Bis(4-amino­pyridinium) dichromate(VI)

Trabelsi, S.; Roisnel, T.; Dhaouadi, H.; Marouani, H.

doi:10.1107/S1600536814013579

Bis(4-aminopyridinium) dichromate(VI)

S. Trabelsi, T. Roisnel, H. Dhaouadi and H. Marouani

The asymmetric unit of the title salt, (C₅H₇N₂)₂[Cr₂O₇], contains four independent cations and two independent dichromate anions. The crystal structure consists of discrete dichromate anions with an eclipsed conformation stacked in layers parallel to (010) at y = 1/4 and y = 3/4. These layers are linked via 4-aminopyridinium cations by N—H

O and weak C—H

O hydrogen bonds, forming a three-dimensional supramolecular network. In addition, π–π interactions are present in this structure; the shortest distance separating mean planes through 4-aminopyridinium cations is 3.679 (6) Å.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536814013579/bh2500sup1.cif Contains datablocks I, global
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536814013579/bh2500Isup2.hkl Contains datablock I
	Chemical Markup Language (CML) file https://doi.org/10.1107/S1600536814013579/bh2500Isup3.cml Supplementary material

CCDC reference: 1007743

checkCIF report

Key indicators

Single-crystal X-ray study
T = 150 K
Mean (C-C) = 0.004 Å
R factor = 0.035
wR factor = 0.097
Data-to-parameter ratio = 16.5

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No syntax errors found



Alert level C
PLAT906_ALERT_3_C Large K value in the Analysis of Variance ......      3.233 Check
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          6 Why ?
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          5 Why ?
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          5 Note
PLAT934_ALERT_3_C Number of (Iobs-Icalc)/SigmaW > 10 Outliers ....          1 Check

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF     Please Do !
PLAT007_ALERT_5_G Number of Unrefined Donor-H Atoms ..............         12 Why ?
PLAT042_ALERT_1_G Calc. and Reported MoietyFormula Strings  Differ     Please Check
PLAT112_ALERT_2_G ADDSYM Detects Additional (Pseudo) Symm. Elem...          Z Check
PLAT128_ALERT_4_G Alternate Setting for Input Space-Group  P21/c        P21/n Note
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          4 Note
PLAT790_ALERT_4_G Centre of Gravity not Within Unit Cell: Resd.  #          3 Note
              C5 H7 N2

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   5 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   7 ALERT level G = General information/check it is not something unexpected

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   5 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

Comment top

Usually, pyridine can serve as an efficient bioisostere of benzene in drug design, and considerable interest has been shown in pyridine derivatives in the field of modern agrochemistry and medicinal chemistry, because substitution of the benzene by pyridine may result in good biological activity and low toxicity of molecules containing the pyridyl moiety (Patani & LaVoie, 1996; Ma & Huang, 2003). In this work, we report the preparation and the structural investigation of a new organic dichromate, (C₅H₇N₂)₂·Cr₂O₇, (I).

The asymmetric unit of (I) is composed of two independent dichromate anions and four independent 4-aminopyridinium cations (Fig. 1). The structure of the compound consists of discrete dichromate ions with an eclipsed conformation stacked in layers parallel to the (010) plane at y = 0.25 and 0.75. These layers are linked via the 4-aminopidridinium cations by N—H···O and C—H···O hydrogen bonds, forming a three-dimensional supramolecular network as shown in figure 2.

Interatomic bond lengths and angles of the dichromate anions spread respectively within the ranges [1.6038 (17)–1.8059 (17) Å] and [105.42 (8)–112.22 (10)°] for O—Cr—O angles and [120.12 (9)–125.63 (9)°] for Cr—O—Cr angles. These geometrical features have also been noticed in other related crystal structure (Trabelsi et al., 2012; Lennartson & Håkansson, 2009).

In this atomic arrangement four independent 4-aminopyridinium cations are present. Examination of the organic cations shows that the bond distances and angles show no significant difference from those obtained in oxalate and picrate salts involving the same organic group (Fun et al., 2009; Ramesh et al., 2010). Each 4-aminopyridinium cations is planar, with a maximum deviation of 0.0024 (2) Å. The shortest inter-planar distance between nearby pyridine rings is 3.679 (6) Å, which is much shorter than 3.80 Å, indicating the formation of π–π interactions (Fig. 3, Janiak, 2000).

The established H-bonds of types N—H···O and C—H···O involve O atoms of the dichromate anions as acceptors, and the protonated N atoms and carbon atoms of 4-aminopyridinium as donors.

Related literature top

For properties of pyridine-based compounds, see: Patani & LaVoie (1996); Ma & Huang (2003). For related structures, see: Trabelsi et al. (2012); Lennartson & Håkansson (2009); Fun et al. (2009); Ramesh et al. (2010). For aromatic π–π stacking interactions, see: Janiak (2000).

Experimental top

Single crystals of the title compound were prepared at room temperature by dissolving CrO₃ (0.10 g, 1 mmol) and 4-aminopyridine (Fampridine, 0.09 g, 1 mmol) in distilled water (20 ml). The resulting solution was stirred during 1 h, filtered and then evaporated slowly at room temperature until the formation of orange prismatic single crystals.

Structure description top

The established H-bonds of types N—H···O and C—H···O involve O atoms of the dichromate anions as acceptors, and the protonated N atoms and carbon atoms of 4-aminopyridinium as donors.

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 2012) and CRYSCAL (T. Roisnel, local program).

Figures top

	Fig. 1. An ORTEP view of (I) with the atom-labeling scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are represented as small spheres of arbitrary radii.
	Fig. 2. Projection of (I) along the a axis. The H-atoms not involved in H-bonding are omitted.
	Fig. 3. Perspective view showing the π—π interactions between adjacent 4-aminopyridinium groups. Dichromate anions have been omitted for clarity.

Bis(4-aminopyridinium) dichromate(VI) top

Crystal data top

(C₅H₇N₂)₂[Cr₂O₇]	F(000) = 1648
M_r = 406.25	D_x = 1.796 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 5472 reflections
a = 13.8505 (4) Å	θ = 2.7–27.3°
b = 16.2486 (4) Å	µ = 1.49 mm⁻¹
c = 15.2586 (4) Å	T = 150 K
β = 118.923 (2)°	Prism, orange
V = 3005.65 (14) Å³	0.58 × 0.5 × 0.4 mm
Z = 8

Data collection top

Bruker APEXII diffractometer	5506 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.042
CCD rotation images, thin slices scans	θ_max = 27.5°, θ_min = 2.9°
Absorption correction: multi-scan (SADABS; Bruker, 2006)	h = −17→17
T_min = 0.469, T_max = 0.552	k = −16→21
23461 measured reflections	l = −17→19
6868 independent reflections

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)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.097	H-atom parameters constrained
S = 1.07	w = 1/[σ²(F_o²) + (0.0409P)² + 1.1738P] where P = (F_o² + 2F_c²)/3
6868 reflections	(Δ/σ)_max = 0.001
415 parameters	Δρ_max = 0.41 e Å⁻³
0 restraints	Δρ_min = −0.58 e Å⁻³
0 constraints

Crystal data top

(C₅H₇N₂)₂[Cr₂O₇]	V = 3005.65 (14) Å³
M_r = 406.25	Z = 8
Monoclinic, P2₁/c	Mo Kα radiation
a = 13.8505 (4) Å	µ = 1.49 mm⁻¹
b = 16.2486 (4) Å	T = 150 K
c = 15.2586 (4) Å	0.58 × 0.5 × 0.4 mm
β = 118.923 (2)°

Data collection top

Bruker APEXII diffractometer	6868 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2006)	5506 reflections with I > 2σ(I)
T_min = 0.469, T_max = 0.552	R_int = 0.042
23461 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.035	0 restraints
wR(F²) = 0.097	H-atom parameters constrained
S = 1.07	Δρ_max = 0.41 e Å⁻³
6868 reflections	Δρ_min = −0.58 e Å⁻³
415 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cr1	0.30978 (3)	0.25913 (2)	0.87600 (3)	0.01226 (10)
Cr2	0.14056 (3)	0.25667 (2)	0.64724 (3)	0.01334 (10)
O1	0.36183 (14)	0.34529 (10)	0.86547 (12)	0.0217 (4)
O2	0.37986 (14)	0.18108 (11)	0.87204 (13)	0.0251 (4)
O3	0.30456 (14)	0.25734 (9)	0.97973 (12)	0.0175 (4)
O4	0.16957 (13)	0.25140 (9)	0.77567 (12)	0.0141 (3)
O5	0.25558 (15)	0.24640 (9)	0.64455 (13)	0.0206 (4)
O6	0.05649 (17)	0.18307 (12)	0.58819 (13)	0.0335 (5)
O7	0.08641 (15)	0.34537 (11)	0.60243 (13)	0.0257 (4)
Cr3	0.86884 (3)	0.24904 (2)	0.83351 (3)	0.01316 (10)
Cr4	0.63121 (3)	0.25479 (2)	0.63638 (3)	0.01368 (10)
O8	0.85329 (15)	0.17165 (11)	0.89157 (13)	0.0285 (4)
O9	0.84062 (15)	0.33450 (11)	0.87063 (13)	0.0256 (4)
O10	0.99257 (14)	0.25074 (9)	0.84773 (13)	0.0187 (4)
O11	0.77849 (14)	0.23816 (9)	0.70058 (12)	0.0179 (4)
O12	0.60940 (16)	0.35133 (11)	0.61015 (15)	0.0314 (5)
O13	0.58360 (15)	0.20101 (13)	0.53587 (14)	0.0334 (5)
O14	0.57985 (15)	0.22726 (11)	0.70728 (13)	0.0261 (4)
N1	0.10279 (16)	0.40072 (12)	−0.14295 (15)	0.0211 (5)
HN1	0.0888	0.3498	−0.1597	0.025*
C1	0.1345 (2)	0.45034 (15)	−0.19490 (19)	0.0210 (5)
H1	0.1399	0.4292	−0.2490	0.025*
C2	0.1588 (2)	0.53063 (14)	−0.16971 (18)	0.0179 (5)
H2	0.1804	0.5642	−0.2065	0.021*
C3	0.15119 (19)	0.56323 (14)	−0.08699 (17)	0.0156 (5)
C4	0.11508 (19)	0.50918 (14)	−0.03606 (18)	0.0181 (5)
H4	0.1068	0.5284	0.0174	0.022*
C5	0.0925 (2)	0.42948 (15)	−0.06501 (19)	0.0211 (5)
H5	0.0696	0.3942	−0.0307	0.025*
N2	0.17652 (18)	0.64076 (12)	−0.05892 (16)	0.0237 (5)
H2A	0.1712	0.6594	−0.0087	0.028*
H2B	0.1983	0.6726	−0.0909	0.028*
N3	0.36147 (17)	0.39842 (12)	0.12358 (15)	0.0212 (5)
HN3	0.3460	0.3468	0.1153	0.025*
C6	0.3965 (2)	0.43597 (15)	0.06512 (19)	0.0217 (5)
H6	0.4039	0.4059	0.0168	0.026*
C7	0.4210 (2)	0.51765 (14)	0.07674 (18)	0.0188 (5)
H7	0.4446	0.5433	0.0360	0.023*
C8	0.41064 (18)	0.56376 (14)	0.15032 (17)	0.0154 (5)
C9	0.37277 (19)	0.52161 (15)	0.20893 (17)	0.0176 (5)
H9	0.3633	0.5497	0.2573	0.021*
C10	0.3502 (2)	0.43966 (15)	0.19426 (18)	0.0213 (5)
H10	0.3267	0.4119	0.2338	0.026*
N4	0.43612 (18)	0.64317 (12)	0.16345 (16)	0.0229 (5)
H4A	0.4593	0.6673	0.1269	0.027*
H4B	0.4295	0.6705	0.2085	0.027*
N5	0.66256 (17)	0.60129 (12)	0.39258 (16)	0.0238 (5)
HN5	0.6758	0.6531	0.3940	0.029*
C11	0.6760 (2)	0.55244 (16)	0.32819 (19)	0.0244 (6)
H11	0.6991	0.5753	0.2856	0.029*
C12	0.6565 (2)	0.47016 (15)	0.32428 (18)	0.0190 (5)
H12	0.6668	0.4372	0.2797	0.023*
C13	0.62036 (19)	0.43485 (14)	0.38822 (18)	0.0165 (5)
C14	0.6076 (2)	0.48867 (14)	0.45475 (18)	0.0186 (5)
H14	0.5847	0.4680	0.4986	0.022*
C15	0.6286 (2)	0.57029 (15)	0.45493 (18)	0.0208 (5)
H15	0.6194	0.6052	0.4986	0.025*
N6	0.59854 (18)	0.35547 (12)	0.38491 (17)	0.0243 (5)
H6A	0.5759	0.3352	0.4239	0.029*
H6B	0.6069	0.3240	0.3438	0.029*
N7	0.89889 (16)	0.60146 (12)	0.66303 (15)	0.0190 (4)
HN7	0.9067	0.6532	0.6768	0.023*
C16	0.9173 (2)	0.57268 (15)	0.58964 (18)	0.0193 (5)
H16	0.9388	0.6088	0.5549	0.023*
C17	0.9048 (2)	0.49117 (14)	0.56583 (18)	0.0176 (5)
H17	0.9179	0.4719	0.5152	0.021*
C18	0.87181 (18)	0.43586 (14)	0.61778 (17)	0.0147 (5)
C19	0.8537 (2)	0.46897 (14)	0.69469 (17)	0.0173 (5)
H19	0.8317	0.4348	0.7307	0.021*
C20	0.8684 (2)	0.55068 (14)	0.71542 (18)	0.0193 (5)
H20	0.8574	0.5720	0.7664	0.023*
N8	0.85990 (17)	0.35635 (12)	0.59675 (16)	0.0224 (5)
H8A	0.8723	0.3373	0.5505	0.027*
H8B	0.8398	0.3237	0.6293	0.027*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cr1	0.01379 (19)	0.01437 (19)	0.00998 (19)	0.00100 (14)	0.00682 (15)	0.00061 (13)
Cr2	0.0164 (2)	0.0147 (2)	0.01068 (19)	−0.00082 (14)	0.00786 (16)	−0.00082 (13)
O1	0.0222 (9)	0.0246 (9)	0.0173 (9)	−0.0072 (7)	0.0087 (8)	0.0028 (7)
O2	0.0254 (10)	0.0302 (10)	0.0190 (9)	0.0122 (8)	0.0101 (8)	−0.0010 (7)
O3	0.0242 (9)	0.0174 (9)	0.0133 (8)	−0.0004 (7)	0.0110 (7)	0.0004 (6)
O4	0.0140 (8)	0.0178 (9)	0.0118 (8)	−0.0018 (6)	0.0074 (7)	−0.0005 (6)
O5	0.0264 (10)	0.0203 (9)	0.0237 (10)	0.0048 (7)	0.0189 (8)	0.0033 (7)
O6	0.0422 (12)	0.0414 (12)	0.0202 (10)	−0.0249 (10)	0.0176 (9)	−0.0157 (8)
O7	0.0315 (11)	0.0282 (10)	0.0198 (9)	0.0136 (8)	0.0143 (8)	0.0090 (7)
Cr3	0.0135 (2)	0.0144 (2)	0.01207 (19)	−0.00019 (14)	0.00655 (16)	0.00043 (14)
Cr4	0.0156 (2)	0.0147 (2)	0.01179 (19)	0.00095 (14)	0.00741 (16)	−0.00091 (13)
O8	0.0246 (10)	0.0328 (11)	0.0250 (10)	−0.0072 (8)	0.0095 (8)	0.0110 (8)
O9	0.0253 (10)	0.0289 (10)	0.0210 (9)	0.0056 (8)	0.0101 (8)	−0.0072 (8)
O10	0.0162 (9)	0.0168 (9)	0.0233 (9)	−0.0012 (6)	0.0097 (8)	−0.0010 (7)
O11	0.0169 (9)	0.0228 (9)	0.0128 (8)	0.0018 (7)	0.0063 (7)	−0.0024 (7)
O12	0.0348 (12)	0.0212 (10)	0.0418 (12)	0.0093 (8)	0.0213 (10)	0.0123 (8)
O13	0.0224 (10)	0.0478 (13)	0.0247 (10)	0.0023 (9)	0.0072 (8)	−0.0187 (9)
O14	0.0280 (10)	0.0314 (10)	0.0237 (10)	−0.0016 (8)	0.0164 (9)	0.0043 (8)
N1	0.0185 (11)	0.0118 (10)	0.0255 (12)	−0.0007 (8)	0.0046 (9)	−0.0024 (8)
C1	0.0188 (13)	0.0218 (13)	0.0200 (13)	0.0039 (10)	0.0074 (11)	−0.0039 (10)
C2	0.0185 (13)	0.0184 (12)	0.0194 (13)	0.0039 (10)	0.0113 (11)	0.0036 (10)
C3	0.0121 (11)	0.0141 (11)	0.0191 (12)	0.0003 (9)	0.0065 (10)	0.0010 (9)
C4	0.0164 (12)	0.0219 (13)	0.0159 (12)	−0.0011 (10)	0.0078 (10)	0.0021 (9)
C5	0.0187 (13)	0.0189 (12)	0.0223 (13)	−0.0001 (10)	0.0072 (11)	0.0071 (10)
N2	0.0328 (13)	0.0157 (10)	0.0320 (13)	−0.0039 (9)	0.0233 (11)	−0.0041 (9)
N3	0.0219 (11)	0.0107 (10)	0.0277 (12)	−0.0011 (8)	0.0094 (10)	0.0004 (8)
C6	0.0221 (13)	0.0216 (13)	0.0225 (13)	0.0008 (10)	0.0117 (11)	−0.0039 (10)
C7	0.0244 (14)	0.0179 (12)	0.0187 (13)	−0.0006 (10)	0.0140 (11)	−0.0008 (10)
C8	0.0120 (11)	0.0162 (12)	0.0153 (12)	0.0013 (9)	0.0046 (10)	0.0000 (9)
C9	0.0173 (12)	0.0219 (12)	0.0147 (12)	0.0024 (10)	0.0085 (10)	0.0020 (9)
C10	0.0174 (13)	0.0237 (13)	0.0215 (13)	0.0008 (10)	0.0085 (11)	0.0074 (10)
N4	0.0346 (13)	0.0152 (10)	0.0272 (12)	−0.0019 (9)	0.0216 (11)	−0.0025 (9)
N5	0.0226 (12)	0.0129 (10)	0.0287 (12)	−0.0010 (9)	0.0066 (10)	0.0048 (9)
C11	0.0215 (14)	0.0286 (14)	0.0228 (14)	−0.0014 (11)	0.0105 (11)	0.0095 (11)
C12	0.0176 (13)	0.0256 (13)	0.0163 (12)	−0.0012 (10)	0.0101 (11)	−0.0011 (10)
C13	0.0137 (12)	0.0165 (12)	0.0178 (12)	−0.0004 (9)	0.0064 (10)	0.0001 (9)
C14	0.0194 (13)	0.0211 (13)	0.0171 (12)	0.0007 (10)	0.0102 (11)	0.0007 (10)
C15	0.0194 (13)	0.0176 (12)	0.0189 (13)	0.0025 (10)	0.0042 (11)	−0.0030 (10)
N6	0.0342 (13)	0.0172 (11)	0.0322 (12)	−0.0065 (9)	0.0246 (11)	−0.0050 (9)
N7	0.0203 (11)	0.0118 (10)	0.0214 (11)	0.0017 (8)	0.0072 (9)	0.0006 (8)
C16	0.0175 (13)	0.0201 (13)	0.0187 (13)	0.0008 (10)	0.0076 (10)	0.0074 (10)
C17	0.0169 (12)	0.0209 (13)	0.0173 (12)	−0.0001 (10)	0.0102 (10)	0.0009 (9)
C18	0.0114 (11)	0.0152 (11)	0.0173 (12)	0.0004 (9)	0.0067 (10)	0.0010 (9)
C19	0.0192 (13)	0.0187 (12)	0.0165 (12)	0.0018 (10)	0.0106 (10)	0.0028 (9)
C20	0.0212 (13)	0.0206 (12)	0.0169 (12)	0.0048 (10)	0.0100 (11)	−0.0010 (10)
N8	0.0312 (13)	0.0165 (10)	0.0284 (12)	−0.0045 (9)	0.0215 (11)	−0.0037 (9)

Geometric parameters (Å, º) top

Cr1—O2	1.6158 (17)	C7—H7	0.9300
Cr1—O1	1.6178 (17)	C8—N4	1.327 (3)
Cr1—O3	1.6193 (16)	C8—C9	1.413 (3)
Cr1—O4	1.8041 (17)	C9—C10	1.361 (3)
Cr2—O6	1.6072 (18)	C9—H9	0.9300
Cr2—O7	1.6160 (17)	C10—H10	0.9300
Cr2—O5	1.6219 (18)	N4—H4A	0.8600
Cr2—O4	1.8020 (16)	N4—H4B	0.8600
Cr3—O8	1.6115 (17)	N5—C11	1.344 (3)
Cr3—O9	1.6175 (17)	N5—C15	1.347 (3)
Cr3—O10	1.6202 (17)	N5—HN5	0.8600
Cr3—O11	1.8044 (17)	C11—C12	1.360 (3)
Cr4—O13	1.6038 (17)	C11—H11	0.9300
Cr4—O12	1.6109 (18)	C12—C13	1.415 (3)
Cr4—O14	1.6188 (17)	C12—H12	0.9300
Cr4—O11	1.8059 (17)	C13—N6	1.320 (3)
N1—C1	1.345 (3)	C13—C14	1.414 (3)
N1—C5	1.348 (3)	C14—C15	1.357 (3)
N1—HN1	0.8600	C14—H14	0.9300
C1—C2	1.356 (3)	C15—H15	0.9300
C1—H1	0.9300	N6—H6A	0.8600
C2—C3	1.419 (3)	N6—H6B	0.8600
C2—H2	0.9300	N7—C16	1.347 (3)
C3—N2	1.322 (3)	N7—C20	1.351 (3)
C3—C4	1.415 (3)	N7—HN7	0.8600
C4—C5	1.355 (3)	C16—C17	1.362 (3)
C4—H4	0.9300	C16—H16	0.9300
C5—H5	0.9300	C17—C18	1.412 (3)
N2—H2A	0.8600	C17—H17	0.9300
N2—H2B	0.8600	C18—N8	1.322 (3)
N3—C10	1.341 (3)	C18—C19	1.419 (3)
N3—C6	1.350 (3)	C19—C20	1.357 (3)
N3—HN3	0.8600	C19—H19	0.9300
C6—C7	1.360 (3)	C20—H20	0.9300
C6—H6	0.9300	N8—H8A	0.8600
C7—C8	1.413 (3)	N8—H8B	0.8600

O2—Cr1—O1	111.77 (10)	C8—C7—H7	119.8
O2—Cr1—O3	109.52 (8)	N4—C8—C7	120.9 (2)
O1—Cr1—O3	110.20 (8)	N4—C8—C9	121.9 (2)
O2—Cr1—O4	109.46 (8)	C7—C8—C9	117.2 (2)
O1—Cr1—O4	108.93 (8)	C10—C9—C8	119.7 (2)
O3—Cr1—O4	106.84 (8)	C10—C9—H9	120.1
O6—Cr2—O7	111.36 (10)	C8—C9—H9	120.1
O6—Cr2—O5	111.31 (9)	N3—C10—C9	121.0 (2)
O7—Cr2—O5	109.97 (9)	N3—C10—H10	119.5
O6—Cr2—O4	107.12 (8)	C9—C10—H10	119.5
O7—Cr2—O4	108.44 (8)	C8—N4—H4A	120.0
O5—Cr2—O4	108.51 (8)	C8—N4—H4B	120.0
O8—Cr3—O9	110.98 (11)	H4A—N4—H4B	120.0
O8—Cr3—O10	110.71 (9)	C11—N5—C15	121.0 (2)
O9—Cr3—O10	110.95 (9)	C11—N5—HN5	119.5
O8—Cr3—O11	109.70 (9)	C15—N5—HN5	119.5
O9—Cr3—O11	108.91 (8)	N5—C11—C12	121.2 (2)
O10—Cr3—O11	105.42 (8)	N5—C11—H11	119.4
O13—Cr4—O12	110.61 (10)	C12—C11—H11	119.4
O13—Cr4—O14	112.22 (10)	C11—C12—C13	119.8 (2)
O12—Cr4—O14	110.18 (9)	C11—C12—H12	120.1
O13—Cr4—O11	105.75 (8)	C13—C12—H12	120.1
O12—Cr4—O11	107.90 (9)	N6—C13—C14	121.7 (2)
O14—Cr4—O11	110.01 (9)	N6—C13—C12	121.3 (2)
Cr2—O4—Cr1	120.12 (9)	C14—C13—C12	116.9 (2)
Cr3—O11—Cr4	125.63 (9)	C15—C14—C13	120.3 (2)
C1—N1—C5	121.1 (2)	C15—C14—H14	119.8
C1—N1—HN1	119.5	C13—C14—H14	119.8
C5—N1—HN1	119.5	N5—C15—C14	120.8 (2)
N1—C1—C2	121.1 (2)	N5—C15—H15	119.6
N1—C1—H1	119.4	C14—C15—H15	119.6
C2—C1—H1	119.4	C13—N6—H6A	120.0
C1—C2—C3	119.8 (2)	C13—N6—H6B	120.0
C1—C2—H2	120.1	H6A—N6—H6B	120.0
C3—C2—H2	120.1	C16—N7—C20	121.3 (2)
N2—C3—C4	121.5 (2)	C16—N7—HN7	119.4
N2—C3—C2	121.4 (2)	C20—N7—HN7	119.4
C4—C3—C2	117.1 (2)	N7—C16—C17	120.5 (2)
C5—C4—C3	120.1 (2)	N7—C16—H16	119.7
C5—C4—H4	120.0	C17—C16—H16	119.7
C3—C4—H4	120.0	C16—C17—C18	120.2 (2)
N1—C5—C4	120.9 (2)	C16—C17—H17	119.9
N1—C5—H5	119.6	C18—C17—H17	119.9
C4—C5—H5	119.6	N8—C18—C17	121.5 (2)
C3—N2—H2A	120.0	N8—C18—C19	121.3 (2)
C3—N2—H2B	120.0	C17—C18—C19	117.2 (2)
H2A—N2—H2B	120.0	C20—C19—C18	119.8 (2)
C10—N3—C6	121.6 (2)	C20—C19—H19	120.1
C10—N3—HN3	119.2	C18—C19—H19	120.1
C6—N3—HN3	119.2	N7—C20—C19	121.0 (2)
N3—C6—C7	120.1 (2)	N7—C20—H20	119.5
N3—C6—H6	119.9	C19—C20—H20	119.5
C7—C6—H6	119.9	C18—N8—H8A	120.0
C6—C7—C8	120.4 (2)	C18—N8—H8B	120.0
C6—C7—H7	119.8	H8A—N8—H8B	120.0

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—HN1···O10ⁱ	0.86	2.13	2.842 (3)	140
N1—HN1···O4ⁱⁱ	0.86	2.42	3.065 (2)	133
N2—H2A···O9ⁱⁱⁱ	0.86	2.19	3.022 (3)	162
N2—H2B···O11^iv	0.86	2.13	2.978 (3)	167
N3—HN3···O5^v	0.86	2.14	2.871 (3)	142
N3—HN3···O3ⁱⁱ	0.86	2.36	3.003 (3)	132
N4—H4A···O13^iv	0.86	2.32	3.067 (3)	145
N4—H4A···O1ⁱⁱⁱ	0.86	2.43	3.042 (3)	128
N4—H4B···O14ⁱⁱⁱ	0.86	2.14	2.965 (3)	160
N5—HN5···O5ⁱⁱⁱ	0.86	2.11	2.890 (3)	151
N5—HN5···O3^vi	0.86	2.48	3.094 (3)	129
N6—H6A···O2^v	0.86	2.45	2.998 (3)	122
N6—H6B···O14^v	0.86	2.10	2.923 (3)	160
N7—HN7···O10^vii	0.86	2.26	2.900 (3)	131
N7—HN7···O4^vi	0.86	2.22	2.927 (2)	139
N8—H8A···O8^v	0.86	2.31	3.121 (3)	156
N8—H8B···O11	0.86	2.17	3.033 (3)	176
C1—H1···O7ⁱⁱ	0.93	2.43	3.305 (3)	156
C5—H5···O6^v	0.93	2.28	3.192 (3)	165
C6—H6···O1ⁱⁱ	0.93	2.31	3.204 (3)	161
C9—H9···O12ⁱⁱⁱ	0.93	2.47	3.359 (3)	161
C10—H10···O2^v	0.93	2.40	3.209 (3)	145
C11—H11···O1ⁱⁱⁱ	0.93	2.41	3.205 (3)	144
C14—H14···O12	0.93	2.46	3.248 (3)	143
C15—H15···O2^vi	0.93	2.32	3.244 (3)	171
C16—H16···O7ⁱⁱⁱ	0.93	2.37	3.197 (3)	148

Symmetry codes: (i) x−1, y, z−1; (ii) x, y, z−1; (iii) −x+1, −y+1, −z+1; (iv) −x+1, y+1/2, −z+1/2; (v) x, −y+1/2, z−1/2; (vi) −x+1, y+1/2, −z+3/2; (vii) −x+2, y+1/2, −z+3/2.