Effect of pH on the charge-assisted hydrogen-bonded assembly of the anionic [Cu(oxalate)₂]²⁻ building unit and N,N′-ditopic cations

By the solvothermal reaction under acidic conditions of Cu(NO₃)₂·3H₂O, Na₂C₂O₄ and the N,N′-ditopic organic coligands 1-(pyridin-4-yl)piperazine (ppz) and 1,2-bis­(pyridin-4-yl)ethane (bpa), two novel anionic copper(II) coordination compounds were obtained, namely the one-dimensional coordination polymer catena-poly[4-(pyridin-1-ium-4-yl)piperazin-1-ium [[(oxalato-κ²O¹,O²)copper(II)]-μ-oxalato-κ³O¹,O²:O^1′]], {(C₉H₁₅N₃)[Cu(C₂O₄)₂)]}_n or {(H₂ppz)[Cu(C₂O₄)₂]}_n, (I), and the discrete ionic complex 4,4′-(ethane-1,2-di­yl)di­pyridinium bis­(oxalato-κ²O¹,O²)copper(II), (C₁₂H₁₄N₂)[Cu(C₂O₄)₂] or (H₂bpa)[Cu(C₂O₄)₂], (II). The products were characterized by single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, thermogravimetric analyses and UV and IR spectroscopic techniques. The [Cu(C₂O₄)₂]²⁻ units for (I) and (II) are stabilized by H₂ppz²⁺ and H₂bpa²⁺ cations, respectively, via charge-assisted hydrogen bonds. Also, a study of the pH-controlled synthesis of this system shows that (I) was obtained at pH values of 2–4. When using bpa, a two-dimensional square-grid network of [Cu(C₂O₄)(bpa)]_n was obtained at a pH of 4. This indicates that the pH of the reaction also plays a key role in the structural assembly and coordination abilities of oxalate and N,N′-ditopic coligands.

Computing details

For both structures, data collection: APEX2 (Bruker, 2013); cell refinement: SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: SHELXL (Sheldrick, 2008); software used to prepare material for publication: SHELXL (Sheldrick, 2008).

(compoundI)

Crystal data

(C9H15N3)[Cu(C2O4)2]	F(000) = 828
Mr = 404.82	Dx = 1.866 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 10.8492 (7) Å	Cell parameters from 3578 reflections
b = 14.2931 (7) Å	θ = 2.8–26.1°
c = 9.8604 (5) Å	µ = 1.57 mm^−1
β = 109.543 (2)°	T = 298 K
V = 1440.95 (14) Å^3	Block, blue
Z = 4	0.09 × 0.04 × 0.03 mm

Data collection

Bruker D8 QUEST PHOTON 100 diffractometer	1975 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.075
φ and ω scans	θmax = 26.4°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2015)	h = −13→13
Tmin = 0.698, Tmax = 0.745	k = −17→17
16649 measured reflections	l = −11→12
2940 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.044	H-atom parameters constrained
wR(F^2) = 0.099	w = 1/[σ^2(Fo^2) + (0.0437P)^2 + 0.8867P] where P = (Fo^2 + 2Fc^2)/3
S = 1.02	(Δ/σ)max < 0.001
2940 reflections	Δρmax = 0.38 e Å^−3
226 parameters	Δρmin = −0.53 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cu1	0.09599 (4)	0.33925 (3)	0.09871 (4)	0.02876 (16)
O1	0.2621 (2)	0.38727 (18)	0.2210 (2)	0.0341 (6)
O2	0.0825 (2)	0.28723 (18)	0.2768 (2)	0.0323 (6)
O3	0.1877 (2)	0.2978 (2)	0.5141 (2)	0.0401 (7)
O4	0.3686 (2)	0.41202 (18)	0.4525 (2)	0.0388 (7)
O5	0.0981 (2)	0.41985 (19)	−0.0589 (2)	0.0403 (7)
O6	−0.0328 (3)	0.4559 (2)	−0.2808 (3)	0.0556 (9)
O7	−0.2078 (2)	0.32768 (18)	−0.2495 (2)	0.0336 (6)
O8	−0.0797 (2)	0.30645 (17)	−0.0221 (2)	0.0279 (6)
N1	0.7960 (3)	0.3676 (2)	0.4723 (3)	0.0253 (7)
H1A	0.8251	0.3102	0.4654	0.030*
H1B	0.8299	0.3859	0.5635	0.030*
N2	0.6386 (3)	0.39167 (19)	0.1755 (3)	0.0212 (6)
N3	0.4296 (3)	0.3887 (2)	−0.2589 (3)	0.0300 (7)
H3	0.3875	0.3860	−0.3498	0.036*
C1	0.2777 (3)	0.3786 (3)	0.3551 (3)	0.0247 (8)
C2	0.1728 (3)	0.3167 (2)	0.3880 (4)	0.0268 (8)
C3	−0.0075 (4)	0.4131 (3)	−0.1673 (4)	0.0318 (9)
C4	−0.1085 (3)	0.3434 (2)	−0.1486 (4)	0.0248 (8)
C5	0.8386 (3)	0.4323 (3)	0.3789 (3)	0.0285 (8)
H5A	0.9333	0.4316	0.4075	0.034*
H5B	0.8114	0.4955	0.3909	0.034*
C6	0.7807 (3)	0.4041 (3)	0.2228 (3)	0.0276 (8)
H6A	0.8015	0.4517	0.1637	0.033*
H6B	0.8208	0.3460	0.2082	0.033*
C7	0.5903 (3)	0.3366 (2)	0.2739 (3)	0.0253 (8)
H7A	0.6090	0.2710	0.2652	0.030*
H7B	0.4961	0.3437	0.2456	0.030*
C8	0.6517 (3)	0.3663 (3)	0.4290 (3)	0.0263 (8)
H8A	0.6206	0.4283	0.4416	0.032*
H8B	0.6253	0.3234	0.4904	0.032*
C9	0.5496 (4)	0.4250 (2)	−0.2129 (4)	0.0294 (9)
H9	0.5849	0.4495	−0.2792	0.035*
C10	0.6212 (3)	0.4269 (2)	−0.0704 (3)	0.0257 (8)
H10	0.7051	0.4520	−0.0403	0.031*
C11	0.5688 (3)	0.3909 (2)	0.0324 (3)	0.0213 (8)
C12	0.4395 (3)	0.3562 (2)	−0.0223 (4)	0.0302 (9)
H12	0.3992	0.3333	0.0406	0.036*
C13	0.3735 (4)	0.3562 (2)	−0.1666 (4)	0.0328 (9)
H13	0.2884	0.3334	−0.2013	0.039*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0222 (3)	0.0441 (3)	0.0159 (2)	−0.0088 (2)	0.00100 (17)	0.0042 (2)
O1	0.0259 (14)	0.0556 (17)	0.0180 (13)	−0.0145 (12)	0.0034 (11)	0.0018 (12)
O2	0.0238 (14)	0.0509 (17)	0.0184 (12)	−0.0092 (12)	0.0021 (11)	0.0042 (12)
O3	0.0388 (16)	0.0619 (19)	0.0184 (13)	−0.0122 (14)	0.0079 (12)	0.0008 (12)
O4	0.0367 (16)	0.0547 (17)	0.0182 (13)	−0.0153 (13)	0.0003 (12)	−0.0034 (12)
O5	0.0340 (16)	0.0581 (18)	0.0212 (13)	−0.0214 (13)	−0.0010 (12)	0.0062 (12)
O6	0.057 (2)	0.071 (2)	0.0251 (15)	−0.0309 (16)	−0.0048 (13)	0.0184 (15)
O7	0.0211 (14)	0.0534 (17)	0.0211 (13)	−0.0067 (12)	0.0002 (11)	0.0041 (12)
O8	0.0235 (13)	0.0408 (14)	0.0166 (12)	−0.0089 (11)	0.0033 (10)	0.0059 (11)
N1	0.0273 (17)	0.0320 (17)	0.0151 (14)	0.0023 (13)	0.0053 (12)	0.0018 (12)
N2	0.0173 (15)	0.0288 (16)	0.0164 (14)	−0.0041 (12)	0.0042 (12)	−0.0007 (12)
N3	0.036 (2)	0.0321 (18)	0.0144 (15)	0.0054 (15)	−0.0015 (13)	−0.0006 (13)
C1	0.0170 (19)	0.036 (2)	0.0191 (18)	0.0019 (15)	0.0030 (15)	−0.0011 (16)
C2	0.027 (2)	0.033 (2)	0.0186 (18)	0.0064 (16)	0.0056 (15)	0.0013 (16)
C3	0.033 (2)	0.039 (2)	0.0216 (19)	−0.0078 (17)	0.0070 (17)	0.0032 (17)
C4	0.0190 (19)	0.034 (2)	0.0215 (17)	0.0018 (16)	0.0077 (15)	−0.0014 (16)
C5	0.023 (2)	0.035 (2)	0.0215 (18)	−0.0069 (16)	−0.0007 (15)	0.0022 (16)
C6	0.022 (2)	0.038 (2)	0.0218 (18)	−0.0069 (16)	0.0063 (15)	0.0023 (16)
C7	0.0217 (19)	0.033 (2)	0.0195 (17)	−0.0055 (16)	0.0051 (14)	0.0009 (16)
C8	0.026 (2)	0.034 (2)	0.0198 (18)	0.0022 (16)	0.0095 (15)	0.0049 (15)
C9	0.034 (2)	0.034 (2)	0.0217 (18)	0.0071 (17)	0.0122 (17)	0.0036 (16)
C10	0.024 (2)	0.033 (2)	0.0180 (18)	0.0038 (16)	0.0046 (15)	0.0007 (15)
C11	0.027 (2)	0.0179 (18)	0.0175 (17)	0.0023 (15)	0.0056 (14)	−0.0010 (14)
C12	0.029 (2)	0.036 (2)	0.0210 (19)	−0.0055 (17)	0.0011 (16)	0.0023 (16)
C13	0.031 (2)	0.029 (2)	0.030 (2)	−0.0055 (17)	−0.0007 (17)	−0.0008 (17)

Geometric parameters (Å, º)

Cu1—O1	1.928 (2)	N3—H3	0.8600
Cu1—O8	1.938 (2)	C1—C2	1.559 (5)
Cu1—O5	1.941 (2)	C3—C4	1.537 (5)
Cu1—O2	1.957 (2)	C5—C6	1.509 (4)
Cu1—O3^i	2.466 (3)	C5—H5A	0.9700
O1—C1	1.282 (4)	C5—H5B	0.9700
O2—C2	1.273 (4)	C6—H6A	0.9700
O3—C2	1.229 (4)	C6—H6B	0.9700
O4—C1	1.220 (4)	C7—C8	1.510 (4)
O5—C3	1.283 (4)	C7—H7A	0.9700
O6—C3	1.223 (4)	C7—H7B	0.9700
O7—C4	1.218 (4)	C8—H8A	0.9700
O8—C4	1.293 (4)	C8—H8B	0.9700
N1—C8	1.479 (4)	C9—C10	1.360 (5)
N1—C5	1.484 (4)	C9—H9	0.9300
N1—H1A	0.8900	C10—C11	1.414 (5)
N1—H1B	0.8900	C10—H10	0.9300
N2—C11	1.360 (4)	C11—C12	1.414 (5)
N2—C6	1.465 (4)	C12—C13	1.362 (5)
N2—C7	1.475 (4)	C12—H12	0.9300
N3—C9	1.332 (5)	C13—H13	0.9300
N3—C13	1.336 (5)
O1—Cu1—O8	172.78 (11)	N1—C5—H5A	109.5
O1—Cu1—O5	91.74 (10)	C6—C5—H5A	109.5
O8—Cu1—O5	85.64 (9)	N1—C5—H5B	109.5
O1—Cu1—O2	84.78 (9)	C6—C5—H5B	109.5
O8—Cu1—O2	96.11 (9)	H5A—C5—H5B	108.0
O5—Cu1—O2	165.58 (11)	N2—C6—C5	113.1 (3)
O3^i—Cu1—O1	95.50 (9)	N2—C6—H6A	109.0
O3^i—Cu1—O2	99.30 (9)	C5—C6—H6A	109.0
O3^i—Cu1—O5	94.96 (9)	N2—C6—H6B	109.0
O3^i—Cu1—O8	91.44 (9)	C5—C6—H6B	109.0
C1—O1—Cu1	112.6 (2)	H6A—C6—H6B	107.8
C2—O2—Cu1	112.3 (2)	N2—C7—C8	112.5 (3)
C3—O5—Cu1	112.1 (2)	N2—C7—H7A	109.1
C4—O8—Cu1	111.4 (2)	C8—C7—H7A	109.1
C8—N1—C5	110.4 (3)	N2—C7—H7B	109.1
C8—N1—H1A	109.6	C8—C7—H7B	109.1
C5—N1—H1A	109.6	H7A—C7—H7B	107.8
C8—N1—H1B	109.6	N1—C8—C7	111.2 (3)
C5—N1—H1B	109.6	N1—C8—H8A	109.4
H1A—N1—H1B	108.1	C7—C8—H8A	109.4
C11—N2—C6	119.5 (3)	N1—C8—H8B	109.4
C11—N2—C7	118.8 (3)	C7—C8—H8B	109.4
C6—N2—C7	115.0 (2)	H8A—C8—H8B	108.0
C9—N3—C13	121.3 (3)	N3—C9—C10	121.0 (3)
C9—N3—H3	119.4	N3—C9—H9	119.5
C13—N3—H3	119.4	C10—C9—H9	119.5
O4—C1—O1	124.6 (3)	C9—C10—C11	120.4 (3)
O4—C1—C2	120.8 (3)	C9—C10—H10	119.8
O1—C1—C2	114.5 (3)	C11—C10—H10	119.8
O3—C2—O2	127.0 (3)	N2—C11—C12	122.4 (3)
O3—C2—C1	118.5 (3)	N2—C11—C10	121.5 (3)
O2—C2—C1	114.5 (3)	C12—C11—C10	116.1 (3)
O6—C3—O5	126.1 (3)	C13—C12—C11	120.4 (3)
O6—C3—C4	118.9 (3)	C13—C12—H12	119.8
O5—C3—C4	115.0 (3)	C11—C12—H12	119.8
O7—C4—O8	125.1 (3)	N3—C13—C12	120.8 (4)
O7—C4—C3	119.5 (3)	N3—C13—H13	119.6
O8—C4—C3	115.4 (3)	C12—C13—H13	119.6
N1—C5—C6	110.9 (3)

Symmetry code: (i) x, −y+1/2, z−1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O6^ii	0.89	2.01	2.819 (4)	150
N1—H1B···O7^ii	0.89	2.18	2.816 (3)	128
N3—H3···O3^iii	0.86	2.48	3.107 (4)	131
N3—H3···O4^iii	0.86	1.93	2.718 (3)	152
C5—H5A···O6^iv	0.97	2.49	3.048 (5)	116
C6—H6A···O5^iv	0.97	2.53	3.478 (5)	167
C6—H6B···O7^v	0.97	2.55	3.323 (5)	136
C7—H7A···O7^v	0.97	2.48	3.272 (4)	139
C7—H7B···O1	0.97	2.55	3.498 (4)	167
C8—H8A···O4^vi	0.97	2.50	3.410 (5)	157
C8—H8B···O7^ii	0.97	2.60	3.073 (3)	110

Symmetry codes: (ii) x+1, y, z+1; (iii) x, y, z−1; (iv) −x+1, −y+1, −z; (v) x+1, −y+1/2, z+1/2; (vi) −x+1, −y+1, −z+1.

(compoundII)

Crystal data

(C12H14N2)[Cu(C2O4)2]	Z = 1
Mr = 425.83	F(000) = 217
Triclinic, P1	Dx = 1.833 Mg m^−3
a = 3.8486 (1) Å	Mo Kα radiation, λ = 0.71073 Å
b = 10.2380 (3) Å	Cell parameters from 5637 reflections
c = 10.6080 (4) Å	θ = 3.5–26.2°
α = 109.382 (2)°	µ = 1.47 mm^−1
β = 95.641 (2)°	T = 298 K
γ = 97.930 (2)°	Block, purple
V = 385.85 (2) Å^3	0.09 × 0.04 × 0.03 mm

Data collection

Bruker D8 QUEST PHOTON 100 diffractometer	1370 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.064
φ and ω scans	θmax = 26.0°, θmin = 3.9°
Absorption correction: multi-scan (SADABS; Bruker, 2015)	h = −4→4
Tmin = 0.481, Tmax = 0.745	k = −12→12
11134 measured reflections	l = −13→13
1515 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.033	H-atom parameters constrained
wR(F^2) = 0.087	w = 1/[σ^2(Fo^2) + (0.0423P)^2 + 0.2752P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max < 0.001
1515 reflections	Δρmax = 0.41 e Å^−3
124 parameters	Δρmin = −0.36 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cu1	0.0000	0.5000	0.0000	0.02811 (17)
O1	0.0783 (5)	0.68107 (18)	0.14009 (17)	0.0323 (4)
O2	0.3594 (5)	0.78730 (19)	0.35205 (18)	0.0358 (4)
O3	0.3273 (5)	0.45021 (18)	0.12059 (17)	0.0338 (4)
O4	0.6076 (5)	0.54334 (19)	0.33262 (18)	0.0355 (4)
N1	−0.1332 (5)	0.7665 (2)	0.5689 (2)	0.0281 (5)
H1	−0.2503	0.7127	0.4888	0.034*
C1	0.2779 (6)	0.6865 (2)	0.2468 (2)	0.0245 (5)
C2	0.4187 (6)	0.5490 (3)	0.2350 (2)	0.0263 (5)
C3	0.0221 (7)	0.7072 (3)	0.6474 (3)	0.0303 (6)
H3	0.0060	0.6078	0.6165	0.036*
C4	0.2072 (7)	0.7888 (3)	0.7739 (3)	0.0284 (5)
H4	0.3163	0.7460	0.8303	0.034*
C5	0.2320 (6)	0.9337 (3)	0.8176 (2)	0.0234 (5)
C6	0.0655 (6)	0.9909 (3)	0.7315 (3)	0.0273 (5)
H6	0.0786	1.0899	0.7587	0.033*
C7	−0.1169 (6)	0.9054 (3)	0.6079 (2)	0.0286 (5)
H7	−0.2321	0.9449	0.5497	0.034*
C8	0.4292 (6)	1.0343 (3)	0.9522 (2)	0.0260 (5)
H8A	0.2683	1.0964	0.9971	0.031*
H8B	0.6310	1.0946	0.9358	0.031*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0395 (3)	0.0210 (2)	0.0181 (2)	0.00929 (18)	−0.00867 (17)	0.00160 (17)
O1	0.0441 (10)	0.0239 (9)	0.0231 (9)	0.0114 (8)	−0.0090 (8)	0.0027 (7)
O2	0.0460 (11)	0.0269 (9)	0.0238 (9)	0.0099 (8)	−0.0095 (8)	−0.0023 (7)
O3	0.0483 (11)	0.0245 (9)	0.0214 (9)	0.0120 (8)	−0.0112 (8)	0.0014 (7)
O4	0.0476 (11)	0.0310 (10)	0.0237 (9)	0.0113 (8)	−0.0112 (8)	0.0069 (8)
N1	0.0288 (11)	0.0315 (12)	0.0166 (10)	0.0019 (9)	−0.0021 (8)	0.0018 (9)
C1	0.0268 (12)	0.0231 (12)	0.0205 (12)	0.0037 (9)	−0.0013 (9)	0.0053 (10)
C2	0.0293 (12)	0.0252 (12)	0.0227 (12)	0.0036 (10)	−0.0012 (10)	0.0082 (10)
C3	0.0361 (14)	0.0210 (12)	0.0293 (13)	0.0057 (10)	0.0023 (11)	0.0034 (10)
C4	0.0317 (13)	0.0319 (13)	0.0230 (12)	0.0082 (10)	0.0002 (10)	0.0116 (10)
C5	0.0203 (11)	0.0278 (12)	0.0197 (12)	0.0038 (9)	0.0036 (9)	0.0052 (10)
C6	0.0291 (12)	0.0239 (12)	0.0279 (13)	0.0062 (10)	0.0028 (10)	0.0075 (10)
C7	0.0286 (12)	0.0362 (14)	0.0234 (12)	0.0060 (10)	−0.0006 (10)	0.0151 (11)
C8	0.0279 (12)	0.0260 (12)	0.0220 (12)	0.0061 (10)	0.0000 (10)	0.0062 (10)

Geometric parameters (Å, º)

Cu1—O1^i	1.9145 (16)	C3—C4	1.382 (4)
Cu1—O1	1.9145 (16)	C3—H3	0.9500
Cu1—O3^i	1.9431 (17)	C4—C5	1.386 (4)
Cu1—O3	1.9432 (17)	C4—H4	0.9500
O1—C1	1.285 (3)	C5—C6	1.390 (3)
O2—C1	1.220 (3)	C5—C8	1.506 (3)
O3—C2	1.274 (3)	C6—C7	1.366 (4)
O4—C2	1.228 (3)	C6—H6	0.9500
N1—C3	1.326 (3)	C7—H7	0.9500
N1—C7	1.333 (3)	C8—C8^ii	1.513 (5)
N1—H1	0.8800	C8—H8A	0.9900
C1—C2	1.548 (3)	C8—H8B	0.9900
O1^i—Cu1—O1	180.00 (11)	C4—C3—H3	119.8
O1^i—Cu1—O3^i	85.73 (7)	C3—C4—C5	119.4 (2)
O1—Cu1—O3^i	94.27 (7)	C3—C4—H4	120.3
O1^i—Cu1—O3	94.27 (7)	C5—C4—H4	120.3
O1—Cu1—O3	85.73 (7)	C4—C5—C6	118.0 (2)
O3^i—Cu1—O3	180.0	C4—C5—C8	124.6 (2)
C1—O1—Cu1	112.67 (15)	C6—C5—C8	117.4 (2)
C2—O3—Cu1	111.56 (15)	C7—C6—C5	120.3 (2)
C3—N1—C7	121.9 (2)	C7—C6—H6	119.8
C3—N1—H1	119.1	C5—C6—H6	119.8
C7—N1—H1	119.1	N1—C7—C6	120.0 (2)
O2—C1—O1	126.1 (2)	N1—C7—H7	120.0
O2—C1—C2	119.5 (2)	C6—C7—H7	120.0
O1—C1—C2	114.4 (2)	C5—C8—C8^ii	115.2 (3)
O4—C2—O3	125.5 (2)	C5—C8—H8A	108.5
O4—C2—C1	119.2 (2)	C8^ii—C8—H8A	108.5
O3—C2—C1	115.4 (2)	C5—C8—H8B	108.5
N1—C3—C4	120.4 (2)	C8^ii—C8—H8B	108.5
N1—C3—H3	119.8	H8A—C8—H8B	107.5

Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, −y+2, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2^iii	0.88	2.36	2.951 (3)	125
N1—H1···O4^iii	0.88	1.92	2.753 (3)	156
C3—H3···O4^iv	0.95	2.43	3.157 (4)	133
C6—H6···O1^v	0.95	2.42	3.326 (4)	159

Symmetry codes: (iii) x−1, y, z; (iv) −x+1, −y+1, −z+1; (v) −x, −y+2, −z+1.