cis-Di­chloridobis(1,10-phenanthroline)chromium(III) chloride

In the title complex, [CrCl₂(C₁₂H₈N₂)₂]Cl, the Cr^III ion is situated on a twofold rotation axis and displays a slightly distorted octa­hedral CrCl₂N₄ coordination geometry. The Cr environment is composed of a cis arrangement of two 1,10-phenanthroline and two chloride ligands. The chloride counter-anion exhibits half-occupation and is equally disordered over two positions.

Related literature

For background to chromium(III) complexes, see: Vincent (2000). For the structure of a related Cr(III) complex with phenanthroline ligands, see: Birk et al. (2008).

Experimental

Crystal data

• [CrCl₂(C₁₂H₈N₂)₂]Cl

• M_r = 518.76

• Monoclinic, C 2/c

• a = 15.446 (7) Å

• b = 13.762 (6) Å

• c = 12.536 (5) Å

• β = 100.398 (6)°

• V = 2621.1 (19) ų

• Z = 4

• Mo Kα radiation

• μ = 0.76 mm⁻¹

• T = 298 K

• 0.40 × 0.10 × 0.10 mm

Data collection

• Bruker SMART CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 2000) T_min = 0.751, T_max = 0.928

• 5182 measured reflections

• 2265 independent reflections

• 1778 reflections with I > 2σ(I)

• R_int = 0.039

Refinement

• R[F² > 2σ(F²)] = 0.070

• wR(F²) = 0.211

• S = 1.07

• 2265 reflections

• 150 parameters

• H-atom parameters constrained

• Δρ_max = 0.92 e Å⁻³

• Δρ_min = −0.35 e Å⁻³

Table 1
Selected bond lengths (Å)

Cr1—N1	2.062 (4)
Cr1—N2	2.073 (4)
Cr1—Cl1	2.2941 (15)

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

S1. Comment

Chromium is known to activate enzymes, maintain protein stability and enhance carbohydrate metabolism. Organic chromium (III) sources have been shown to enhance the availability of chromium. Nutritionists believe organic chromium should be supplemented in most animal diets. A search has therefore been underway to identify the biologically active form of chromium, viz. the biomolecule that binds chromium(III) and possesses an intrinsic function associated with insulin action in mammals (Vincent, 2000). We designed and synthesized a new chromium complex, [CrCl₂(C₁₂H₈N₂)₂]Cl.

The Cr atom has site symmetry 2 and exhibits a distorted octahedral coordination, defined of four N atoms [Cr—N1: 2.062 (4) Å, Cr—N2: 2.073 (4) Å] from two symmetry-related 1,10-phenanthroline ligands and of two symmetry-related Cl ligands [2.2941 (15) Å]. The ligands are in a cis arrangement (Fig. 1.). The two planar 1,10-phenanthroline ligands show an approximate perpendicular orientation to each other [N1—Cr1—N2A: 91.81 (14) °, N2—Cr1—N2A: 88.5 (2) °]. These values are similar to that of the structure of the related compound cis-difluoridobis(1,10-phenanthroline)chromium(III) perchlorate monohydrate (Birk et al., 2008).

The crystal packing of the title compound is displayed in Fig. 2.

Related literature

For background to chromium(III) complexes, see: Vincent et al. (2000). For the structure of a related Cr(III) complex with phenanthroline ligands, see: Birk et al. (2008).

S2. Experimental

The title compound was prepared by the following method. CrCl₃^.6H₂O (0.665 g, 0.0025 mol) and zinc powder (0.1 g, 0.0015 mol) were added into methanol (30 ml) and then refluxed for 1 h. To the mixture 1,10-phenanthroline (0.99 g, 0.0050 mol) in methanol (20 ml) was added dropwise and allowed to reflux for another 30 min. The solution was put aside and X-ray quality crystals were obtained after two days at room temperature.

S3. Refinement

The H atoms were treated as riding atoms, with C—H (CH) = 0.93 Å, and with U_iso(H) = 1.5 U_eq (parent atom).

Computing details

Data collection: SMART (Bruker 2000); cell refinement: SAINT (Bruker 2000); data reduction: SAINT (Bruker 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level; H atoms were omitted for clarity. [Symmetry code A: -x + 1, y, -z + 3/2.]
	Fig. 2. The crystal structure of title compound, projected along the c-axis.

cis-Dichloridobis(1,10-phenanthroline)chromium(III) chloride

Crystal data

[CrCl2(C12H8N2)2]Cl	F(000) = 1052
Mr = 518.76	Dx = 1.315 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 1354 reflections
a = 15.446 (7) Å	θ = 2.7–19.9°
b = 13.762 (6) Å	µ = 0.76 mm^−1
c = 12.536 (5) Å	T = 298 K
β = 100.398 (6)°	Block, red
V = 2621.1 (19) Å^3	0.40 × 0.10 × 0.10 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	2265 independent reflections
Radiation source: fine-focus sealed tube	1778 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
ϕ and ω scans	θmax = 25.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 2000)	h = −18→18
Tmin = 0.751, Tmax = 0.928	k = −16→16
5182 measured reflections	l = −7→14

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)] = 0.070	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.211	H-atom parameters constrained
S = 1.07	w = 1/[σ^2(Fo^2) + (0.1164P)^2 + 5.5982P] where P = (Fo^2 + 2Fc^2)/3
2265 reflections	(Δ/σ)max < 0.001
150 parameters	Δρmax = 0.92 e Å^−3
0 restraints	Δρmin = −0.35 e Å^−3

Special details

Experimental. the Cl-counter anion is only half occupied and equally disordered over two positions.

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	Occ. (<1)
Cr1	0.5000	0.83468 (7)	0.7500	0.0338 (4)
Cl1	0.60948 (7)	0.94883 (9)	0.76093 (10)	0.0481 (4)
N1	0.5196 (2)	0.8199 (3)	0.9163 (3)	0.0386 (9)
N2	0.5952 (2)	0.7267 (3)	0.7714 (3)	0.0383 (9)
C1	0.6878 (3)	0.6322 (4)	0.9120 (4)	0.0467 (12)
C2	0.7141 (4)	0.6151 (4)	1.0254 (5)	0.0600 (14)
H2	0.7577	0.5695	1.0490	0.072*
C3	0.6771 (4)	0.6636 (4)	1.0997 (5)	0.0576 (14)
H3	0.6957	0.6507	1.1731	0.069*
C4	0.6099 (3)	0.7344 (4)	1.0672 (4)	0.0495 (12)
C5	0.5685 (4)	0.7889 (4)	1.1387 (4)	0.0582 (14)
H5	0.5837	0.7789	1.2131	0.070*
C6	0.5068 (4)	0.8555 (4)	1.0999 (4)	0.0555 (14)
H6	0.4806	0.8923	1.1475	0.067*
C7	0.4820 (3)	0.8693 (4)	0.9869 (4)	0.0478 (12)
H7	0.4381	0.9142	0.9612	0.057*
C8	0.5826 (3)	0.7539 (3)	0.9552 (4)	0.0380 (10)
C9	0.6226 (3)	0.7021 (3)	0.8779 (4)	0.0370 (10)
C10	0.7257 (4)	0.5865 (4)	0.8319 (5)	0.0588 (14)
H10	0.7682	0.5387	0.8506	0.071*
C11	0.6995 (4)	0.6130 (5)	0.7255 (5)	0.0650 (16)
H11	0.7250	0.5839	0.6718	0.078*
C12	0.6345 (4)	0.6836 (4)	0.6980 (5)	0.0531 (13)
H12	0.6180	0.7012	0.6255	0.064*
Cl2	0.6999 (6)	0.6655 (4)	0.4261 (5)	0.157 (3)	0.50

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cr1	0.0324 (6)	0.0364 (6)	0.0334 (6)	0.000	0.0081 (4)	0.000
Cl1	0.0390 (7)	0.0488 (7)	0.0549 (8)	−0.0079 (5)	0.0043 (5)	0.0066 (5)
N1	0.040 (2)	0.041 (2)	0.037 (2)	−0.0041 (17)	0.0121 (17)	−0.0010 (16)
N2	0.0376 (19)	0.039 (2)	0.040 (2)	0.0022 (16)	0.0107 (16)	0.0015 (17)
C1	0.040 (3)	0.047 (3)	0.053 (3)	0.002 (2)	0.007 (2)	0.006 (2)
C2	0.053 (3)	0.062 (3)	0.061 (3)	0.012 (3)	−0.001 (3)	0.015 (3)
C3	0.057 (3)	0.064 (4)	0.046 (3)	0.000 (3)	−0.005 (3)	0.010 (3)
C4	0.051 (3)	0.055 (3)	0.041 (3)	−0.009 (2)	0.004 (2)	−0.001 (2)
C5	0.070 (4)	0.068 (4)	0.037 (3)	−0.005 (3)	0.009 (2)	0.001 (3)
C6	0.069 (3)	0.062 (3)	0.039 (3)	−0.002 (3)	0.020 (3)	−0.012 (2)
C7	0.054 (3)	0.047 (3)	0.045 (3)	0.004 (2)	0.016 (2)	−0.005 (2)
C8	0.035 (2)	0.041 (2)	0.038 (2)	−0.0057 (19)	0.0053 (18)	0.0008 (19)
C9	0.034 (2)	0.036 (2)	0.041 (2)	−0.0036 (18)	0.0070 (19)	0.001 (2)
C10	0.052 (3)	0.055 (3)	0.071 (4)	0.021 (3)	0.016 (3)	0.008 (3)
C11	0.070 (4)	0.064 (4)	0.068 (4)	0.025 (3)	0.031 (3)	−0.004 (3)
C12	0.059 (3)	0.057 (3)	0.047 (3)	0.011 (3)	0.020 (3)	−0.002 (2)
Cl2	0.265 (8)	0.125 (4)	0.101 (4)	−0.037 (5)	0.086 (5)	−0.027 (3)

Geometric parameters (Å, º)

Cr1—N1	2.062 (4)	C3—C4	1.428 (8)
Cr1—N1^i	2.062 (4)	C3—H3	0.9300
Cr1—N2^i	2.073 (4)	C4—C5	1.408 (8)
Cr1—N2	2.073 (4)	C4—C8	1.417 (7)
Cr1—Cl1	2.2941 (15)	C5—C6	1.348 (8)
Cr1—Cl1^i	2.2941 (15)	C5—H5	0.9300
N1—C7	1.330 (6)	C6—C7	1.411 (7)
N1—C8	1.356 (6)	C6—H6	0.9300
N2—C12	1.330 (6)	C7—H7	0.9300
N2—C9	1.368 (6)	C8—C9	1.431 (6)
C1—C10	1.399 (8)	C10—C11	1.372 (8)
C1—C9	1.403 (7)	C10—H10	0.9300
C1—C2	1.426 (8)	C11—C12	1.395 (8)
C2—C3	1.353 (8)	C11—H11	0.9300
C2—H2	0.9300	C12—H12	0.9300
N1—Cr1—N1^i	168.7 (2)	C4—C3—H3	119.5
N1—Cr1—N2^i	91.81 (14)	C5—C4—C8	116.2 (5)
N1^i—Cr1—N2^i	80.07 (15)	C5—C4—C3	124.9 (5)
N1—Cr1—N2	80.07 (15)	C8—C4—C3	118.9 (5)
N1^i—Cr1—N2	91.81 (14)	C6—C5—C4	120.4 (5)
N2^i—Cr1—N2	88.5 (2)	C6—C5—H5	119.8
N1—Cr1—Cl1	92.00 (11)	C4—C5—H5	119.8
N1^i—Cr1—Cl1	95.73 (11)	C5—C6—C7	120.0 (5)
N2^i—Cr1—Cl1	175.09 (11)	C5—C6—H6	120.0
N2—Cr1—Cl1	89.14 (11)	C7—C6—H6	120.0
N1—Cr1—Cl1^i	95.73 (11)	N1—C7—C6	121.8 (5)
N1^i—Cr1—Cl1^i	92.00 (11)	N1—C7—H7	119.1
N2^i—Cr1—Cl1^i	89.14 (11)	C6—C7—H7	119.1
N2—Cr1—Cl1^i	175.09 (10)	N1—C8—C4	123.3 (4)
Cl1—Cr1—Cl1^i	93.56 (8)	N1—C8—C9	117.4 (4)
C7—N1—C8	118.3 (4)	C4—C8—C9	119.3 (4)
C7—N1—Cr1	128.4 (3)	N2—C9—C1	123.1 (4)
C8—N1—Cr1	113.2 (3)	N2—C9—C8	116.2 (4)
C12—N2—C9	117.7 (4)	C1—C9—C8	120.6 (4)
C12—N2—Cr1	129.2 (3)	C11—C10—C1	119.4 (5)
C9—N2—Cr1	113.0 (3)	C11—C10—H10	120.3
C10—C1—C9	117.3 (5)	C1—C10—H10	120.3
C10—C1—C2	124.2 (5)	C10—C11—C12	119.9 (5)
C9—C1—C2	118.5 (5)	C10—C11—H11	120.1
C3—C2—C1	121.7 (5)	C12—C11—H11	120.1
C3—C2—H2	119.1	N2—C12—C11	122.5 (5)
C1—C2—H2	119.1	N2—C12—H12	118.7
C2—C3—C4	121.1 (5)	C11—C12—H12	118.7
C2—C3—H3	119.5
N1^i—Cr1—N1—C7	−137.2 (4)	Cr1—N1—C7—C6	−175.5 (4)
N2^i—Cr1—N1—C7	−93.5 (4)	C5—C6—C7—N1	−1.8 (8)
N2—Cr1—N1—C7	178.4 (4)	C7—N1—C8—C4	0.4 (7)
Cl1—Cr1—N1—C7	89.6 (4)	Cr1—N1—C8—C4	177.3 (4)
Cl1^i—Cr1—N1—C7	−4.2 (4)	C7—N1—C8—C9	−179.5 (4)
N1^i—Cr1—N1—C8	46.3 (3)	Cr1—N1—C8—C9	−2.6 (5)
N2^i—Cr1—N1—C8	90.0 (3)	C5—C4—C8—N1	−0.8 (7)
N2—Cr1—N1—C8	1.9 (3)	C3—C4—C8—N1	−179.7 (4)
Cl1—Cr1—N1—C8	−86.9 (3)	C5—C4—C8—C9	179.2 (4)
Cl1^i—Cr1—N1—C8	179.3 (3)	C3—C4—C8—C9	0.2 (7)
N1—Cr1—N2—C12	−177.2 (5)	C12—N2—C9—C1	−1.9 (7)
N1^i—Cr1—N2—C12	10.7 (4)	Cr1—N2—C9—C1	−178.7 (4)
N2^i—Cr1—N2—C12	90.7 (4)	C12—N2—C9—C8	176.5 (4)
Cl1—Cr1—N2—C12	−85.0 (4)	Cr1—N2—C9—C8	−0.3 (5)
Cl1^i—Cr1—N2—C12	151.5 (11)	C10—C1—C9—N2	0.1 (7)
N1—Cr1—N2—C9	−0.8 (3)	C2—C1—C9—N2	177.4 (5)
N1^i—Cr1—N2—C9	−172.9 (3)	C10—C1—C9—C8	−178.3 (5)
N2^i—Cr1—N2—C9	−92.9 (3)	C2—C1—C9—C8	−1.0 (7)
Cl1—Cr1—N2—C9	91.4 (3)	N1—C8—C9—N2	2.0 (6)
Cl1^i—Cr1—N2—C9	−32.1 (15)	C4—C8—C9—N2	−178.0 (4)
C10—C1—C2—C3	177.9 (5)	N1—C8—C9—C1	−179.6 (4)
C9—C1—C2—C3	0.8 (8)	C4—C8—C9—C1	0.5 (7)
C1—C2—C3—C4	−0.1 (9)	C9—C1—C10—C11	1.4 (8)
C2—C3—C4—C5	−179.3 (6)	C2—C1—C10—C11	−175.7 (6)
C2—C3—C4—C8	−0.4 (8)	C1—C10—C11—C12	−1.2 (9)
C8—C4—C5—C6	−0.2 (8)	C9—N2—C12—C11	2.2 (8)
C3—C4—C5—C6	178.7 (5)	Cr1—N2—C12—C11	178.4 (4)
C4—C5—C6—C7	1.4 (9)	C10—C11—C12—N2	−0.7 (9)
C8—N1—C7—C6	0.9 (7)

Symmetry code: (i) −x+1, y, −z+3/2.