Tris(1,10-phenanthroline)­zinc(II) dichromate tetrahydrate

Ejsmont, K.; Wasielewski, M.; Zaleski, J.

doi:10.1107/S1600536802006402

Tris(1,10-phenanthroline)zinc(II) dichromate tetrahydrate

K. Ejsmont, M. Wasielewski and J. Zaleski

The title compound, [Zn(C₁₂H₈N₂)₃][Cr₂O₇]·4H₂O, was obtained by mixing 1,10-phenanthroline (phen), potassium chromate and zinc sulfate solutions. The asymmetric unit is composed of a [Zn(phen)₃]²⁺ cation, a Cr₂O₇²⁻ anion and four water molecules. The Zn^II ion is in a distorted octahedral environment, coordinated by six N atoms from three phen molecules. The cations are connected to anions by weak C—H

O hydrogen bonds, with shortest H

O distances of ca 2.27–2.33 Å. The Cr₂O₇²⁻ anion is in a staggered conformation. Two of the four crystallographically independent water molecules are ordered, and two others are disordered, each over two sites.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802006402/bt6130sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536802006402/bt6130Isup2.hkl Contains datablock I

CCDC reference: 164033

checkCIF report

Key indicators

Single-crystal X-ray study
T = 293 K
Mean (C-C) = 0.007 Å
H-atom completeness 76%
Disorder in solvent or counterion
R factor = 0.047
wR factor = 0.177
Data-to-parameter ratio = 13.5

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



PLAT_302  Alert C Anion/Solvent Disorder .......................      13.00 Perc.

PLAT_710  Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle #     19
                   N2B -ZN1 -N2A -C12A  129.80  0.80   1.555   1.555   1.555   1.555

PLAT_710  Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle #     24
                   N2B -ZN1 -N2A -C9A   -54.50  0.90   1.555   1.555   1.555   1.555

PLAT_710  Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle #     39
                   N2A -ZN1 -N2B -C12B  116.50  0.80   1.555   1.555   1.555   1.555

PLAT_710  Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle #     44
                   N2A -ZN1 -N2B -C9B   -67.70  0.90   1.555   1.555   1.555   1.555

General Notes



FORMU_01  There is a discrepancy between the atom counts in the
          _chemical_formula_sum and the formula from the _atom_site* data.
          Atom count from _chemical_formula_sum:C36 H32 Cr2 N6 O11 Zn1
          Atom count from the _atom_site data:  C36 H24 Cr2 N6 O11 Zn1

CELLZ_01
         From the CIF: _cell_formula_units_Z    8
         From the CIF: _chemical_formula_sum  C36 H32 Cr2 N6 O11 Zn
         TEST: Compare cell contents of formula and atom_site data

         atom    Z*formula  cif sites diff
         C        288.00    288.00    0.00
         H        256.00    192.00   64.00
         Cr        16.00     16.00    0.00
         N         48.00     48.00    0.00
         O         88.00     88.00    0.00
         Zn         8.00      8.00    0.00
          Difference between formula and atom_site contents detected.
          WARNING: H atoms missing from atom site list. Is this intentional?


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 5 Alert Level C = Please check

Comment top

Metal complexes containing the chromate(VI) or dichromate(VI) anion, CrO₄^2- or Cr₂O₇^2-, as a ligand are attracting current attention due to their spectroscopic (Cieślak-Golonka et al., 1988, 1991), structural (Dave & Czeruszewicz, 1994), magnetic (Gili & Lorenzo-Luis, 1999), thermal (Bensch et al., 1987; Repka et al., 1998), catalytic (Bensch et al., 1987), and supramolecular (Hayashi et al., 1998) properties.

Chromate(VI) and dichromate(VI) complexes have been long recognized to cause genotoxic and mutagenic effects in living cells, leading to development of cancer in humans (Cieślak-Golonka, 1995). Considering the redox pathways of the carcinogenic Cr^VI anion and the interaction of its metabolites Cr^V, Cr^IV and Cr^III with DNA (Stearns & Wetterhahn, 1997; Lay & Levina, 1998; Codd & Lay, 1999), the lowering of its mutagenic activity was explained by the mode of the chromate ion binding to the metal–organic ligand core. Metal chromate(VI) complexes with 1,10-phenanthroline or 2,2'-bipyridyl tested by the standard Ames test exhibited markedly lower activity than the reference compounds potassium dichromate and potassium chromate (Szyba et al., 1992).

Because the observed carcinogenecity of Cr^VI depends on the ability of its oxoanions to cross the cell membrane by the anion-transport system, the symmetry of the forming Cr^VI species may influence the effectivity of the membrane crossing. The coordination chemistry of compounds with chromium(VI) anions (chromates, dichromates, polychromates, etc.) as ligands has been reviewed recently (Gili & Lorenzo-Luis, 1999). In the nickel(II) chromate complexes with 2,2'-bipyridine (bpy), viz. Ni(CrO₄)(bpy)_x, where x = 2 or 3, the mode of coordination of the chromate ion (non- or one-coordinating anion) was found to be dependent on the Ni:bpy ratio (Bronowska et al., 2000).

We were trying to obtain a complex in which the chromate ions would be coordinated to the Zn metal, similar to in case of [Mn₂(Cr₂O₇)₂(bpy)₄] (Dave & Czeruszewicz, 1994). Instead of the dichromate bonded to the Zn^II ion, an ionic structure, (I), built up of [Zn(phen)₃]²⁺ cations, Cr₂O₇^2- anions and water molecules was obtained.

The perspective view of the [Zn(phen)₃]²⁺ cation with the atomic labelling scheme is presented in Fig. 1 and the packing diagram of [Zn(phen)₃][Cr₂O₇]·4H₂O is shown in Fig. 2. The cations are connected to anions by weak C—H···O hydrogen bonds, with shortest H···O distances of ca 2.27–2.33 Å. The Zn^II ion is in distorted octahedral environment coordinated with six N atoms from three phenanthroline molecules. The Zn–N bond lengths are in the range 2.115 (4)–2.215 (4) Å. The N—Zn—N angles involving the same phenanthroline molecule are in the range 75.7 (1)–78.2 (1)°, and are significantly smaller than the octahedral value of 90°. The N—Zn—N angles cis to each other comprising N atoms from different phenanthroline molecules are in the range 90.1 (1)–104.1 (1)°, wheras those trans to each other are in the range 164.5 (1)–170.7 (1)°.

There is one Cr₂O₇^2- anion in the independent part of the unit cell. It is almost in a staggered conformation, opposite to the situation found in K₂Cr₂O₇. In potassium dichromate, two CrO₄^2- tetrahedra are in a nearly eclipsed conformation (Lőfgren, 1971), when viewed along the line joining the Cr atoms. The O—Cr—O bond angles in (I) are between 106.9 (2) and 112.2 (2)°, close to the tetraedral value of 109.28°. The Cr—O—Cr bridging angle is 130.4 (2)°. The O—Cr—O—Cr torsion angles are close to ca 24°. The Cr—O terminal bond lengths are in the range 1.592 (4)–1.609 (3)Åand the bridging Cr—O bonds are longer and in the range 1.758 (4)–1.791 (3) Å.

There are four crystallographically independent water molecules in the structure. Two are ordered and the remaining two are disordered over two sites each. We refined the occupancy factors of the disordered molecules. They converged close to 0.5 and were subsequently fixed at that value. The O atoms of the water molecules are separated by 2.96–3.05 Å and are connected to each other and to dichromate anions by O—H···O hydrogen bonds, forming chains parallel to the a direction, separating the [Zn(phen)₃]²⁺ cations.

Experimental top

The title complex was synthesized by adding stoichiometric amounts of 1,10-phenanthroline in acetone (0.75 M) to K₂CrO₄ in water (0.25 M), followed by the addition of ZnSO₄ (0.25 M). The yellow–orange reaction mixture was allowed to stand for a few days at room temperature. The precipitated orange microcrystals were of X-ray quality and were filtered off, washed with water and acetone, and dried.

Computing details top

Data collection: KM-4 Software (Kuma, 1998); cell refinement: KM-4 Software; data reduction: KM-4 Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1990); software used to prepare material for publication: SHELXL97.

Figures top

	Fig. 1. The molecular structure of the complex cation of (I) showing the atomic labeling scheme. Displacement ellipsoids are at the 50% probability level.
	Fig. 2. Packing diagram of tris(1,10-phenanthroline)zinc(II) dichromate tetrahydrate.

(I) top

Crystal data top

[Zn(C₁₂H₈N₂)₃][Cr₂O₇]·4H₂O	F(000) = 3648
M_r = 894.05	D_x = 1.485 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 26.687 (5) Å	Cell parameters from 36 reflections
b = 17.867 (4) Å	θ = 10–15°
c = 17.471 (3) Å	µ = 1.19 mm⁻¹
β = 106.23 (3)°	T = 293 K
V = 7998 (3) Å³	Plate, orange
Z = 8	0.63 × 0.50 × 0.37 mm

Data collection top

Kuma KM-4 diffractometer	4863 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.024
Graphite monochromator	θ_max = 25.1°, θ_min = 2.0°
ω–θ scans	h = −30→31
Absorption correction: ψ scans empirical (using intensity measurements) via ψ scans (Sheldrick, 1990)	k = −18→21
T_min = 0.493, T_max = 0.643	l = −20→0
9494 measured reflections	2 standard reflections every 50 reflections
7062 independent reflections	intensity decay: 6.2%

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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.177	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.1234P)² + 2.6927P] where P = (F_o² + 2F_c²)/3
7062 reflections	(Δ/σ)_max = 0.002
523 parameters	Δρ_max = 0.78 e Å⁻³
0 restraints	Δρ_min = −0.38 e Å⁻³

Crystal data top

[Zn(C₁₂H₈N₂)₃][Cr₂O₇]·4H₂O	V = 7998 (3) Å³
M_r = 894.05	Z = 8
Monoclinic, C2/c	Mo Kα radiation
a = 26.687 (5) Å	µ = 1.19 mm⁻¹
b = 17.867 (4) Å	T = 293 K
c = 17.471 (3) Å	0.63 × 0.50 × 0.37 mm
β = 106.23 (3)°

Data collection top

Kuma KM-4 diffractometer	4863 reflections with I > 2σ(I)
Absorption correction: ψ scans empirical (using intensity measurements) via ψ scans (Sheldrick, 1990)	R_int = 0.024
T_min = 0.493, T_max = 0.643	2 standard reflections every 50 reflections
9494 measured reflections	intensity decay: 6.2%
7062 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.047	0 restraints
wR(F²) = 0.177	H-atom parameters constrained
S = 1.05	Δρ_max = 0.78 e Å⁻³
7062 reflections	Δρ_min = −0.38 e Å⁻³
523 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Zn1	0.133759 (18)	0.17085 (3)	0.15369 (3)	0.04417 (17)
Cr1	0.32526 (3)	0.05375 (4)	−0.34666 (4)	0.0533 (2)
Cr2	0.22544 (3)	0.13131 (4)	−0.31004 (4)	0.0483 (2)
O1	0.37010 (19)	0.0475 (3)	−0.2642 (2)	0.1063 (16)
O2	0.2934 (2)	−0.0218 (2)	−0.3633 (3)	0.0991 (15)
O3	0.34845 (16)	0.0686 (2)	−0.4207 (2)	0.0763 (10)
O4	0.28432 (14)	0.1291 (2)	−0.3401 (2)	0.0670 (9)
O5	0.23087 (16)	0.0774 (2)	−0.2344 (2)	0.0779 (11)
O6	0.21705 (17)	0.2160 (2)	−0.2872 (3)	0.0819 (11)
O7	0.17735 (15)	0.1046 (2)	−0.3814 (2)	0.0744 (10)
N1A	0.15558 (13)	0.27106 (19)	0.10435 (18)	0.0435 (8)
N2A	0.16413 (13)	0.12892 (19)	0.06091 (19)	0.0440 (8)
N1B	0.19952 (13)	0.1454 (2)	0.2502 (2)	0.0452 (8)
N2B	0.11402 (14)	0.2248 (2)	0.2517 (2)	0.0505 (9)
N1C	0.05443 (14)	0.1798 (2)	0.0727 (2)	0.0504 (9)
N2C	0.09575 (14)	0.0642 (2)	0.1702 (2)	0.0497 (8)
C1A	0.15247 (19)	0.3409 (3)	0.1272 (3)	0.0563 (11)
H1A	0.1452	0.3494	0.1772	0.080*
C2A	0.1603 (2)	0.4021 (3)	0.0836 (3)	0.0692 (14)
H2A	0.1567	0.4520	0.1018	0.080*
C3A	0.1716 (2)	0.3902 (3)	0.0131 (3)	0.0671 (13)
H3A	0.1768	0.4319	−0.0185	0.080*
C4A	0.17623 (17)	0.3173 (3)	−0.0128 (3)	0.0525 (11)
C5A	0.16782 (15)	0.2594 (2)	0.0349 (2)	0.0421 (9)
C6A	0.1902 (2)	0.2996 (3)	−0.0845 (3)	0.0622 (12)
H6A	0.1957	0.3395	−0.1180	0.080*
C7A	0.1960 (2)	0.2294 (3)	−0.1044 (3)	0.0658 (14)
H7A	0.2055	0.2190	−0.1524	0.080*
C8A	0.18789 (16)	0.1675 (3)	−0.0569 (2)	0.0516 (11)
C9A	0.17283 (15)	0.1829 (2)	0.0124 (2)	0.0415 (9)
C10A	0.19516 (19)	0.0923 (3)	−0.0734 (3)	0.0616 (12)
H10A	0.2047	0.0789	−0.1207	0.080*
C11A	0.1879 (2)	0.0391 (3)	−0.0234 (3)	0.0653 (13)
H11A	0.1943	−0.0123	−0.0332	0.080*
C12A	0.17215 (18)	0.0587 (2)	0.0434 (3)	0.0512 (10)
H12A	0.1666	0.0199	0.0781	0.080*
C1B	0.24200 (18)	0.1087 (3)	0.2486 (3)	0.0552 (11)
H1B	0.2462	0.0948	0.1977	0.080*
C2B	0.2809 (2)	0.0892 (3)	0.3179 (3)	0.0675 (14)
H2B	0.3115	0.0629	0.3143	0.080*
C3B	0.2749 (2)	0.1084 (3)	0.3895 (3)	0.0684 (14)
H3B	0.3011	0.0951	0.4376	0.080*
C4B	0.2306 (2)	0.1471 (3)	0.3941 (3)	0.0583 (12)
C5B	0.19368 (17)	0.1661 (2)	0.3222 (2)	0.0456 (9)
C6B	0.2204 (3)	0.1691 (3)	0.4678 (3)	0.0774 (17)
H6B	0.2444	0.1537	0.5173	0.080*
C7B	0.1792 (3)	0.2092 (3)	0.4685 (3)	0.0742 (16)
H7B	0.1747	0.2246	0.5188	0.080*
C8B	0.1408 (2)	0.2302 (3)	0.3956 (3)	0.0595 (12)
C9B	0.14864 (18)	0.2076 (2)	0.3238 (2)	0.0488 (10)
C10B	0.0979 (2)	0.2751 (3)	0.3919 (3)	0.0692 (14)
H10B	0.0921	0.2934	0.4404	0.080*
C11B	0.0644 (2)	0.2941 (3)	0.3204 (4)	0.0731 (15)
H11B	0.0347	0.3256	0.3174	0.080*
C12B	0.07336 (19)	0.2665 (3)	0.2515 (3)	0.0659 (13)
H12B	0.0489	0.2778	0.2010	0.080*
C1C	0.0352 (2)	0.2341 (3)	0.0215 (3)	0.0617 (12)
H1C	0.0571	0.2759	0.0185	0.080*
C2C	−0.0165 (2)	0.2326 (3)	−0.0290 (3)	0.0710 (14)
H2C	−0.0291	0.2726	−0.0660	0.080*
C3C	−0.0474 (2)	0.1752 (3)	−0.0246 (3)	0.0681 (14)
H3C	−0.0826	0.1743	−0.0584	0.080*
C4C	−0.02889 (18)	0.1173 (3)	0.0283 (3)	0.0597 (12)
C5C	0.02332 (16)	0.1203 (3)	0.0762 (2)	0.0479 (10)
C6C	−0.0594 (2)	0.0541 (4)	0.0357 (4)	0.0762 (16)
H6C	−0.0955	0.0524	0.0059	0.080*
C7C	−0.0394 (2)	−0.0010 (4)	0.0851 (4)	0.0794 (17)
H7C	−0.0613	−0.0430	0.0878	0.080*
C8C	0.01386 (19)	−0.0015 (3)	0.1328 (3)	0.0617 (12)
C9C	0.04481 (17)	0.0609 (3)	0.1287 (3)	0.0505 (10)
C10C	0.0374 (2)	−0.0605 (3)	0.1824 (3)	0.0714 (15)
H10C	0.0174	−0.1041	0.1873	0.080*
C11C	0.0883 (2)	−0.0559 (3)	0.2233 (3)	0.0692 (14)
H11C	0.1051	−0.0961	0.2574	0.080*
C12C	0.1163 (2)	0.0077 (3)	0.2159 (3)	0.0611 (12)
H12C	0.1523	0.0111	0.2459	0.080*
O8	0.1143 (2)	0.2743 (4)	−0.3093 (4)	0.158 (3)
O9	0.0498 (4)	0.2288 (5)	−0.2041 (6)	0.214 (4)
O10	0.4170 (5)	−0.0799 (7)	−0.1507 (10)	0.159 (5)	0.50
O11	0.4309 (6)	0.0529 (9)	−0.4847 (12)	0.196 (7)	0.50
O12	0.0299 (6)	0.3759 (9)	−0.1288 (11)	0.180 (6)	0.50
O13	0.4687 (6)	0.0857 (9)	−0.1411 (14)	0.228 (8)	0.50

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Zn1	0.0451 (3)	0.0529 (3)	0.0355 (3)	−0.0008 (2)	0.0130 (2)	0.0031 (2)
Cr1	0.0588 (5)	0.0584 (5)	0.0478 (4)	−0.0056 (3)	0.0233 (3)	−0.0111 (3)
Cr2	0.0584 (4)	0.0495 (4)	0.0413 (4)	−0.0018 (3)	0.0207 (3)	−0.0054 (3)
O1	0.104 (3)	0.142 (4)	0.060 (2)	0.040 (3)	0.001 (2)	−0.017 (2)
O2	0.126 (4)	0.072 (3)	0.126 (4)	−0.033 (3)	0.080 (3)	−0.033 (3)
O3	0.085 (3)	0.086 (3)	0.073 (2)	−0.006 (2)	0.047 (2)	−0.0069 (19)
O4	0.072 (2)	0.067 (2)	0.072 (2)	0.0017 (17)	0.0366 (18)	−0.0017 (17)
O5	0.087 (3)	0.100 (3)	0.0529 (19)	0.005 (2)	0.0294 (19)	0.0182 (19)
O6	0.097 (3)	0.056 (2)	0.105 (3)	−0.0055 (19)	0.049 (2)	−0.024 (2)
O7	0.077 (2)	0.085 (3)	0.0555 (19)	−0.013 (2)	0.0085 (17)	−0.0068 (18)
N1A	0.0467 (19)	0.0469 (19)	0.0367 (17)	−0.0023 (15)	0.0112 (14)	−0.0056 (14)
N2A	0.0450 (19)	0.046 (2)	0.0384 (17)	−0.0022 (15)	0.0082 (15)	0.0006 (14)
N1B	0.0479 (19)	0.0492 (19)	0.0388 (17)	−0.0056 (16)	0.0126 (15)	0.0034 (15)
N2B	0.049 (2)	0.062 (2)	0.0449 (19)	−0.0022 (17)	0.0194 (16)	−0.0022 (16)
N1C	0.0451 (19)	0.058 (2)	0.048 (2)	0.0015 (17)	0.0133 (16)	−0.0036 (17)
N2C	0.047 (2)	0.056 (2)	0.0473 (19)	−0.0045 (17)	0.0153 (16)	0.0037 (16)
C1A	0.062 (3)	0.057 (3)	0.052 (2)	−0.007 (2)	0.020 (2)	−0.008 (2)
C2A	0.079 (4)	0.045 (3)	0.080 (4)	−0.007 (2)	0.017 (3)	−0.005 (2)
C3A	0.081 (4)	0.049 (3)	0.070 (3)	−0.007 (2)	0.020 (3)	0.014 (2)
C4A	0.051 (2)	0.057 (3)	0.046 (2)	−0.007 (2)	0.0098 (19)	0.0095 (19)
C5A	0.038 (2)	0.050 (2)	0.0369 (19)	−0.0034 (17)	0.0069 (16)	0.0036 (17)
C6A	0.067 (3)	0.080 (3)	0.044 (2)	−0.006 (3)	0.022 (2)	0.014 (2)
C7A	0.060 (3)	0.104 (4)	0.038 (2)	−0.007 (3)	0.020 (2)	0.003 (3)
C8A	0.042 (2)	0.075 (3)	0.038 (2)	−0.002 (2)	0.0112 (17)	−0.008 (2)
C9A	0.038 (2)	0.055 (2)	0.0305 (18)	−0.0012 (17)	0.0074 (16)	−0.0007 (16)
C10A	0.058 (3)	0.080 (4)	0.049 (2)	0.000 (2)	0.017 (2)	−0.019 (2)
C11A	0.059 (3)	0.068 (3)	0.069 (3)	0.003 (2)	0.017 (2)	−0.022 (3)
C12A	0.056 (3)	0.045 (2)	0.052 (2)	0.0005 (19)	0.015 (2)	−0.0028 (19)
C1B	0.052 (3)	0.057 (3)	0.056 (3)	0.002 (2)	0.013 (2)	0.001 (2)
C2B	0.057 (3)	0.060 (3)	0.077 (4)	0.004 (2)	0.004 (3)	0.013 (3)
C3B	0.070 (3)	0.057 (3)	0.063 (3)	0.002 (3)	−0.007 (3)	0.009 (2)
C4B	0.074 (3)	0.049 (3)	0.044 (2)	−0.015 (2)	0.004 (2)	0.005 (2)
C5B	0.053 (2)	0.044 (2)	0.039 (2)	−0.0113 (19)	0.0114 (18)	0.0060 (17)
C6B	0.108 (5)	0.072 (4)	0.041 (3)	−0.020 (3)	0.003 (3)	0.005 (2)
C7B	0.113 (5)	0.071 (4)	0.038 (2)	−0.015 (3)	0.020 (3)	−0.002 (2)
C8B	0.086 (3)	0.055 (3)	0.044 (2)	−0.022 (3)	0.030 (2)	−0.006 (2)
C9B	0.061 (3)	0.049 (2)	0.040 (2)	−0.017 (2)	0.0195 (19)	−0.0001 (18)
C10B	0.089 (4)	0.069 (3)	0.065 (3)	−0.019 (3)	0.047 (3)	−0.020 (3)
C11B	0.061 (3)	0.083 (4)	0.085 (4)	−0.001 (3)	0.037 (3)	−0.018 (3)
C12B	0.054 (3)	0.081 (4)	0.066 (3)	0.002 (3)	0.022 (2)	−0.005 (3)
C1C	0.058 (3)	0.071 (3)	0.052 (3)	0.006 (2)	0.008 (2)	0.011 (2)
C2C	0.060 (3)	0.087 (4)	0.058 (3)	0.014 (3)	0.003 (2)	0.003 (3)
C3C	0.050 (3)	0.089 (4)	0.058 (3)	0.011 (3)	0.003 (2)	−0.011 (3)
C4C	0.046 (2)	0.079 (3)	0.056 (3)	−0.003 (2)	0.016 (2)	−0.019 (2)
C5C	0.043 (2)	0.058 (3)	0.045 (2)	0.0001 (19)	0.0159 (18)	−0.0105 (19)
C6C	0.048 (3)	0.091 (4)	0.084 (4)	−0.014 (3)	0.010 (3)	−0.015 (3)
C7C	0.059 (3)	0.095 (5)	0.089 (4)	−0.034 (3)	0.027 (3)	−0.026 (4)
C8C	0.065 (3)	0.067 (3)	0.062 (3)	−0.016 (2)	0.032 (2)	−0.012 (2)
C9C	0.048 (2)	0.060 (3)	0.048 (2)	−0.008 (2)	0.0212 (19)	−0.012 (2)
C10C	0.081 (4)	0.069 (3)	0.074 (3)	−0.021 (3)	0.037 (3)	−0.002 (3)
C11C	0.080 (4)	0.059 (3)	0.077 (3)	−0.002 (3)	0.036 (3)	0.010 (2)
C12C	0.065 (3)	0.062 (3)	0.059 (3)	0.001 (2)	0.021 (2)	0.009 (2)
O8	0.090 (4)	0.165 (6)	0.186 (6)	0.015 (4)	−0.017 (4)	−0.049 (5)
O9	0.174 (7)	0.199 (8)	0.274 (10)	0.011 (6)	0.069 (7)	−0.028 (7)
O10	0.096 (7)	0.120 (8)	0.252 (13)	−0.024 (6)	0.034 (8)	0.003 (9)
O11	0.141 (9)	0.200 (12)	0.309 (15)	−0.043 (8)	0.167 (10)	−0.121 (11)
O12	0.159 (11)	0.166 (11)	0.210 (13)	−0.035 (9)	0.044 (10)	0.035 (10)
O13	0.124 (10)	0.165 (12)	0.356 (17)	0.004 (9)	0.004 (11)	0.103 (12)

Geometric parameters (Å, º) top

Zn1—N1B	2.115 (4)	C5A—C9A	1.439 (6)
Zn1—N1A	2.137 (3)	C6A—C7A	1.323 (8)
Zn1—N2A	2.140 (3)	C7A—C8A	1.435 (7)
Zn1—N2B	2.155 (4)	C8A—C10A	1.399 (7)
Zn1—N1C	2.199 (4)	C8A—C9A	1.404 (6)
Zn1—N2C	2.215 (4)	C10A—C11A	1.342 (7)
Cr1—O2	1.579 (4)	C11A—C12A	1.390 (7)
Cr1—O1	1.599 (4)	C1B—C2B	1.402 (7)
Cr1—O3	1.605 (3)	C2B—C3B	1.348 (8)
Cr1—O4	1.758 (4)	C3B—C4B	1.392 (8)
Cr2—O7	1.592 (4)	C4B—C5B	1.404 (6)
Cr2—O6	1.596 (4)	C4B—C6B	1.441 (8)
Cr2—O5	1.609 (3)	C5B—C9B	1.419 (7)
Cr2—O4	1.791 (3)	C6B—C7B	1.316 (9)
N1A—C1A	1.320 (6)	C7B—C8B	1.445 (8)
N1A—C5A	1.358 (5)	C8B—C10B	1.385 (8)
N2A—C12A	1.323 (5)	C8B—C9B	1.388 (6)
N2A—C9A	1.346 (5)	C10B—C11B	1.361 (8)
N1B—C1B	1.316 (6)	C11B—C12B	1.383 (7)
N1B—C5B	1.362 (5)	C1C—C2C	1.415 (7)
N2B—C12B	1.315 (6)	C2C—C3C	1.330 (8)
N2B—C9B	1.372 (6)	C3C—C4C	1.384 (7)
N1C—C1C	1.322 (6)	C4C—C5C	1.411 (6)
N1C—C5C	1.361 (6)	C4C—C6C	1.418 (8)
N2C—C12C	1.310 (6)	C5C—C9C	1.415 (6)
N2C—C9C	1.351 (6)	C6C—C7C	1.320 (8)
C1A—C2A	1.380 (7)	C7C—C8C	1.434 (8)
C2A—C3A	1.365 (8)	C8C—C10C	1.398 (8)
C3A—C4A	1.396 (7)	C8C—C9C	1.401 (6)
C4A—C5A	1.386 (6)	C10C—C11C	1.348 (8)
C4A—C6A	1.438 (7)	C11C—C12C	1.385 (7)

N1B—Zn1—N1A	104.0 (1)	N1A—C5A—C9A	117.0 (3)
N1B—Zn1—N2A	97.0 (1)	C4A—C5A—C9A	120.1 (4)
N1A—Zn1—N2A	77.5 (1)	C7A—C6A—C4A	121.0 (4)
N1B—Zn1—N2B	78.2 (1)	C6A—C7A—C8A	122.1 (4)
N1A—Zn1—N2B	95.8 (1)	C10A—C8A—C9A	117.1 (4)
N2A—Zn1—N2B	170.7 (1)	C10A—C8A—C7A	124.6 (4)
N1B—Zn1—N1C	164.5 (1)	C9A—C8A—C7A	118.3 (4)
N1A—Zn1—N1C	90.1 (1)	N2A—C9A—C8A	122.9 (4)
N2A—Zn1—N1C	92.2 (1)	N2A—C9A—C5A	117.6 (3)
N2B—Zn1—N1C	94.2 (1)	C8A—C9A—C5A	119.5 (4)
N1B—Zn1—N2C	91.1 (1)	C11A—C10A—C8A	119.4 (4)
N1A—Zn1—N2C	163.6 (1)	C10A—C11A—C12A	120.1 (5)
N2A—Zn1—N2C	94.7 (1)	N2A—C12A—C11A	122.6 (4)
N2B—Zn1—N2C	93.4 (1)	N1B—C1B—C2B	122.6 (5)
N1C—Zn1—N2C	75.7 (1)	C3B—C2B—C1B	119.2 (5)
O2—Cr1—O1	109.6 (3)	C2B—C3B—C4B	120.2 (5)
O2—Cr1—O3	107.6 (2)	C3B—C4B—C5B	117.5 (5)
O1—Cr1—O3	112.2 (2)	C3B—C4B—C6B	124.2 (5)
O2—Cr1—O4	110.7 (2)	C5B—C4B—C6B	118.3 (5)
O1—Cr1—O4	108.5 (2)	N1B—C5B—C4B	121.9 (4)
O3—Cr1—O4	108.2 (2)	N1B—C5B—C9B	118.4 (4)
O7—Cr2—O6	110.0 (2)	C4B—C5B—C9B	119.7 (4)
O7—Cr2—O5	109.3 (2)	C7B—C6B—C4B	121.6 (5)
O6—Cr2—O5	110.4 (2)	C6B—C7B—C8B	121.5 (5)
O7—Cr2—O4	110.2 (2)	C10B—C8B—C9B	117.3 (5)
O6—Cr2—O4	106.9 (2)	C10B—C8B—C7B	124.4 (5)
O5—Cr2—O4	110.1 (2)	C9B—C8B—C7B	118.2 (5)
Cr1—O4—Cr2	130.4 (2)	N2B—C9B—C8B	122.1 (4)
C1A—N1A—C5A	117.8 (4)	N2B—C9B—C5B	117.1 (4)
C1A—N1A—Zn1	128.6 (3)	C8B—C9B—C5B	120.8 (4)
C5A—N1A—Zn1	113.1 (3)	C11B—C10B—C8B	120.6 (5)
C12A—N2A—C9A	117.8 (4)	C10B—C11B—C12B	118.7 (5)
C12A—N2A—Zn1	128.8 (3)	N2B—C12B—C11B	122.9 (5)
C9A—N2A—Zn1	113.2 (3)	N1C—C1C—C2C	122.3 (5)
C1B—N1B—C5B	118.5 (4)	C3C—C2C—C1C	119.4 (5)
C1B—N1B—Zn1	128.1 (3)	C2C—C3C—C4C	120.2 (5)
C5B—N1B—Zn1	113.2 (3)	C3C—C4C—C5C	118.5 (5)
C12B—N2B—C9B	118.2 (4)	C3C—C4C—C6C	123.3 (5)
C12B—N2B—Zn1	129.5 (3)	C5C—C4C—C6C	118.2 (5)
C9B—N2B—Zn1	112.2 (3)	N1C—C5C—C4C	121.1 (4)
C1C—N1C—C5C	118.5 (4)	N1C—C5C—C9C	118.3 (4)
C1C—N1C—Zn1	127.7 (3)	C4C—C5C—C9C	120.6 (4)
C5C—N1C—Zn1	113.8 (3)	C7C—C6C—C4C	121.1 (5)
C12C—N2C—C9C	118.6 (4)	C6C—C7C—C8C	122.5 (5)
C12C—N2C—Zn1	127.9 (3)	C10C—C8C—C9C	117.5 (5)
C9C—N2C—Zn1	113.4 (3)	C10C—C8C—C7C	124.5 (5)
N1A—C1A—C2A	123.4 (5)	C9C—C8C—C7C	117.9 (5)
C3A—C2A—C1A	118.7 (5)	N2C—C9C—C8C	121.8 (4)
C2A—C3A—C4A	120.0 (4)	N2C—C9C—C5C	118.6 (4)
C5A—C4A—C3A	117.2 (4)	C8C—C9C—C5C	119.5 (4)
C5A—C4A—C6A	119.0 (4)	C11C—C10C—C8C	119.6 (5)
C3A—C4A—C6A	123.8 (4)	C10C—C11C—C12C	119.3 (5)
N1A—C5A—C4A	122.9 (4)	N2C—C12C—C11C	123.0 (5)

O2—Cr1—O4—Cr2	28.1 (4)	C10A—C8A—C9A—N2A	−1.7 (6)
O1—Cr1—O4—Cr2	−92.2 (3)	C7A—C8A—C9A—N2A	179.8 (4)
O3—Cr1—O4—Cr2	145.8 (3)	C10A—C8A—C9A—C5A	176.3 (4)
O7—Cr2—O4—Cr1	−80.0 (3)	C7A—C8A—C9A—C5A	−2.2 (6)
O6—Cr2—O4—Cr1	160.6 (3)	N1A—C5A—C9A—N2A	1.1 (5)
O5—Cr2—O4—Cr1	40.7 (3)	C4A—C5A—C9A—N2A	−179.9 (4)
N1B—Zn1—N1A—C1A	−83.9 (4)	N1A—C5A—C9A—C8A	−177.0 (3)
N2A—Zn1—N1A—C1A	−178.2 (4)	C4A—C5A—C9A—C8A	2.0 (6)
N2B—Zn1—N1A—C1A	−4.7 (4)	C9A—C8A—C10A—C11A	−0.4 (7)
N1C—Zn1—N1A—C1A	89.6 (4)	C7A—C8A—C10A—C11A	178.1 (5)
N2C—Zn1—N1A—C1A	118.9 (5)	C8A—C10A—C11A—C12A	1.4 (7)
N1B—Zn1—N1A—C5A	105.0 (3)	C9A—N2A—C12A—C11A	−1.4 (6)
N2A—Zn1—N1A—C5A	10.7 (3)	Zn1—N2A—C12A—C11A	174.1 (3)
N2B—Zn1—N1A—C5A	−175.8 (3)	C10A—C11A—C12A—N2A	−0.6 (7)
N1C—Zn1—N1A—C5A	−81.5 (3)	C5B—N1B—C1B—C2B	1.0 (7)
N2C—Zn1—N1A—C5A	−52.2 (6)	Zn1—N1B—C1B—C2B	−173.8 (3)
N1B—Zn1—N2A—C12A	71.3 (4)	N1B—C1B—C2B—C3B	0.0 (8)
N1A—Zn1—N2A—C12A	174.2 (4)	C1B—C2B—C3B—C4B	0.2 (8)
N2B—Zn1—N2A—C12A	129.8 (8)	C2B—C3B—C4B—C5B	−1.4 (7)
N1C—Zn1—N2A—C12A	−96.3 (4)	C2B—C3B—C4B—C6B	179.1 (5)
N2C—Zn1—N2A—C12A	−20.4 (4)	C1B—N1B—C5B—C4B	−2.3 (6)
N1B—Zn1—N2A—C9A	−113.0 (3)	Zn1—N1B—C5B—C4B	173.2 (3)
N1A—Zn1—N2A—C9A	−10.1 (3)	C1B—N1B—C5B—C9B	178.1 (4)
N2B—Zn1—N2A—C9A	−54.5 (9)	Zn1—N1B—C5B—C9B	−6.4 (5)
N1C—Zn1—N2A—C9A	79.5 (3)	C3B—C4B—C5B—N1B	2.5 (7)
N2C—Zn1—N2A—C9A	155.3 (3)	C6B—C4B—C5B—N1B	−178.0 (4)
N1A—Zn1—N1B—C1B	−84.4 (4)	C3B—C4B—C5B—C9B	−177.9 (4)
N2A—Zn1—N1B—C1B	−5.5 (4)	C6B—C4B—C5B—C9B	1.6 (6)
N2B—Zn1—N1B—C1B	−177.4 (4)	C3B—C4B—C6B—C7B	176.2 (5)
N1C—Zn1—N1B—C1B	120.7 (5)	C5B—C4B—C6B—C7B	−3.4 (8)
N2C—Zn1—N1B—C1B	89.4 (4)	C4B—C6B—C7B—C8B	2.9 (9)
N1A—Zn1—N1B—C5B	100.6 (3)	C6B—C7B—C8B—C10B	−176.8 (5)
N2A—Zn1—N1B—C5B	179.5 (3)	C6B—C7B—C8B—C9B	−0.6 (8)
N2B—Zn1—N1B—C5B	7.5 (3)	C12B—N2B—C9B—C8B	2.7 (6)
N1C—Zn1—N1B—C5B	−54.3 (6)	Zn1—N2B—C9B—C8B	−173.6 (3)
N2C—Zn1—N1B—C5B	−85.7 (3)	C12B—N2B—C9B—C5B	−176.6 (4)
N1B—Zn1—N2B—C12B	176.4 (4)	Zn1—N2B—C9B—C5B	7.1 (5)
N1A—Zn1—N2B—C12B	73.2 (4)	C10B—C8B—C9B—N2B	−3.9 (7)
N2A—Zn1—N2B—C12B	116.5 (8)	C7B—C8B—C9B—N2B	179.7 (4)
N1C—Zn1—N2B—C12B	−17.3 (4)	C10B—C8B—C9B—C5B	175.4 (4)
N2C—Zn1—N2B—C12B	−93.2 (4)	C7B—C8B—C9B—C5B	−1.1 (6)
N1B—Zn1—N2B—C9B	−7.8 (3)	N1B—C5B—C9B—N2B	−0.6 (6)
N1A—Zn1—N2B—C9B	−111.0 (3)	C4B—C5B—C9B—N2B	179.8 (4)
N2A—Zn1—N2B—C9B	−67.7 (9)	N1B—C5B—C9B—C8B	−179.9 (4)
N1C—Zn1—N2B—C9B	158.5 (3)	C4B—C5B—C9B—C8B	0.5 (6)
N2C—Zn1—N2B—C9B	82.6 (3)	C9B—C8B—C10B—C11B	1.9 (7)
N1B—Zn1—N1C—C1C	152.1 (5)	C7B—C8B—C10B—C11B	178.0 (5)
N1A—Zn1—N1C—C1C	−3.7 (4)	C8B—C10B—C11B—C12B	1.2 (8)
N2A—Zn1—N1C—C1C	−81.2 (4)	C9B—N2B—C12B—C11B	0.6 (8)
N2B—Zn1—N1C—C1C	92.1 (4)	Zn1—N2B—C12B—C11B	176.2 (4)
N2C—Zn1—N1C—C1C	−175.5 (4)	C10B—C11B—C12B—N2B	−2.5 (9)
N1B—Zn1—N1C—C5C	−29.8 (7)	C5C—N1C—C1C—C2C	0.4 (7)
N1A—Zn1—N1C—C5C	174.4 (3)	Zn1—N1C—C1C—C2C	178.5 (4)
N2A—Zn1—N1C—C5C	96.9 (3)	N1C—C1C—C2C—C3C	0.8 (8)
N2B—Zn1—N1C—C5C	−89.8 (3)	C1C—C2C—C3C—C4C	−0.5 (8)
N2C—Zn1—N1C—C5C	2.6 (3)	C2C—C3C—C4C—C5C	−1.0 (7)
N1B—Zn1—N2C—C12C	−10.1 (4)	C2C—C3C—C4C—C6C	−179.4 (5)
N1A—Zn1—N2C—C12C	147.8 (4)	C1C—N1C—C5C—C4C	−2.0 (6)
N2A—Zn1—N2C—C12C	87.1 (4)	Zn1—N1C—C5C—C4C	179.7 (3)
N2B—Zn1—N2C—C12C	−88.3 (4)	C1C—N1C—C5C—C9C	177.4 (4)
N1C—Zn1—N2C—C12C	178.2 (4)	Zn1—N1C—C5C—C9C	−0.9 (5)
N1B—Zn1—N2C—C9C	167.6 (3)	C3C—C4C—C5C—N1C	2.3 (6)
N1A—Zn1—N2C—C9C	−34.5 (6)	C6C—C4C—C5C—N1C	−179.2 (4)
N2A—Zn1—N2C—C9C	−95.2 (3)	C3C—C4C—C5C—C9C	−177.1 (4)
N2B—Zn1—N2C—C9C	89.4 (3)	C6C—C4C—C5C—C9C	1.5 (7)
N1C—Zn1—N2C—C9C	−4.1 (3)	C3C—C4C—C6C—C7C	177.5 (5)
C5A—N1A—C1A—C2A	1.0 (7)	C5C—C4C—C6C—C7C	−1.0 (8)
Zn1—N1A—C1A—C2A	−169.8 (4)	C4C—C6C—C7C—C8C	−1.2 (9)
N1A—C1A—C2A—C3A	0.3 (8)	C6C—C7C—C8C—C10C	−176.2 (6)
C1A—C2A—C3A—C4A	−1.4 (8)	C6C—C7C—C8C—C9C	2.7 (8)
C2A—C3A—C4A—C5A	1.3 (7)	C12C—N2C—C9C—C8C	−0.7 (6)
C2A—C3A—C4A—C6A	−177.3 (5)	Zn1—N2C—C9C—C8C	−178.6 (3)
C1A—N1A—C5A—C4A	−1.1 (6)	C12C—N2C—C9C—C5C	−176.9 (4)
Zn1—N1A—C5A—C4A	171.1 (3)	Zn1—N2C—C9C—C5C	5.2 (5)
C1A—N1A—C5A—C9A	177.9 (4)	C10C—C8C—C9C—N2C	0.7 (7)
Zn1—N1A—C5A—C9A	−10.0 (4)	C7C—C8C—C9C—N2C	−178.3 (4)
C3A—C4A—C5A—N1A	−0.1 (6)	C10C—C8C—C9C—C5C	176.9 (4)
C6A—C4A—C5A—N1A	178.6 (4)	C7C—C8C—C9C—C5C	−2.1 (7)
C3A—C4A—C5A—C9A	−179.0 (4)	N1C—C5C—C9C—N2C	−3.0 (6)
C6A—C4A—C5A—C9A	−0.3 (6)	C4C—C5C—C9C—N2C	176.4 (4)
C5A—C4A—C6A—C7A	−1.3 (7)	N1C—C5C—C9C—C8C	−179.2 (4)
C3A—C4A—C6A—C7A	177.3 (5)	C4C—C5C—C9C—C8C	0.1 (6)
C4A—C6A—C7A—C8A	1.1 (8)	C9C—C8C—C10C—C11C	−0.6 (7)
C6A—C7A—C8A—C10A	−177.7 (5)	C7C—C8C—C10C—C11C	178.3 (5)
C6A—C7A—C8A—C9A	0.7 (7)	C8C—C10C—C11C—C12C	0.6 (8)
C12A—N2A—C9A—C8A	2.6 (6)	C9C—N2C—C12C—C11C	0.6 (7)
Zn1—N2A—C9A—C8A	−173.7 (3)	Zn1—N2C—C12C—C11C	178.2 (4)
C12A—N2A—C9A—C5A	−175.5 (4)	C10C—C11C—C12C—N2C	−0.6 (8)
Zn1—N2A—C9A—C5A	8.3 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1A—H1A···O1ⁱ	0.96	2.49	3.297 (6)	141
C12B—H12B···O13ⁱ	0.96	2.64	3.277 (16)	124
C1B—H1B···O2ⁱⁱ	0.96	2.27	3.100 (6)	144
C12A—H12A···O7ⁱⁱ	0.96	2.33	3.186 (6)	149
C3A—H3A···O2ⁱⁱⁱ	0.96	2.55	3.400 (7)	148
C6A—H6A···O2ⁱⁱⁱ	0.96	2.53	3.381 (7)	148
C3B—H3B···O3^iv	0.96	2.49	3.423 (6)	164
C6B—H6B···O4^iv	0.96	2.46	3.388 (6)	163
C11B—H11B···O13^v	0.96	2.62	3.540 (18)	161
C7A—H7A···O6	0.96	2.46	3.402 (6)	167
C10A—H10A···O5	0.96	2.28	3.222 (6)	166

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

Experimental details

Crystal data
Chemical formula	[Zn(C₁₂H₈N₂)₃][Cr₂O₇]·4H₂O
M_r	894.05
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	293
a, b, c (Å)	26.687 (5), 17.867 (4), 17.471 (3)
β (°)	106.23 (3)
V (Å³)	7998 (3)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	1.19
Crystal size (mm)	0.63 × 0.50 × 0.37

Data collection
Diffractometer	Kuma KM-4 diffractometer
Absorption correction	ψ scans empirical (using intensity measurements) via ψ scans (Sheldrick, 1990)
T_min, T_max	0.493, 0.643
No. of measured, independent and observed [I > 2σ(I)] reflections	9494, 7062, 4863
R_int	0.024
(sin θ/λ)_max (Å⁻¹)	0.596

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.047, 0.177, 1.05
No. of reflections	7062
No. of parameters	523
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.78, −0.38

Computer programs: KM-4 Software (Kuma, 1998), KM-4 Software, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Sheldrick, 1990), SHELXL97.

Selected geometric parameters (Å, º) top

Zn1—N1B	2.115 (4)	Cr1—O1	1.599 (4)
Zn1—N1A	2.137 (3)	Cr1—O3	1.605 (3)
Zn1—N2A	2.140 (3)	Cr1—O4	1.758 (4)
Zn1—N2B	2.155 (4)	Cr2—O7	1.592 (4)
Zn1—N1C	2.199 (4)	Cr2—O6	1.596 (4)
Zn1—N2C	2.215 (4)	Cr2—O5	1.609 (3)
Cr1—O2	1.579 (4)	Cr2—O4	1.791 (3)

N1B—Zn1—N1A	104.0 (1)	N1C—Zn1—N2C	75.7 (1)
N1B—Zn1—N2A	97.0 (1)	O2—Cr1—O1	109.6 (3)
N1A—Zn1—N2A	77.5 (1)	O2—Cr1—O3	107.6 (2)
N1B—Zn1—N2B	78.2 (1)	O1—Cr1—O3	112.2 (2)
N1A—Zn1—N2B	95.8 (1)	O2—Cr1—O4	110.7 (2)
N2A—Zn1—N2B	170.7 (1)	O1—Cr1—O4	108.5 (2)
N1B—Zn1—N1C	164.5 (1)	O3—Cr1—O4	108.2 (2)
N1A—Zn1—N1C	90.1 (1)	O7—Cr2—O6	110.0 (2)
N2A—Zn1—N1C	92.2 (1)	O7—Cr2—O5	109.3 (2)
N2B—Zn1—N1C	94.2 (1)	O6—Cr2—O5	110.4 (2)
N1B—Zn1—N2C	91.1 (1)	O7—Cr2—O4	110.2 (2)
N1A—Zn1—N2C	163.6 (1)	O6—Cr2—O4	106.9 (2)
N2A—Zn1—N2C	94.7 (1)	O5—Cr2—O4	110.1 (2)
N2B—Zn1—N2C	93.4 (1)	Cr1—O4—Cr2	130.4 (2)

O2—Cr1—O4—Cr2	28.1 (4)