Dioxidomolybdenum(VI) complex featuring a 2,4-di­fluoro-substituted amine bis­(phenolate) ligand

Bowen, C.L.; Wile, B.M.

doi:10.1107/S2414314621005162

metal-organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 6| Part 5| May 2021| x210516

https://doi.org/10.1107/S2414314621005162

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Dioxidomolybdenum(VI) complex featuring a 2,4-difluoro-substituted amine bis(phenolate) ligand

Christina L. Bowen ^a and Bradley M. Wile ^a ^*

^aThe School of Science, Technology, and Mathematics, Ohio Northern University, 525 S. Main Street, Ada, OH 45810, USA
^*Correspondence e-mail: b-wile@onu.edu

Edited by S. Parkin, University of Kentucky, USA (Received 1 April 2021; accepted 13 May 2021; online 21 May 2021)

Synthetic complexes containing a cis-[MoO₂]²⁺ core are well-established models for the molybdenum co-factor (Moco). Here we report the crystal structure of such a model complex bearing a tetradentate amine bis(phenolate) ligand with fluorine substituents on the phenolate rings, namely, [2,2′-({[2-(dimethylamino)ethyl]azanediyl}bis(methylene))bis(4,6-difluorophenolato)]dioxidomolybdenum(VI)), [Mo(C₁₈H₁₈F₄N₂O₂)O₂]. Distortion from idealized octahedral symmetry about the Mo center is evident in the large O=Mo=O angle [108.54 (4)°] and the small N–Mo–O_phenolate angles [79.79 (4), 81.21 (3), 77.83 (3), and 84.59 (3)°]. The dihedral angle between the phenolate rings is 60.06 (4)°, and π–π stacking is observed between aromatic rings related by inversion (1 − x, 1 − y, 1 − z). The lower data-collection temperature of 150 K vs room-temperature data collection reported previously [KOWXIF; Cao et al. (2014 ). Transit. Met. Chem. 39, 933–937] and larger 2θ range for data collection (5.8–66.6° versus 6–54.96°) led to a structure with lower R₁ and ωR₂ values (0.019 and 0.049 vs 0.0310 and 0.0566 for KOWXIF). Comparison of the metrical parameters with KOWXIF suggests that this dataset offers a more realistic depiction of bonding within the Mo^VI=O moiety.

Keywords: crystal structure; molybdenum; oxo; Moco.

CCDC reference: 2083619

Structure description

Molybdenum-containing metalloenzymes are abundant and serve as excellent motivation for biomimetic catalyst development. The relevance of xanthine oxidase, DMSO reductase, sulfite oxidase to oxygen atom transfer and proton-coupled electron-transfer reactions have driven interest in related mononuclear Mo complexes for generating H₂ or expanding opportunities for storage of energy generated by increasingly efficient solar cells. The native enzymes contain a molybdenum cofactor (Moco) in which the Mo^VI=O moiety is supported by dithiolene-containing molybdopterin ligands (Kisker et al., 1997 ). A robust molybdenum–oxo complex bearing a pentadentate pyridyl ligand was notably shown to catalytically generate H₂ from water at a low overpotential (Karunadasa et al., 2010 ). Related molybdenum–oxo complexes featuring an amine bis(phenolate) moiety have been similarly shown to promote H₂ generation (Cao et al., 2014) and oxygen atom transfer (Maurya et al., 2016 ). Insight into the structural features that enable such activity at the Mo=O moiety are thus an important component of iterating the design of these species for use as sustainable aqueous catalysts.

The Mo complex reported here (2, Fig. 1) is chemically identical to that reported by Cao et al. (2014, KOWXIF). The lower collection temperature (150 K versus room temperature in KOWXIF) and larger 2θ range for data collection (5.8–66.6° versus 6–54.96° in the previous report) led to a structure solution with lower R₁ and ωR₂ values (0.019 and 0.049 versus 0.0310 and 0.0566 in KOWXIF). Slight differences in the bond lengths for the compound in these structures warrant further comment and may be of interest from a mechanistic perspective. For example, it is generally accepted that an Mo=O bond in the cis-[MoO₂]²⁺ core of DMSO reductase model compounds is formally strengthened (consistent with Mo≡O) during oxygen atom transfer (Enemark, et al., 2004 ).

Figure 1
Molecular structure of 2 with 50% displacement ellipsoids and the numbering scheme for non-H atoms.

Both structures have P $[\overline{1}]$ space-group symmetry, though a, c, β, and γ were different by ±3 s.u. While the Mo—O(phenolate) and Mo—N bonds in this structure are nearly identical to those reported by Cao et al., the Mo=O bond lengths reported here are notably longer than those in KOWXIF and are in line with expectations for related Mo^VI–oxo species (Enemark, et al., 2004). However, these differences in bond length are within the accuracy limits for light atoms imposed by the spherical atom scattering factor approximation (e.g. Dawson, 1964 ). Relevant lengths and angles for both are summarized in Table 1. Differences in the metrical parameters for these structures suggest that the model presented here gives a better representation of the bonding for 2, when compared with other Mo^VI oxo species.

Table 1
Comparison of lengths and angles between this work and previous report

	This work (CLB-1–87)	KOWXIF (Cao et al., 2014)
Mo—O1	1.9788 (8)	1.976 (3)
Mo—O2	1.9287 (8)	1.919 (3)
Mo—O3	1.7062 (8)	1.693 (2)	difference greater than ±3 s.u.
Mo—O4	1.7123 (7)	1.700 (3)	difference greater than ±3 s.u.
Mo—N1	2.4008 (8)	2.395 (3)
Mo—N2	2.4117 (9)	2.412 (3)

O1—Mo1—O3	98.19 (4)	98.6 (1)
O1—Mo1—O4	93.41 (4)	93.4 (1)
O1—Mo1—N1	79.79 (3)	79.7 (1)
O1—Mo1—N2	84.59 (3)	84.5 (1)
O2—Mo1—O3	99.96 (4)	99.9 (1)
O2—Mo1—O4	95.43 (4)	95.8 (1)
O2—Mo1—N1	77.83 (3)	77.5 (1)
O2—Mo1—N2	81.21 (3)	81.0 (1)
O3—Mo1—O4	108.54 (4)	108.2 (1)
N1—Mo1—N2	73.84 (3)	73.8 (1)

N1—C1—C2—N2	−55.84 (11)	56.4 (4)

No hydrogen bonding was observed, though short contacts exist between inversion-related molecules contained in the unit cell. The orientation of one phenolate ring brings the ortho carbons C16 and C18ⁱ [symmetry code: (i) 1 − x, 1 − y, 1 − z] in close proximity [3.2807 (15) Å, i.e. ∼0.12 Å closer than the sum of the vdW radii]. Close contact is noted for the para F3 and proximal meta C16ⁱⁱ [symmetry code: (ii) 2 − x, 2 − y, 1 − z] of an adjacent inversion-related molecule [3.1622 (14) Å, i.e. ∼0.01 Å closer than the sum of the vdW radii]. This marginally short contact is consistent with π–π stacking between the phenolate rings related by the inversion center; this interaction is shown in Fig. 2. A similar, though much more pronounced contact is noted between ortho F2 and the amine methyl group, C3ⁱⁱⁱ [symmetry code: (iii) −x, −y, −z] [2.9229 (13) Å, ∼0.247 Å closer than the sum of the vdW radii]. Each Mo^VI=O moiety lies above planes defined by the amine bis(phenolate) ligand and the other oxo [0.3037 (4) Å above the plane defined by O1, O2, O4, and N2; 0.2696 (4) Å above the plane defined by O1, O2, O3, and N1]. This distortion from an ideal octahedral geometry is consistent with related Mo^VI oxo species, and is evident in the large O3—Mo1—O4 bond angle [108.54 (4)°]. The dihedral between aromatic rings was found to be 60.06 (4)°. The torsion angle along the diamine N1—C1—C2—N2 [−55.84 (11)°] is consistent with the syn conformation of amine donors within the unstrained five-membered ring formed upon chelation.

Figure 2
Packing plot (viewed along b) showing π–π stacking of fluorinated (F3, F4) phenolate rings related by inversion. Orange dots represent centers of inversion.

Synthesis and crystallization

The ligand H₂ONNO^F (1) was prepared by the method reported previously (Graziano et al., 2019 ). The Mo complex (2) was prepared using a modified version of the method reported by Lehtonen & Sillanpää (2005 ). The reaction scheme is shown in Fig. 3. MoO₂(acac)₂ (0.330 g, 1.01 mmol) and the ligand H₂ONNO^F (1; 0.373 g, 1.00 mmol) were combined in a 20 ml scintillation vial with a PTFE-coated stir bar and suspended in 10 ml of anhydrous methanol. The reaction mixture was left to stir for 4 h at 295 K, at which time solvent and other volatiles were removed in vacuo to yield a yellow solid (0.500 g, 1.00 mmol, >99%). The product was purified by column chromatography on silica using an increasing linear gradient of dichloromethane in acetone as the eluent. After removing the solvent and other volatiles, single crystals suitable for diffraction studies were obtained by slow evaporation from a concentrated solution of acetone. Characterization data for this compound match those previously reported by Cao et al. (2014). M.p. = 463–467 K.

Figure 3
Reaction scheme.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. No disorder or solvent were present.

Table 2
Experimental details

Crystal data
Chemical formula	[Mo(C₁₈H₁₈F₄N₂O₂)O₂]
M_r	498.28
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	150
a, b, c (Å)	7.3179 (4), 8.0093 (4), 17.5057 (9)
α, β, γ (°)	91.8513 (18), 92.9102 (18), 116.6842 (16)
V (Å³)	913.82 (8)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.79
Crystal size (mm)	0.26 × 0.24 × 0.15

Data collection
Diffractometer	Bruker AXS D8 Quest CMOS diffractometer
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.702, 0.747
No. of measured, independent and observed [I > 2σ(I)] reflections	47859, 7013, 6541
R_int	0.027
(sin θ/λ)_max (Å⁻¹)	0.772

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.019, 0.049, 1.12
No. of reflections	7013
No. of parameters	266
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.92, −0.48
Computer programs: APEX3 and SAINT (Bruker, 2018 ), SHELXT (Sheldrick, 2015a ), SHELXL2018/3 (Sheldrick, 2015b ), ShelXle (Hübschle et al., 2011 ) and Mercury (Macrae et al., 2020 ).

Structural data

CCDC reference: 2083619

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S2414314621005162/pk4033sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314621005162/pk4033Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2018); cell refinement: SAINT (Bruker, 2018); data reduction: SAINT (Bruker, 2018); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b), ShelXle (Hübschle et al., 2011); molecular graphics: Mercury (Macrae et al., 2020).

[2,2'-({[2-(Dimethylamino)ethyl]azanediyl}bis(methylene))bis(4,6-difluorophenolato)]dioxidomolybdenum(VI)), top

Crystal data top

[Mo(C₁₈H₁₈F₄N₂O₂)O₂]	Z = 2
M_r = 498.28	F(000) = 500
Triclinic, P1	D_x = 1.811 Mg m⁻³
a = 7.3179 (4) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.0093 (4) Å	Cell parameters from 9173 reflections
c = 17.5057 (9) Å	θ = 2.3–33.2°
α = 91.8513 (18)°	µ = 0.79 mm⁻¹
β = 92.9102 (18)°	T = 150 K
γ = 116.6842 (16)°	Block, orange
V = 913.82 (8) Å³	0.26 × 0.24 × 0.15 mm

Data collection top

Bruker AXS D8 Quest CMOS diffractometer	7013 independent reflections
Radiation source: fine focus sealed tube X-ray source	6541 reflections with I > 2σ(I)
Triumph curved graphite crystal monochromator	R_int = 0.027
Detector resolution: 10.4167 pixels mm^-1	θ_max = 33.3°, θ_min = 2.9°
ω and phi scans	h = −11→11
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	k = −12→12
T_min = 0.702, T_max = 0.747	l = −26→25
47859 measured reflections

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.019	H-atom parameters constrained
wR(F²) = 0.049	w = 1/[σ²(F_o²) + (0.0194P)² + 0.4598P] where P = (F_o² + 2F_c²)/3
S = 1.12	(Δ/σ)_max = 0.001
7013 reflections	Δρ_max = 0.92 e Å⁻³
266 parameters	Δρ_min = −0.48 e Å⁻³
0 restraints	Extinction correction: SHELXL2018/3 (Sheldrick 2015b), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0171 (8)

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.

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

	x	y	z	U_iso*/U_eq
Mo1	0.35403 (2)	0.27852 (2)	0.23176 (2)	0.01088 (3)
F1	0.30483 (14)	0.85179 (12)	−0.04843 (5)	0.03105 (18)
F2	0.23146 (13)	0.24459 (11)	−0.02051 (4)	0.02510 (15)
F3	0.77983 (14)	0.98402 (12)	0.50141 (5)	0.0357 (2)
F4	0.74459 (12)	0.40003 (12)	0.42642 (5)	0.02571 (15)
O2	0.24235 (12)	0.28426 (11)	0.13025 (4)	0.01475 (13)
O1	0.37637 (12)	0.30006 (11)	0.34515 (4)	0.01499 (13)
O3	0.39279 (13)	0.08489 (11)	0.21952 (5)	0.01831 (15)
O4	0.58252 (12)	0.47327 (11)	0.22506 (5)	0.01743 (14)
N1	0.18199 (13)	0.46786 (12)	0.25408 (5)	0.01204 (14)
N2	0.00004 (13)	0.06353 (12)	0.24545 (5)	0.01375 (15)
C1	−0.03936 (15)	0.35240 (15)	0.22876 (6)	0.01565 (18)
H1A	−0.055488	0.333606	0.172183	0.019*
H1B	−0.118429	0.419086	0.244487	0.019*
C2	−0.12266 (16)	0.16343 (15)	0.26393 (7)	0.01739 (18)
H2A	−0.119764	0.181957	0.320249	0.021*
H2B	−0.267036	0.086095	0.244251	0.021*
C3	−0.08879 (17)	−0.05342 (15)	0.17262 (6)	0.01864 (19)
H3A	−0.099801	0.024782	0.132488	0.028*
H3B	−0.225312	−0.153590	0.180273	0.028*
H3C	0.000294	−0.108430	0.157166	0.028*
C4	−0.01342 (18)	−0.06387 (16)	0.30686 (7)	0.0197 (2)
H4A	−0.157319	−0.152867	0.311224	0.029*
H4B	0.043768	0.009500	0.355647	0.029*
H4C	0.064405	−0.132458	0.294289	0.029*
C5	0.27534 (17)	0.63562 (14)	0.20820 (6)	0.01565 (18)
H5A	0.419181	0.712021	0.228692	0.019*
H5B	0.201603	0.711773	0.216119	0.019*
C6	0.27467 (16)	0.59822 (14)	0.12285 (6)	0.01432 (17)
C7	0.29093 (17)	0.74157 (16)	0.07532 (6)	0.01792 (19)
H7	0.303492	0.856995	0.096826	0.021*
C8	0.28844 (18)	0.71284 (17)	−0.00284 (7)	0.0202 (2)
C9	0.26776 (18)	0.54719 (17)	−0.03773 (6)	0.0203 (2)
H9	0.265023	0.529975	−0.091799	0.024*
C10	0.25135 (17)	0.40861 (16)	0.01002 (6)	0.01692 (18)
C11	0.25771 (15)	0.43022 (14)	0.08992 (6)	0.01363 (16)
C12	0.19506 (17)	0.53698 (15)	0.33577 (6)	0.01572 (18)
H12A	0.159066	0.642284	0.336701	0.019*
H12B	0.091704	0.435217	0.363450	0.019*
C13	0.40118 (16)	0.60117 (15)	0.37784 (6)	0.01528 (17)
C14	0.50261 (19)	0.77546 (16)	0.41804 (6)	0.0204 (2)
H14	0.449901	0.864217	0.415639	0.024*
C15	0.6818 (2)	0.81511 (17)	0.46142 (7)	0.0238 (2)
C16	0.76763 (18)	0.69352 (18)	0.46549 (7)	0.0229 (2)
H16	0.892175	0.725565	0.495342	0.028*
C17	0.66479 (17)	0.52275 (16)	0.42429 (6)	0.01820 (19)
C18	0.47924 (16)	0.47139 (14)	0.38146 (6)	0.01454 (17)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Mo1	0.01022 (4)	0.01143 (4)	0.01228 (4)	0.00609 (3)	0.00069 (3)	0.00012 (3)
F1	0.0408 (5)	0.0298 (4)	0.0230 (4)	0.0155 (4)	0.0016 (3)	0.0148 (3)
F2	0.0352 (4)	0.0255 (4)	0.0153 (3)	0.0151 (3)	−0.0014 (3)	−0.0060 (3)
F3	0.0359 (5)	0.0233 (4)	0.0305 (4)	−0.0005 (3)	−0.0042 (3)	−0.0120 (3)
F4	0.0204 (3)	0.0338 (4)	0.0257 (4)	0.0149 (3)	−0.0020 (3)	0.0034 (3)
O2	0.0190 (3)	0.0142 (3)	0.0122 (3)	0.0086 (3)	0.0002 (3)	0.0003 (2)
O1	0.0168 (3)	0.0141 (3)	0.0131 (3)	0.0064 (3)	−0.0015 (3)	0.0004 (2)
O3	0.0197 (4)	0.0168 (3)	0.0226 (4)	0.0121 (3)	0.0000 (3)	−0.0005 (3)
O4	0.0132 (3)	0.0168 (3)	0.0207 (4)	0.0052 (3)	0.0030 (3)	0.0011 (3)
N1	0.0128 (3)	0.0130 (3)	0.0117 (3)	0.0070 (3)	0.0008 (3)	0.0003 (3)
N2	0.0130 (4)	0.0134 (4)	0.0146 (4)	0.0056 (3)	0.0011 (3)	0.0011 (3)
C1	0.0116 (4)	0.0176 (4)	0.0199 (5)	0.0088 (3)	−0.0005 (3)	0.0006 (3)
C2	0.0114 (4)	0.0181 (4)	0.0228 (5)	0.0066 (3)	0.0032 (3)	0.0013 (4)
C3	0.0171 (4)	0.0155 (4)	0.0183 (5)	0.0035 (4)	−0.0019 (4)	−0.0024 (4)
C4	0.0220 (5)	0.0165 (4)	0.0196 (5)	0.0073 (4)	0.0040 (4)	0.0067 (4)
C5	0.0218 (5)	0.0123 (4)	0.0142 (4)	0.0088 (4)	0.0018 (3)	0.0012 (3)
C6	0.0147 (4)	0.0148 (4)	0.0136 (4)	0.0067 (3)	0.0007 (3)	0.0019 (3)
C7	0.0195 (5)	0.0169 (4)	0.0180 (5)	0.0086 (4)	0.0009 (4)	0.0047 (4)
C8	0.0194 (5)	0.0226 (5)	0.0178 (5)	0.0084 (4)	0.0009 (4)	0.0086 (4)
C9	0.0187 (5)	0.0276 (5)	0.0132 (4)	0.0092 (4)	0.0004 (4)	0.0041 (4)
C10	0.0165 (4)	0.0203 (5)	0.0133 (4)	0.0080 (4)	−0.0004 (3)	−0.0012 (3)
C11	0.0130 (4)	0.0159 (4)	0.0119 (4)	0.0065 (3)	0.0002 (3)	0.0009 (3)
C12	0.0183 (4)	0.0188 (4)	0.0129 (4)	0.0108 (4)	0.0025 (3)	−0.0004 (3)
C13	0.0177 (4)	0.0154 (4)	0.0111 (4)	0.0060 (3)	0.0020 (3)	0.0001 (3)
C14	0.0250 (5)	0.0170 (5)	0.0155 (5)	0.0062 (4)	0.0032 (4)	−0.0019 (4)
C15	0.0247 (5)	0.0192 (5)	0.0152 (5)	−0.0006 (4)	0.0014 (4)	−0.0041 (4)
C16	0.0177 (5)	0.0267 (5)	0.0138 (5)	0.0008 (4)	−0.0008 (4)	0.0007 (4)
C17	0.0149 (4)	0.0230 (5)	0.0137 (4)	0.0059 (4)	0.0006 (3)	0.0030 (4)
C18	0.0146 (4)	0.0158 (4)	0.0107 (4)	0.0046 (3)	0.0007 (3)	0.0011 (3)

Geometric parameters (Å, º) top

Mo1—O3	1.7062 (8)	C4—H4A	0.9800
Mo1—O4	1.7123 (8)	C4—H4B	0.9800
Mo1—O2	1.9287 (8)	C4—H4C	0.9800
Mo1—O1	1.9788 (8)	C5—C6	1.5137 (15)
Mo1—N1	2.4008 (8)	C5—H5A	0.9900
Mo1—N2	2.4117 (9)	C5—H5B	0.9900
F1—C8	1.3554 (13)	C6—C11	1.3968 (14)
F2—C10	1.3444 (13)	C6—C7	1.4048 (15)
F3—C15	1.3605 (14)	C7—C8	1.3779 (16)
F4—C17	1.3506 (14)	C7—H7	0.9500
O2—C11	1.3494 (12)	C8—C9	1.3835 (18)
O1—C18	1.3494 (12)	C9—C10	1.3767 (16)
N1—C5	1.4894 (13)	C9—H9	0.9500
N1—C1	1.4936 (13)	C10—C11	1.3997 (14)
N1—C12	1.4994 (13)	C12—C13	1.4993 (15)
N2—C4	1.4825 (14)	C12—H12A	0.9900
N2—C2	1.4863 (14)	C12—H12B	0.9900
N2—C3	1.4890 (14)	C13—C18	1.3945 (15)
C1—C2	1.5202 (15)	C13—C14	1.3956 (15)
C1—H1A	0.9900	C14—C15	1.3809 (18)
C1—H1B	0.9900	C14—H14	0.9500
C2—H2A	0.9900	C15—C16	1.377 (2)
C2—H2B	0.9900	C16—C17	1.3835 (16)
C3—H3A	0.9800	C16—H16	0.9500
C3—H3B	0.9800	C17—C18	1.3965 (15)
C3—H3C	0.9800

O3—Mo1—O4	108.54 (4)	H4A—C4—H4C	109.5
O3—Mo1—O2	99.96 (4)	H4B—C4—H4C	109.5
O4—Mo1—O2	95.43 (4)	N1—C5—C6	116.27 (8)
O3—Mo1—O1	98.19 (4)	N1—C5—H5A	108.2
O4—Mo1—O1	93.41 (4)	C6—C5—H5A	108.2
O2—Mo1—O1	156.09 (3)	N1—C5—H5B	108.2
O3—Mo1—N1	160.10 (4)	C6—C5—H5B	108.2
O4—Mo1—N1	91.35 (3)	H5A—C5—H5B	107.4
O2—Mo1—N1	77.83 (3)	C11—C6—C7	119.31 (10)
O1—Mo1—N1	79.79 (3)	C11—C6—C5	123.44 (9)
O3—Mo1—N2	86.27 (4)	C7—C6—C5	117.24 (9)
O4—Mo1—N2	165.19 (3)	C8—C7—C6	119.25 (10)
O2—Mo1—N2	81.21 (3)	C8—C7—H7	120.4
O1—Mo1—N2	84.59 (3)	C6—C7—H7	120.4
N1—Mo1—N2	73.84 (3)	F1—C8—C7	119.02 (11)
C11—O2—Mo1	130.56 (7)	F1—C8—C9	117.80 (11)
C18—O1—Mo1	118.88 (6)	C7—C8—C9	123.17 (10)
C5—N1—C1	110.73 (8)	C10—C9—C8	116.50 (10)
C5—N1—C12	107.20 (8)	C10—C9—H9	121.7
C1—N1—C12	107.89 (8)	C8—C9—H9	121.7
C5—N1—Mo1	108.18 (6)	F2—C10—C9	119.27 (10)
C1—N1—Mo1	107.55 (6)	F2—C10—C11	117.50 (10)
C12—N1—Mo1	115.29 (6)	C9—C10—C11	123.23 (10)
C4—N2—C2	109.15 (9)	O2—C11—C6	124.11 (9)
C4—N2—C3	107.68 (9)	O2—C11—C10	117.37 (9)
C2—N2—C3	109.18 (8)	C6—C11—C10	118.50 (9)
C4—N2—Mo1	109.89 (6)	C13—C12—N1	114.57 (8)
C2—N2—Mo1	111.74 (6)	C13—C12—H12A	108.6
C3—N2—Mo1	109.11 (6)	N1—C12—H12A	108.6
N1—C1—C2	110.46 (8)	C13—C12—H12B	108.6
N1—C1—H1A	109.6	N1—C12—H12B	108.6
C2—C1—H1A	109.6	H12A—C12—H12B	107.6
N1—C1—H1B	109.6	C18—C13—C14	120.78 (10)
C2—C1—H1B	109.6	C18—C13—C12	116.82 (9)
H1A—C1—H1B	108.1	C14—C13—C12	122.11 (10)
N2—C2—C1	111.22 (9)	C15—C14—C13	118.05 (11)
N2—C2—H2A	109.4	C15—C14—H14	121.0
C1—C2—H2A	109.4	C13—C14—H14	121.0
N2—C2—H2B	109.4	F3—C15—C16	118.40 (11)
C1—C2—H2B	109.4	F3—C15—C14	118.20 (12)
H2A—C2—H2B	108.0	C16—C15—C14	123.39 (11)
N2—C3—H3A	109.5	C15—C16—C17	117.20 (11)
N2—C3—H3B	109.5	C15—C16—H16	121.4
H3A—C3—H3B	109.5	C17—C16—H16	121.4
N2—C3—H3C	109.5	F4—C17—C16	119.01 (10)
H3A—C3—H3C	109.5	F4—C17—C18	118.73 (10)
H3B—C3—H3C	109.5	C16—C17—C18	122.26 (11)
N2—C4—H4A	109.5	O1—C18—C13	120.64 (9)
N2—C4—H4B	109.5	O1—C18—C17	121.10 (10)
H4A—C4—H4B	109.5	C13—C18—C17	118.26 (10)
N2—C4—H4C	109.5

C5—N1—C1—C2	168.55 (8)	C9—C10—C11—O2	−179.23 (10)
C12—N1—C1—C2	−74.42 (10)	F2—C10—C11—C6	−178.89 (9)
Mo1—N1—C1—C2	50.54 (9)	C9—C10—C11—C6	2.21 (16)
C4—N2—C2—C1	152.57 (9)	C5—N1—C12—C13	−79.49 (11)
C3—N2—C2—C1	−89.97 (10)	C1—N1—C12—C13	161.21 (9)
Mo1—N2—C2—C1	30.82 (10)	Mo1—N1—C12—C13	41.02 (11)
N1—C1—C2—N2	−55.84 (11)	N1—C12—C13—C18	−57.38 (13)
C1—N1—C5—C6	−61.33 (11)	N1—C12—C13—C14	128.74 (11)
C12—N1—C5—C6	−178.78 (9)	C18—C13—C14—C15	−0.08 (16)
Mo1—N1—C5—C6	56.29 (10)	C12—C13—C14—C15	173.57 (10)
N1—C5—C6—C11	−21.87 (15)	C13—C14—C15—F3	−179.23 (10)
N1—C5—C6—C7	157.75 (9)	C13—C14—C15—C16	1.60 (18)
C11—C6—C7—C8	0.42 (16)	F3—C15—C16—C17	179.98 (11)
C5—C6—C7—C8	−179.21 (10)	C14—C15—C16—C17	−0.85 (18)
C6—C7—C8—F1	−179.79 (10)	C15—C16—C17—F4	179.60 (10)
C6—C7—C8—C9	0.90 (18)	C15—C16—C17—C18	−1.46 (17)
F1—C8—C9—C10	−179.97 (10)	Mo1—O1—C18—C13	68.58 (11)
C7—C8—C9—C10	−0.66 (17)	Mo1—O1—C18—C17	−112.20 (9)
C8—C9—C10—F2	−179.82 (10)	C14—C13—C18—O1	177.19 (10)
C8—C9—C10—C11	−0.93 (17)	C12—C13—C18—O1	3.22 (14)
Mo1—O2—C11—C6	−31.59 (15)	C14—C13—C18—C17	−2.06 (16)
Mo1—O2—C11—C10	149.93 (8)	C12—C13—C18—C17	−176.03 (9)
C7—C6—C11—O2	179.65 (10)	F4—C17—C18—O1	2.58 (15)
C5—C6—C11—O2	−0.74 (16)	C16—C17—C18—O1	−176.36 (10)
C7—C6—C11—C10	−1.89 (15)	F4—C17—C18—C13	−178.18 (9)
C5—C6—C11—C10	177.72 (10)	C16—C17—C18—C13	2.88 (16)
F2—C10—C11—O2	−0.32 (14)

Comparison of lengths and angles between this work and previous report top

	This work (CLB-1-87)	KOWXIF (Cao et al., 2014)
Mo—O1	1.9788 (8)	1.976 (3)
Mo—O2	1.9287 (8)	1.919 (3)
Mo—O3	1.7062 (8)	1.693 (2)	difference greater than ±3 s.u.
Mo—O4	1.7123 (7)	1.700 (3)	difference greater than ±3 s.u.
Mo—N1	2.4008 (8)	2.395 (3)
Mo—N2	2.4117 (9)	2.412 (3)

O1—Mo1—O3	98.19 (4)	98.6 (1)
O1—Mo1—O4	93.41 (4)	93.4 (1)
O1—Mo1—N1	79.79 (3)	79.7 (1)
O1—Mo1—N2	84.59 (3)	84.5 (1)
O2—Mo1—O3	99.96 (4)	99.9 (1)
O2—Mo1—O4	95.43 (4)	95.8 (1)
O2—Mo1—N1	77.83 (3)	77.5 (1)
O2—Mo1—N2	81.21 (3)	81.0 (1)
O3—Mo1—O4	108.54 (4)	108.2 (1)
N1—Mo1—N2	73.84 (3)	73.8 (1)

N1—C1—C2—N2	-55.84 (11)	56.4 (4)

Acknowledgements

Data collection and refinement were conducted by Matthias Zeller (Purdue University). The authors wish to thank Brendan Graziano for helpful discussions.

Funding information

This material is based upon work supported by the National Science Foundation through the Major Research Instrumentation Program under grant No. CHE 1625543 (funding for the single-crystal X-ray diffractometer). Acknowledgment is made to the donors of The American Chemical Society Petroleum Research Fund for support of this research (grant No. 56549-UR3). Partial funding for this project was provided by the Getty College of Arts and Sciences at Ohio Northern University.

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