4'	120.1	C11—Cr—C6	164.20 (7)
C4'—C5'—C6'	120.35 (17)	C12—Cr—C6	100.73 (7)
C4'—C5'—H5'	119.8	C13—Cr—C6	102.28 (7)
C6'—C5'—H5'	119.8	C5—Cr—C6	37.14 (6)
C6—C5—C10	122.61 (15)	C11—Cr—C8	104.82 (7)
C6—C5—Cr	73.52 (9)	C12—Cr—C8	166.28 (7)
C10—C5—Cr	74.51 (9)	C13—Cr—C8	95.93 (7)
C6—C5—H5	118.7	C5—Cr—C8	78.10 (6)
C10—C5—H5	118.7	C6—Cr—C8	65.85 (6)
Cr—C5—H5	125	C11—Cr—C10	98.15 (7)
C7—C6—C5	119.02 (15)	C12—Cr—C10	106.65 (7)
C7—C6—Cr	73.38 (9)	C13—Cr—C10	161.49 (7)
C5—C6—Cr	69.34 (9)	C5—Cr—C10	36.94 (6)
C7—C6—H6	120.5	C6—Cr—C10	66.68 (6)
C5—C6—H6	120.5	C8—Cr—C10	66.26 (6)
Cr—C6—H6	129	C11—Cr—C7	139.56 (7)
C5'—C6'—C1'	120.73 (17)	C12—Cr—C7	132.48 (7)
C5'—C6'—H6'	119.6	C13—Cr—C7	84.71 (7)
C1'—C6'—H6'	119.6	C5—Cr—C7	65.78 (6)
O7—C7—C6	124.88 (15)	C6—Cr—C7	36.20 (6)
O7—C7—C8	115.21 (14)	C8—Cr—C7	36.40 (6)
C6—C7—C8	119.89 (14)	C10—Cr—C7	77.84 (6)
O7—C7—Cr	130.14 (11)	C11—Cr—C9	88.31 (7)
C6—C7—Cr	70.42 (9)	C12—Cr—C9	141.22 (7)
C8—C7—Cr	70.62 (9)	C13—Cr—C9	128.98 (7)
C9—C8—C7	119.56 (15)	C5—Cr—C9	65.09 (6)
C9—C8—Cr	73.51 (9)	C6—Cr—C9	76.78 (6)
C7—C8—Cr	72.98 (9)	C8—Cr—C9	36.18 (6)
C9—C8—H8	120.2	C10—Cr—C9	36.22 (6)
C7—C8—H8	120.2	C7—Cr—C9	64.57 (6)
Cr—C8—H8	124.9

C6'—C1'—C2'—C3'	−0.4 (3)	C7—C6—Cr—C9	−64.80 (10)
C2—C1'—C2'—C3'	178.97 (16)	C5—C6—Cr—C9	66.02 (10)
C2'—C1'—C2—O5	17.3 (2)	C9—C8—Cr—C11	65.59 (11)
C6'—C1'—C2—O5	−163.39 (14)	C7—C8—Cr—C11	−165.45 (10)
C2'—C1'—C2—C3	−104.93 (18)	C9—C8—Cr—C12	−88.2 (3)
C6'—C1'—C2—C3	74.42 (19)	C7—C8—Cr—C12	40.8 (3)
C1'—C2'—C3'—C4'	−0.5 (3)	C9—C8—Cr—C13	158.32 (10)
O5—C2—C3—C4	61.99 (17)	C7—C8—Cr—C13	−72.72 (10)
C1'—C2—C3—C4	−177.69 (14)	C9—C8—Cr—C5	−63.83 (10)
C2—C3—C4—C10	−47.68 (18)	C7—C8—Cr—C5	65.13 (10)
C2'—C3'—C4'—C5'	0.6 (3)	C9—C8—Cr—C6	−100.86 (11)
C3'—C4'—C5'—C6'	0.3 (3)	C7—C8—Cr—C6	28.10 (9)
C10—C5—C6—C7	−2.7 (2)	C9—C8—Cr—C10	−26.92 (10)
Cr—C5—C6—C7	56.02 (14)	C7—C8—Cr—C10	102.04 (10)
C10—C5—C6—Cr	−58.68 (14)	C9—C8—Cr—C7	−128.96 (15)
C4'—C5'—C6'—C1'	−1.2 (3)	C7—C8—Cr—C9	128.96 (15)
C2'—C1'—C6'—C5'	1.2 (3)	C5—C10—Cr—C11	155.21 (10)
C2—C1'—C6'—C5'	−178.16 (16)	C9—C10—Cr—C11	−75.77 (10)
C5—C6—C7—O7	−179.96 (15)	C4—C10—Cr—C11	40.00 (16)
Cr—C6—C7—O7	−125.88 (16)	C5—C10—Cr—C12	65.34 (11)
C5—C6—C7—C8	−1.7 (2)	C9—C10—Cr—C12	−165.64 (10)
Cr—C6—C7—C8	52.36 (14)	C4—C10—Cr—C12	−49.87 (16)
C5—C6—C7—Cr	−54.07 (13)	C5—C10—Cr—C13	−85.5 (2)
O7—C7—C8—C9	−174.85 (14)	C9—C10—Cr—C13	43.5 (3)
C6—C7—C8—C9	6.7 (2)	C4—C10—Cr—C13	159.3 (2)
Cr—C7—C8—C9	59.01 (14)	C9—C10—Cr—C5	129.02 (14)
O7—C7—C8—Cr	126.14 (13)	C4—C10—Cr—C5	−115.21 (18)
C6—C7—C8—Cr	−52.27 (14)	C5—C10—Cr—C6	−29.40 (9)
C7—C8—C9—O5	175.10 (14)	C9—C10—Cr—C6	99.61 (10)
Cr—C8—C9—O5	−126.16 (14)	C4—C10—Cr—C6	−144.62 (16)
C7—C8—C9—C10	−7.7 (2)	C5—C10—Cr—C8	−102.12 (10)
Cr—C8—C9—C10	51.09 (14)	C9—C10—Cr—C8	26.90 (9)
C7—C8—C9—Cr	−58.74 (14)	C4—C10—Cr—C8	142.67 (16)
C6—C5—C10—C9	1.9 (2)	C5—C10—Cr—C7	−65.70 (10)
Cr—C5—C10—C9	−56.37 (13)	C9—C10—Cr—C7	63.32 (10)
C6—C5—C10—C4	−176.23 (15)	C4—C10—Cr—C7	179.09 (16)
Cr—C5—C10—C4	125.55 (15)	C5—C10—Cr—C9	−129.02 (14)
C6—C5—C10—Cr	58.22 (14)	C4—C10—Cr—C9	115.77 (18)
O5—C9—C10—C5	−179.62 (15)	O7—C7—Cr—C11	−85.11 (17)
C8—C9—C10—C5	3.3 (2)	C6—C7—Cr—C11	155.29 (11)
Cr—C9—C10—C5	54.18 (13)	C8—C7—Cr—C11	21.99 (14)
O5—C9—C10—C4	−1.5 (2)	O7—C7—Cr—C12	85.04 (17)
C8—C9—C10—C4	−178.53 (15)	C6—C7—Cr—C12	−34.57 (13)
Cr—C9—C10—C4	−127.70 (15)	C8—C7—Cr—C12	−167.87 (11)
O5—C9—C10—Cr	126.20 (16)	O7—C7—Cr—C13	0.38 (15)
C8—C9—C10—Cr	−50.83 (14)	C6—C7—Cr—C13	−119.22 (11)
C3—C4—C10—C5	−163.05 (15)	C8—C7—Cr—C13	107.48 (11)
C3—C4—C10—C9	18.9 (2)	O7—C7—Cr—C5	149.67 (16)
C3—C4—C10—Cr	−74.28 (18)	C6—C7—Cr—C5	30.06 (9)
C8—C9—O5—C2	−167.67 (14)	C8—C7—Cr—C5	−103.24 (10)
C10—C9—O5—C2	15.1 (2)	O7—C7—Cr—C6	119.60 (19)
Cr—C9—O5—C2	107.28 (16)	C8—C7—Cr—C6	−133.30 (14)
C1'—C2—O5—C9	−169.74 (13)	O7—C7—Cr—C8	−107.10 (18)
C3—C2—O5—C9	−45.31 (19)	C6—C7—Cr—C8	133.30 (14)
C6—C7—O7—C71	1.2 (2)	O7—C7—Cr—C10	−173.42 (16)
C8—C7—O7—C71	−177.07 (14)	C6—C7—Cr—C10	66.97 (10)
Cr—C7—O7—C71	−91.82 (17)	C8—C7—Cr—C10	−66.33 (10)
C6—C5—Cr—C11	−164.93 (10)	O7—C7—Cr—C9	−137.65 (16)
C10—C5—Cr—C11	−33.24 (13)	C6—C7—Cr—C9	102.75 (10)
C6—C5—Cr—C12	108.86 (11)	C8—C7—Cr—C9	−30.55 (9)
C10—C5—Cr—C12	−119.45 (10)	O5—C9—Cr—C11	−11.15 (14)
C6—C5—Cr—C13	20.10 (15)	C8—C9—Cr—C11	−118.27 (11)
C10—C5—Cr—C13	151.78 (11)	C10—C9—Cr—C11	106.27 (10)
C10—C5—Cr—C6	131.69 (15)	O5—C9—Cr—C12	−95.13 (17)
C6—C5—Cr—C8	−65.53 (10)	C8—C9—Cr—C12	157.75 (12)
C10—C5—Cr—C8	66.16 (10)	C10—C9—Cr—C12	22.30 (15)
C6—C5—Cr—C10	−131.69 (15)	O5—C9—Cr—C13	78.91 (16)
C6—C5—Cr—C7	−29.35 (10)	C8—C9—Cr—C13	−28.21 (13)
C10—C5—Cr—C7	102.34 (10)	C10—C9—Cr—C13	−163.67 (10)
C6—C5—Cr—C9	−101.28 (11)	O5—C9—Cr—C5	−148.41 (16)
C10—C5—Cr—C9	30.41 (9)	C8—C9—Cr—C5	104.47 (11)
C7—C6—Cr—C11	−84.6 (3)	C10—C9—Cr—C5	−30.99 (9)
C5—C6—Cr—C11	46.3 (3)	O5—C9—Cr—C6	174.13 (15)
C7—C6—Cr—C12	154.79 (10)	C8—C9—Cr—C6	67.01 (10)
C5—C6—Cr—C12	−74.38 (11)	C10—C9—Cr—C6	−68.45 (10)
C7—C6—Cr—C13	62.79 (11)	O5—C9—Cr—C8	107.12 (18)
C5—C6—Cr—C13	−166.38 (11)	C10—C9—Cr—C8	−135.45 (15)
C7—C6—Cr—C5	−130.82 (15)	O5—C9—Cr—C10	−117.42 (18)
C7—C6—Cr—C8	−28.25 (9)	C8—C9—Cr—C10	135.45 (15)
C5—C6—Cr—C8	102.57 (11)	O5—C9—Cr—C7	137.85 (16)
C7—C6—Cr—C10	−101.56 (10)	C8—C9—Cr—C7	30.73 (10)
C5—C6—Cr—C10	29.26 (9)	C10—C9—Cr—C7	−104.73 (10)
C5—C6—Cr—C7	130.82 (15)

Experimental details

Crystal data
Chemical formula	[Cr(C₁₆H₁₆O₂)(CO)₃]
M_r	376.32
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	173
a, b, c (Å)	9.8422 (2), 12.3850 (3), 15.0146 (3)
β (°)	115.171 (1)
V (Å³)	1656.42 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.72
Crystal size (mm)	0.41 × 0.34 × 0.24

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (Bruker, 2004)
T_min, T_max	0.757, 0.847
No. of measured, independent and observed [I > 2σ(I)] reflections	12982, 3985, 3224
R_int	0.030
(sin θ/λ)_max (Å⁻¹)	0.661

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.030, 0.085, 1.07
No. of reflections	3985
No. of parameters	227
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.25, −0.40

Computer programs: APEX2 (Bruker, 2005), SAINT-Plus (Bruker, 2004), SAINT-Plus and XPREP (Bruker, 2004), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Putz, 2005), WinGX (Farrugia, 1999).

Acknowledgements

Financial assistance from the University of the Free State and SASOL to JHvanT is gratefully acknowledged. Opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of SASOL. We would like to express our gratitude to the School of Chemistry at the University of the Witwatersrand for the use of the diffractometer. Special thanks are due to Dr M. A. Fernandes.

References

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