A copper complex of an unusual hy­droxy–carboxyl­ate ligand: [Cu(bpy)(C4H4O6)]

Gao, S.; Fronczek, F.R.; Maverick, A.W.

doi:10.1107/S2056989021001286

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ISSN: 2056-9890

Volume 77| Part 3| March 2021| Pages 282-285

https://doi.org/10.1107/S2056989021001286

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A copper complex of an unusual hydroxy–carboxylate ligand: [Cu(bpy)(C₄H₄O₆)]

Sen Gao,^a Frank R. Fronczek ^a and Andrew W. Maverick ^a ^*

^aDepartment of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
^*Correspondence e-mail: maverick@lsu.edu

Edited by S. Parkin, University of Kentucky, USA (Received 14 January 2021; accepted 2 February 2021; online 19 February 2021)

A copper(II) complex, (2,2′-bipyridine-κ²N,N′)[2-hydroxy-2-(hydroxymethyl-κO)propanedioato-κ²O¹,O³]copper(II), [Cu(C₄H₄O₆)(C₁₀H₈N₂)], containing the unusual anionic chelating ligand 2-(hydroxymethyl)tartronate, has been synthesized. [Cu(bpy)₂(NO₃)](NO₃) was mixed with ascorbic acid and Dabco (1,4-diazabicyclo[2.2.2]octane) in DMF (dimethylformamide) solution in the presence of air to produce the title compound. The structure consists of square-pyramidal complexes that are joined by Cu⋯O contacts [2.703 (2) Å] into centrosymmetric dimers. The C₄H₄O₆²⁻ ligand, which occupies three coordination sites at Cu, has previously been identified as an oxidation product of ascorbate ion.

Keywords: crystal structure; copper(II) complex; tartronate; square pyramidal; dimerization.

CCDC reference: 1966752

1. Chemical context

Copper complexes have drawn recent attention owing to applications in redox reactions (Zubair et al., 2019 ; Maity et al., 2010 ; Wang et al., 2006 ) and oxygen transport (Sheykhi et al., 2018 ; Liu et al., 2016 ; Tadsanaprasittipol et al., 1998 ; Kato et al., 2016 ). The 2,2′-bipyridine ligand has been used in a variety of supramolecular architectures (Fei et al., 2013 ; John et al., 2004 ; Seco et al., 2000 ; Barquín et al., 2010 ; Yuan et al., 2008 ).

As a common reducing reagent, ascorbic acid has also been investigated in complex synthesis and redox reactions (Creutz, 1981 ; Niemelä, 1987 ; Sorouraddin et al., 2000 ). For example, we have recently observed that mixtures of Cu complexes and ascorbate react with O₂ to produce Cu^II oxalate complexes (Khamespanah et al., 2021 ). However, to our knowledge, the particular degradation product of ascorbic acid observed here, 2-(hydroxymethyl)tartronic acid [2-(hydroxymethyl)-2-hydroxy-1,3-propanedioic acid], has been reported only a few times. It was identified by mass spectrometry as a product of oxidation of ascorbic acid (Niemelä, 1987; Löwendahl & Petersson, 1976 ) and two carbohydrates (Löwendahl et al., 1975a ,b ). We have now isolated compound (I), a copper(II) complex of the 2-(hydroxymethyl)tartronate anion (see Scheme), and its crystal structure is reported here.

The preparation of the title complex is shown in Fig. 1. A solution of [(bpy)₂Cu(ONO₂)]NO₃ and Dabco (1,4-diazabicyclo[2.2.2]octane) turned from blue to dark brown on addition of ascorbic acid, suggesting reduction of Cu^II to Cu^I. The solution was then exposed to air. It turned green over a period of several days, and the title compound (I) could be crystallized (Fig. 2).

Figure 1
Preparation of the title compound, Cu(bpy)(C₄H₄O₆) (I)

, with [DabcoH₂](NO₃)₂ (II) as byproduct.

Figure 2
Crystal structure of (I)

. Ellipsoids are drawn at the 50% probability level; hydrogen atoms are displayed but not labeled. Primed and unprimed atoms are related by an inversion center, which brings the two square-pyramidal Cu(bpy)(C₄H₄O₆) moieties into contact [Cu⋯O1′ = 2.703 (2) Å]. The inset is a schematic illustration of the dimerization.

In this procedure, Dabco also crystallizes, in its doubly protonated form as colorless [DabcoH₂](NO₃)₂ (II). We could not isolate the title compound (I) when Dabco was omitted from the reaction mixture. We determined the structure of (II) as well (Gao et al., 2020 ). Although this structure was reported previously by Knope & Cahill (2007 ), the new structure provides improved resolution.

2. Structural commentary

The Cu atom in (I) adopts a square-pyramidal geometry, with coordination to two bpy N atoms and three O atoms from the 2-(hydroxymethyl)tartronate anion (C₄H₄O₆^2–).

The two inversion-related complexes in the unit cell make a dimer via two Cu⋯O contacts: Cu1⋯O1′ = 2.703 (2) Å. This kind of dimerization (see inset in Fig. 2) is commonly observed in 4- and 5-coordinate Cu^II complexes. It is discussed further in the Database survey section.

3. Supramolecular features

The structure of (I) includes two O—H⋯O hydrogen bonds, one intramolecular and one intermolecular; see Table 1. The intermolecular hydrogen bonds form centrosymmetric hydrogen-bonded dimers with graph set R₂²(12) (Etter et al., 1990 ). These dimers are linked into chains in the [100] direction, as illustrated in Fig. 3.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2O⋯O4ⁱ	0.88 (2)	1.85 (2)	2.723 (3)	169 (4)
O5—H5O⋯O6	0.93 (2)	1.80 (3)	2.549 (3)	136 (3)
Symmetry code: (i) .

Figure 3
Packing structure of (I)

, showing the intermolecular O2—H2O⋯O4 hydrogen bonds.

4. Database survey

A survey of the Cambridge Structural Database (Version 5.40; Groom et al., 2016 ) yielded four five-coordinate Cu^II complexes with 2,2′-bipyridine, one alcohol, and two carboxylate ligands [CSD refcodes DAXVED (Antolini et al., 1984 ), SEKXAI (Devereux et al., 2006 ), TERTEQ (Ma et al., 2006 ), and VAJTIL (Zhang et al., 2010 )]. The Cu atoms in these structures have a square-pyramidal geometry, with the alcohol ligand in the apical position, as in (I), with the following average angles and distances: N—Cu—N, 81.3 (10)°; Cu—N, 2.004 (13) Å; Cu—O(carboxylate), 1.949 (15) Å; and Cu—O(alcohol), 2.32 (6) Å. These are similar to values in (I): N—Cu—N, 81.35 (9)°; Cu—N, 1.985 (2), 1.990 (2) Å; Cu—O, 1.9587 (19), 1.935 (2), and 2.384 (2) Å, respectively.

Another group of structures closely related to (I) is Cu(bpy)(malonate) (malonate = 1,3-propanedioate); see Fig. 4. There are 14 such structures in the CSD, in all of which [as in (I)] the malonate C—O bonds are bent significantly out of the CuN₂O₂ coordination plane. Of these, seven [FIXDUM (Cui et al., 2005 ), SAYCUQ (Gasque et al., 1998 ), TIPZAT02 (Cernak, 2016 ), UNOJOY, UNOJUE, UNOKAL (Jaramillo-García et al., 2016 ), and XECFOC (Manochitra et al., 2012 )] are monomeric, with R₂ = H and syn H₂O ligands [Fig. 4(b)]. This arrangement is similar to that observed in the Cu(bpy)(C₄H₄O₆) moiety of (I), except that (I) contains an apical alcohol ligand rather than H₂O. Because the alcohol in (I) is part of a small chelate ring, its coordination is bent slightly away from perpendicularity to the CuO₂N₂ plane [N1—Cu1—O2 104.04 (9), N2—Cu1—O2 91.77 (9)°]; the average N—Cu—OH₂ angle in the above seven published structures is 93 (3)°.

Figure 4
Generalized structures of [Cu(bpy)(malonate)] complexes: (a) showing the typical bending of the malonate ligand, with syn and anti coordination sites; (b) an example with H₂O in the syn position, as can occur when R₂ is small.

In four structures [PUJJUC (Ghosh et al., 2020 ), CIJNEQ (Dey et al., 2013 ), MEHYON (Guan et al., 1998a ,b ), and WAHVOR (Pasán et al., 2004 )], bulky R₂ groups prevent syn coordination, and there are anti H₂O ligands. In four structures [PUJJUC (Ghosh et al., 2020), CELSIW01 (Reinoso et al., 2007 ), CIJNEQ (Dey et al., 2013), and PESBAR (Baldomá et al., 2006 )], dimers form as illustrated in Fig. 2, with Cu⋯O distances ranging from 2.315 (2) to 2.494 (3) Å. (Note: PUJJUC and CIJNEQ each contain two molecules in the asymmetric unit, one a five-coordinate monomer and the other a dimer of four-coordinate complexes.) As far as we are aware, the present complex [Cu(bpy)(C₄H₄O₆)] (I) is the only example of a Cu(bpy)(malonate) in which a five-coordinate species dimerizes. Our structure shows a considerably larger Cu⋯O distance in its dimers than the above four published examples. This is likely because of the apical alcohol ligand in (I): a five-coordinate species is less likely to form strong Cu⋯O associations than a four-coordinate species.

5. Synthesis and crystallization

General procedures. Reagents were used as received, from Sigma–Aldrich. FTIR spectra were recorded on a Bruker Tensor 27 spectrometer in attenuated total reflectance mode.

Synthesis of Cu(bpy)(C₄H₄O₆). To a mixture of [Cu(bpy)₂(NO₃)](NO₃) (Marjani et al., 2005 ) (25.5 mg, 0.075 mmol, in 2 mL of DMF) and Dabco (8.4 mg, 0.075 mmol, in 1 mL of DMF), ascorbic acid (13.2 mg, 0.075 mmol, in 1 mL of DMF) was added. The mixture turned to dark brownish-red. It was stirred for two days in air, during which time it turned green, and filtered. The filtrate was used for vapor diffusion with diethyl ether. Crystals of Cu(bpy)(C₄H₄O₆) [(I), blue] and [DabcoH₂](NO₃)₂ [(II), colorless] formed, which were suitable for X-ray analysis.

Cu(bpy)(C₄H₄O₆). FTIR (cm⁻¹) 3036m, 2853w, 1704s, 1667m, 1612m, 1412m, 1391m, 1362m, 1312m, 1204s, 1149s, 1055m, 1036m, 778m, 732m, 639w.

6. Refinement

Crystal data, data collection, and structure refinement are summarized in Table 2. All H atoms were visible in difference-Fourier maps. Coordinates of those on O were refined with O—H distances restrained to 0.88 (2) Å. Those on C were positioned geometrically (C—H = 0.95 Å for aromatic C, 0.99 Å for CH₂) and treated as riding. Displacement parameters for H were assigned as U_eq(H) = 1.2U_eq(C) and 1.5U_eq(O).

Table 2
Experimental details

Crystal data
Chemical formula	[Cu(C₄H₄O₆)(C₁₀H₈N₂)]
M_r	367.80
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	90
a, b, c (Å)	7.6516 (5), 9.9272 (6), 10.0722 (6)
α, β, γ (°)	95.204 (4), 107.729 (4), 111.462 (4)
V (Å³)	660.34 (7)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	1.69
Crystal size (mm)	0.15 × 0.09 × 0.07

Data collection
Diffractometer	Bruker Kappa APEXII DUO CCD
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.838, 0.891
No. of measured, independent and observed [I > 2σ(I)] reflections	18442, 4041, 2675
R_int	0.063
(sin θ/λ)_max (Å⁻¹)	0.715

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.105, 1.02
No. of reflections	4041
No. of parameters	214
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.74, −0.56
Computer programs: APEX3 and SAINT (Bruker, 2016 ), SHELXT2014/5 (Sheldrick, 2015a ), SHELXL2014/7 (Sheldrick, 2015b ), Mercury (Macrae et al., 2020 ), and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1966752

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989021001286/pk2655sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989021001286/pk2655Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT2014/5 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2020); software used to prepare material for publication: publCIF (Westrip, 2010).

(2,2'-Bipyridine-κ²N,N')[2-hydroxy-2-(hydroxymethyl-κO)propanedioato-κ²O¹,O³]copper(II) top

Crystal data top

[Cu(C₄H₄O₆)(C₁₀H₈N₂)]	Z = 2
M_r = 367.80	F(000) = 374
Triclinic, P1	D_x = 1.850 Mg m⁻³
a = 7.6516 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.9272 (6) Å	Cell parameters from 3354 reflections
c = 10.0722 (6) Å	θ = 2.2–29.3°
α = 95.204 (4)°	µ = 1.69 mm⁻¹
β = 107.729 (4)°	T = 90 K
γ = 111.462 (4)°	Fragment, light blue
V = 660.34 (7) Å³	0.15 × 0.09 × 0.07 mm

Data collection top

Bruker Kappa APEXII DUO CCD diffractometer	4041 independent reflections
Radiation source: fine-focus sealed tube	2675 reflections with I > 2σ(I)
TRIUMPH curved graphite monochromator	R_int = 0.063
φ and ω scans	θ_max = 30.6°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −10→10
T_min = 0.838, T_max = 0.891	k = −14→14
18442 measured reflections	l = −14→14

Refinement top

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)] = 0.049	Hydrogen site location: mixed
wR(F²) = 0.105	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ²(F_o²) + (0.0436P)² + 0.3982P] where P = (F_o² + 2F_c²)/3
4041 reflections	(Δ/σ)_max < 0.001
214 parameters	Δρ_max = 0.74 e Å⁻³
2 restraints	Δρ_min = −0.56 e Å⁻³

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
Cu1	0.60628 (6)	0.63056 (4)	0.41304 (4)	0.01841 (12)
O1	0.7261 (3)	0.5158 (2)	0.52799 (19)	0.0200 (5)
O2	0.9188 (3)	0.7153 (3)	0.3763 (2)	0.0247 (5)
H2O	0.931 (6)	0.635 (3)	0.346 (4)	0.037*
O3	0.7221 (3)	0.7944 (2)	0.5778 (2)	0.0241 (5)
O4	0.9916 (3)	0.5149 (2)	0.6990 (2)	0.0239 (5)
O5	1.2089 (3)	0.8062 (3)	0.7594 (2)	0.0296 (5)
H5O	1.178 (6)	0.869 (4)	0.813 (3)	0.044*
O6	0.9741 (4)	0.9263 (3)	0.7840 (2)	0.0337 (6)
N1	0.4537 (4)	0.7282 (3)	0.2933 (2)	0.0170 (5)
N2	0.4699 (4)	0.4750 (3)	0.2317 (2)	0.0166 (5)
C1	0.4522 (5)	0.8585 (3)	0.3373 (3)	0.0201 (6)
H1	0.5308	0.9116	0.4337	0.024*
C2	0.3410 (5)	0.9188 (3)	0.2483 (3)	0.0217 (7)
H2	0.3409	1.0109	0.2833	0.026*
C3	0.2293 (4)	0.8435 (3)	0.1071 (3)	0.0195 (6)
H3	0.1527	0.8836	0.0433	0.023*
C4	0.2309 (4)	0.7080 (3)	0.0597 (3)	0.0180 (6)
H4	0.1567	0.6548	−0.0372	0.022*
C5	0.3422 (4)	0.6519 (3)	0.1558 (3)	0.0142 (6)
C6	0.3512 (4)	0.5078 (3)	0.1208 (3)	0.0142 (6)
C7	0.2500 (4)	0.4119 (3)	−0.0127 (3)	0.0155 (6)
H7	0.1676	0.4365	−0.0892	0.019*
C8	0.2703 (4)	0.2792 (3)	−0.0335 (3)	0.0180 (6)
H8	0.2000	0.2107	−0.1239	0.022*
C9	0.3938 (5)	0.2480 (3)	0.0789 (3)	0.0191 (6)
H9	0.4109	0.1583	0.0665	0.023*
C10	0.4924 (4)	0.3482 (3)	0.2098 (3)	0.0180 (6)
H10	0.5788	0.3267	0.2866	0.022*
C11	0.9051 (5)	0.5800 (3)	0.6238 (3)	0.0217 (7)
C12	1.0222 (5)	0.7493 (4)	0.6426 (3)	0.0247 (7)
C13	0.8962 (5)	0.8297 (4)	0.6718 (3)	0.0258 (7)
C14	1.0784 (5)	0.7878 (4)	0.5103 (3)	0.0284 (7)
H14A	1.1263	0.8965	0.5195	0.034*
H14B	1.1917	0.7614	0.5117	0.034*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.0245 (2)	0.0195 (2)	0.00897 (15)	0.01379 (17)	−0.00134 (13)	−0.00131 (13)
O1	0.0255 (12)	0.0221 (12)	0.0104 (9)	0.0137 (10)	−0.0002 (8)	0.0018 (8)
O2	0.0272 (12)	0.0276 (13)	0.0172 (10)	0.0135 (11)	0.0035 (9)	0.0032 (9)
O3	0.0257 (12)	0.0268 (13)	0.0147 (10)	0.0143 (11)	−0.0012 (9)	−0.0040 (9)
O4	0.0247 (12)	0.0272 (12)	0.0202 (10)	0.0155 (10)	0.0031 (9)	0.0053 (9)
O5	0.0283 (13)	0.0337 (14)	0.0213 (11)	0.0169 (11)	−0.0006 (9)	−0.0024 (10)
O6	0.0366 (14)	0.0325 (14)	0.0221 (11)	0.0185 (12)	−0.0035 (10)	−0.0070 (10)
N1	0.0182 (13)	0.0181 (13)	0.0128 (10)	0.0084 (11)	0.0030 (9)	0.0005 (10)
N2	0.0212 (13)	0.0163 (13)	0.0129 (11)	0.0104 (11)	0.0045 (10)	0.0013 (10)
C1	0.0244 (17)	0.0168 (15)	0.0183 (13)	0.0108 (13)	0.0051 (12)	−0.0005 (12)
C2	0.0279 (18)	0.0163 (16)	0.0237 (15)	0.0138 (14)	0.0079 (13)	0.0037 (12)
C3	0.0195 (16)	0.0195 (16)	0.0223 (14)	0.0123 (13)	0.0052 (12)	0.0071 (12)
C4	0.0149 (15)	0.0242 (17)	0.0143 (13)	0.0095 (13)	0.0034 (11)	0.0031 (12)
C5	0.0136 (14)	0.0142 (14)	0.0145 (12)	0.0063 (12)	0.0046 (10)	0.0005 (11)
C6	0.0125 (14)	0.0167 (15)	0.0113 (12)	0.0060 (12)	0.0022 (10)	0.0019 (11)
C7	0.0116 (14)	0.0165 (15)	0.0140 (12)	0.0038 (12)	0.0020 (10)	0.0005 (11)
C8	0.0173 (15)	0.0170 (15)	0.0142 (12)	0.0039 (12)	0.0040 (11)	−0.0016 (11)
C9	0.0241 (16)	0.0142 (15)	0.0214 (14)	0.0101 (13)	0.0092 (12)	0.0022 (12)
C10	0.0202 (16)	0.0201 (16)	0.0155 (13)	0.0108 (13)	0.0056 (11)	0.0044 (12)
C11	0.0310 (18)	0.0229 (17)	0.0115 (12)	0.0158 (15)	0.0035 (12)	0.0006 (12)
C12	0.0257 (17)	0.0276 (18)	0.0162 (13)	0.0123 (15)	0.0010 (12)	0.0019 (13)
C13	0.0288 (18)	0.0260 (18)	0.0209 (15)	0.0149 (15)	0.0036 (13)	0.0015 (14)
C14	0.0271 (18)	0.0294 (19)	0.0235 (15)	0.0108 (16)	0.0049 (13)	0.0008 (14)

Geometric parameters (Å, º) top

Cu1—O3	1.935 (2)	C2—H2	0.9500
Cu1—O1	1.9587 (19)	C3—C4	1.391 (4)
Cu1—N1	1.985 (2)	C3—H3	0.9500
Cu1—N2	1.990 (2)	C4—C5	1.383 (4)
Cu1—O2	2.384 (2)	C4—H4	0.9500
O1—C11	1.288 (3)	C5—C6	1.474 (4)
O2—C14	1.417 (4)	C6—C7	1.381 (4)
O2—H2O	0.880 (18)	C7—C8	1.387 (4)
O3—C13	1.275 (4)	C7—H7	0.9500
O4—C11	1.236 (3)	C8—C9	1.377 (4)
O5—C12	1.417 (4)	C8—H8	0.9500
O5—H5O	0.929 (18)	C9—C10	1.380 (4)
O6—C13	1.236 (4)	C9—H9	0.9500
N1—C1	1.334 (4)	C10—H10	0.9500
N1—C5	1.355 (3)	C11—C12	1.549 (5)
N2—C10	1.339 (4)	C12—C13	1.532 (4)
N2—C6	1.358 (3)	C12—C14	1.558 (4)
C1—C2	1.375 (4)	C14—H14A	0.9900
C1—H1	0.9500	C14—H14B	0.9900
C2—C3	1.383 (4)

O3—Cu1—O1	91.06 (8)	N1—C5—C6	114.2 (2)
O3—Cu1—N1	91.97 (9)	C4—C5—C6	124.4 (2)
O1—Cu1—N1	173.29 (10)	N2—C6—C7	121.5 (3)
O3—Cu1—N2	173.32 (9)	N2—C6—C5	114.4 (2)
O1—Cu1—N2	95.56 (9)	C7—C6—C5	124.1 (2)
N1—Cu1—N2	81.35 (9)	C6—C7—C8	119.1 (3)
O3—Cu1—O2	90.05 (9)	C6—C7—H7	120.4
O1—Cu1—O2	81.94 (8)	C8—C7—H7	120.4
N1—Cu1—O2	104.04 (9)	C9—C8—C7	119.0 (3)
N2—Cu1—O2	91.77 (9)	C9—C8—H8	120.5
C11—O1—Cu1	120.61 (19)	C7—C8—H8	120.5
C14—O2—Cu1	108.93 (18)	C8—C9—C10	119.5 (3)
C14—O2—H2O	106 (2)	C8—C9—H9	120.3
Cu1—O2—H2O	106 (2)	C10—C9—H9	120.3
C13—O3—Cu1	121.7 (2)	N2—C10—C9	121.9 (3)
C12—O5—H5O	96 (2)	N2—C10—H10	119.1
C1—N1—C5	119.1 (2)	C9—C10—H10	119.1
C1—N1—Cu1	125.71 (19)	O4—C11—O1	124.3 (3)
C5—N1—Cu1	115.18 (19)	O4—C11—C12	117.9 (3)
C10—N2—C6	119.0 (2)	O1—C11—C12	117.8 (2)
C10—N2—Cu1	126.08 (19)	O5—C12—C13	108.3 (2)
C6—N2—Cu1	114.81 (18)	O5—C12—C11	111.3 (2)
N1—C1—C2	122.5 (3)	C13—C12—C11	109.2 (3)
N1—C1—H1	118.8	O5—C12—C14	105.0 (3)
C2—C1—H1	118.8	C13—C12—C14	110.5 (3)
C1—C2—C3	119.0 (3)	C11—C12—C14	112.4 (2)
C1—C2—H2	120.5	O6—C13—O3	125.2 (3)
C3—C2—H2	120.5	O6—C13—C12	117.0 (3)
C2—C3—C4	119.0 (3)	O3—C13—C12	117.8 (3)
C2—C3—H3	120.5	O2—C14—C12	114.7 (3)
C4—C3—H3	120.5	O2—C14—H14A	108.6
C5—C4—C3	119.0 (3)	C12—C14—H14A	108.6
C5—C4—H4	120.5	O2—C14—H14B	108.6
C3—C4—H4	120.5	C12—C14—H14B	108.6
N1—C5—C4	121.4 (3)	H14A—C14—H14B	107.6

C5—N1—C1—C2	0.1 (5)	C6—N2—C10—C9	−2.0 (4)
Cu1—N1—C1—C2	−179.4 (2)	Cu1—N2—C10—C9	−178.8 (2)
N1—C1—C2—C3	−1.3 (5)	C8—C9—C10—N2	0.8 (5)
C1—C2—C3—C4	0.8 (5)	Cu1—O1—C11—O4	−179.0 (2)
C2—C3—C4—C5	0.8 (4)	Cu1—O1—C11—C12	−1.0 (4)
C1—N1—C5—C4	1.5 (4)	O4—C11—C12—O5	−6.9 (4)
Cu1—N1—C5—C4	−178.9 (2)	O1—C11—C12—O5	175.0 (2)
C1—N1—C5—C6	−178.4 (3)	O4—C11—C12—C13	−126.3 (3)
Cu1—N1—C5—C6	1.2 (3)	O1—C11—C12—C13	55.6 (3)
C3—C4—C5—N1	−2.0 (4)	O4—C11—C12—C14	110.7 (3)
C3—C4—C5—C6	177.9 (3)	O1—C11—C12—C14	−67.4 (4)
C10—N2—C6—C7	1.6 (4)	Cu1—O3—C13—O6	−175.1 (3)
Cu1—N2—C6—C7	178.7 (2)	Cu1—O3—C13—C12	6.5 (4)
C10—N2—C6—C5	−178.2 (3)	O5—C12—C13—O6	1.0 (4)
Cu1—N2—C6—C5	−1.1 (3)	C11—C12—C13—O6	122.3 (3)
N1—C5—C6—N2	−0.1 (4)	C14—C12—C13—O6	−113.5 (3)
C4—C5—C6—N2	−179.9 (3)	O5—C12—C13—O3	179.6 (3)
N1—C5—C6—C7	−179.9 (3)	C11—C12—C13—O3	−59.1 (4)
C4—C5—C6—C7	0.3 (5)	C14—C12—C13—O3	65.1 (4)
N2—C6—C7—C8	0.0 (4)	Cu1—O2—C14—C12	19.3 (3)
C5—C6—C7—C8	179.8 (3)	O5—C12—C14—O2	167.8 (3)
C6—C7—C8—C9	−1.2 (4)	C13—C12—C14—O2	−75.7 (3)
C7—C8—C9—C10	0.8 (4)	C11—C12—C14—O2	46.6 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2O···O4ⁱ	0.88 (2)	1.85 (2)	2.723 (3)	169 (4)
O5—H5O···O6	0.93 (2)	1.80 (3)	2.549 (3)	136 (3)

Symmetry code: (i) −x+2, −y+1, −z+1.

Funding information

Funding for this research was provided by the West Professorship, Louisiana State University. The diffractometer purchase and upgrades were made possible by grants from the Louisiana Board of Regents.

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