X-ray studies on crystalline complexes involving amino acids and peptides. XXXV. Invariance and variability in amino acid aggregation in the complexes of maleic acid with L-histidine and L-­lysine

The crystal structures of complexes of maleic acid with L-­histidine and L-lysine have been determined. The two crystallographically independent amino acid molecules in the L-histidine complex have different closed conformations, while the lysine molecule in its complex has the most favourable conformation sterically with an all-trans sidechain trans to the α-carboxylate group. The maleic acid molecules exist as semi-maleate ions of similar conformation and contain a symmetric O...H...O hydrogen bond. Amino acid cations and semi-maleate anions aggregate into alternate layers in both the structures. The arrangement of molecules in the histidine layer in L-histidine semi-maleate is closer to that in the crystals of the free amino acid than in other L-histidine complexes. On the other hand, the arrangement of lysine molecules in its semi-maleate complex is different from any observed so far. However, the well established characteristic interaction patterns involving amino and carboxylate groups still play a major role in holding the molecules together in the crystal of the complex.

Computing details

For both compounds, data collection: CAD4; cell refinement: CAD4; data reduction: CAD4; program(s) used to solve structure: SHELXS86 (Sheldrick, 1985); program(s) used to refine structure: SHELXL93 (Sheldrick, 1993); molecular graphics: ORTEP-III. Software used to prepare material for publication: MS-WORD ver 6.0 for (I); MS-WORD Ver 6.0 for (II).

(I)

Crystal data

C6H10N3O2^+·C4H3O4^−	Z = 2
Mr = 271	F(000) = 284
Triclinic, P1	Dx = 1.549 Mg m^−3
Hall symbol: P 1	Cu Kα radiation, λ = 1.5418 Å
a = 5.3893 (12) Å	Cell parameters from 25 reflections
b = 9.3851 (13) Å	θ = 15–60°
c = 12.3681 (9) Å	µ = 1.12 mm^−1
α = 107.054 (9)°	T = 293 K
β = 98.569 (12)°	Needle, colourless
γ = 97.303 (14)°	0.65 × 0.45 × 0.12 mm
V = 581.7 (2) Å^3

Data collection

CAD4 diffractometer	Rint = 0.019
Radiation source: Fine-focus sealed tube	θmax = 70.0°, θmin = 0.0°
ω–2θ scans	h = 0→6
Absorption correction: ψ scan North et al., 1968	k = −11→11
Tmin = 0.644, Tmax = 0.762	l = −15→14
2372 measured reflections	3 standard reflections every 100 reflections
2123 independent reflections	intensity decay: 5%
2097 reflections with I > 2σ(I)

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.051	Calculated w = 1/[s^2(Fo^2) + ( 0.0905P)^2 + 0.4731P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.147	(Δ/σ)max = −0.014
S = 1.07	Δρmax = 0.27 e Å^−3
2370 reflections	Δρmin = −0.31 e Å^−3
350 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2l^3/sin(2q)]^-1/4
3 restraints	Extinction coefficient: 0.0452 (58)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.33 (38)

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 on F² for ALL reflections except for 2 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating Rfactor_obs 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
O1	1.0698 (9)	0.9202 (5)	0.7196 (5)	0.0696 (14)
O2	0.7819 (8)	0.7412 (4)	0.5848 (3)	0.0513 (10)
C1	0.8621 (10)	0.8722 (5)	0.6534 (4)	0.0368 (10)
C2	0.6750 (9)	0.9844 (4)	0.6567 (4)	0.0331 (9)
H2	0.5551	0.9641	0.7050	0.040*
N1	0.8189 (8)	1.1413 (4)	0.7145 (3)	0.0338 (8)
H1N1	0.9095	1.1472	0.7825	0.051*
H2N1	0.7100	1.2056	0.7250	0.051*
H3N1	0.9235	1.1651	0.6706	0.051*
C3	0.5175 (9)	0.9708 (5)	0.5395 (4)	0.0379 (10)
H3A	0.4143	0.8701	0.5068	0.045*
H3B	0.4026	1.0432	0.5506	0.045*
C4	0.6779 (10)	0.9983 (5)	0.4560 (4)	0.0376 (10)
C8	0.8455 (10)	0.9186 (5)	0.4034 (4)	0.0384 (10)
HC8	0.8889	0.8293	0.4122	0.046*
N7	0.9379 (10)	0.9959 (5)	0.3350 (4)	0.0471 (11)
HN7	1.0464	0.9684	0.2922	0.057*
C6	0.8380 (12)	1.1160 (6)	0.3442 (4)	0.0446 (12)
HC6	0.8729	1.1868	0.3067	0.054*
N5	0.6770 (8)	1.1212 (4)	0.4162 (4)	0.0388 (9)
HN5	0.5863	1.1903	0.4351	0.047*
O11	0.1888 (7)	0.2614 (4)	0.6112 (3)	0.0411 (8)
O12	0.5983 (7)	0.3724 (4)	0.6656 (3)	0.0429 (8)
C11	0.3627 (9)	0.3703 (5)	0.6358 (4)	0.0310 (9)
C12	0.2953 (8)	0.5242 (4)	0.6356 (3)	0.0300 (9)
H12	0.3975	0.5623	0.5874	0.036*
N11	0.0210 (7)	0.5050 (4)	0.5820 (3)	0.0333 (8)
H1N11	−0.0114	0.4361	0.5122	0.050*
H2N11	−0.0127	0.5930	0.5759	0.050*
H3N11	−0.0765	0.4744	0.6259	0.050*
C13	0.3580 (9)	0.6420 (5)	0.7559 (4)	0.0333 (10)
H13A	0.5351	0.6478	0.7893	0.040*
H13B	0.3403	0.7402	0.7480	0.040*
C14	0.1965 (9)	0.6118 (5)	0.8377 (4)	0.0320 (9)
C18	0.0377 (10)	0.6953 (5)	0.8891 (4)	0.0382 (11)
HC18	0.0037	0.7860	0.8794	0.046*
N17	−0.0663 (9)	0.6240 (5)	0.9586 (4)	0.0408 (9)
HN17	−0.1742	0.6554	1.0007	0.049*
C16	0.0280 (11)	0.4991 (6)	0.9494 (4)	0.0425 (12)
HC16	−0.0111	0.4299	0.9876	0.051*
N15	0.1878 (8)	0.4882 (4)	0.8769 (3)	0.0370 (9)
HN15	0.2722	0.4160	0.8574	0.044*
O21	0.3955 (9)	0.3564 (5)	0.4009 (3)	0.0573 (11)
O22	0.7140 (10)	0.4150 (6)	0.3198 (5)	0.0698 (13)
HO22	0.738 (2)	0.4756 (11)	0.253 (8)	0.105*
C23	0.4928 (12)	0.4260 (6)	0.3431 (4)	0.0456 (12)
C24	0.3482 (12)	0.5335 (6)	0.3037 (5)	0.0485 (13)
H24	0.2050	0.5509	0.3359	0.058*
C25	0.3918 (11)	0.6090 (6)	0.2295 (5)	0.0456 (12)
H25	0.2749	0.6710	0.2191	0.055*
C26	0.5947 (11)	0.6097 (6)	0.1616 (4)	0.0425 (12)
O27	0.7763 (10)	0.5345 (7)	0.1759 (5)	0.080 (2)
O28	0.5888 (8)	0.6812 (4)	0.0946 (3)	0.0532 (10)
O31	0.4629 (8)	0.2533 (4)	0.8772 (3)	0.0512 (10)
O32	0.1476 (8)	0.1996 (5)	0.9626 (4)	0.0561 (11)
C33	0.3675 (10)	0.1864 (6)	0.9379 (5)	0.0418 (11)
C34	0.5142 (10)	0.0830 (6)	0.9800 (4)	0.0443 (12)
H34	0.6571	0.0647	0.9480	0.053*
C35	0.4732 (10)	0.0127 (6)	1.0562 (4)	0.0431 (11)
H35	0.5935	−0.0464	1.0690	0.052*
C36	0.2702 (10)	0.0118 (6)	1.1245 (4)	0.0424 (12)
O37	0.0891 (10)	0.0846 (6)	1.1113 (4)	0.0700 (14)
HO37	0.0927 (19)	0.1419 (11)	1.057 (8)	0.105*
O38	0.2824 (9)	−0.0571 (5)	1.1950 (3)	0.0559 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.062 (3)	0.040 (2)	0.098 (3)	0.018 (2)	−0.014 (3)	0.020 (2)
O2	0.063 (2)	0.029 (2)	0.064 (2)	0.015 (2)	0.012 (2)	0.016 (2)
C1	0.045 (3)	0.029 (2)	0.046 (2)	0.011 (2)	0.012 (2)	0.022 (2)
C2	0.040 (2)	0.023 (2)	0.039 (2)	0.008 (2)	0.011 (2)	0.012 (2)
N1	0.045 (2)	0.023 (2)	0.035 (2)	0.0084 (15)	0.008 (2)	0.0106 (14)
C3	0.037 (2)	0.030 (2)	0.046 (3)	0.003 (2)	0.007 (2)	0.012 (2)
C4	0.044 (3)	0.030 (2)	0.036 (2)	0.003 (2)	0.002 (2)	0.012 (2)
C8	0.050 (3)	0.033 (2)	0.038 (2)	0.016 (2)	0.014 (2)	0.014 (2)
N7	0.062 (3)	0.046 (2)	0.035 (2)	0.007 (2)	0.013 (2)	0.015 (2)
C6	0.061 (3)	0.040 (2)	0.035 (2)	0.007 (2)	0.006 (2)	0.019 (2)
N5	0.046 (2)	0.032 (2)	0.040 (2)	0.012 (2)	0.005 (2)	0.013 (2)
O11	0.046 (2)	0.032 (2)	0.049 (2)	0.0044 (14)	0.013 (2)	0.0171 (13)
O12	0.043 (2)	0.033 (2)	0.059 (2)	0.0087 (14)	0.012 (2)	0.0245 (15)
C11	0.035 (2)	0.031 (2)	0.034 (2)	0.009 (2)	0.013 (2)	0.015 (2)
C12	0.035 (2)	0.026 (2)	0.032 (2)	0.004 (2)	0.009 (2)	0.0128 (15)
N11	0.042 (2)	0.027 (2)	0.034 (2)	0.007 (2)	0.007 (2)	0.0140 (14)
C13	0.039 (2)	0.025 (2)	0.036 (2)	0.004 (2)	0.007 (2)	0.010 (2)
C14	0.040 (2)	0.026 (2)	0.027 (2)	0.006 (2)	0.003 (2)	0.006 (2)
C18	0.054 (3)	0.030 (2)	0.031 (2)	0.009 (2)	0.006 (2)	0.011 (2)
N17	0.048 (2)	0.041 (2)	0.036 (2)	0.013 (2)	0.015 (2)	0.012 (2)
C16	0.055 (3)	0.039 (2)	0.035 (2)	0.008 (2)	0.012 (2)	0.013 (2)
N15	0.053 (2)	0.028 (2)	0.032 (2)	0.012 (2)	0.010 (2)	0.0104 (14)
O21	0.086 (3)	0.052 (2)	0.048 (2)	0.020 (2)	0.025 (2)	0.029 (2)
O22	0.072 (3)	0.087 (3)	0.087 (3)	0.041 (3)	0.033 (3)	0.062 (3)
C23	0.060 (3)	0.044 (3)	0.037 (2)	0.012 (2)	0.014 (2)	0.017 (2)
C24	0.052 (3)	0.053 (3)	0.049 (3)	0.013 (3)	0.015 (2)	0.026 (2)
C25	0.049 (3)	0.047 (3)	0.049 (3)	0.016 (2)	0.012 (2)	0.024 (2)
C26	0.053 (3)	0.042 (2)	0.035 (2)	0.012 (2)	0.007 (2)	0.017 (2)
O27	0.075 (3)	0.120 (4)	0.089 (4)	0.048 (3)	0.042 (3)	0.076 (4)
O28	0.070 (3)	0.060 (2)	0.045 (2)	0.023 (2)	0.021 (2)	0.029 (2)
O31	0.062 (3)	0.052 (2)	0.055 (2)	0.017 (2)	0.023 (2)	0.032 (2)
O32	0.052 (2)	0.077 (3)	0.066 (3)	0.030 (2)	0.026 (2)	0.049 (2)
C33	0.047 (3)	0.040 (2)	0.044 (3)	0.008 (2)	0.013 (2)	0.020 (2)
C34	0.046 (3)	0.047 (3)	0.044 (3)	0.011 (2)	0.013 (2)	0.019 (2)
C35	0.047 (3)	0.047 (3)	0.044 (3)	0.018 (2)	0.014 (2)	0.022 (2)
C36	0.047 (3)	0.044 (3)	0.037 (2)	0.005 (2)	0.005 (2)	0.016 (2)
O37	0.065 (3)	0.104 (4)	0.078 (3)	0.038 (3)	0.033 (2)	0.066 (3)
O38	0.079 (3)	0.059 (2)	0.049 (2)	0.026 (2)	0.026 (2)	0.032 (2)

Geometric parameters (Å, º)

O1—C1	1.228 (7)	C14—N15	1.380 (6)
O2—C1	1.249 (6)	C18—N17	1.373 (6)
C1—C2	1.544 (6)	N17—C16	1.318 (7)
C2—N1	1.486 (5)	C16—N15	1.325 (7)
C2—C3	1.528 (7)	O21—C23	1.230 (7)
C3—C4	1.499 (7)	O22—C23	1.276 (8)
C4—C8	1.364 (7)	C23—C24	1.496 (8)
C4—N5	1.381 (6)	C24—C25	1.343 (8)
C8—N7	1.373 (6)	C25—C26	1.475 (8)
N7—C6	1.292 (7)	C26—O28	1.209 (6)
C6—N5	1.328 (7)	C26—O27	1.298 (8)
O11—C11	1.226 (6)	O31—C33	1.238 (7)
O12—C11	1.264 (6)	O32—C33	1.279 (7)
C11—C12	1.534 (5)	C33—C34	1.485 (7)
C12—N11	1.492 (6)	C34—C35	1.328 (7)
C12—C13	1.530 (6)	C35—C36	1.479 (7)
C13—C14	1.493 (6)	C36—O38	1.227 (6)
C14—C18	1.338 (7)	C36—O37	1.278 (8)
O1—C1—O2	127.3 (5)	C18—C14—C13	128.8 (4)
O1—C1—C2	116.8 (4)	N15—C14—C13	125.1 (4)
O2—C1—C2	115.8 (4)	C14—C18—N17	108.2 (4)
N1—C2—C3	110.6 (3)	C16—N17—C18	108.0 (4)
N1—C2—C1	109.0 (4)	N17—C16—N15	108.9 (4)
C3—C2—C1	114.9 (4)	C16—N15—C14	108.8 (4)
C4—C3—C2	113.1 (4)	O21—C23—O22	123.0 (6)
C8—C4—N5	105.5 (4)	O21—C23—C24	117.7 (6)
C8—C4—C3	131.6 (4)	O22—C23—C24	119.2 (5)
N5—C4—C3	122.9 (5)	C25—C24—C23	130.4 (6)
C4—C8—N7	106.6 (4)	C24—C25—C26	130.6 (5)
C6—N7—C8	110.2 (5)	O28—C26—O27	121.6 (5)
N7—C6—N5	108.4 (5)	O28—C26—C25	119.2 (5)
C6—N5—C4	109.4 (4)	O27—C26—C25	119.2 (5)
O11—C11—O12	127.0 (4)	O31—C33—O32	122.8 (5)
O11—C11—C12	118.5 (4)	O31—C33—C34	117.7 (5)
O12—C11—C12	114.4 (4)	O32—C33—C34	119.5 (5)
N11—C12—C13	110.9 (4)	C35—C34—C33	130.1 (5)
N11—C12—C11	110.1 (3)	C34—C35—C36	131.4 (5)
C13—C12—C11	112.9 (3)	O38—C36—O37	121.1 (5)
C14—C13—C12	115.1 (4)	O38—C36—C35	118.8 (5)
C18—C14—N15	106.1 (4)	O37—C36—C35	120.0 (5)

(II)

Crystal data

C6H15N2O2^+·C4H3O4^−	F(000) = 280
Mr = 262	Dx = 1.414 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.70930 Å
Hall symbol: P 2y1	Cell parameters from 25 reflections
a = 9.854 (4) Å	θ = 0–13°
b = 7.136 (2) Å	µ = 0.12 mm^−1
c = 9.7388 (1) Å	T = 293 K
β = 115.887 (12)°	Needle, colourless
V = 616.1 (3) Å^3	0.49 × 0.25 × 0.10 mm
Z = 2

Data collection

CAD4 diffractometer	1097 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.057
Graphite monochromator	θmax = 28.0°, θmin = 2.3°
ω–2/q scans	h = −12→11
Absorption correction: ψ scan North et al., 1968	k = 0→9
Tmin = 0.965, Tmax = 0.988	l = 0→12
1759 measured reflections	3 standard reflections every 60 min
1598 independent reflections

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.057	Calculated w = 1/[s^2(Fo^2) + ( 0.0823P)^2 + 0.3879P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.169	(Δ/σ)max < 0.001
S = 1.06	Δρmax = 0.34 e Å^−3
1598 reflections	Δρmin = −0.31 e Å^−3
167 parameters	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2l^3/sin(2q)]^-1/4
3 restraints	Extinction coefficient: 0.0121 (77)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881
Secondary atom site location: difference Fourier map	Absolute structure parameter: −0.59 (311)

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 on F² for ALL reflections except for 0 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating _R_factor_obs 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
N1	0.4769 (4)	0.6481 (8)	0.6095 (4)	0.0317 (9)
H1N1	0.5082 (4)	0.6760 (8)	0.5389 (4)	0.048*
H2N1	0.3781 (4)	0.6690 (8)	0.5723 (4)	0.048*
H3N1	0.4958 (4)	0.5280 (8)	0.6354 (4)	0.048*
O2	0.8134 (4)	0.8491 (6)	0.8937 (5)	0.0416 (10)
O1	0.7635 (4)	0.5686 (5)	0.7829 (4)	0.0378 (9)
C1	0.7268 (5)	0.7245 (7)	0.8118 (5)	0.0255 (10)
C2	0.5583 (5)	0.7681 (7)	0.7471 (5)	0.0235 (9)
H1C2	0.5404 (5)	0.9007 (7)	0.7189 (5)	0.035*
C3	0.5067 (5)	0.7232 (8)	0.8699 (5)	0.0278 (11)
H1C3	0.5768 (5)	0.7805 (8)	0.9648 (5)	0.042*
H2C3	0.5121 (5)	0.5886 (8)	0.8856 (5)	0.042*
C4	0.3476 (5)	0.7882 (8)	0.8356 (5)	0.0292 (12)
H1C4	0.3423 (5)	0.9238 (8)	0.8274 (5)	0.044*
H2C4	0.2764 (5)	0.7363 (8)	0.7387 (5)	0.044*
C5	0.3054 (5)	0.7259 (8)	0.9607 (5)	0.0284 (10)
H1C5	0.3165 (5)	0.5910 (8)	0.9723 (5)	0.043*
H2C5	0.3743 (5)	0.7827 (8)	1.0564 (5)	0.043*
C6	0.1456 (5)	0.7790 (10)	0.9276 (6)	0.0390 (15)
H1C6	0.1311 (5)	0.9119 (10)	0.9048 (6)	0.059*
H2C6	0.0759 (5)	0.7110 (10)	0.8384 (6)	0.059*
N7	0.1119 (4)	0.7364 (7)	1.0587 (4)	0.0298 (9)
H1N7	0.0172 (4)	0.7692 (7)	1.0357 (4)	0.045*
H2N7	0.1746 (4)	0.8003 (7)	1.1403 (4)	0.045*
H3N7	0.1235 (4)	0.6142 (7)	1.0787 (4)	0.045*
O12	0.2976 (4)	0.3213 (6)	0.7425 (4)	0.0417 (10)
O11	0.4121 (4)	0.2541 (7)	0.5990 (4)	0.0431 (10)
C13	0.2992 (5)	0.2478 (8)	0.6247 (5)	0.0290 (10)
C14	0.1628 (5)	0.1499 (9)	0.5124 (5)	0.0332 (11)
HC14	0.1728 (5)	0.0983 (9)	0.4296 (5)	0.050*
C15	0.0280 (6)	0.1241 (8)	0.5115 (6)	0.0324 (11)
HC15	−0.0406 (6)	0.0570 (8)	0.4282 (6)	0.049*
C16	−0.0305 (5)	0.1857 (8)	0.6227 (6)	0.0366 (14)
O18	−0.1642 (4)	0.1561 (8)	0.5894 (5)	0.0502 (11)
O17	0.0588 (4)	0.2590 (7)	0.7501 (4)	0.0441 (10)
HO17	0.187 (3)	0.278 (11)	0.764 (6)	0.066*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.024 (2)	0.042 (2)	0.032 (2)	−0.004 (2)	0.015 (2)	−0.003 (2)
O2	0.027 (2)	0.042 (2)	0.056 (2)	−0.005 (2)	0.019 (2)	−0.005 (2)
O1	0.036 (2)	0.032 (2)	0.050 (2)	0.010 (2)	0.023 (2)	0.003 (2)
C1	0.021 (2)	0.028 (3)	0.030 (2)	0.002 (2)	0.015 (2)	0.006 (2)
C2	0.021 (2)	0.022 (2)	0.029 (2)	−0.001 (2)	0.012 (2)	0.001 (2)
C3	0.023 (2)	0.032 (3)	0.032 (2)	0.002 (2)	0.015 (2)	0.002 (2)
C4	0.024 (2)	0.035 (3)	0.033 (2)	0.002 (2)	0.017 (2)	0.003 (2)
C5	0.026 (2)	0.029 (3)	0.037 (2)	0.002 (2)	0.020 (2)	0.002 (2)
C6	0.027 (2)	0.064 (4)	0.033 (2)	0.005 (3)	0.019 (2)	0.003 (3)
N7	0.025 (2)	0.032 (2)	0.039 (2)	0.001 (2)	0.020 (2)	0.000 (2)
O12	0.035 (2)	0.059 (3)	0.034 (2)	−0.014 (2)	0.017 (2)	−0.013 (2)
O11	0.037 (2)	0.052 (2)	0.051 (2)	−0.004 (2)	0.029 (2)	−0.003 (2)
C13	0.032 (2)	0.024 (2)	0.035 (2)	0.000 (2)	0.018 (2)	0.001 (2)
C14	0.032 (3)	0.039 (3)	0.031 (2)	0.001 (2)	0.015 (2)	−0.009 (2)
C15	0.035 (3)	0.029 (3)	0.032 (2)	−0.003 (2)	0.014 (2)	−0.004 (2)
C16	0.028 (2)	0.048 (4)	0.035 (3)	−0.001 (2)	0.015 (2)	0.007 (2)
O18	0.029 (2)	0.072 (3)	0.053 (2)	−0.003 (2)	0.021 (2)	0.001 (2)
O17	0.034 (2)	0.070 (3)	0.032 (2)	−0.006 (2)	0.0181 (15)	−0.010 (2)

Geometric parameters (Å, º)

N1—C2	1.494 (6)	C6—N7	1.485 (5)
O2—C1	1.249 (6)	O12—C13	1.268 (6)
O1—C1	1.239 (6)	O11—C13	1.244 (5)
C1—C2	1.529 (6)	C13—C14	1.485 (7)
C2—C3	1.524 (6)	C14—C15	1.337 (7)
C3—C4	1.526 (6)	C15—C16	1.498 (7)
C4—C5	1.516 (6)	C16—O18	1.230 (6)
C5—C6	1.511 (6)	C16—O17	1.278 (6)
O1—C1—O2	126.7 (4)	N7—C6—C5	111.6 (4)
O1—C1—C2	117.4 (4)	O11—C13—O12	122.2 (5)
O2—C1—C2	115.8 (4)	O11—C13—C14	118.0 (4)
N1—C2—C3	110.6 (4)	O12—C13—C14	119.7 (4)
N1—C2—C1	108.3 (4)	C15—C14—C13	130.3 (4)
C3—C2—C1	108.0 (4)	C14—C15—C16	130.5 (5)
C2—C3—C4	115.3 (4)	O18—C16—O17	122.1 (5)
C5—C4—C3	110.5 (4)	O18—C16—C15	117.7 (5)
C6—C5—C4	112.4 (4)	O17—C16—C15	120.2 (4)