Structure and magnetic properties of a copper(II) coordination polymer based on azide, pyridine and homophthalic acid

The azide anion is a short bridging ligand that has been used extensively to construct magnetic coordination polymers, and fundamental magneto-structural correlations have been substanti­ated by theoretical calculations. The copper(II) coordination polymer poly[bis­([mu]-azido-[kappa]²N¹:N¹)([mu]₄-homo­phthal­ato-[kappa]⁴O:O':O'':O''')bis­(pyridine-[kappa]N)dicopper(II)], [Cu₂(C₉H₆O₄)(N₃)₂(C₅H₅N)₂]_n, was synthesized from homophthalic acid (2-carb­oxy­phenyl­acetic acid), pyridine and azide (N₃^-) by a hydro­thermal reaction. Single-crystal structure analysis indicated that it features a one-dimensional chain structure which is comprised of ([mu]_1,1-N₃^-)([mu]-syn-syn-COO^-)₂- and ([mu]_1,1-N₃^-)₂-bridged tetra­nuclear Cu^II units. Magnetic measurements revealed that the compound exhibits dominant anti­ferromagnetic behaviour.

S1. Introduction

Magnetic coordination polymers (CPs) have aroused considerable inter­est with regard to understanding magnetic phenomena and fundamental magneto-structural correlations, as well as for their possible applications as functional magnetic materials (Wang, Avendano et al., 2011; Weng et al., 2011). The azide anion (N₃⁻), as a typical short bridging ligand, has been used extensively to construct magnetic CPs and fundamental magneto-structural correlations have been discovered and established, and also substanti­ated by theoretical calculations (Zeng et al., 2009). In general, the two common bridging modes observed for the azide ligand are µ_1,3-N₃⁻ (end-to-end, EE) and µ_1,1-N₃⁻ (end-on, EO). The former mainly mediates anti­ferromagnetic coupling, apart from a few exceptions where ferromagnetic coupling through this pathway was also discovered. The EO mode is known as both ferromagnetic and anti­ferromagnetic depending not only on the M—N—M bond angle, but also on the nature of the metal ion, i.e. the magnetic orbitals involved in each case. The azide anion often co-operates with other organic ligands to control its bridging mode and magnetic coupling type. Organic amines, Schiff bases, carboxyl­ates and nitro­gen heterocycles, including pyridine derivatives, as co-ligands have been used successfully in the construction of CPs with inter­esting architectures and magnetic properties (Zhang et al., 2014; Mandal et al., 2008; Biswas et al., 2010; Wang et al., 2009). Herein, homophthalic acid (H₂hmph) has been chosen as a co-ligand with N₃⁻ to occupy some coordination sites of the metal ion and the avoid bridging ligands further linking of the strands of the CPs, thus lowering the dimensionality of the obtained material. Pyridine (py) was also introduced into the system as a base to facilitate incorporation of the above ligands in the same complex. The coordination polymer, namely [Cu₂(hmph)(N₃)₂(py)₂]_n, (I), including hmph²⁻, N₃⁻ and py, was synthesized under hydro­thermal conditions.

S2. Experimental

CAUTION! The metal–azide compound is potentially explosive and should be handled with care and in small amounts. All chemicals used were obtained from commercial sources and used without further purification. Elemental analyses for C, H and N were carried out on a German Elementary Vario EL III instrument. The FT–IR spectra were performed on a Nicolet Magna 750 F T–IR spectrometer using KBr pellets in the range 4000–400 cm⁻¹. Thermogravimetric analysis was recorded on a NETZSCH STA 449 C unit at a heating rate of 10 K min⁻¹ under a nitro­gen atmosphere. The powder X-ray diffraction (XRD) patterns were collected by a Rigaku DMAX2500 X-ray diffractometer using Cu Kα radiation (λ = 0.154 nm). Magnetic data were obtained with a Quantum Design MPMS XL SQUID magnetometer. During the magnetic measurement, the powder sample was enwrapped by a film, then fixed in the capsule for measurement and the backgrounds of the film and capsule were corrected. Diamagnetic corrections for the complex were estimated from Pascal's constants.

S2.1. Synthesis and crystallization

A mixture of Cu(NO₃)₂·3H₂O (121 mg, 0.5 mmol) and H₂hmph (72 mg, 0.4 mmol) was dissolved in H₂O (10 ml). Afterwards, NaN₃ solution (0.5 ml, 1 mol l⁻¹) and pyridine (0.4 ml) were added into above solution dropwise under ultrasonic agitation until a black–green solution was obtained. The above solution was then sealed into a Pyrex tube. After heating at 358 K for 48 h, the solution yielded strip-shaped crystals of (I) which were collected and washed with water. The formation of compound (I) strongly depends on the synthetic conditions (stoichiometry of rea­cta­nts and temperature) and the synthetic procedure followed (yield 67%, based on NaN₃). Selected IR data (KBr pellet, cm⁻¹): 2071 (b), 1607 (b), 1543 (b), 1542 (m), 1486 (w), 1447 (b), 1399 (b), 1295 (w), 1067 (w), 730 (m), 696 (m), 636 (w). Analysis calculated (%) for C₁₉H₁₆Cu₂N₈O₄: C 41.68, H 2.95, N 20.47; found: C 41.50, H 2.92, N 20.11%.

S2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. H atoms were generated geometrically and held in the riding mode for the final refinement, with C—H = 0.95 (aromatic) or 0.99 Å (methyl­ene) and U_iso(H) = 1.2 U_eq (C).

S3. Results and discussion

X-ray single-crystal diffraction analysis reveals that [Cu₂(hmph)(N₃)₂(py)₂]_n, (I), crystallizes in the triclinic P1 space group. As shown in Fig. 1(a), the asymmetric unit comprises two crystallographically independent Cu^II ions (Cu1 and Cu2), one hmph²⁻ anion, two pyridine ligands and two azide anions. Each unique Cu^II ion lies in a slightly distorted square-pyramidal coordination environment. The four basal sites of atom Cu1 are occupied by two carboxyl­ate O atoms [O1A and O4; symmetry code: (A) −x, −y + 1, −z + 1] from two hmph²⁻ anions and two symmetry-equivalent N atoms [N6 and N6B;symmetry code: (B) −x + 1, −y, −z + 1] from two azide anions, while the apical site is ligated by one azide N atom (N5). The basal plane of atom Cu2 is composed of two pyridine N atoms (N1 and N2), one azide N atom (N5) and one carboxyl­ate O atom (O3), leaving the apical site occupied by one carboxyl­ate O atom (O2A). The two independent azide anions both adopt EO bridging modes. Atom N5 of an azide anion bridges Cu1 and Cu2 [Cu1—N5 = 2.244 (2) Å and Cu2—N5 = 1.978 (2) Å], while atom N6 atom of the other azide anion bridges two equivalent Cu1 atoms [Cu1—N6B = 1.996 (2) Å and Cu1—N6 = 2.009 (2) Å]. All the above Cu—N bond lengths match those observed in related compounds, though the Cu1—N5 bond length is longer than the others. Atoms Cu1 and Cu2 are triply bridged into a binuclear unit by one µ_1,1-N₃⁻ anion and two µ_1,1-syn-syn-COO⁻ groups, with the Cu1···Cu2 distance being 3.3271 (9) Å (Fig. 1b). Moreover, symmetry-equivalent atoms Cu1 and Cu1B are doubly bridged by two µ_1,1-N₃⁻ anions [Cu1···Cu1B = 3.1264 (10) Å; Fig. 1b]. The Cu1—N5—Cu2 and Cu1—N6—Cu1B angles (θ) are 103.80 (10) and 102.62 (9)°, respectively, in close agreement with the minimum energy for θ ≈ 100°, respectively (Ruiz et al., 1998). As a result, a tetra­nuclear Cu^II unit is formed by two triple bridges (µ_1,1-N₃⁻)(µ-syn-syn-COO⁻)₂ and one double bridges (µ_1,1-N₃⁻)₂ (Fig. 1b). Adjacent tetra­nuclear Cu^II units are doubly linked via two symmetry-equivalent hmph²⁻ anions, resulting in a one-dimensional chain (Fig. 1c).

Neighbouring chains inter­act weakly through C—H···π inter­actions between the C18–H18 group and the C3–C8 ring (Fig. 2 and Table 3), leading to a two-dimensional supra­molecular layer lying parallel to the ab plane (Fig. 3). The hmph²⁻ ligands are suspended from the two sides of the layers in up and down orientations. The Cg2···Cg2B [Cg2 is the centroid of the N1–C17 ring; symmetry code: (B) −x + 1, −y, −z + 2], with separation distance of 4.729 Å between neighbouring layers (Fig. 2). The perpendicular distances from Cg2 to the plane of the N1B–C17B ring is 3.825 Å. Possible weak π–π inter­actions between adjacent layers may contribute to the stability of the alignment of the layers along the c axis. Hydrogen bonds are observed between neighbouring layers (Fig. 4 and Table 4), which may play an important role in assembling the two-dimensional layers into a three-dimensional supra­molecular architecture (Fig. 5). The hydrogen bonds involve pyridine C–H groups as donors and terminal azide N atoms as acceptors, wherein N3C simultaneously accepts H atoms of the C15D—H15D and C19D—H19D groups, and atom N8 simultaneously accepts H atoms from the C19D—H19D and C18D—H18D groups (Fig. 4).

The combination of azide anion and co-ligand carboxyl­ate acid often afford mixed (µ_1,1-N₃⁻)(µ-syn-syn-COO⁻) (Gao et al., 2011; Wang, Zhang et al., 2011), (µ_1,1-N₃⁻)₂(µ-syn-syn-COO⁻) (Jia et al., 2011; Wang, Zhang et al., 2011; Ma et al., 2009) and (µ_1,1-N₃⁻)(µ-syn-syn-COO⁻)₂ (Wang, Sun et al., 2011; Wang et al., 2010) bridges. When nitro­gen heterocyclic rings are employed as co-ligands, (µ_1,1-N₃⁻)₂ bridges (Li et al., 2010; Cheng et al., 2014) are often obtained if the nitro­gen heterocyclic ring is disabled by bridging metal ions. The above bridges usually bring about one-dimensional infinite –M–bridges–M– chains. In this system, (µ_1,1-N₃⁻)(µ-syn-syn-COO⁻)₂ and (µ_1,1-N₃⁻)₂ are observed simultaneously in compound (I). But the generation of a (µ_1,1-N₃⁻)(µ-syn-syn-COO⁻)₂ and (µ_1,1-N₃⁻)₂ bridged tetra­nuclear Cu^II unit rather than an –M–bridges–M– chain is rare and unexpected.

The phase purity of (I) was confirmed by X-ray powder diffraction analysis (XRD; Fig. 6). The peak positions of observed XRD patterns are in good agreement with those simulated from single-crystal X-ray data, indicating that the pure phase is obtained. The thermal gravimetric analysis (TGA) was performed in the range 298–1073 K under a nitro­gen atmosphere. The TGA curve is shown in Fig. S1 (see Supporting information) and exhibits a short plateau from 298 to 453 K, with nearly no loss of weight and subsequently begins to decompose rapidly.

The variable-temperature magnetic susceptibilities (χ_M) of (I) were measured in the range 2–300 K under 1000 Oe. Plots of χ_MT, χ_M and 1/χ_M versus T of (I) are presented in Fig. 7. The χ_MT value of 0.482 cm⁻³ K mol⁻¹ per Cu^II ion at room temperature is larger than the expected value for an isolated Cu^II ion of spin S = 1/2 (the theoretical value is 0.375 cm³ K mol⁻¹ with g = 2) (Gao et al., 2011; Yan et al., 2011). Upon decreasing the temperature, the χ_MT value remains almost constant until about 110 K and below this temperature down to 30 K decreases moderately. The χ_MT value descends steeply upon further cooling and attained a value of 0.034 cm³ K mol⁻¹ at 2 K. The curve clearly indicates that dominant anti­ferromagnetic coupling is operating. In addition, the temperature dependence of χ_M⁻¹ follows the Curie–Weiss law above 10 K and the linear fit by the equation 1/χ_M = (T–θ)/C gives C = 0.491 cm³ K mol⁻¹ and θ = −4.531 K, which is consistent with the anti­ferromagnetic behaviour. In the structure of (I), the magneto-structure model of a tetra­nuclear Cu^II unit can be described as Cu2-J_A-Cu1-J_B-Cu1B-J_A-Cu2B, where J_B refers to the magnetic exchange mediated by the (µ_1,1-N₃⁻)₂ double bridges and J_A for the magnetic exchange mediated by the (µ_1,1-N₃⁻)(µ-syn-syn-COO⁻)₂ system. For Cu^II ions, EO-azide mediates ferromagnetic coupling for the angle of Cu^II–N₃(EO)–Cu^II below critical value (104° in theory and 108° in experiment) and syn–syn carboxyl­ate bridge usually transmits anti­ferromagnetic exchange inter­action. The ferromagnetic coupling is estimated between the (µ_1,1-N₃⁻)₂ bridged Cu1 and Cu1B due to Cu1—N6—Cu1B angle 102.63°, which can account for the large χ_MT value at room temperature. The coupling inter­action between Cu1 and Cu2 bridged by (µ_1,1-N₃⁻)(µ-syn-syn-COO⁻)₂ is ambiguous as µ_1,1-N₃⁻ [Cu1–N5–Cu2 = 103.80 (10)°] and µ-syn-syn-COO⁻ mediate contrary coupling inter­actions, wherein the sign and value for J_A depend on the result of the synergistic or competitive combination of these mechanisms. In view of the global anti­ferromagnetic nature of compound (I), (µ_1,1-N₃⁻)(µ-syn-syn-COO⁻)₂ will mediate anti­ferromagnetic coupling if the (µ_1,1-N₃⁻)₂ mediate ferromagnetic coupling.

In conclusion, a new coordination polymer, [Cu₂(hmph)(N₃)₂(py)₂]_n, (I), was synthesized successfully and characterized as a one-dimensional chain structure composed of tetra­nuclear Cu^II units bridged by (µ_1,1-N₃⁻)(µ-syn–syn-COO⁻)₂ and (µ_1,1-N₃⁻)₂, and exhibits dominant anti­ferromagnetic behaviour.

Computing details

Data collection: CrystalClear (Rigaku, 2007); cell refinement: CrystalClear (Rigaku, 2007); data reduction: CrystalClear (Rigaku, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: SHELXL97 (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The crystal structure of (I), showing (a) the coordination environment of the Cu^II ions, (b) the tetranuclear Cu^II unit and (c) the one-dimensional chain structure. All H atoms have been omitted for clarity. [Symmetry codes: (A) −x, −y + 1, −z + 1; (B) −x + 1, −y, −z + 1; (C) x + 1, y − 1, z.]
	Fig. 2. C—H···π interaction between adjacent chains and possilbe π–π interaction between neighboring layers in (I). [Symmetry codes: (A) −x + 1, −y + 1, −z + 1; (B) −x + 1, −y, −z + 2.]
	Fig. 3. Two-dimensional layer with C—H···π interactions (dashed lines) between two adjacent one-dimensional chains in (I).
	Fig. 4. The intermolecular C—H···N interactions (dashed lines) in (I). [Symmetry codes: (C) −x + 1, −y, −z + 1; (D) x, y, z − 1.]
	Fig. 5. A view of the three-dimensional supramolecular framework of (I) formed through weak interlayer C—H···N hydrogen-bond interactions (dashed lines).
	Fig. 6. The X-ray powder diffraction patterns of (I).
	Fig. 7. χM and χMT versus T curves for (I). Inset: χM^−1 versus T plot. The solid lines represent the best-fit curves.

Poly[bis(µ-azido-κ²N¹:N¹–)(µ₄-homophthalato-κ⁴O:O':O'':O''')bis(pyridine-κN)dicopper(II)]

Crystal data

[Cu2(C9H6O4)(N3)2(C5H5N)2]	Z = 2
Mr = 547.48	F(000) = 552
Triclinic, P1	Dx = 1.647 Mg m^−3
a = 9.882 (4) Å	Mo Kα radiation, λ = 0.71073 Å
b = 11.070 (3) Å	Cell parameters from 1239 reflections
c = 12.287 (4) Å	θ = 2.2–27.5°
α = 66.194 (18)°	µ = 1.97 mm^−1
β = 78.01 (2)°	T = 293 K
γ = 63.966 (16)°	Block, black
V = 1104.3 (7) Å^3	0.30 × 0.23 × 0.22 mm

Data collection

Rigaku Mercury CCD area-detector diffractometer	5028 independent reflections
Radiation source: fine-focus sealed tube	4082 reflections with I > 2σ(I)
Detector resolution: 13.6612 pixels mm^-1	Rint = 0.022
CCD_Profile_fitting scans	θmax = 27.5°, θmin = 2.3°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2007)	h = −10→12
Tmin = 0.657, Tmax = 1.000	k = −14→14
8686 measured reflections	l = −14→15

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.092	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0495P)^2] where P = (Fo^2 + 2Fc^2)/3
5028 reflections	(Δ/σ)max = 0.001
298 parameters	Δρmax = 0.46 e Å^−3
0 restraints	Δρmin = −0.54 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
Cu1	0.36342 (3)	0.14165 (3)	0.50231 (3)	0.03635 (10)
O1	−0.1711 (2)	0.84805 (17)	0.41597 (17)	0.0441 (4)
N1	0.3515 (3)	0.3105 (2)	0.78573 (19)	0.0419 (5)
C1	−0.0868 (3)	0.7563 (2)	0.3688 (2)	0.0316 (5)
Cu2	0.31029 (3)	0.39131 (3)	0.61025 (2)	0.03316 (10)
O2	−0.1144 (2)	0.65952 (18)	0.36432 (16)	0.0403 (4)
N2	0.1908 (2)	0.5859 (2)	0.62475 (18)	0.0363 (5)
C2	0.0599 (3)	0.7717 (2)	0.3128 (2)	0.0359 (5)
H2A	0.0415	0.8750	0.2781	0.043*
H2B	0.1341	0.7243	0.3757	0.043*
O3	0.2959 (2)	0.49060 (17)	0.43412 (15)	0.0401 (4)
N3	0.6700 (3)	0.0489 (3)	0.7195 (3)	0.0774 (9)
C3	0.1254 (3)	0.7072 (2)	0.2173 (2)	0.0347 (5)
O4	0.2818 (2)	0.32776 (16)	0.37669 (15)	0.0416 (4)
N4	0.5736 (3)	0.1312 (2)	0.6570 (2)	0.0465 (5)
C4	0.0839 (3)	0.7957 (3)	0.1007 (2)	0.0499 (7)
H4	0.0214	0.8946	0.0848	0.060*
N5	0.4745 (3)	0.2167 (2)	0.58917 (19)	0.0406 (5)
C5	0.1294 (4)	0.7461 (3)	0.0078 (3)	0.0593 (8)
H5	0.0981	0.8099	−0.0705	0.071*
N6	0.5394 (3)	0.0660 (2)	0.3979 (2)	0.0490 (6)
C6	0.2206 (4)	0.6038 (3)	0.0286 (3)	0.0593 (8)
H6	0.2544	0.5684	−0.0351	0.071*
N7	0.5826 (3)	0.1288 (3)	0.3026 (2)	0.0478 (6)
C7	0.2626 (3)	0.5125 (3)	0.1435 (2)	0.0471 (7)
H7	0.3235	0.4135	0.1581	0.057*
N8	0.6239 (4)	0.1878 (4)	0.2143 (2)	0.0949 (12)
C8	0.2184 (3)	0.5614 (2)	0.2383 (2)	0.0340 (5)
C9	0.2690 (3)	0.4519 (2)	0.3604 (2)	0.0347 (5)
C10	0.2486 (3)	0.6856 (3)	0.5829 (3)	0.0476 (7)
H10	0.3460	0.6641	0.5449	0.057*
C11	0.1711 (4)	0.8189 (3)	0.5934 (3)	0.0580 (8)
H11	0.2139	0.8887	0.5623	0.070*
C12	0.0305 (4)	0.8494 (3)	0.6498 (3)	0.0641 (9)
H12	−0.0247	0.9400	0.6590	0.077*
C13	−0.0278 (4)	0.7472 (3)	0.6921 (3)	0.0627 (8)
H13	−0.1245	0.7657	0.7311	0.075*
C14	0.0549 (3)	0.6173 (3)	0.6777 (3)	0.0499 (7)
H14	0.0131	0.5469	0.7068	0.060*
C15	0.3075 (5)	0.1771 (5)	0.9853 (3)	0.0943 (15)
H15	0.2532	0.1234	1.0402	0.113*
C16	0.2779 (4)	0.2381 (4)	0.8669 (3)	0.0762 (12)
H16	0.2002	0.2276	0.8419	0.091*
C17	0.4586 (4)	0.3247 (4)	0.8233 (3)	0.0611 (8)
H17	0.5143	0.3756	0.7665	0.073*
C18	0.4916 (5)	0.2684 (4)	0.9410 (3)	0.0766 (11)
H18	0.5683	0.2813	0.9649	0.092*
C19	0.4142 (5)	0.1939 (4)	1.0236 (3)	0.0750 (11)
H19	0.4348	0.1549	1.1058	0.090*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.03781 (19)	0.02448 (15)	0.04126 (18)	−0.01043 (13)	0.01113 (14)	−0.01464 (13)
O1	0.0404 (10)	0.0351 (9)	0.0612 (11)	−0.0172 (8)	0.0187 (9)	−0.0289 (8)
N1	0.0428 (13)	0.0406 (11)	0.0413 (12)	−0.0150 (10)	0.0013 (10)	−0.0167 (9)
C1	0.0312 (12)	0.0258 (10)	0.0314 (11)	−0.0087 (9)	−0.0005 (10)	−0.0072 (9)
Cu2	0.03457 (18)	0.02883 (16)	0.03533 (17)	−0.01254 (13)	0.00422 (13)	−0.01340 (12)
O2	0.0380 (10)	0.0411 (9)	0.0537 (10)	−0.0228 (8)	0.0111 (8)	−0.0265 (8)
N2	0.0414 (12)	0.0320 (10)	0.0397 (11)	−0.0161 (9)	0.0002 (9)	−0.0159 (9)
C2	0.0317 (12)	0.0282 (11)	0.0481 (14)	−0.0126 (10)	0.0049 (11)	−0.0161 (10)
O3	0.0508 (11)	0.0313 (8)	0.0366 (9)	−0.0162 (8)	0.0004 (8)	−0.0117 (7)
N3	0.0591 (19)	0.0660 (18)	0.0699 (19)	0.0050 (15)	−0.0163 (16)	−0.0149 (15)
C3	0.0302 (12)	0.0309 (11)	0.0391 (13)	−0.0138 (10)	0.0076 (10)	−0.0112 (10)
O4	0.0493 (11)	0.0256 (8)	0.0441 (10)	−0.0107 (8)	−0.0007 (9)	−0.0121 (7)
N4	0.0418 (13)	0.0379 (12)	0.0465 (13)	−0.0089 (11)	0.0039 (11)	−0.0127 (10)
C4	0.0436 (16)	0.0366 (14)	0.0478 (16)	−0.0079 (12)	0.0032 (13)	−0.0055 (12)
N5	0.0391 (12)	0.0352 (11)	0.0441 (12)	−0.0101 (10)	0.0003 (10)	−0.0169 (10)
C5	0.064 (2)	0.0579 (18)	0.0374 (15)	−0.0196 (16)	0.0005 (14)	−0.0050 (13)
N6	0.0533 (14)	0.0287 (10)	0.0452 (13)	−0.0117 (10)	0.0213 (11)	−0.0105 (9)
C6	0.071 (2)	0.0628 (18)	0.0370 (15)	−0.0214 (17)	0.0068 (15)	−0.0210 (14)
N7	0.0434 (13)	0.0578 (14)	0.0394 (12)	−0.0234 (12)	0.0053 (10)	−0.0143 (11)
C7	0.0528 (17)	0.0407 (14)	0.0411 (14)	−0.0132 (13)	0.0060 (13)	−0.0177 (12)
N8	0.080 (2)	0.137 (3)	0.0384 (15)	−0.057 (2)	0.0068 (15)	0.0073 (17)
C8	0.0321 (13)	0.0311 (11)	0.0367 (12)	−0.0130 (10)	0.0069 (10)	−0.0137 (10)
C9	0.0322 (13)	0.0282 (11)	0.0385 (13)	−0.0090 (10)	0.0067 (10)	−0.0138 (10)
C10	0.0490 (16)	0.0403 (14)	0.0582 (17)	−0.0232 (13)	0.0013 (14)	−0.0175 (13)
C11	0.081 (2)	0.0390 (15)	0.0651 (19)	−0.0304 (15)	−0.0171 (18)	−0.0148 (14)
C12	0.072 (2)	0.0401 (15)	0.086 (2)	−0.0088 (15)	−0.022 (2)	−0.0337 (16)
C13	0.0450 (17)	0.0574 (18)	0.091 (2)	−0.0106 (15)	0.0083 (17)	−0.0469 (18)
C14	0.0410 (15)	0.0460 (15)	0.075 (2)	−0.0221 (13)	0.0136 (14)	−0.0359 (15)
C15	0.114 (3)	0.138 (4)	0.046 (2)	−0.087 (3)	−0.008 (2)	−0.003 (2)
C16	0.090 (3)	0.112 (3)	0.0431 (17)	−0.072 (3)	−0.0044 (18)	−0.0067 (18)
C17	0.063 (2)	0.079 (2)	0.0533 (18)	−0.0425 (18)	−0.0029 (16)	−0.0191 (16)
C18	0.080 (3)	0.099 (3)	0.067 (2)	−0.044 (2)	−0.021 (2)	−0.025 (2)
C19	0.091 (3)	0.087 (3)	0.0460 (18)	−0.035 (2)	−0.0154 (19)	−0.0164 (18)

Geometric parameters (Å, º)

Cu1—O1^i	1.9343 (19)	C4—H4	0.9500
Cu1—O4	1.9414 (17)	C5—C6	1.373 (4)
Cu1—N6^ii	1.996 (2)	C5—H5	0.9500
Cu1—N6	2.009 (2)	N6—N7	1.196 (3)
Cu1—N5	2.244 (2)	N6—Cu1^ii	1.996 (2)
O1—C1	1.262 (3)	C6—C7	1.382 (4)
O1—Cu1^i	1.9343 (19)	C6—H6	0.9500
N1—C16	1.315 (4)	N7—N8	1.118 (3)
N1—C17	1.329 (4)	C7—C8	1.389 (3)
N1—Cu2	2.025 (2)	C7—H7	0.9500
C1—O2	1.239 (3)	C8—C9	1.510 (3)
C1—C2	1.520 (3)	C10—C11	1.379 (4)
Cu2—N5	1.978 (2)	C10—H10	0.9500
Cu2—O3	1.9956 (18)	C11—C12	1.378 (5)
Cu2—N2	2.014 (2)	C11—H11	0.9500
Cu2—O2^i	2.1738 (18)	C12—C13	1.362 (4)
O2—Cu2^i	2.1737 (18)	C12—H12	0.9500
N2—C14	1.325 (3)	C13—C14	1.372 (4)
N2—C10	1.335 (3)	C13—H13	0.9500
C2—C3	1.503 (3)	C14—H14	0.9500
C2—H2A	0.9900	C15—C19	1.348 (5)
C2—H2B	0.9900	C15—C16	1.367 (5)
O3—C9	1.260 (3)	C15—H15	0.9500
N3—N4	1.142 (3)	C16—H16	0.9500
C3—C4	1.392 (4)	C17—C18	1.370 (5)
C3—C8	1.406 (3)	C17—H17	0.9500
O4—C9	1.257 (3)	C18—C19	1.360 (5)
N4—N5	1.199 (3)	C18—H18	0.9500
C4—C5	1.372 (4)	C19—H19	0.9500
O1^i—Cu1—O4	95.14 (8)	C4—C5—C6	119.5 (3)
O1^i—Cu1—N6^ii	90.72 (9)	C4—C5—H5	120.2
O4—Cu1—N6^ii	167.42 (9)	C6—C5—H5	120.2
O1^i—Cu1—N6	152.05 (9)	N7—N6—Cu1^ii	127.6 (2)
O4—Cu1—N6	92.45 (8)	N7—N6—Cu1	129.66 (19)
N6^ii—Cu1—N6	77.38 (9)	Cu1^ii—N6—Cu1	102.62 (9)
O1^i—Cu1—N5	108.31 (8)	C5—C6—C7	119.2 (3)
O4—Cu1—N5	93.72 (8)	C5—C6—H6	120.4
N6^ii—Cu1—N5	94.99 (10)	C7—C6—H6	120.4
N6—Cu1—N5	97.96 (10)	N8—N7—N6	179.2 (4)
C1—O1—Cu1^i	125.78 (16)	C6—C7—C8	121.9 (3)
C16—N1—C17	117.0 (3)	C6—C7—H7	119.1
C16—N1—Cu2	122.1 (2)	C8—C7—H7	119.1
C17—N1—Cu2	120.9 (2)	C7—C8—C3	119.1 (2)
O2—C1—O1	126.0 (2)	C7—C8—C9	117.5 (2)
O2—C1—C2	119.4 (2)	C3—C8—C9	123.4 (2)
O1—C1—C2	114.6 (2)	O4—C9—O3	126.5 (2)
N5—Cu2—O3	90.58 (8)	O4—C9—C8	114.6 (2)
N5—Cu2—N2	164.06 (9)	O3—C9—C8	118.9 (2)
O3—Cu2—N2	87.59 (8)	N2—C10—C11	121.9 (3)
N5—Cu2—N1	90.51 (9)	N2—C10—H10	119.1
O3—Cu2—N1	168.71 (8)	C11—C10—H10	119.1
N2—Cu2—N1	88.28 (9)	C12—C11—C10	119.0 (3)
N5—Cu2—O2^i	101.65 (8)	C12—C11—H11	120.5
O3—Cu2—O2^i	95.65 (8)	C10—C11—H11	120.5
N2—Cu2—O2^i	94.29 (8)	C13—C12—C11	118.8 (3)
N1—Cu2—O2^i	95.14 (8)	C13—C12—H12	120.6
C1—O2—Cu2^i	137.08 (16)	C11—C12—H12	120.6
C14—N2—C10	118.5 (2)	C12—C13—C14	119.2 (3)
C14—N2—Cu2	121.13 (17)	C12—C13—H13	120.4
C10—N2—Cu2	120.38 (19)	C14—C13—H13	120.4
C3—C2—C1	112.9 (2)	N2—C14—C13	122.7 (3)
C3—C2—H2A	109.0	N2—C14—H14	118.7
C1—C2—H2A	109.0	C13—C14—H14	118.7
C3—C2—H2B	109.0	C19—C15—C16	119.5 (4)
C1—C2—H2B	109.0	C19—C15—H15	120.3
H2A—C2—H2B	107.8	C16—C15—H15	120.3
C9—O3—Cu2	127.89 (15)	N1—C16—C15	123.4 (3)
C4—C3—C8	117.4 (2)	N1—C16—H16	118.3
C4—C3—C2	117.9 (2)	C15—C16—H16	118.3
C8—C3—C2	124.6 (2)	N1—C17—C18	122.3 (3)
C9—O4—Cu1	133.93 (17)	N1—C17—H17	118.8
N3—N4—N5	178.4 (3)	C18—C17—H17	118.8
C5—C4—C3	122.8 (3)	C19—C18—C17	119.8 (3)
C5—C4—H4	118.6	C19—C18—H18	120.1
C3—C4—H4	118.6	C17—C18—H18	120.1
N4—N5—Cu2	125.42 (19)	C15—C19—C18	117.9 (3)
N4—N5—Cu1	120.31 (17)	C15—C19—H19	121.0
Cu2—N5—Cu1	103.80 (10)	C18—C19—H19	121.0

Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x+1, −y, −z+1.