Crystal structure and identification of resonance forms of diethyl 2-(3-oxoiso-1,3-di­hydro­benzo­furan-1-yl­idene)malonate

Tyumentsev, M.S.; Foreman, M.R.S.J.; Steenari, B.-M.; Slawin, A.M.Z.

doi:10.1107/S2056989017013962

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ISSN: 2056-9890

Volume 73| Part 10| October 2017| Pages 1576-1579

https://doi.org/10.1107/S2056989017013962

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Crystal structure and identification of resonance forms of diethyl 2-(3-oxoiso-1,3-dihydrobenzofuran-1-ylidene)malonate

Mikhail S. Tyumentsev,^a ^* Mark R. StJ. Foreman,^a Britt-Marie Steenari ^a and Alexandra M. Z. Slawin ^b

^aNuclear Chemistry and Industrial Materials Recycling, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden, SE 41296, and ^bSchool of Chemistry, University of St. Andrews, Purdie Building, North Haugh, St. Andrews, Fife, Scotland, KY16 9ST
^*Correspondence e-mail: miktyu@chalmers.se

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 25 August 2017; accepted 27 September 2017; online 29 September 2017)

The reaction of diethyl malonate with phthaloyl chloride in acetonitrile in the presence of triethylamine and magnesium chloride results in the formation of the title compound, diethyl 2-(3-oxo-1,3-dihydro-2-benzofuran-1-ylidene)propanedioate, C₁₅H₁₄O₆. One of the ester groups of the diethyl malonate fragment is almost coplanar with the isobenzofuran unit, while the plane of the other group is perpendicular to it [dihedral angles = 5.45 (3) and 83.30 (3)°, respectively]. The C—C and C—O distances both in the heterocyclic furan ring and the diethyl malonate fragment are indicative of the dipolar delocalization occurring within the isobenzofuran unit. This delocalization is likely to be responsible for the unusual intermolecular O⋯O contact [2.756 (2) Å], established between the O atom of the furan ring and the carbonyl O atom of the diethyl malonate fragment. In the crystal, weak C—H⋯O interactions are observed, which link the molecules into [100] chains.

Keywords: crystal structure; 3-alkylidene-3H-isobenzofuran-1-ones; delocalization; enolate.

CCDC reference: 1543053

1. Chemical context

The structural analysis of diethyl 2-(3-oxoisobenzofuran-1(3H)-ylidene)malonate (I) was undertaken as part of a study into the synthesis of new reagents for the recovery of trivalent lanthanide metal ions by liquid–liquid extraction. We intended to prepare 2,2′-phthaloylbis(N,N,N′,N′-tetrabutylmalonamide) (II), which is similar to the reported earlier 2,2′-[1,2-phenylenebis(methylene)]bis(N,N,N′,N′-tetrabutylmalonamide) (III) (Tyumentsev et al., 2016 ), from the respective tetraethyl 2,2′-phthaloyldimalonate (IV). In turn (IV) was to be made by the reaction of diethyl malonate with phthaloyl chloride. It is already known that acid chlorides react with diethyl malonate when treated with a combination of triethylamine and a mild Lewis acid (magnesium chloride) in acetonitrile (Rathke & Cowan, 1985 ). Instead of (IV), an organic product, which contained two ethyl groups in different electronic environments, was obtained in this reaction. Crystals of this compound were grown and examined with single-crystal X-ray diffractometry, and the product was found to be the title compound, (I). The formation of (I) can be rationalized by the nucleophilic attack of the oxygen atom (in an enol form) of the keto-diethylmalonate group on the carbon atom of the unreacted acid chloride group. The mechanism of the formation of (I) was proposed by Naik et al. (1988 ), who obtained this compound by another reaction.

2. Structural commentary

Compound (I) crystallizes with one molecule in the asymmetric unit (Fig. 1). Atoms C8, C9, C10, C11, C12, O9 and O10 are almost coplanar with the isobenzofuran unit (r.m.s. deviation = 0.024 Å), as shown by the dihedral angle of 5.45 (3)° between these groupings. This mean plane is intercepted nearly perpendicularly by the mean plane of the other ester group (O12, C12, O13, C13, and C14), with a dihedral angle of 83.30 (3)° and the torsion angles C9—C8—C12—O12 and C9—C8—C12—O13 of 90.2 (1)° and −89.6 (1)°, respectively. The bond lengths in the carbocyclic ring of the isobenzofuran unit range from 1.386 (2) Å to 1.398 (2) Å. In the heterocyclic furan ring the distances C2—C2A = 1.469 (2) Å and C6A—C7 = 1.472 (2) Å are very similar, while the C2—O1 and C7—O1 distances are significantly different. The C2—O1 bond distance of 1.394 (1) Å perfectly matches the corresponding distances in phthalic anhydride [1.396 (5) Å and 1.393 (6) Å (Bates & Cutler, 1977 )]. The shorter C7—O1 distance of 1.385 (1) Å strongly suggests that the bond between the endocyclic oxygen atom O1 and the non-carbonyl carbon atom C7 has an order greater than 1. In the diethyl malonate fragment the distances C8—C9 [1.489 (2) Å] and C8—C12 [1.507 (1) Å] are different most likely due to the particular conformation adopted by the molecule. The bond lengths for the atoms, associated with both the furan ring of the isobenzofuran unit and the diethyl malonate fragment, indicate that the dipolar resonance form (Ia) of (I) makes a considerable contribution to its overall molecular electronic structure (Fig. 2).

Figure 1
The molecular structure of (I), showing displacement ellipsoids drawn at the 50% probability level.

Figure 2
Chemical diagram of a molecule (I) and its possible resonance forms (Ia) and (Ib).

According to the structure of the resonance form (Ia) a partial positive charge is localized on the oxygen atom of the heterocyclic furan ring, and one of the carbonyl oxygen atoms of the diethyl malonate fragment carries a partial negative charge, which should lead to an electrostatic attraction of these two oxygen atoms. In the structure of (I) the O1 and O9 atoms are nearly coplanar (the torsion angles C7—C8—C9—O9 and C9—C8—C7—O1 equal to −10.6 (2)° and 0.7 (2)°, respectively), and the distance O1⋯O9 is 2.756 (2) Å. It can be argued that simple electrostatic attraction is responsible for this close contact.

3. Supramolecular features

The possible non van der Waals contact in the crystal of (I) is a very weak C—H⋯O interaction (Table 1), which links the molecules into [100] C(8) chains. A parallel-displaced π–π stacking interaction between molecules of (I) is observed with an interplanar distance of 3.423 Å (Fig. 3) and intermolecular furan–benzene and benzene–benzene centroid-to-centroid distances of 3.5379 (13) and 3.7859 (14) Å, respectively.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O9ⁱ	0.95	2.48	3.0689 (18)	120
Symmetry code: (i) .

Figure 3
Molecules of (I) interacting via parallel-displaced π–π stacking.

4. Database survey

In the structure of 3-(3-oxo-1,3-dihydroisobenzofuran-1-ylidene)pentane-2,4-dione (HIFQUJ; Portilla et al., 2007 ) the dominant resonance form resembles (Ib). No contact was observed between the endocyclic oxygen atom and the carbonyl oxygen atom of the acetyl group (the distance between these atoms exceeds 4 Å). In 2-methoxyethyl 3-oxo-2-(3-oxo-2-benzofuran-1(3H)-ylidene)butanoate (UBAVIE; Mkrtchyan et al., 2011 ), no close contacts exist between the endocyclic oxygen atom and any other oxygen atoms.

In methyl 4,4-dimethyl-3-oxo-2-(3-oxo-2-benzofuran-1(3H)-ylidene)pentanoate (UBAVEA; Mkrtchyan et al., 2011), neither of the two carbonyl oxygen atoms of the methyl 4,4-dimethyl-3-oxopentanoate fragment are within the same plane as the isobenzofuran unit. The shortest intermolecular O⋯O contact is 3.161 Å, which occurs between the endocyclic oxygen atom and that carbonyl oxygen atom, which is closest to the plane of the isobenzofuran unit. The torsion angle O4—C15—C9—C8 in UBAVEA is 26.81°, while the corresponding torsion angle in (I), C7—C8—C9—O9, is 10.6 (2)°.

5. Synthesis and crystallization

The title compound was prepared by the reaction of diethyl malonate with phthaloyl chloride in acetonitrile in the presence of triethylamine and magnesium chloride (Rathke & Cowan, 1985). The reagents for the synthesis were purchased from Aldrich and were used as supplied. The crude product was washed with petroleum ether on filter paper and recrystallized from cyclohexane solution as colorless crystals (69% yield); m.p. 345–346 K. ¹H NMR (400 MHz, CDCl₃) δ 1.38 (m, 6H), 4.39 (m, 4H), 7.72 (t, J = 6.7 Hz, 1H), 7.80 (t, J = 7.4 Hz, 1H), 7.99 (d, J = 7.8 Hz, 1H), 8.65 (d, J = 8.2 Hz, 1H). ¹³C NMR (400 MHz, CDCl₃) δ 135.36; 132.93; 127.58; 126.11; 125.84; 62.18; 62.06; 14.04; 14.01. Found: C, 62.08; H, 4.94%. C₁₅H₁₄O₆ Theoretical: C, 62.07; H, 4.86%. The crystalline product was found to be stable to air, water and brief exposure to 1 M hydrochloric acid.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. H atoms were refined using the riding model with C—H = 0.95–0.99 Å and U_iso(H) = 1.2U_eq(C).

Table 2
Experimental details

Crystal data
Chemical formula	C₁₅H₁₄O₆
M_r	290.27
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	93
a, b, c (Å)	7.942 (2), 9.453 (3), 10.226 (2)
α, β, γ (°)	67.706 (15), 72.228 (16), 86.41 (2)
V (Å³)	675.2 (3)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.11
Crystal size (mm)	0.30 × 0.20 × 0.15

Data collection
Diffractometer	Rigaku XtaLAB P200
Absorption correction	Multi-scan (REQAB; Rigaku, 1998 )
T_min, T_max	0.829, 0.983
No. of measured, independent and observed [F² > 2.0σ(F²)] reflections	9890, 2466, 2278
R_int	0.031
(sin θ/λ)_max (Å⁻¹)	0.602

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.028, 0.078, 1.07
No. of reflections	2466
No. of parameters	192
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.25, −0.18
Computer programs: CrystalClear-SM Expert (Rigaku, 2014 ), SIR2011 (Burla et al., 2012 ), SHELXL2013 (Sheldrick, 2008 ) and CrystalStructure (Rigaku, 2014).

Supporting information

CCDC reference: 1543053

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989017013962/hb7700sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989017013962/hb7700Isup3.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2056989017013962/hb7700Isup3.cml

checkCIF report

Computing details top

Data collection: CrystalClear-SM Expert (Rigaku, 2014); cell refinement: CrystalClear-SM Expert (Rigaku, 2014); data reduction: CrystalClear-SM Expert (Rigaku, 2014); program(s) used to solve structure: SIR2011 (Burla et al., 2012); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008); molecular graphics: CrystalStructure (Rigaku, 2014); software used to prepare material for publication: CrystalStructure (Rigaku, 2014).

Diethyl 2-(3-oxo-1,3-dihydro-2-benzofuran-1-ylidene)propanedioate top

Crystal data top

C₁₅H₁₄O₆	Z = 2
M_r = 290.27	F(000) = 304.00
Triclinic, P1	D_x = 1.428 Mg m⁻³
a = 7.942 (2) Å	Mo Kα radiation, λ = 0.71075 Å
b = 9.453 (3) Å	Cell parameters from 2290 reflections
c = 10.226 (2) Å	θ = 2.3–27.5°
α = 67.706 (15)°	µ = 0.11 mm⁻¹
β = 72.228 (16)°	T = 93 K
γ = 86.41 (2)°	Prism, colorless
V = 675.2 (3) Å³	0.30 × 0.20 × 0.15 mm

Data collection top

Rigaku XtaLAB P200 diffractometer	2278 reflections with F² > 2.0σ(F²)
Detector resolution: 5.814 pixels mm^-1	R_int = 0.031
ω scans	θ_max = 25.3°, θ_min = 2.3°
Absorption correction: multi-scan (REQAB; Rigaku, 1998)	h = −9→9
T_min = 0.829, T_max = 0.983	k = −11→11
9890 measured reflections	l = −12→12
2466 independent reflections

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.078	H-atom parameters constrained
S = 1.07	w = 1/[σ²(F_o²) + (0.0425P)² + 0.0953P] where P = (F_o² + 2F_c²)/3
2466 reflections	(Δ/σ)_max < 0.001
192 parameters	Δρ_max = 0.25 e Å⁻³
0 restraints	Δρ_min = −0.18 e Å⁻³
Primary atom site location: structure-invariant direct methods

Special details top

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.

Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F². R-factor (gt) are based on F. The threshold expression of F² > 2.0 sigma(F²) is used only for calculating R-factor (gt).

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

	x	y	z	U_iso*/U_eq
O1	0.78603 (9)	0.26223 (8)	−0.08336 (8)	0.01823 (18)
O2	0.88520 (10)	0.18829 (9)	−0.27766 (9)	0.0250 (2)
O9	0.92060 (10)	0.33329 (10)	0.10424 (10)	0.0292 (2)
O10	0.71494 (9)	0.40999 (9)	0.26677 (8)	0.02015 (19)
O12	0.34235 (10)	0.41829 (8)	0.23018 (8)	0.02202 (19)
O13	0.39408 (9)	0.17091 (8)	0.34225 (8)	0.01784 (18)
C2	0.76082 (14)	0.20746 (12)	−0.18525 (12)	0.0188 (2)
C2A	0.56886 (14)	0.18300 (12)	−0.15155 (12)	0.0176 (2)
C3	0.47681 (14)	0.12685 (12)	−0.21879 (12)	0.0203 (2)
H3	0.5367	0.0970	−0.2992	0.024*
C4	0.29321 (14)	0.11623 (12)	−0.16343 (12)	0.0209 (2)
H4	0.2255	0.0764	−0.2053	0.025*
C5	0.20674 (14)	0.16332 (12)	−0.04692 (12)	0.0199 (2)
H5	0.0809	0.1570	−0.0126	0.024*
C6	0.30017 (13)	0.21919 (12)	0.02009 (12)	0.0181 (2)
H6	0.2406	0.2513	0.0990	0.022*
C6A	0.48425 (14)	0.22634 (11)	−0.03286 (11)	0.0164 (2)
C7	0.62379 (13)	0.27243 (11)	0.01279 (11)	0.0164 (2)
C8	0.61249 (13)	0.31329 (11)	0.12678 (12)	0.0170 (2)
C9	0.76891 (13)	0.35264 (12)	0.16046 (12)	0.0182 (2)
C10	0.85459 (14)	0.45643 (13)	0.30998 (13)	0.0233 (3)
H10A	0.9277	0.5452	0.2271	0.028*
H10B	0.9323	0.3712	0.3371	0.028*
C11	0.76446 (15)	0.49876 (14)	0.44073 (13)	0.0267 (3)
H11A	0.6954	0.4091	0.5228	0.032*
H11B	0.6853	0.5810	0.4131	0.032*
H11C	0.8537	0.5338	0.4718	0.032*
C12	0.43443 (13)	0.31193 (12)	0.23574 (11)	0.0162 (2)
C13	0.22714 (13)	0.15072 (12)	0.46014 (12)	0.0202 (2)
H13A	0.1283	0.1846	0.4175	0.024*
H13B	0.2327	0.2116	0.5192	0.024*
C14	0.19989 (14)	−0.01740 (12)	0.55625 (12)	0.0220 (2)
H14A	0.1880	−0.0757	0.4978	0.026*
H14B	0.0921	−0.0353	0.6404	0.026*
H14C	0.3018	−0.0506	0.5931	0.026*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0135 (4)	0.0209 (4)	0.0182 (4)	0.0008 (3)	−0.0019 (3)	−0.0076 (3)
O2	0.0191 (4)	0.0308 (5)	0.0227 (4)	0.0033 (3)	−0.0006 (3)	−0.0122 (4)
O9	0.0152 (4)	0.0410 (5)	0.0386 (5)	0.0039 (3)	−0.0071 (4)	−0.0241 (4)
O10	0.0160 (4)	0.0236 (4)	0.0251 (4)	0.0010 (3)	−0.0078 (3)	−0.0125 (3)
O12	0.0203 (4)	0.0195 (4)	0.0236 (4)	0.0050 (3)	−0.0050 (3)	−0.0073 (3)
O13	0.0145 (4)	0.0173 (4)	0.0184 (4)	0.0013 (3)	−0.0019 (3)	−0.0056 (3)
C2	0.0194 (5)	0.0169 (5)	0.0174 (5)	0.0022 (4)	−0.0042 (4)	−0.0048 (4)
C2A	0.0175 (5)	0.0155 (5)	0.0167 (5)	0.0024 (4)	−0.0038 (4)	−0.0040 (4)
C3	0.0233 (6)	0.0199 (5)	0.0179 (5)	0.0036 (4)	−0.0061 (4)	−0.0080 (4)
C4	0.0226 (5)	0.0202 (6)	0.0220 (6)	0.0018 (4)	−0.0103 (5)	−0.0075 (5)
C5	0.0165 (5)	0.0203 (5)	0.0215 (6)	0.0022 (4)	−0.0066 (4)	−0.0060 (4)
C6	0.0171 (5)	0.0188 (5)	0.0174 (5)	0.0027 (4)	−0.0044 (4)	−0.0066 (4)
C6A	0.0174 (5)	0.0136 (5)	0.0162 (5)	0.0015 (4)	−0.0055 (4)	−0.0033 (4)
C7	0.0134 (5)	0.0140 (5)	0.0176 (5)	0.0012 (4)	−0.0028 (4)	−0.0032 (4)
C8	0.0153 (5)	0.0146 (5)	0.0188 (5)	0.0012 (4)	−0.0047 (4)	−0.0043 (4)
C9	0.0173 (5)	0.0157 (5)	0.0201 (5)	0.0007 (4)	−0.0051 (4)	−0.0055 (4)
C10	0.0190 (5)	0.0230 (6)	0.0338 (7)	0.0014 (4)	−0.0136 (5)	−0.0126 (5)
C11	0.0286 (6)	0.0274 (6)	0.0314 (7)	0.0030 (5)	−0.0162 (5)	−0.0137 (5)
C12	0.0164 (5)	0.0176 (5)	0.0169 (5)	0.0001 (4)	−0.0071 (4)	−0.0073 (4)
C13	0.0153 (5)	0.0220 (6)	0.0198 (6)	0.0009 (4)	−0.0003 (4)	−0.0081 (5)
C14	0.0188 (5)	0.0213 (6)	0.0217 (6)	−0.0005 (4)	−0.0023 (4)	−0.0064 (5)

Geometric parameters (Å, º) top

O1—C7	1.3854 (12)	C6—C6A	1.3916 (15)
O1—C2	1.3940 (13)	C6—H6	0.9500
O2—C2	1.1997 (13)	C6A—C7	1.4719 (14)
O9—C9	1.2019 (13)	C7—C8	1.3377 (15)
O10—C9	1.3391 (13)	C8—C9	1.4888 (14)
O10—C10	1.4579 (13)	C8—C12	1.5070 (14)
O12—C12	1.1995 (13)	C10—C11	1.4986 (16)
O13—C12	1.3435 (13)	C10—H10A	0.9900
O13—C13	1.4591 (12)	C10—H10B	0.9900
C2—C2A	1.4695 (15)	C11—H11A	0.9800
C2A—C3	1.3862 (15)	C11—H11B	0.9800
C2A—C6A	1.3919 (15)	C11—H11C	0.9800
C3—C4	1.3886 (16)	C13—C14	1.5055 (16)
C3—H3	0.9500	C13—H13A	0.9900
C4—C5	1.3978 (16)	C13—H13B	0.9900
C4—H4	0.9500	C14—H14A	0.9800
C5—C6	1.3904 (15)	C14—H14B	0.9800
C5—H5	0.9500	C14—H14C	0.9800

C7—O1—C2	109.90 (8)	O9—C9—O10	124.58 (10)
C9—O10—C10	115.85 (8)	O9—C9—C8	125.85 (10)
C12—O13—C13	116.01 (8)	O10—C9—C8	109.55 (9)
O2—C2—O1	120.62 (10)	O10—C10—C11	106.67 (9)
O2—C2—C2A	132.18 (11)	O10—C10—H10A	110.4
O1—C2—C2A	107.20 (9)	C11—C10—H10A	110.4
C3—C2A—C6A	122.56 (10)	O10—C10—H10B	110.4
C3—C2A—C2	129.50 (10)	C11—C10—H10B	110.4
C6A—C2A—C2	107.95 (9)	H10A—C10—H10B	108.6
C2A—C3—C4	117.04 (10)	C10—C11—H11A	109.5
C2A—C3—H3	121.5	C10—C11—H11B	109.5
C4—C3—H3	121.5	H11A—C11—H11B	109.5
C3—C4—C5	120.88 (10)	C10—C11—H11C	109.5
C3—C4—H4	119.6	H11A—C11—H11C	109.5
C5—C4—H4	119.6	H11B—C11—H11C	109.5
C6—C5—C4	121.67 (10)	O12—C12—O13	124.83 (10)
C6—C5—H5	119.2	O12—C12—C8	126.32 (10)
C4—C5—H5	119.2	O13—C12—C8	108.85 (8)
C5—C6—C6A	117.49 (10)	O13—C13—C14	106.78 (8)
C5—C6—H6	121.3	O13—C13—H13A	110.4
C6A—C6—H6	121.3	C14—C13—H13A	110.4
C6—C6A—C2A	120.32 (10)	O13—C13—H13B	110.4
C6—C6A—C7	132.70 (10)	C14—C13—H13B	110.4
C2A—C6A—C7	106.98 (9)	H13A—C13—H13B	108.6
C8—C7—O1	121.51 (9)	C13—C14—H14A	109.5
C8—C7—C6A	130.55 (10)	C13—C14—H14B	109.5
O1—C7—C6A	107.90 (9)	H14A—C14—H14B	109.5
C7—C8—C9	123.84 (9)	C13—C14—H14C	109.5
C7—C8—C12	120.08 (9)	H14A—C14—H14C	109.5
C9—C8—C12	115.97 (9)	H14B—C14—H14C	109.5

C7—O1—C2—O2	−179.09 (9)	C6—C6A—C7—O1	−177.86 (10)
C7—O1—C2—C2A	0.60 (11)	C2A—C6A—C7—O1	2.72 (11)
O2—C2—C2A—C3	1.1 (2)	O1—C7—C8—C9	0.65 (16)
O1—C2—C2A—C3	−178.50 (10)	C6A—C7—C8—C9	178.04 (9)
O2—C2—C2A—C6A	−179.21 (11)	O1—C7—C8—C12	−175.47 (8)
O1—C2—C2A—C6A	1.15 (11)	C6A—C7—C8—C12	1.92 (17)
C6A—C2A—C3—C4	0.54 (15)	C10—O10—C9—O9	2.55 (15)
C2—C2A—C3—C4	−179.85 (10)	C10—O10—C9—C8	−179.01 (8)
C2A—C3—C4—C5	1.21 (15)	C7—C8—C9—O9	−10.62 (17)
C3—C4—C5—C6	−1.41 (16)	C12—C8—C9—O9	165.65 (10)
C4—C5—C6—C6A	−0.18 (15)	C7—C8—C9—O10	170.96 (9)
C5—C6—C6A—C2A	1.90 (15)	C12—C8—C9—O10	−12.77 (12)
C5—C6—C6A—C7	−177.45 (10)	C9—O10—C10—C11	−173.45 (9)
C3—C2A—C6A—C6	−2.15 (15)	C13—O13—C12—O12	−1.65 (14)
C2—C2A—C6A—C6	178.17 (9)	C13—O13—C12—C8	178.17 (8)
C3—C2A—C6A—C7	177.35 (9)	C7—C8—C12—O12	−93.36 (14)
C2—C2A—C6A—C7	−2.32 (11)	C9—C8—C12—O12	90.22 (13)
C2—O1—C7—C8	175.88 (9)	C7—C8—C12—O13	86.82 (11)
C2—O1—C7—C6A	−2.03 (10)	C9—C8—C12—O13	−89.60 (10)
C6—C6A—C7—C8	4.48 (19)	C12—O13—C13—C14	173.90 (8)
C2A—C6A—C7—C8	−174.94 (11)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O9ⁱ	0.95	2.48	3.0689 (18)	120

Symmetry code: (i) x−1, y, z.

Funding information

The research leading to these results received funding from the European Community's Seventh Framework Programme ([FP7/2007–2013]) under grant agreement No. 607411 (MC-ITN EREAN: European Rare Earth Magnet Recycling Network). This publication reflects only the authors' views, exempting the Community from any liability. Project website: https://www.erean.eu.

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