Bromido([eta]⁵-carboxy­cyclo­penta­dien­yl)­dinitro­sylchromium(0) and ([eta]⁵-ben­zoyl­cyclo­penta­dien­yl)­bromido­di­nitrosylchromium(0)

In the structures of each of the title compounds, [CrBr(C₆H₅O₂)(NO)₂], (I), and [CrBr(C₁₂H₉O)(NO)₂], (II), one of the nitrosyl groups is located at a site away from the exocyclic carbonyl C atom of the cyclo­penta­dienyl (Cp) ring, with twist angles of 174.5 (3) and 172.5 (1)°. The observed orientation is surprising, since the NO group is expected to be situated trans to an electron-rich C atom in the ring. The organic carbonyl plane is turned away from the Cp ring plane by 5.6 (8) and 15.2 (3)°in (I) and (II), respectively. The exocyclic C-C bond in (I) is bent out of the Cp ring plane towards the Cr atom by 2.8 (3)°, but is coplanar with the Cp ring in (II); the angle is 0.1 (1)°.

S1. Comment

Although CpCr(NO)₂(Br) was first reported in 1956 (Piper & Wilkinson, 1956), the difficulties encountered in making it undergo electrophilic aromatic substitution reactions such as Friedel–Crafts acylation have blocked the way to the synthesis of its Cp derivatives (Rausch et al., 1980). A novel method of replacing two carbonyl groups with a nitrosyl and a chloro ligand using hydrogen chloride/isoamylnitrite has been reported by Wang & Hwu (1990) to convert (1) to (2) (see the first scheme below). The analogous bromide compounds [η⁵–(C₅H₄–COOH]Cr(NO)₂Br, (I), and [η⁵–(C₅H₄–COC₆H₅)]Cr(NO)₂Br, (II), were prepared with the use of hydrogen bromide/isoamylnitrite from (5) and (6), respectively (Wang et al., 2007).

Wang et al. (1995, 1999) reported the qualitative relationship of the nonplanarity of the Cp–exocyclic carbon to the substituent π-donor and π-acceptor interactions. The π-donor substituents and the ipso-C atoms to which they are attached are bent away from the Cr(CO)₂NO fragments, while the π-acceptor substituents and the ipso-C atoms to which they are attached lie approximately in the Cp plane or are bent slightly toward the Cr(CO)₂NO fragments. The magnitudes and directions of these distortions from planarity with the Cp ring appear to be due primarily to electronic effects. In the hope of confirming these hypotheses, compounds (I) and (II) were studied. The molecular structures of (I) and (II) are shown in Figs. 1 and 2, respectively. Selected bond distances and angles are given in Tables 1 and 2.

The coordination geometry about the Cr center in each case is approximately a distorted tetrahedron with two nitrosyl groups, the Cp group and a Br atom as the four coordination sites. It is worth pointing out that for both structures one of the nitrosyl groups is located at a site away from the exocyclic C atom, i.e. the Br group is located at a site close to the exocyclic C atom.

The twist angle, defined as the torsion angle between the nitrosyl atom N2, the Cr atom, the Cp center and the ring C atom bearing the exocyclic C atom, is 174.5 (3)° for (I) and 172.5 (1)° for (II). The preference for isomer i (see the scheme below) over the symmetrical isomer ii may be related to the ability of the exocyclic double bond to donate electron density to the Cr atom if it is in a position trans to the better π-accepting ligand, i.e. NO⁺. As a result, the exocyclic C6 atoms of (I) and (II) are bent towards the Cr atom, with θ angles of 2.8 (3) and 0.1 (1)°, respectively. The θ angle is defined as the angle between the exocyclic C—C bond (C1—C6) and the corresponding Cp ring, with a positive angle toward the metal and a negative angle away from the metal.

The fact that the electron-withdrawing carbonyl group on the Cp ring orients itself trans to the stronger electron-withdrawing NO rather than a weaker electron-withdrawing ligand is startling (Rogers et al., 1988). It is interesting to discover that the contribution of the canonical form i to (I) or (II) to some extent was revealed by the carbon–carbon bond lengths in the cyclopentadienyl ring. Comparatively, shorter bond lengths for C2—C3 and C4—C5, and longer bond lengths for C1—C2, C3—C4 and C1—C5, are observed in both (I) and (II).

In view of the shortness of the Cr—N(nitrosyl) distances in (I) and (II) (ca 1.71 Å) compared with the Cr—N(isothiocyanate) distance of 1.983 (3) Å in compound (7) (Wang et al., 2007), appreciable d_π back-donation from the Cr atom to the π* orbitals of the nitrosyl group is demonstrated. It appears that the canonical form iv rather than iii makes a greater contribution to the chromium–nitrosyl bonding. The lesser contribution of v with respect that of iv is reflected by the Cr—N—O angles of ca 171°. These values are similar to those found in (8) [171.2 (5) and 172.1 (4)°] and (9) [176.0 (5) and 174.3 (4)°] (Wang et al., 1991).

The two Cr–centroid [Cp(Cr)] distances agree with the values of 1.844 Å in (1) and 1.884 Å in (η⁵–C₁₃H₉)Cr(CO)₂(NO) (Atwood et al., 1979). The average Cr—C(ring) distances of 2.209 (4) and 2.215 (4) Å are close to the value in (2) (2.20 Å). The average C—C distance in the ring [Cp(Cr)] is 1.409 (6) and 1.403 (6)Å for compound (I) and (II), respectively. In the case of (I), the exocyclic C1—C6 bond is considerably shorter than those found in [η⁵–(1–vinylferrocenyl)methylcyclopentadienyl]dicarbonylnitrosylchromium [1.507 (6) Å; Wang et al., 1989] and (1–cynichrodenoylferrocenyl)cynichrodenylmethane [1.512 (8) Å; Wang et al.,1990], but is comparable to that found in (12) [1.470 (8) Å; Rogers et al., 1988]. Again, the contribution of canonical form i to compound (I) may account for the difference.

It is interesting to note the difference between the structures of (I) and (II). The resonance between the carbonyl and phenyl ring diminishes the extent of the contribution of i to (II). This entails the longer exocyclic C—C bond, a smaller θ [0.1 (1) versus 2.8 (3)°], and a larger dihedral angle between the carbonyl plane and the corresponding Cp(Cr) plane. The results indicate that the resonance between the carbonyl and phenyl group overwhelms the resonance between the carbonyl and Cp(Cr) group. It is conceivable that the two electron-withdrawing nitrosyl groups and the bromide ion on Cr atom deplete the electron density on the Cp(Cr) ring. The π electrons on the Cp(Cr) ring are less available to resonate with the C≡O group. In the case of (II), the carbonyl plane (C1/C6/O3/C7) is turned away from the Cp(Cr) and phenyl rings by 15.2 (3) and 24.5 (1)°, respectively. This rotation might be the result of intramolecular steric interference between atoms H5 and H8. This is supported by the enlargement of bond angles C5—C1—C6 and C8—C7—C6 to 131.8 (4) and 123.2 (4)°, respectively. As a result of the steric interference, the dihedral angle between the Cp(Cr) and benzene rings is quite large [35.3 (1)°].

S2. Experimental

Through a solution of (η⁵-carboxycyclopentadienyl)dicarbonylnitrosylchromium (cynichrodenoic acid), (5) (2.49 g, 9.56 mmol), in 30 ml of 2-propanol, hydrogen bromide was bubbled for 5 min. After cooling to 273–283 K with stirring for 20 min (an orange–red solution resulted), isoamyl nitrite (2.6 ml, 19.12 mmol) was added slowly. Carbon oxide evolved and the solution subsequently changed to dark green. The reaction mixture was stirred continuously for 1 h. After concentration of the solution to 10 ml, dichloromethane (30 ml) was added and a large quantity of dark-green solid precipitated out. The solid was obtained through frit filtration and washed several times with distilled water. Compound (I) (yield 2.24 g, 74%) was obtained after vacuum drying (Wang et al., 2007). An X-ray sample (granular black–brown crystals) was prepared by recrystallization using the solvent expansion method from hexane–tetrahydrofuran (5:2) at 273 K for 48 h. The same procedure was followed for the preparation of compound (II) (in 90% yield), starting from (η⁵–benzoylcyclopentadienyl)dicarbonylnitrosylchromium (benzoylcynichrodene), (6) (1.23 g, 4.00 mmol).

S3. Refinement

The O3 hydroxy H atom in (I) was refined. All other H atoms in (I) and (II) were placed in geometrically calculated positions, with U_iso(H) values of 1.2U_eq(parent atom). The hydroxyl H atom in (I) was refined.

Computing details

For both compounds, data collection: CAD-4 (Enraf–Nonius, 1994). Cell refinement: CAD-4 (Enraf–Nonius, 1994 for (I); CAD-4 (Enraf–Nonius, 1994) for (II). For both compounds, data reduction: NRCVAX DATRD2 (Gabe et al., 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Version 6.10; Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Version 6.10; Sheldrick, 2008).

Figures

	Fig. 1. The molecular configuration of (I); anisotropic displacement ellipsoids are drawn at the 30% probability level. H atoms have been omitted for clarity.
	Fig. 2. The molecular configuration of (II); anisotropic displacement ellipsoids are drawn at the 30% probability level. H atoms have been omitted for clarity.

(I) Bromido(η⁵-carboxycyclopentadienyl)dinitrosylchromium(0)

Crystal data

[CrBr(C6H5O2)(NO)2]	F(000) = 584
Mr = 301.03	Dx = 2.115 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 7.6395 (19) Å	θ = 7.9–14.0°
b = 10.591 (2) Å	µ = 5.42 mm^−1
c = 12.122 (2) Å	T = 293 K
β = 105.40 (2)°	Block, dark brown
V = 945.6 (4) Å^3	0.50 × 0.40 × 0.30 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	1408 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.040
Graphite monochromator	θmax = 27.5°, θmin = 2.6°
ω–2θ scans, 0.80+0.35tanθ	h = −9→9
Absorption correction: ψ scan (North et al., 1968)	k = 0→13
Tmin = 0.141, Tmax = 0.236	l = 0→15
2378 measured reflections	3 standard reflections every 60 min
2168 independent reflections	intensity decay: none

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)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.100	H atoms treated by a mixture of independent and constrained refinement
S = 0.99	w = 1/[σ^2(Fo^2) + (0.0575P)^2] where P = (Fo^2 + 2Fc^2)/3
2168 reflections	(Δ/σ)max = 0.005
131 parameters	Δρmax = 0.51 e Å^−3
0 restraints	Δρmin = −0.61 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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
Cr1	0.36595 (7)	0.10857 (6)	0.24597 (5)	0.03117 (17)
Br1	0.36451 (7)	0.30386 (5)	0.35484 (4)	0.05872 (19)
N1	0.5041 (5)	0.0169 (4)	0.3494 (3)	0.0442 (8)
N2	0.5362 (4)	0.1432 (3)	0.1840 (3)	0.0387 (7)
C1	0.0958 (5)	0.0356 (4)	0.2461 (3)	0.0333 (8)
C2	0.1862 (5)	−0.0532 (4)	0.1919 (4)	0.0385 (9)
H2	0.2198	−0.1348	0.2172	0.046*
C3	0.2157 (5)	0.0033 (4)	0.0949 (3)	0.0426 (10)
H3	0.2732	−0.0338	0.0443	0.051*
C4	0.1426 (5)	0.1275 (4)	0.0863 (3)	0.0411 (9)
H4	0.1448	0.1862	0.0297	0.049*
C5	0.0674 (5)	0.1452 (4)	0.1777 (3)	0.0380 (9)
H5	0.0079	0.2177	0.1916	0.046*
C6	0.0472 (5)	0.0184 (4)	0.3540 (3)	0.0356 (8)
O1	0.5907 (5)	−0.0574 (4)	0.4102 (3)	0.0686 (10)
O2	0.6457 (4)	0.1541 (4)	0.1345 (3)	0.0630 (9)
O3	−0.0410 (4)	0.1076 (3)	0.3847 (3)	0.0503 (8)
O4	0.0956 (4)	−0.0810 (2)	0.4107 (2)	0.0460 (7)
H	−0.040 (7)	0.102 (5)	0.447 (5)	0.064 (17)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cr1	0.0294 (3)	0.0384 (3)	0.0281 (3)	−0.0041 (3)	0.0119 (2)	−0.0022 (3)
Br1	0.0763 (4)	0.0523 (3)	0.0580 (3)	−0.0210 (2)	0.0360 (3)	−0.0228 (2)
N1	0.0411 (19)	0.057 (2)	0.0355 (18)	−0.0024 (17)	0.0118 (15)	−0.0019 (17)
N2	0.0329 (17)	0.052 (2)	0.0338 (17)	−0.0073 (15)	0.0125 (14)	−0.0020 (15)
C1	0.0304 (19)	0.040 (2)	0.0317 (19)	−0.0034 (15)	0.0117 (16)	−0.0002 (16)
C2	0.039 (2)	0.036 (2)	0.043 (2)	−0.0028 (17)	0.0144 (18)	−0.0078 (18)
C3	0.037 (2)	0.060 (3)	0.031 (2)	−0.0054 (19)	0.0093 (16)	−0.009 (2)
C4	0.037 (2)	0.055 (3)	0.032 (2)	−0.0032 (19)	0.0087 (16)	0.0071 (19)
C5	0.0297 (18)	0.043 (2)	0.043 (2)	0.0010 (16)	0.0123 (16)	0.0036 (18)
C6	0.036 (2)	0.037 (2)	0.039 (2)	−0.0089 (16)	0.0192 (17)	−0.0030 (17)
O1	0.071 (2)	0.080 (2)	0.048 (2)	0.016 (2)	0.0035 (18)	0.0163 (19)
O2	0.0448 (18)	0.096 (3)	0.058 (2)	−0.0099 (17)	0.0314 (16)	−0.0007 (19)
O3	0.062 (2)	0.0496 (18)	0.053 (2)	0.0112 (15)	0.0396 (17)	0.0054 (16)
O4	0.0644 (19)	0.0339 (15)	0.0443 (17)	−0.0023 (13)	0.0221 (15)	0.0041 (13)

Geometric parameters (Å, º)

Cr1—N2	1.706 (3)	C1—C6	1.462 (5)
Cr1—N1	1.710 (4)	C2—C3	1.390 (6)
Cr1—C2	2.184 (4)	C2—H2	0.9300
Cr1—C3	2.191 (4)	C3—C4	1.422 (6)
Cr1—C1	2.204 (4)	C3—H3	0.9300
Cr1—C4	2.223 (4)	C4—C5	1.390 (6)
Cr1—C5	2.244 (4)	C4—H4	0.9300
Cr1—Br1	2.4551 (8)	C5—H5	0.9300
N1—O1	1.158 (4)	C6—O4	1.258 (5)
N2—O2	1.158 (4)	C6—O3	1.272 (5)
C1—C5	1.409 (5)	O3—H	0.75 (5)
C1—C2	1.426 (5)
N2—Cr1—N1	92.92 (16)	C2—C1—C6	126.8 (4)
N2—Cr1—C2	121.91 (16)	C5—C1—Cr1	73.1 (2)
N1—Cr1—C2	89.49 (17)	C2—C1—Cr1	70.3 (2)
N2—Cr1—C3	91.87 (16)	C6—C1—Cr1	120.3 (3)
N1—Cr1—C3	114.10 (17)	C3—C2—C1	108.2 (4)
C2—Cr1—C3	37.06 (15)	C3—C2—Cr1	71.7 (2)
N2—Cr1—C1	154.07 (15)	C1—C2—Cr1	71.8 (2)
N1—Cr1—C1	101.30 (15)	C3—C2—H2	125.9
C2—Cr1—C1	37.93 (14)	C1—C2—H2	125.9
C3—Cr1—C1	62.57 (15)	Cr1—C2—H2	122.3
N2—Cr1—C4	95.48 (15)	C2—C3—C4	108.1 (4)
N1—Cr1—C4	150.54 (17)	C2—C3—Cr1	71.2 (2)
C2—Cr1—C4	62.20 (16)	C4—C3—Cr1	72.5 (2)
C3—Cr1—C4	37.57 (15)	C2—C3—H3	125.9
C1—Cr1—C4	61.97 (14)	C4—C3—H3	125.9
N2—Cr1—C5	128.29 (16)	Cr1—C3—H3	122.1
N1—Cr1—C5	137.50 (15)	C5—C4—C3	107.7 (4)
C2—Cr1—C5	61.88 (15)	C5—C4—Cr1	72.7 (2)
C3—Cr1—C5	61.59 (15)	C3—C4—Cr1	70.0 (2)
C1—Cr1—C5	36.93 (14)	C5—C4—H4	126.2
C4—Cr1—C5	36.26 (14)	C3—C4—H4	126.2
N2—Cr1—Br1	99.69 (12)	Cr1—C4—H4	122.9
N1—Cr1—Br1	100.03 (12)	C4—C5—C1	109.0 (4)
C2—Cr1—Br1	136.87 (10)	C4—C5—Cr1	71.1 (2)
C3—Cr1—Br1	143.33 (12)	C1—C5—Cr1	70.0 (2)
C1—Cr1—Br1	99.04 (10)	C4—C5—H5	125.5
C4—Cr1—Br1	106.27 (12)	C1—C5—H5	125.5
C5—Cr1—Br1	84.45 (11)	Cr1—C5—H5	125.0
O1—N1—Cr1	171.6 (3)	O4—C6—O3	124.2 (4)
O2—N2—Cr1	172.0 (3)	O4—C6—C1	119.1 (3)
C5—C1—C2	106.9 (3)	O3—C6—C1	116.7 (4)
C5—C1—C6	126.3 (3)	C6—O3—H	112 (4)

(II) (η⁵-benzoylcyclopentadienyl)bromidodinitrosylchromium(0)

Crystal data

[CrBr(C12H9O)(NO)2]	F(000) = 712
Mr = 361.12	Dx = 1.865 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 12.1936 (13) Å	θ = 8.9–15.2°
b = 6.5027 (9) Å	µ = 4.00 mm^−1
c = 16.305 (2) Å	T = 293 K
β = 95.731 (10)°	Block, brown
V = 1286.4 (3) Å^3	0.55 × 0.45 × 0.30 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	1881 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.040
Graphite monochromator	θmax = 27.5°, θmin = 1.7°
ω–2θ scans	h = −15→15
Absorption correction: ψ scan North et al., 1968	k = 0→8
Tmin = 0.220, Tmax = 0.333	l = 0→21
3233 measured reflections	3 standard reflections every 60 min
2952 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.037	H-atom parameters constrained
wR(F^2) = 0.130	w = 1/[σ^2(Fo^2) + (0.0713P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max = 0.001
2952 reflections	Δρmax = 0.40 e Å^−3
173 parameters	Δρmin = −0.61 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0043 (9)

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
Cr1	0.14034 (5)	0.13650 (9)	0.88831 (3)	0.03404 (19)
Br1	0.10425 (4)	−0.22495 (8)	0.85592 (3)	0.0651 (2)
N1	0.1574 (3)	0.2166 (6)	0.7898 (2)	0.0441 (8)
N2	0.0073 (3)	0.2220 (6)	0.8815 (2)	0.0467 (8)
C1	0.3137 (3)	0.1278 (6)	0.9477 (2)	0.0356 (8)
C2	0.2466 (3)	0.0263 (7)	1.0000 (2)	0.0435 (9)
H2	0.2533	−0.1111	1.0155	0.052*
C3	0.1689 (4)	0.1623 (8)	1.0251 (2)	0.0483 (10)
H3	0.1154	0.1326	1.0602	0.058*
C4	0.1855 (3)	0.3526 (7)	0.9880 (3)	0.0480 (10)
H4	0.1440	0.4708	0.9936	0.058*
C5	0.2742 (3)	0.3348 (6)	0.9413 (2)	0.0394 (9)
H5	0.3030	0.4396	0.9110	0.047*
C6	0.4058 (3)	0.0223 (6)	0.9113 (2)	0.0386 (9)
C7	0.4939 (3)	0.1441 (6)	0.8757 (2)	0.0365 (8)
C8	0.5205 (3)	0.3432 (7)	0.8990 (2)	0.0437 (9)
H8	0.4802	0.4100	0.9366	0.052*
C9	0.6070 (3)	0.4453 (8)	0.8671 (3)	0.0551 (12)
H9	0.6247	0.5794	0.8832	0.066*
C10	0.6666 (3)	0.3453 (9)	0.8110 (3)	0.0615 (14)
H10	0.7245	0.4125	0.7894	0.074*
C11	0.6405 (4)	0.1489 (9)	0.7873 (3)	0.0590 (13)
H11	0.6805	0.0836	0.7492	0.071*
C12	0.5545 (3)	0.0444 (7)	0.8196 (2)	0.0457 (10)
H12	0.5378	−0.0904	0.8038	0.055*
O1	0.1722 (3)	0.2894 (7)	0.7282 (2)	0.0768 (11)
O2	−0.0771 (3)	0.3023 (7)	0.8817 (3)	0.0809 (11)
O3	0.4117 (2)	−0.1651 (5)	0.9143 (2)	0.0535 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cr1	0.0331 (3)	0.0359 (3)	0.0335 (3)	0.0035 (2)	0.0050 (2)	0.0024 (3)
Br1	0.0687 (4)	0.0445 (3)	0.0807 (4)	−0.0027 (2)	−0.0003 (3)	−0.0023 (2)
N1	0.0452 (18)	0.049 (2)	0.0368 (18)	−0.0013 (16)	−0.0002 (14)	0.0028 (16)
N2	0.0375 (18)	0.053 (2)	0.050 (2)	0.0047 (16)	0.0044 (15)	−0.0017 (17)
C1	0.0368 (19)	0.037 (2)	0.0324 (18)	0.0001 (16)	0.0000 (14)	0.0030 (16)
C2	0.047 (2)	0.051 (3)	0.0325 (19)	0.0013 (19)	0.0034 (16)	0.0105 (18)
C3	0.048 (2)	0.068 (3)	0.0301 (19)	0.000 (2)	0.0110 (16)	0.002 (2)
C4	0.047 (2)	0.053 (3)	0.044 (2)	0.006 (2)	0.0054 (18)	−0.016 (2)
C5	0.040 (2)	0.038 (2)	0.040 (2)	0.0006 (17)	0.0014 (16)	0.0002 (17)
C6	0.0353 (19)	0.043 (2)	0.0368 (19)	0.0031 (17)	−0.0024 (15)	0.0012 (17)
C7	0.0325 (17)	0.044 (2)	0.0315 (18)	0.0056 (16)	−0.0025 (14)	0.0039 (16)
C8	0.040 (2)	0.050 (2)	0.040 (2)	−0.0024 (18)	−0.0004 (16)	−0.0067 (19)
C9	0.048 (2)	0.057 (3)	0.056 (3)	−0.008 (2)	−0.012 (2)	0.008 (2)
C10	0.033 (2)	0.085 (4)	0.065 (3)	−0.002 (2)	0.002 (2)	0.027 (3)
C11	0.044 (2)	0.082 (4)	0.053 (3)	0.018 (2)	0.017 (2)	0.010 (3)
C12	0.040 (2)	0.051 (3)	0.045 (2)	0.0120 (18)	0.0034 (17)	−0.0008 (19)
O1	0.085 (3)	0.105 (3)	0.0401 (18)	−0.020 (2)	0.0055 (17)	0.0258 (19)
O2	0.0461 (19)	0.103 (3)	0.094 (3)	0.028 (2)	0.0103 (18)	−0.006 (2)
O3	0.0556 (18)	0.0384 (17)	0.068 (2)	0.0101 (14)	0.0114 (15)	0.0061 (15)

Geometric parameters (Å, º)

Cr1—N2	1.708 (3)	C4—C5	1.389 (5)
Cr1—N1	1.721 (3)	C4—H4	0.9300
Cr1—C4	2.177 (4)	C5—H5	0.9300
Cr1—C5	2.189 (4)	C6—O3	1.221 (5)
Cr1—C3	2.229 (4)	C6—C7	1.497 (5)
Cr1—C1	2.236 (4)	C7—C8	1.380 (6)
Cr1—C2	2.245 (4)	C7—C12	1.392 (5)
Cr1—Br1	2.4394 (8)	C8—C9	1.391 (6)
N1—O1	1.140 (4)	C8—H8	0.9300
N2—O2	1.154 (4)	C9—C10	1.385 (7)
C1—C2	1.405 (5)	C9—H9	0.9300
C1—C5	1.430 (6)	C10—C11	1.363 (8)
C1—C6	1.489 (5)	C10—H10	0.9300
C2—C3	1.388 (6)	C11—C12	1.396 (6)
C2—H2	0.9300	C11—H11	0.9300
C3—C4	1.401 (7)	C12—H12	0.9300
C3—H3	0.9300
N2—Cr1—N1	92.50 (17)	Cr1—C2—H2	123.7
N2—Cr1—C4	90.33 (16)	C2—C3—C4	107.6 (4)
N1—Cr1—C4	117.15 (17)	C2—C3—Cr1	72.5 (2)
N2—Cr1—C5	119.98 (16)	C4—C3—Cr1	69.4 (2)
N1—Cr1—C5	92.00 (16)	C2—C3—H3	126.2
C4—Cr1—C5	37.09 (15)	C4—C3—H3	126.2
N2—Cr1—C3	95.31 (17)	Cr1—C3—H3	123.5
N1—Cr1—C3	152.85 (18)	C5—C4—C3	108.5 (4)
C4—Cr1—C3	37.06 (18)	C5—C4—Cr1	71.9 (2)
C5—Cr1—C3	61.66 (16)	C3—C4—Cr1	73.5 (3)
N2—Cr1—C1	152.50 (16)	C5—C4—H4	125.7
N1—Cr1—C1	102.37 (15)	C3—C4—H4	125.7
C4—Cr1—C1	62.33 (15)	Cr1—C4—H4	120.6
C5—Cr1—C1	37.69 (15)	C4—C5—C1	108.3 (4)
C3—Cr1—C1	61.49 (14)	C4—C5—Cr1	71.0 (2)
N2—Cr1—C2	128.62 (16)	C1—C5—Cr1	72.9 (2)
N1—Cr1—C2	137.74 (16)	C4—C5—H5	125.9
C4—Cr1—C2	61.18 (16)	C1—C5—H5	125.9
C5—Cr1—C2	61.36 (15)	Cr1—C5—H5	121.9
C3—Cr1—C2	36.14 (16)	O3—C6—C1	119.2 (4)
C1—Cr1—C2	36.55 (14)	O3—C6—C7	120.1 (4)
N2—Cr1—Br1	98.63 (13)	C1—C6—C7	120.6 (3)
N1—Cr1—Br1	97.21 (12)	C8—C7—C12	119.5 (4)
C4—Cr1—Br1	144.12 (13)	C8—C7—C6	123.2 (4)
C5—Cr1—Br1	139.85 (11)	C12—C7—C6	117.2 (4)
C3—Cr1—Br1	107.22 (13)	C7—C8—C9	120.8 (4)
C1—Cr1—Br1	102.23 (10)	C7—C8—H8	119.6
C2—Cr1—Br1	86.86 (12)	C9—C8—H8	119.6
O1—N1—Cr1	172.6 (4)	C10—C9—C8	119.4 (5)
O2—N2—Cr1	171.3 (4)	C10—C9—H9	120.3
C2—C1—C5	105.9 (3)	C8—C9—H9	120.3
C2—C1—C6	122.2 (4)	C11—C10—C9	120.3 (4)
C5—C1—C6	131.8 (4)	C11—C10—H10	119.9
C2—C1—Cr1	72.1 (2)	C9—C10—H10	119.9
C5—C1—Cr1	69.4 (2)	C10—C11—C12	120.8 (4)
C6—C1—Cr1	123.9 (2)	C10—C11—H11	119.6
C3—C2—C1	109.6 (4)	C12—C11—H11	119.6
C3—C2—Cr1	71.3 (2)	C7—C12—C11	119.3 (4)
C1—C2—Cr1	71.4 (2)	C7—C12—H12	120.4
C3—C2—H2	125.2	C11—C12—H12	120.4
C1—C2—H2	125.2