Crystal structure of a μ-oxo vanadium(V) dimer coordinated by a salan ligand

Kallingal, I.A.; Alvarado, A.A.; Stieber, S.C.E.; John, A.

doi:10.1107/S2056989025008631

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ISSN: 2056-9890

Volume 81| Part 11| November 2025| Pages 1014-1017

https://doi.org/10.1107/S2056989025008631

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Crystal structure of a μ-oxo vanadium(V) dimer coordinated by a salan ligand

Isha A. Kallingal,^a Anais A. Alvarado,^a S. Chantal E. Stieber ^a and Alex John ^a ^*

^aDepartment of Chemistry & Biochemistry, Cal Poly Pomona, 3801 W. Temple Ave., Pomona, CA 91768, USA
^*Correspondence e-mail: [email protected]

Edited by B. Therrien, University of Neuchâtel, Switzerland (Received 27 August 2025; accepted 1 October 2025; online 14 October 2025)

A μ-oxo vanadium(V) dimeric complex, μ-oxido-bis[(2,2′-{[ethane-1,2-diylbis(azanediyl)]bis(methylene)}diphenolato)oxidovanadium(V)], [V₂(C₁₆H₁₈N₂O₂)₂O₃] (1), was crystallized by slow evaporation from an ethanol solution. The μ-oxo dimer crystallizes in the monoclinic space group C2/c where the salan ligand 1a coordinates to the vanadium center in a κ²N,κ²O fashion, forming a distorted octahedral geometry. The bridging oxo ligand lies on a crystallographic twofold axis. The unit cell consists of four molecules of 1 that are linked by C—H⋯·π_arene interactions as well as intramolecular hydrogen bonding.

Keywords: crystal structure; vanadium(V); μ-oxo dimer; salan ligand; octahedral geometry.

CCDC reference: 2492548

1. Chemical context

Vanadium compounds have been a subject of sustained investigation due to the varied oxidation states displayed by vanadium, which render unique reactivity to its compounds (Hu et al., 2023 ). In nature, vanadium is found in enzymes such as nitrogenases, nitrate reductases, and haloperoxidase etc (Hu et al., 2012 ; Eady, 1996 ; Butler & Walker, 1993 ). Complexes featuring a vanadium IV or V center with an oxovanadium (VO²⁺, VO³⁺) or dioxovanadium (VO₂⁺) core along with their μ-oxo or μ-alkoxo-bridged dimers are well-known and are commonly encountered in biochemical, pharmacological, and catalytic studies. Synthetic applications of such complexes include epoxidations, alcohol oxidations, sulfoxidation, hydrogenation, cross-coupling reactions, oligomerization and polymerization, deoxydehydration etc (Drzeżdżon et al., 2024 ; Patra et al., 2021 ; Hasnaoui et al., 2020 ; Hossain et al., 2019 ; Gopaladasu & Nicholas, 2016 ; Chapman & Nicholas, 2013 ; Hosseini Monfared et al., 2011 ; da Silva et al., 2011 ; Hoppe & Limberg, 2007 ; Maity et al., 2007 ; Baran, 2000 ). Modular ligands have been demonstrated to tune the structure and reactivity of the metal center in these oxovanadium and dioxovanadium complexes (Gopaladasu & Nicholas, 2016; Adão et al., 2009 ). Our group is currently exploring the unique reactivity of (di)oxovanadium complexes stabilized by salan ligands in contemporary oxidation and reduction reactions. Ligated metal complexes are readily accessible and offer a platform to establish structure–activity relationships to gain deeper understanding into catalytic processes (Wagner et al., 2024 ; Dereli et al., 2018 ; Steelman et al., 2014 , 2013 ).

2. Structural commentary

Complex 1 crystallizes in the monoclininc space group C2/c where the second half of the molecule is symmetry generated (Fig. 1). The vanadium centers are bridged by one oxygen atom with each vanadium center also having an oxo ligand coordinated. The V=O and V—O_μ-oxo distances of 1.6134 (14) and 1.8233 (8) Å, respectively, are shorter than the V—O_p (p = phenolato) distances of 1.8427 (14) and 1.9235 (14) Å with the V—O_p bond trans to the μ-oxo being longer consistent with a stronger trans-effect. The V—O—V bond angle is 140.32 (12)° while the O_oxido—V—O_μ-oxo bond angle is 100.03 (7)°. Each vanadium center is coordinated to six atoms, with a highly distorted octahedral arrangement. The axial position is defined by the V=O unit with an axial angle of 171.30 (7)° for O1—V1—N1. The axial bond distances of V1—O1 and V1—N1 are 1.6134 (14) and 2.2809 (17) Å, respectively. The equatorial angles deviate from 90° with a O2—V1—O3 angle of 96.56 (6)°, a O3—V1—O4 angle of 92.07 (6)°, a O4—V1—N2 angle of 80.76 (6)°, and an N2—V1—O2 angle of 85.41 (5)°. Combined, the bond distances and angles around the vanadium center reflect a distorted octahedral geometry.

Figure 1
The molecular structure of 1 with 50% probability level ellipsoids. Symmetry code: (_a) 1 − x, y, $[{3\over 2}]$ − z.

3. Supramolecular features

Four molecules of complex 1 are packed within the unit cell, with structural stabilization from intermolecular π interactions with phenyl groups, and intramolecular hydrogen bonding (Fig. 2). The π interaction is found between H1 and the centroid defined by C1–C6 at symmetry position $[{1\over 2}]$ − y, $[{1\over 2}]$ − y, 1 − z with a distance of 2.66 Å. The closest distance is 2.59 Å between C3⋯H1, which is repeated throughout the packing due to the high level of symmetry in the molecule. Intramolecular hydrogen bonding is found between H2a and O1 with a bond distance of 2.11 Å (Fig. 3). Distances to hydrogen atoms are reported without standard deviations because the hydrogen atoms were positionally fixed. The H2a—N2a distance is 1.00 Å, with an O1(1 − x, y, $[{3\over 2}]$ − z)⋯N2a distance of 2.977 (2) Å and an O1(1 − x, y, $[{3\over 2}]$ − z)⋯H2a—N2a angle of 144.0°.

Figure 2
The unit -packing for 1 highlighting intermolecular π interactions.

Figure 3
View of μ-oxido-bis[(2,2′-{[ethane-1,2-diylbis(azanediyl)]bis(methylene)}diphenolato)oxidovanadium(V)] (1), highlighting intramolecular hydrogen bonding.

4. Database survey

A survey of the Cambridge Structural Database (Web accessed August 1, 2025; Groom et al., 2016 ) and SciFinder (2025 ) yielded no exact matches for complex 1. However, salan ligands are ubiquitous in coordination chemistry and have been employed to form complexes with metals from across the periodic table. Specifically, oxovanadium complexes of salan ligands have been previously reported including μ-oxo dimers (Patra et al., 2021; Debnath et al., 2018 ; Reytman et al., 2012 ; Adão et al., 2009). Complex 1 presents an example of a {OV^v(μ-O)V^vO} neutral dinuclear μ-oxo-bridged vanadium(V) complex featuring a tetradentate ligand. The first examples of such complexes based on salan ligands were reported by Correia and coworkers (Adão et al., 2009). These complexes presented a distorted octahedral geometry around the vanadium center and twist-angular configurations with cis-orientation between the phenolate O atoms from the salan ligand (β-cis structure). Complex 1 also displays a β-cis type arrangement of the phenolate O atoms and the V=O bond distance [1.6134 (14) Å] is comparable to that seen in similar complexes [1.621 (6) Å; Adão et al., 2009].

5. Synthesis and crystallization

The salan ligand precursor (1a) used in this study was synthesized by the reductive amination reaction between salicylaldehyde and 1,2-ethylenediamine in a 79% yield. (Wagner et al., 2024) Complexation was achieved by the reaction of 1a with the vanadium precursor [V₂O₄(acac)₂] in ethanol at reflux under a N₂ atmosphere. Complex 1 formed as a dark precipitate and was collected by gravity filtration (77% yield). The resulting dark-purple colored filtrate was stored at room temperature to obtain crystals of the μ-oxo vanadium(V) dimer complex (1) by slow evaporation. ESI-MS analysis of the crystals exhibited the monomer unit [LV^v(O)]⁺ at m/z = 337. Elemental analysis of the precipitate matched a Na[dioxo(L)vanadate] complex. We hypothesize that the vanadate complex is in equilibrium with the μ-oxo dimer which crystallized out of an ethanolic solution.

Synthesis of 1 [LV^v(O)–(μ-O)–LV^v(O)]: In a round-bottom flask, 1a (0.622 g, 2.28 mmol), sodium acetate (0.761 g, 9.28 mmol), and V₂O₄(acac)₂ (0.417 g, 1.14 mmol) were dissolved in 10 mL of ethanol under a nitrogen atmosphere. The mixture was heated to reflux for 2 h. After heating, the mixture was cooled down to room temperature. A dark precipitate formed and it was isolated by gravity filtration. The precipitate was washed with cold methanol and dried overnight under a high vacuum to obtain 1 as a dark solid (0.760 g, 77%). The resulting filtrate was stored at room temperature for slow evaporation and produced dark green crystals of 1 in a few days. FTIR: 3266 (N—H), 942 cm⁻¹ (V=O). ESI-MS (+ve): m/z = 337 [C₁₆H₁₈N₂O₃V]⁺. Elemental analysis for calculated C₁₆H₁₈N₂O₄VNa·3 H₂O: C: 44.66; H: 5.62; N: 6.51. Found: C: 44.61; H: 4.70; N: 5.40.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. Hydrogen atoms were placed in calculated positions using the AFIX command in SHELXL and refined using a riding model.

Table 1
Experimental details

Crystal data
Chemical formula	[V₂(C₁₆H₁₈N₂O₂)₂O₃]
M_r	690.53
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	150
a, b, c (Å)	15.5603 (11), 20.7953 (11), 10.4197 (6)
β (°)	107.622 (3)
V (Å³)	3213.4 (3)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.63
Crystal size (mm)	0.2 × 0.15 × 0.05

Data collection
Diffractometer	Bruker Venture Kappa D8
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.609, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	7304, 3713, 3253
R_int	0.038
(sin θ/λ)_max (Å⁻¹)	0.651

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.043, 0.100, 1.08
No. of reflections	3713
No. of parameters	204
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.50, −0.42
Computer programs: APEX5 (Bruker, 2023 ), SAINT (Bruker, 2020 ), SHELXT (Sheldrick, 2015a ), SHELXL2019/2 (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Supporting information

CCDC reference: 2492548

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989025008631/tx2104sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989025008631/tx2104Isup3.hkl

checkCIF report

Computing details top

µ-Oxido-bis[(2,2'-{[ethane-1,2-diylbis(azanediyl)]bis(methylene)}diphenolato)oxidovanadium(V)] top

Crystal data top

[V₂(C₁₆H₁₈N₂O₂)₂O₃]	F(000) = 1432
M_r = 690.53	D_x = 1.427 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 15.5603 (11) Å	Cell parameters from 9335 reflections
b = 20.7953 (11) Å	θ = 2.3–27.3°
c = 10.4197 (6) Å	µ = 0.63 mm⁻¹
β = 107.622 (3)°	T = 150 K
V = 3213.4 (3) Å³	Prism, green
Z = 4	0.2 × 0.15 × 0.05 mm

Data collection top

Bruker Venture Kappa D8 diffractometer	3253 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.038
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	θ_max = 27.6°, θ_min = 2.3°
T_min = 0.609, T_max = 0.746	h = −20→15
7304 measured reflections	k = −16→27
3713 independent reflections	l = −13→13

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.043	H-atom parameters constrained
wR(F²) = 0.100	w = 1/[σ²(F_o²) + (0.0367P)² + 5.1463P] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max = 0.001
3713 reflections	Δρ_max = 0.50 e Å⁻³
204 parameters	Δρ_min = −0.41 e Å⁻³
0 restraints

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
V1	0.39689 (2)	0.41197 (2)	0.62885 (3)	0.02216 (11)
O1	0.43353 (9)	0.47851 (7)	0.58524 (14)	0.0269 (3)
O2	0.500000	0.38221 (9)	0.750000	0.0241 (4)
O3	0.39756 (10)	0.35637 (7)	0.49145 (14)	0.0284 (3)
O4	0.27065 (9)	0.43015 (7)	0.54986 (14)	0.0258 (3)
N1	0.33431 (12)	0.32747 (8)	0.70801 (17)	0.0266 (4)
H1	0.269592	0.324980	0.652277	0.032*
N2	0.36955 (12)	0.45416 (8)	0.79859 (17)	0.0261 (4)
H2	0.428501	0.455870	0.871711	0.031*
C1	0.39372 (13)	0.29241 (11)	0.4713 (2)	0.0282 (5)
C2	0.38266 (14)	0.24750 (10)	0.5653 (2)	0.0291 (5)
C3	0.38420 (15)	0.18215 (11)	0.5338 (3)	0.0380 (6)
H3	0.377546	0.151094	0.597010	0.046*
C4	0.39509 (16)	0.16141 (12)	0.4138 (3)	0.0440 (6)
H4	0.396727	0.116724	0.395741	0.053*
C5	0.40354 (16)	0.20579 (13)	0.3209 (3)	0.0446 (6)
H5	0.409930	0.191767	0.237450	0.054*
C6	0.40278 (15)	0.27119 (12)	0.3483 (2)	0.0371 (5)
H6	0.408434	0.301655	0.283367	0.045*
C7	0.37424 (15)	0.26437 (10)	0.7020 (2)	0.0317 (5)
H7A	0.336911	0.231242	0.727944	0.038*
H7B	0.434944	0.263112	0.768910	0.038*
C8	0.33584 (16)	0.34377 (11)	0.8470 (2)	0.0330 (5)
H8A	0.397075	0.336843	0.909913	0.040*
H8B	0.293264	0.315829	0.875163	0.040*
C9	0.30904 (15)	0.41335 (11)	0.8504 (2)	0.0312 (5)
H9A	0.245738	0.419340	0.794063	0.037*
H9B	0.313738	0.426014	0.943839	0.037*
C10	0.33729 (14)	0.52175 (10)	0.7745 (2)	0.0288 (5)
H10A	0.385972	0.548440	0.759261	0.035*
H10B	0.325105	0.538053	0.856602	0.035*
C11	0.25374 (14)	0.52991 (10)	0.6570 (2)	0.0266 (4)
C12	0.22502 (13)	0.48466 (10)	0.5526 (2)	0.0242 (4)
C13	0.14539 (14)	0.49649 (12)	0.4483 (2)	0.0313 (5)
H13	0.124709	0.465859	0.378091	0.038*
C14	0.09655 (16)	0.55215 (13)	0.4464 (2)	0.0409 (6)
H14	0.042555	0.559364	0.375081	0.049*
C15	0.12568 (17)	0.59750 (13)	0.5475 (2)	0.0430 (6)
H15	0.092928	0.636278	0.544961	0.052*
C16	0.20313 (16)	0.58549 (11)	0.6523 (2)	0.0340 (5)
H16	0.222328	0.616015	0.723077	0.041*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
V1	0.02398 (18)	0.02299 (19)	0.01842 (17)	−0.00135 (13)	0.00478 (13)	−0.00123 (13)
O1	0.0274 (7)	0.0273 (8)	0.0236 (7)	−0.0011 (6)	0.0042 (6)	0.0024 (6)
O2	0.0246 (10)	0.0222 (10)	0.0240 (10)	0.000	0.0050 (8)	0.000
O3	0.0335 (8)	0.0279 (8)	0.0229 (7)	−0.0009 (6)	0.0073 (6)	−0.0031 (6)
O4	0.0248 (7)	0.0269 (7)	0.0231 (7)	−0.0015 (6)	0.0035 (6)	−0.0035 (6)
N1	0.0266 (9)	0.0261 (9)	0.0282 (9)	−0.0001 (7)	0.0099 (7)	0.0008 (7)
N2	0.0268 (9)	0.0287 (9)	0.0208 (8)	0.0027 (7)	0.0042 (7)	−0.0019 (7)
C1	0.0206 (10)	0.0308 (11)	0.0307 (11)	−0.0003 (8)	0.0043 (8)	−0.0086 (9)
C2	0.0217 (10)	0.0281 (11)	0.0364 (12)	−0.0029 (8)	0.0068 (9)	−0.0049 (9)
C3	0.0279 (11)	0.0293 (12)	0.0572 (15)	−0.0028 (9)	0.0135 (11)	−0.0076 (11)
C4	0.0303 (12)	0.0329 (13)	0.0693 (18)	−0.0028 (10)	0.0159 (12)	−0.0198 (13)
C5	0.0315 (12)	0.0508 (16)	0.0537 (15)	−0.0040 (11)	0.0160 (11)	−0.0275 (13)
C6	0.0313 (12)	0.0435 (14)	0.0372 (12)	−0.0016 (10)	0.0114 (10)	−0.0121 (11)
C7	0.0336 (11)	0.0250 (11)	0.0369 (12)	−0.0025 (9)	0.0115 (10)	0.0013 (9)
C8	0.0389 (12)	0.0345 (12)	0.0285 (11)	0.0004 (10)	0.0147 (10)	0.0037 (9)
C9	0.0349 (12)	0.0376 (13)	0.0233 (10)	0.0017 (10)	0.0121 (9)	0.0000 (9)
C10	0.0300 (11)	0.0288 (11)	0.0243 (10)	0.0026 (9)	0.0034 (8)	−0.0061 (9)
C11	0.0277 (10)	0.0304 (11)	0.0224 (10)	0.0014 (9)	0.0083 (8)	0.0015 (8)
C12	0.0233 (9)	0.0267 (11)	0.0233 (10)	−0.0009 (8)	0.0079 (8)	0.0006 (8)
C13	0.0286 (11)	0.0388 (13)	0.0246 (10)	−0.0010 (9)	0.0053 (9)	−0.0015 (9)
C14	0.0318 (12)	0.0515 (16)	0.0346 (12)	0.0129 (11)	0.0028 (10)	0.0051 (11)
C15	0.0444 (14)	0.0453 (15)	0.0364 (13)	0.0172 (12)	0.0079 (11)	0.0006 (11)
C16	0.0394 (12)	0.0336 (12)	0.0285 (11)	0.0069 (10)	0.0093 (9)	−0.0022 (9)

Geometric parameters (Å, º) top

V1—O1	1.6134 (14)	C5—C6	1.390 (3)
V1—O2	1.8233 (8)	C6—H6	0.9500
V1—O3	1.8427 (14)	C7—H7A	0.9900
V1—O4	1.9235 (14)	C7—H7B	0.9900
V1—N1	2.2809 (17)	C8—H8A	0.9900
V1—N2	2.1295 (17)	C8—H8B	0.9900
O3—C1	1.345 (3)	C8—C9	1.509 (3)
O4—C12	1.343 (2)	C9—H9A	0.9900
N1—H1	1.0000	C9—H9B	0.9900
N1—C7	1.461 (3)	C10—H10A	0.9900
N1—C8	1.481 (3)	C10—H10B	0.9900
N2—H2	1.0000	C10—C11	1.502 (3)
N2—C9	1.485 (3)	C11—C12	1.405 (3)
N2—C10	1.488 (3)	C11—C16	1.391 (3)
C1—C2	1.401 (3)	C12—C13	1.401 (3)
C1—C6	1.403 (3)	C13—H13	0.9500
C2—C3	1.400 (3)	C13—C14	1.381 (3)
C2—C7	1.511 (3)	C14—H14	0.9500
C3—H3	0.9500	C14—C15	1.384 (4)
C3—C4	1.381 (4)	C15—H15	0.9500
C4—H4	0.9500	C15—C16	1.382 (3)
C4—C5	1.373 (4)	C16—H16	0.9500
C5—H5	0.9500

O1—V1—O2	100.03 (7)	C1—C6—H6	119.8
O1—V1—O3	103.52 (7)	C5—C6—C1	120.3 (2)
O1—V1—O4	96.49 (7)	C5—C6—H6	119.8
O1—V1—N1	171.30 (7)	N1—C7—C2	114.10 (18)
O1—V1—N2	93.27 (7)	N1—C7—H7A	108.7
O2—V1—O3	96.56 (6)	N1—C7—H7B	108.7
O2—V1—O4	158.99 (5)	C2—C7—H7A	108.7
O2—V1—N1	82.57 (6)	C2—C7—H7B	108.7
O2—V1—N2	85.41 (5)	H7A—C7—H7B	107.6
O3—V1—O4	92.07 (6)	N1—C8—H8A	110.0
O3—V1—N1	84.32 (6)	N1—C8—H8B	110.0
O3—V1—N2	162.44 (7)	N1—C8—C9	108.62 (18)
O4—V1—N1	79.26 (6)	H8A—C8—H8B	108.3
O4—V1—N2	80.76 (6)	C9—C8—H8A	110.0
N2—V1—N1	78.61 (7)	C9—C8—H8B	110.0
V1—O2—V1ⁱ	140.32 (12)	N2—C9—C8	109.24 (17)
C1—O3—V1	136.97 (14)	N2—C9—H9A	109.8
C12—O4—V1	129.42 (12)	N2—C9—H9B	109.8
V1—N1—H1	107.2	C8—C9—H9A	109.8
C7—N1—V1	116.28 (13)	C8—C9—H9B	109.8
C7—N1—H1	107.2	H9A—C9—H9B	108.3
C7—N1—C8	111.48 (17)	N2—C10—H10A	108.7
C8—N1—V1	107.17 (13)	N2—C10—H10B	108.7
C8—N1—H1	107.2	N2—C10—C11	114.12 (17)
V1—N2—H2	106.2	H10A—C10—H10B	107.6
C9—N2—V1	111.98 (13)	C11—C10—H10A	108.7
C9—N2—H2	106.2	C11—C10—H10B	108.7
C9—N2—C10	112.48 (16)	C12—C11—C10	123.35 (18)
C10—N2—V1	113.04 (12)	C16—C11—C10	117.61 (19)
C10—N2—H2	106.2	C16—C11—C12	119.05 (19)
O3—C1—C2	124.03 (19)	O4—C12—C11	122.41 (18)
O3—C1—C6	116.2 (2)	O4—C12—C13	118.75 (18)
C2—C1—C6	119.8 (2)	C13—C12—C11	118.84 (19)
C1—C2—C7	124.62 (19)	C12—C13—H13	119.6
C3—C2—C1	118.0 (2)	C14—C13—C12	120.8 (2)
C3—C2—C7	117.3 (2)	C14—C13—H13	119.6
C2—C3—H3	119.0	C13—C14—H14	119.7
C4—C3—C2	122.1 (2)	C13—C14—C15	120.5 (2)
C4—C3—H3	119.0	C15—C14—H14	119.7
C3—C4—H4	120.2	C14—C15—H15	120.5
C5—C4—C3	119.6 (2)	C16—C15—C14	119.0 (2)
C5—C4—H4	120.2	C16—C15—H15	120.5
C4—C5—H5	119.9	C11—C16—H16	119.1
C4—C5—C6	120.3 (2)	C15—C16—C11	121.8 (2)
C6—C5—H5	119.9	C15—C16—H16	119.1

V1—O3—C1—C2	3.4 (3)	C1—C2—C3—C4	−0.8 (3)
V1—O3—C1—C6	−175.72 (15)	C1—C2—C7—N1	29.0 (3)
V1—O4—C12—C11	−26.4 (3)	C2—C1—C6—C5	−1.9 (3)
V1—O4—C12—C13	154.26 (15)	C2—C3—C4—C5	−0.9 (4)
V1—N1—C7—C2	−51.4 (2)	C3—C2—C7—N1	−154.50 (19)
V1—N1—C8—C9	41.95 (19)	C3—C4—C5—C6	1.2 (4)
V1—N2—C9—C8	40.7 (2)	C4—C5—C6—C1	0.2 (4)
V1—N2—C10—C11	57.6 (2)	C6—C1—C2—C3	2.2 (3)
O1—V1—O2—V1ⁱ	30.44 (5)	C6—C1—C2—C7	178.6 (2)
O1—V1—O3—C1	163.55 (19)	C7—N1—C8—C9	170.24 (17)
O2—V1—O3—C1	61.6 (2)	C7—C2—C3—C4	−177.5 (2)
O3—V1—O2—V1ⁱ	135.47 (5)	C8—N1—C7—C2	−174.60 (17)
O3—C1—C2—C3	−176.9 (2)	C9—N2—C10—C11	−70.4 (2)
O3—C1—C2—C7	−0.5 (3)	C10—N2—C9—C8	169.30 (17)
O3—C1—C6—C5	177.2 (2)	C10—C11—C12—O4	−0.2 (3)
O4—V1—O2—V1ⁱ	−110.90 (19)	C10—C11—C12—C13	179.2 (2)
O4—V1—O3—C1	−99.3 (2)	C10—C11—C16—C15	179.4 (2)
O4—C12—C13—C14	−179.5 (2)	C11—C12—C13—C14	1.1 (3)
N1—V1—O2—V1ⁱ	−141.16 (4)	C12—C11—C16—C15	−0.3 (3)
N1—V1—O3—C1	−20.27 (19)	C12—C13—C14—C15	0.2 (4)
N1—C8—C9—N2	−55.6 (2)	C13—C14—C15—C16	−1.6 (4)
N2—V1—O2—V1ⁱ	−62.07 (5)	C14—C15—C16—C11	1.7 (4)
N2—V1—O3—C1	−34.0 (3)	C16—C11—C12—O4	179.58 (19)
N2—C10—C11—C12	−20.3 (3)	C16—C11—C12—C13	−1.1 (3)
N2—C10—C11—C16	159.96 (19)

Symmetry code: (i) −x+1, y, −z+3/2.

Acknowledgements

Experimental work was carried out in the Chemistry & Biochemistry Department, College of Science at California State Polytechnic University in Pomona. AJ and SCES would like to acknowledge the Provost's Teacher–Scholar award for facilitating research activities.

Funding information

Funding for this research was provided by: National Science Foundation, Directorate for Mathematical and Physical Sciences (grant No. 2400361 to Alex John; award No. 1847926 to SCES; award No. 1040566); Agricultural Research Institute, California State University (award No. 26-04-116 to A. John).

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