Crystal structure of 1,1′-bis­(2-meth­oxy­carbonyl-2-methyl­prop­yl)ferrocene

Abstract

The Fe atom in the title ferrocene derivative, [Fe(C₁₁H₁₅O₂)₂], is situated on an inversion centre. As a result of the point-group symmetry -1 of the mol­ecule, the ferrocene moiety adopts a staggered conformation. The average Fe—C(Cp) bond length (Cp is cyclo­penta­dien­yl) is 2.045 (4) Å, in agreement with that of other disubstituted ferrocenes. The Fe—C bond length involving the substituted C atom is slightly longer [2.0521 (17) Å] than the remaining Fe—C bond lengths caused by the inductive effect of the methyl­ene group on the Cp ring. Apart from van der Waals forces, no significant inter­molecular inter­actions are observed in the crystal packing.

Related literature  

The inter­est in disubstituted ferrocene compounds has increased due to their applications in the field of homogeneous catalysis, biology and medicine (Atkinson et al., 2004 ▸; Gao et al., 2009 ▸; Ferreira et al., 2006 ▸). The presence of ester groups on these compounds make them promising candidates for the construction of metal-containing polymers (Wilbert et al., 1995 ▸). Related structures have been described by Woodward et al. (1952 ▸); Cetina et al. (2003 ▸); Navarro et al. (2004 ▸); Pérez et al. (2015 ▸).

Experimental  

Crystal data  

• [Fe(C₁₁H₁₅O₂)₂]

• M _r = 414.31

• Triclinic,

• a = 6.273 (3) Å

• b = 8.313 (4) Å

• c = 10.490 (5) Å

• α = 83.833 (6)°

• β = 74.405 (7)°

• γ = 81.652 (8)°

• V = 520.0 (4) ų

• Z = 1

• Mo Kα radiation

• μ = 0.75 mm⁻¹

• T = 296 K

• 0.15 × 0.12 × 0.12 mm

Data collection  

• Bruker APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Krause et al., 2015 ▸) T _min = 0.896, T _max = 0.916

• 2753 measured reflections

• 1793 independent reflections

• 1688 reflections with I > 2σ(I)

• R _int = 0.013

Refinement  

• R[F ² > 2σ(F ²)] = 0.029

• wR(F ²) = 0.074

• S = 1.05

• 1793 reflections

• 124 parameters

• H-atom parameters constrained

• Δρ_max = 0.21 e Å⁻³

• Δρ_min = −0.17 e Å⁻³

Data collection: APEX2 (Bruker, 2012 ▸); cell refinement: SAINT (Bruker, 2012 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▸); molecular graphics: DIAMOND (Brandenburg & Berndt, 1999 ▸); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▸).

Supplementary Material

CCDC reference: 1434467

Additional supporting information: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

S1. Experimental

1,1'-bis(1-methoxy-methyl)ferrocene was first prepared by refluxing 1,1'-bis(hydroxymethyl)ferrocene in methanol and acetic acid (12:1 v/v) for 16 h. Then a solution of 1,1,-bis(1-methoxy-methyl)ferrocene (3.481 g, 12.7 mmol), 1-methoxy-1-(trimethylsiloxy)-2-methyl-1-propene (10.5 ml, 50.8 mmol) and BF₃—OEt₂ (3.5 ml, 27.9 mmol) in CH₂Cl₂ (180 ml) was stirred at 195 K for 15 min. The reaction was quenched with a satured solution of NaHCO₃ and extracted with CH₂Cl₂. The organic phases were combined and dried to give a viscous yellow oil, which was chromatographed over a column of silica gel using ethyl acetate/petroleum ether (1:4 v/v) as the eluent. Yellow crystals of the title compound were obtained by slow evaporation of a solution in dichloromethane/petroleum ether (333-363 K). ¹H NMR (400 MHz, CDCl₃) δ 3.97 (d, 8H, C₅H₄FeC₅H₄), 3.62 (s, 6H, OCH₃), 2.57 (s, 4H, CH₂), 1.08 (s, 12H, C(CH₃)₂). HRMS (ESI): C₂₂H₃₀FeO₄ calcd for [M + H]⁺ 415.1572, found 415.1575.

S2. Refinement

H atoms were placed in calculated positions and thereafter treated as riding atoms, with C—H = 0.98 Å and U_iso(H) = 1.2U_eq(C) (Cp rings CH), 0.97 Å and U_iso(H) = 1.2U_eq(C) (methylene CH₂) and 0.96 Å U_iso(H) = 1.5U_eq(C) (methyl CH₃).

Figures

Fig. 1.

The molecular structure of the title complex, showing displacement ellipsoids drawn at the 50% probability level. All H atoms have been omitted for clarity. Unlabelled atoms are related to labelled ones by the symmetry operation -x, -y + 1, -z + 1.

Fig. 2.

The packing of molecules in the crystal structure of the title compound.

Crystal data

[Fe(C11H15O2)2]	Z = 1
Mr = 414.31	F(000) = 220
Triclinic, P1	Dx = 1.323 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.273 (3) Å	Cell parameters from 1589 reflections
b = 8.313 (4) Å	θ = 3.3–28.2°
c = 10.490 (5) Å	µ = 0.75 mm−1
α = 83.833 (6)°	T = 296 K
β = 74.405 (7)°	Block, yellow
γ = 81.652 (8)°	0.15 × 0.12 × 0.12 mm
V = 520.0 (4) Å3

Data collection

Bruker APEXII CCD diffractometer	1793 independent reflections
Radiation source: fine-focus sealed tube	1688 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.013
φ and ω scans	θmax = 25.0°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −7→5
Tmin = 0.896, Tmax = 0.916	k = −9→9
2753 measured reflections	l = −12→12

Refinement

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)] = 0.029	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.074	H-atom parameters constrained
S = 1.05	w = 1/[σ2(Fo2) + (0.038P)2 + 0.1517P] where P = (Fo2 + 2Fc2)/3
1793 reflections	(Δ/σ)max = 0.001
124 parameters	Δρmax = 0.21 e Å−3
0 restraints	Δρmin = −0.17 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
Fe1	0.0000	0.5000	0.5000	0.03254 (14)
O1	0.6653 (2)	0.24987 (19)	0.15534 (14)	0.0536 (4)
O2	0.4288 (3)	0.2353 (2)	0.03404 (15)	0.0646 (4)
C8	0.4892 (3)	0.1969 (2)	0.13268 (18)	0.0397 (4)
C5	0.1330 (3)	0.3282 (2)	0.36443 (16)	0.0335 (4)
C1	0.1796 (3)	0.4864 (2)	0.30665 (17)	0.0387 (4)
H1A	0.3282	0.5203	0.2685	0.046*
C6	0.2998 (3)	0.1817 (2)	0.37491 (17)	0.0377 (4)
H6A	0.2343	0.1094	0.4496	0.045*
H6B	0.4288	0.2169	0.3931	0.045*
C4	−0.1038 (3)	0.3335 (2)	0.40734 (18)	0.0410 (4)
H4A	−0.1861	0.2426	0.4513	0.049*
C7	0.3785 (3)	0.0848 (2)	0.24845 (18)	0.0372 (4)
C11	0.1817 (4)	0.0227 (3)	0.2186 (2)	0.0547 (6)
H11A	0.2329	−0.0363	0.1400	0.082*
H11B	0.0746	0.1134	0.2049	0.082*
H11C	0.1134	−0.0482	0.2920	0.082*
C10	0.5508 (4)	−0.0594 (3)	0.2709 (2)	0.0519 (5)
H10A	0.6012	−0.1197	0.1930	0.078*
H10B	0.4836	−0.1293	0.3452	0.078*
H10C	0.6753	−0.0192	0.2884	0.078*
C2	−0.0263 (4)	0.5867 (3)	0.31440 (18)	0.0467 (5)
H2A	−0.0442	0.7018	0.2825	0.056*
C9	0.7892 (5)	0.3576 (3)	0.0540 (3)	0.0721 (7)
H9A	0.9106	0.3869	0.0826	0.108*
H9B	0.6925	0.4542	0.0387	0.108*
H9C	0.8468	0.3033	−0.0267	0.108*
C3	−0.1995 (4)	0.4931 (3)	0.3759 (2)	0.0488 (5)
H3A	−0.3593	0.5316	0.3944	0.059*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Fe1	0.0326 (2)	0.0351 (2)	0.0286 (2)	−0.00167 (15)	−0.00463 (15)	−0.00833 (14)
O1	0.0475 (8)	0.0685 (10)	0.0448 (8)	−0.0180 (7)	−0.0123 (7)	0.0122 (7)
O2	0.0833 (12)	0.0734 (11)	0.0426 (8)	−0.0069 (9)	−0.0298 (8)	0.0029 (8)
C8	0.0437 (11)	0.0398 (10)	0.0332 (10)	0.0076 (8)	−0.0094 (8)	−0.0109 (8)
C5	0.0359 (9)	0.0366 (9)	0.0269 (8)	−0.0039 (7)	−0.0040 (7)	−0.0089 (7)
C1	0.0447 (11)	0.0408 (10)	0.0270 (9)	−0.0049 (8)	−0.0019 (8)	−0.0060 (7)
C6	0.0409 (10)	0.0396 (10)	0.0306 (9)	−0.0009 (8)	−0.0075 (8)	−0.0034 (7)
C4	0.0371 (10)	0.0479 (11)	0.0395 (10)	−0.0079 (8)	−0.0069 (8)	−0.0138 (8)
C7	0.0375 (10)	0.0338 (9)	0.0394 (10)	0.0018 (8)	−0.0098 (8)	−0.0073 (8)
C11	0.0513 (12)	0.0519 (13)	0.0651 (14)	−0.0067 (10)	−0.0150 (11)	−0.0224 (11)
C10	0.0533 (13)	0.0396 (11)	0.0557 (12)	0.0082 (9)	−0.0100 (10)	−0.0017 (9)
C2	0.0610 (13)	0.0430 (11)	0.0338 (10)	0.0073 (10)	−0.0139 (9)	−0.0068 (8)
C9	0.0694 (16)	0.0802 (18)	0.0595 (15)	−0.0259 (14)	−0.0050 (13)	0.0195 (13)
C3	0.0414 (11)	0.0622 (13)	0.0449 (11)	0.0074 (10)	−0.0155 (9)	−0.0199 (10)

Geometric parameters (Å, º)

Fe1—C2i	2.043 (2)	C6—C7	1.554 (3)
Fe1—C2	2.043 (2)	C6—H6A	0.9700
Fe1—C4i	2.044 (2)	C6—H6B	0.9700
Fe1—C4	2.044 (2)	C4—C3	1.418 (3)
Fe1—C3i	2.044 (2)	C4—H4A	0.9800
Fe1—C3	2.044 (2)	C7—C11	1.522 (3)
Fe1—C1i	2.0445 (19)	C7—C10	1.536 (3)
Fe1—C1	2.0445 (19)	C11—H11A	0.9600
Fe1—C5i	2.0521 (17)	C11—H11B	0.9600
Fe1—C5	2.0521 (17)	C11—H11C	0.9600
O1—C8	1.333 (3)	C10—H10A	0.9600
O1—C9	1.446 (3)	C10—H10B	0.9600
O2—C8	1.192 (2)	C10—H10C	0.9600
C8—C7	1.522 (3)	C2—C3	1.400 (3)
C5—C1	1.424 (3)	C2—H2A	0.9800
C5—C4	1.428 (3)	C9—H9A	0.9600
C5—C6	1.501 (3)	C9—H9B	0.9600
C1—C2	1.420 (3)	C9—H9C	0.9600
C1—H1A	0.9800	C3—H3A	0.9800
C2i—Fe1—C2	180.0	C2—C1—C5	108.24 (18)
C2i—Fe1—C4i	67.98 (9)	C2—C1—Fe1	69.61 (10)
C2—Fe1—C4i	112.02 (9)	C5—C1—Fe1	69.95 (10)
C2i—Fe1—C4	112.02 (9)	C2—C1—H1A	125.9
C2—Fe1—C4	67.98 (9)	C5—C1—H1A	125.9
C4i—Fe1—C4	180.0	Fe1—C1—H1A	125.9
C2i—Fe1—C3i	40.08 (9)	C5—C6—C7	113.97 (15)
C2—Fe1—C3i	139.92 (9)	C5—C6—H6A	108.8
C4i—Fe1—C3i	40.61 (8)	C7—C6—H6A	108.8
C4—Fe1—C3i	139.39 (8)	C5—C6—H6B	108.8
C2i—Fe1—C3	139.92 (9)	C7—C6—H6B	108.8
C2—Fe1—C3	40.08 (9)	H6A—C6—H6B	107.7
C4i—Fe1—C3	139.39 (8)	C3—C4—C5	108.21 (18)
C4—Fe1—C3	40.61 (8)	C3—C4—Fe1	69.70 (12)
C3i—Fe1—C3	180.0	C5—C4—Fe1	69.92 (10)
C2i—Fe1—C1i	40.65 (8)	C3—C4—H4A	125.9
C2—Fe1—C1i	139.35 (8)	C5—C4—H4A	125.9
C4i—Fe1—C1i	68.18 (8)	Fe1—C4—H4A	125.9
C4—Fe1—C1i	111.82 (8)	C11—C7—C8	110.12 (17)
C3i—Fe1—C1i	68.00 (9)	C11—C7—C10	109.95 (17)
C3—Fe1—C1i	112.00 (9)	C8—C7—C10	108.85 (16)
C2i—Fe1—C1	139.35 (8)	C11—C7—C6	110.52 (16)
C2—Fe1—C1	40.65 (8)	C8—C7—C6	108.53 (15)
C4i—Fe1—C1	111.82 (8)	C10—C7—C6	108.84 (16)
C4—Fe1—C1	68.18 (8)	C7—C11—H11A	109.5
C3i—Fe1—C1	112.00 (9)	C7—C11—H11B	109.5
C3—Fe1—C1	68.00 (9)	H11A—C11—H11B	109.5
C1i—Fe1—C1	180.0	C7—C11—H11C	109.5
C2i—Fe1—C5i	68.48 (8)	H11A—C11—H11C	109.5
C2—Fe1—C5i	111.52 (8)	H11B—C11—H11C	109.5
C4i—Fe1—C5i	40.80 (8)	C7—C10—H10A	109.5
C4—Fe1—C5i	139.20 (8)	C7—C10—H10B	109.5
C3i—Fe1—C5i	68.51 (8)	H10A—C10—H10B	109.5
C3—Fe1—C5i	111.49 (8)	C7—C10—H10C	109.5
C1i—Fe1—C5i	40.67 (7)	H10A—C10—H10C	109.5
C1—Fe1—C5i	139.33 (7)	H10B—C10—H10C	109.5
C2i—Fe1—C5	111.52 (8)	C3—C2—C1	108.31 (18)
C2—Fe1—C5	68.48 (8)	C3—C2—Fe1	69.99 (12)
C4i—Fe1—C5	139.20 (8)	C1—C2—Fe1	69.73 (11)
C4—Fe1—C5	40.80 (8)	C3—C2—H2A	125.8
C3i—Fe1—C5	111.49 (8)	C1—C2—H2A	125.8
C3—Fe1—C5	68.51 (8)	Fe1—C2—H2A	125.8
C1i—Fe1—C5	139.33 (7)	O1—C9—H9A	109.5
C1—Fe1—C5	40.67 (7)	O1—C9—H9B	109.5
C5i—Fe1—C5	180.00 (7)	H9A—C9—H9B	109.5
C8—O1—C9	117.84 (18)	O1—C9—H9C	109.5
O2—C8—O1	123.17 (19)	H9A—C9—H9C	109.5
O2—C8—C7	125.6 (2)	H9B—C9—H9C	109.5
O1—C8—C7	111.19 (16)	C2—C3—C4	108.28 (18)
C1—C5—C4	106.96 (17)	C2—C3—Fe1	69.92 (12)
C1—C5—C6	126.84 (17)	C4—C3—Fe1	69.69 (11)
C4—C5—C6	126.17 (17)	C2—C3—H3A	125.9
C1—C5—Fe1	69.38 (10)	C4—C3—H3A	125.9
C4—C5—Fe1	69.28 (10)	Fe1—C3—H3A	125.9
C6—C5—Fe1	127.75 (13)

Symmetry code: (i) −x, −y+1, −z+1.