Crystal structure of fac-tri­chlorido­[tris­(pyridin-2-yl-N)amine]­chromium(III)

Yamaguchi-Terasaki, Y.; Fujihara, T.; Nagasawa, A.; Kaizaki, S.

doi:10.1107/S2056989014027066

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Volume 71| Part 1| January 2015| Pages 73-75

https://doi.org/10.1107/S2056989014027066

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Crystal structure of fac-trichlorido[tris(pyridin-2-yl-N)amine]chromium(III)

Yukiko Yamaguchi-Terasaki,^a Takashi Fujihara,^b ^* Akira Nagasawa ^c and Sumio Kaizaki ^d

^aToyama National College of Technology, Imizu Campus, 1-2 Ebie-neriya, Imizu city, Toyama 933-0293, Japan, ^bComprehensive Analysis Center for Science, Saitama University, Shimo-Okubo 255, Sakura-ku, Saitama 338-8570, Japan, ^cDepartment of Chemistry, Graduate School of Science and Engineering, Saitama University, Shimo-Okubo 255, Sakura-ku, Saitama 338-8570, Japan, and ^dDepartment of Chemistry, Graduate School of Science, Osaka University, Machikaneyama-cyo 1-1, Toyonaka, Osaka, Japan
^*Correspondence e-mail: fuji@chem.saitama-u.ac.jp

Edited by M. Weil, Vienna University of Technology, Austria (Received 20 November 2014; accepted 10 December 2014; online 1 January 2015)

In the neutral complex molecule of the title compound, fac-[CrCl₃(tpa)] [tpa is tris(pyridin-2-yl)amine; C₁₅H₁₂N₄], the Cr^III ion is bonded to three N atoms that are constrained to a facial arrangement by the tpa ligand and by three chloride ligands, leading to a distorted octahedral coordination sphere. The average Cr—N and Cr—Cl bond lengths are 2.086 (5) and 2.296 (4) Å, respectively. The complex molecule is located on a mirror plane. In the crystal, a combination of C—H⋯N and C—H⋯Cl hydrogen-bonding interactions connect the molecules into a three-dimensional network.

Keywords: crystal structure; chloride ligand; pyridine ligand; chromium(III) complex; facial structural arrangement..

CCDC reference: 1038512

1. Chemical context

One aspect of solvatochromism is the dependence of ligand-field parameters on the solvent coordination sphere. This has been demonstrated by measuring the ligand-field absorption spectra and/or multinuclear NMR spectra for several types of Cr^III complexes in previous studies (Kaizaki, 1996 ; Kaizaki & Takemoto, 1990 ; Terasaki & Kaizaki, 1995 ; Terasaki et al., 1999 ; Yamaguchi-Terasaki et al., 2007a ,b ,c ). As a part of the above-mentioned systematic investigations, we report here the crystal structure of the title compound, fac-[CrCl₃(tpa)], (I), where tpa is tris(pyridin-2-yl)amine.

2. Structural commentary

The molecular structure of (I) is illustrated in Fig. 1. The Cr^III ion is coordinated by three N atoms that are constrained to a facial arrangement by the tpa ligand and three chloride ligands in a slightly distorted octahedral geometry. The entire complex molecule is located on a mirror plane. The average Cr—N bond length of 2.086 (5) Å is comparable to that in the related tpa complex cation fac-[Cr(tpa)(H₂O)₃]³⁺ [2.040 (1) Å; Terasaki et al., 2004 ]. In addition, the average Cr—Cl bond length of the coordinating chlorine atoms being in trans positions to the N atoms [2.296 (4) Å] is similar to those found for other pyridine-chromium(III) complexes, such as mer-[CrCl₃(terpy)] [terpy is 2,2′,2′′-terpyridine; C₁₅H₁₁N₃; 2.292 (1) Å] (Cloete et al., 2007 ); mer-[CrCl₃py₃] [py is pyridine, C₅H₅N; 2.320 (7) Å] (Howard & Hardcastle, 1985 ) or mer-[CrCl₃(Etpy)₃] [Etpy is 4-ethylpyridine, C₇H₉N₃; 2.320 (7) Å] (Modec et al., 2000 ). All bond lengths and angles within the pyridine rings are within normal ranges. The dihedral angles between the least-squares planes of the pyridine rings are 58.33 (6) and 63.37 (8)°.

Figure 1
The molecular structure of (I)

. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry code: (′) x, −y + $[{1\over 2}]$ , z.]

3. Supramolecular features

The chlorine atoms act as hydrogen-bond acceptors, forming intermolecular C—H⋯Cl hydrogen bonds with the pyridine rings (Fig. 2, Table 1). In addition, C—H⋯N hydrogen-bonding interactions are also present, consolidating the molecules into a three-dimensional network.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C7—H7⋯N1ⁱ	0.95	2.75	3.578 (5)	146
C7—H7⋯N1ⁱⁱ	0.95	2.75	3.578 (5)	146
C9—H9⋯Cl1ⁱⁱⁱ	0.95	2.82	3.447 (4)	124
C9—H9⋯Cl1^iv	0.95	2.82	3.447 (4)	124
C4—H4⋯Cl2^v	0.95	2.77	3.534 (4)	138
Symmetry codes: (i) $[x, -y+{\script{1\over 2}}, z-1]$ ; (ii) x, y, z-1; (iii) $[x+{\script{1\over 2}}, y, -z+{\script{3\over 2}}]$ ; (iv) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (v) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+{\script{5\over 2}}]$ .

Figure 2
Hydrogen-bonding interactions in the crystal structure of (I)

, shown as black dashed lines. [Symmetry codes: (ii) x, −y + $[{1\over 2}]$ , z − 1; (iii) x, y, z − 1; (iv) x + $[{1\over 2}]$ , y, −z + $[{3\over 2}]$ ; (v) x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z + $[{3\over 2}]$ ; (vi) x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , −z + $[{5\over 2}]$ .]

4. Synthesis and crystallization

fac-[CrCl₃(tpa)] was synthesized according to a previously reported procedure (Kaizaki & Legg, 1994 ). Green crystals of (I) suitable for X-ray analysis were obtained by slow cooling from the reaction solution. UV–vis(DMSO): λ_max(∊) = 720 (16), 645 (37), 464 (59) nm (L mol⁻¹ cm⁻¹). Elemental analysis, calculated for C₁₅H₁₂C_l3CrN₄: C, 44.31, H, 2.97, N, 13.78%; found: C, 44.29; H, 2.99; N, 13.76%.

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The H atoms were placed in calculated positions, with C—H = 0.95 Å, and refined using a riding model, with U_iso(H) = 1.2U_eq.

Table 2
Experimental details

Crystal data
Chemical formula	[CrCl₃(C₁₅H₁₂N₄)]
M_r	406.64
Crystal system, space group	Orthorhombic, Pnma
Temperature (K)	150
a, b, c (Å)	15.152 (13), 13.704 (12), 8.014 (7)
V (Å³)	1664 (2)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	1.17
Crystal size (mm)	0.06 × 0.05 × 0.04

Data collection
Diffractometer	Bruker APEXII CCD area detector
Absorption correction	Multi-scan (SADABS; Bruker, 2014 )
No. of measured, independent and observed [I > 2σ(I)] reflections	15895, 1779, 1401
R_int	0.061
(sin θ/λ)_max (Å⁻¹)	0.625

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.038, 0.113, 1.20
No. of reflections	1779
No. of parameters	118
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.66, −0.51
Computer programs: APEX2, SAINT and XPREP (Bruker, 2014), SHELXS2014, SHELXL2014 and XCIF (Sheldrick, 2008 ) and ORTEP-3 for Windows (Farrugia, 2012 ).

Supporting information

CCDC reference: 1038512

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2056989014027066/wm5095sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989014027066/wm5095Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2014); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT and XPREP (Bruker, 2014); program(s) used to solve structure: SHELXS2014 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: XCIF (Sheldrick, 2008).

fac-trichlorido[tris(pyridin-2-yl-N)amine]chromium(III) top

Crystal data top

[CrCl₃(C₁₅H₁₂N₄)]	D_x = 1.623 Mg m⁻³
M_r = 406.64	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pnma	Cell parameters from 3388 reflections
a = 15.152 (13) Å	θ = 2.7–26.4°
b = 13.704 (12) Å	µ = 1.17 mm⁻¹
c = 8.014 (7) Å	T = 150 K
V = 1664 (2) Å³	Needle, green
Z = 4	0.06 × 0.05 × 0.04 mm
F(000) = 820

Data collection top

Bruker APEXII CCD area-detector diffractometer	1779 independent reflections
Radiation source: Bruker TXS fine-focus rotating anode	1401 reflections with I > 2σ(I)
Bruker Helios multilayer confocal mirror monochromator	R_int = 0.061
Detector resolution: 8.333 pixels mm^-1	θ_max = 26.4°, θ_min = 2.7°
φ and ω scans	h = −18→18
Absorption correction: multi-scan (SADABS; Bruker, 2014)	k = −17→17
	l = −10→10
15895 measured reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.038	H-atom parameters constrained
wR(F²) = 0.113	w = 1/[σ²(F_o²) + (0.0593P)² + 0.050P] where P = (F_o² + 2F_c²)/3
S = 1.20	(Δ/σ)_max < 0.001
1779 reflections	Δρ_max = 0.66 e Å⁻³
118 parameters	Δρ_min = −0.51 e Å⁻³

Special details top

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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

- 0.0000 (0.0001) x + 13.7040 (0.0118) y - 0.0000 (0.0000) z = 3.4260 (0.0030)

* 0.0000 (0.0000) N2 * 0.0000 (0.0000) C6 * 0.0000 (0.0000) C7 * 0.0000 (0.0000) C8 * 0.0000 (0.0000) C9 * 0.0000 (0.0000) C10

Rms deviation of fitted atoms = 0.0000

- 0.2014 (0.0170) x - 7.1958 (0.0145) y + 6.8195 (0.0076) z = 4.9979 (0.0213)

Angle to previous plane (with approximate esd) = 58.326 ( 0.080 )

* -0.0024 (0.0017) N1_$6 * -0.0057 (0.0019) C1_$6 * 0.0081 (0.0020) C2_$6 * -0.0029 (0.0020) C3_$6 * -0.0049 (0.0019) C4_$6 * 0.0078 (0.0018) C5_$6

Rms deviation of fitted atoms = 0.0057

0.2014 (0.0171) x + 7.1958 (0.0145) y + 6.8195 (0.0076) z = 8.8847 (0.0184)

Angle to previous plane (with approximate esd) = 63.371 ( 0.081 )

* -0.0024 (0.0017) N1 * -0.0057 (0.0019) C1 * 0.0081 (0.0020) C2 * -0.0029 (0.0020) C3 * -0.0049 (0.0019) C4 * 0.0078 (0.0018) C5

Rms deviation of fitted atoms = 0.0057

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

	x	y	z	U_iso*/U_eq
C1	0.89047 (17)	0.06834 (18)	1.2036 (3)	0.0287 (6)
H1	0.8290	0.0568	1.2158	0.034*
C2	0.94935 (19)	0.0033 (2)	1.2726 (4)	0.0336 (7)
H2	0.9287	−0.0516	1.3336	0.040*
C3	1.0382 (2)	0.0186 (2)	1.2521 (4)	0.0355 (7)
H3	1.0796	−0.0262	1.2972	0.043*
C4	1.06674 (17)	0.0997 (2)	1.1654 (4)	0.0309 (6)
H4	1.1279	0.1117	1.1495	0.037*
C5	1.00429 (16)	0.16273 (18)	1.1026 (3)	0.0224 (6)
C10	1.0039 (2)	0.2500	0.8449 (5)	0.0239 (8)
C6	0.8905 (3)	0.2500	0.6541 (5)	0.0328 (9)
H6	0.8292	0.2500	0.6295	0.039*
C7	0.9499 (3)	0.2500	0.5256 (5)	0.0378 (10)
H7	0.9295	0.2500	0.4136	0.045*
C8	1.0383 (3)	0.2500	0.5577 (5)	0.0358 (10)
H8	1.0797	0.2500	0.4688	0.043*
C9	1.0667 (2)	0.2500	0.7224 (5)	0.0293 (9)
H9	1.1277	0.2500	0.7490	0.035*
Cl1	0.75326 (4)	0.37578 (5)	0.89695 (10)	0.0388 (2)
Cl2	0.75220 (6)	0.2500	1.26071 (14)	0.0379 (3)
Cr1	0.83104 (4)	0.2500	1.01679 (7)	0.0239 (2)
N1	0.91747 (13)	0.14774 (15)	1.1195 (3)	0.0225 (5)
N2	0.91684 (19)	0.2500	0.8144 (4)	0.0256 (7)
N3	1.03099 (19)	0.2500	1.0163 (4)	0.0227 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0299 (13)	0.0202 (13)	0.0360 (16)	−0.0023 (11)	0.0030 (12)	0.0013 (12)
C2	0.0433 (16)	0.0167 (13)	0.0407 (17)	0.0001 (12)	0.0019 (13)	0.0046 (12)
C3	0.0413 (16)	0.0190 (14)	0.0462 (18)	0.0045 (12)	−0.0051 (13)	0.0039 (13)
C4	0.0268 (13)	0.0264 (14)	0.0394 (16)	0.0011 (11)	−0.0038 (12)	−0.0018 (13)
C5	0.0259 (13)	0.0145 (13)	0.0267 (14)	0.0022 (10)	−0.0001 (10)	−0.0007 (10)
C10	0.0296 (19)	0.0151 (17)	0.027 (2)	0.000	0.0023 (16)	0.000
C6	0.039 (2)	0.024 (2)	0.035 (2)	0.000	−0.0078 (19)	0.000
C7	0.061 (3)	0.027 (2)	0.026 (2)	0.000	0.000 (2)	0.000
C8	0.052 (3)	0.022 (2)	0.034 (2)	0.000	0.015 (2)	0.000
C9	0.034 (2)	0.0163 (18)	0.038 (2)	0.000	0.0086 (18)	0.000
Cl1	0.0309 (4)	0.0240 (4)	0.0615 (5)	0.0046 (3)	−0.0127 (3)	0.0036 (3)
Cl2	0.0295 (5)	0.0309 (6)	0.0534 (7)	0.000	0.0160 (4)	0.000
Cr1	0.0191 (3)	0.0170 (3)	0.0356 (4)	0.000	−0.0005 (2)	0.000
N1	0.0240 (11)	0.0161 (10)	0.0276 (12)	−0.0001 (8)	0.0011 (9)	−0.0018 (9)
N2	0.0288 (16)	0.0196 (16)	0.0285 (17)	0.000	−0.0012 (13)	0.000
N3	0.0225 (15)	0.0162 (15)	0.0295 (17)	0.000	0.0011 (12)	0.000

Geometric parameters (Å, º) top

C1—N1	1.344 (3)	C6—C7	1.367 (6)
C1—C2	1.377 (4)	C6—H6	0.9500
C1—H1	0.9500	C7—C8	1.363 (7)
C2—C3	1.372 (4)	C7—H7	0.9500
C2—H2	0.9500	C8—C9	1.388 (6)
C3—C4	1.380 (4)	C8—H8	0.9500
C3—H3	0.9500	C9—H9	0.9500
C4—C5	1.376 (4)	Cl1—Cr1	2.2983 (15)
C4—H4	0.9500	Cl2—Cr1	2.2909 (19)
C5—N1	1.338 (3)	Cr1—N2	2.079 (3)
C5—N3	1.440 (3)	Cr1—N1ⁱ	2.087 (2)
C10—N2	1.342 (4)	Cr1—N1	2.087 (2)
C10—C9	1.366 (5)	Cr1—Cl1ⁱ	2.2983 (15)
C10—N3	1.434 (5)	N3—C5ⁱ	1.440 (3)
C6—N2	1.345 (5)

N1—C1—C2	121.9 (3)	C10—C9—C8	117.9 (4)
N1—C1—H1	119.1	C10—C9—H9	121.1
C2—C1—H1	119.1	C8—C9—H9	121.1
C3—C2—C1	119.2 (3)	N2—Cr1—N1ⁱ	85.14 (10)
C3—C2—H2	120.4	N2—Cr1—N1	85.14 (10)
C1—C2—H2	120.4	N1ⁱ—Cr1—N1	84.35 (13)
C2—C3—C4	119.4 (3)	N2—Cr1—Cl2	172.72 (9)
C2—C3—H3	120.3	N1ⁱ—Cr1—Cl2	89.46 (8)
C4—C3—H3	120.3	N1—Cr1—Cl2	89.46 (8)
C5—C4—C3	118.3 (3)	N2—Cr1—Cl1ⁱ	89.69 (8)
C5—C4—H4	120.9	N1ⁱ—Cr1—Cl1ⁱ	171.91 (6)
C3—C4—H4	120.9	N1—Cr1—Cl1ⁱ	89.03 (8)
N1—C5—C4	122.9 (2)	Cl2—Cr1—Cl1ⁱ	95.12 (5)
N1—C5—N3	116.9 (2)	N2—Cr1—Cl1	89.69 (8)
C4—C5—N3	120.2 (2)	N1ⁱ—Cr1—Cl1	89.03 (8)
N2—C10—C9	123.6 (4)	N1—Cr1—Cl1	171.91 (6)
N2—C10—N3	117.1 (3)	Cl2—Cr1—Cl1	95.12 (5)
C9—C10—N3	119.3 (3)	Cl1ⁱ—Cr1—Cl1	97.18 (7)
N2—C6—C7	121.6 (4)	C5—N1—C1	118.3 (2)
N2—C6—H6	119.2	C5—N1—Cr1	118.28 (17)
C7—C6—H6	119.2	C1—N1—Cr1	123.39 (18)
C8—C7—C6	120.3 (4)	C10—N2—C6	117.7 (3)
C8—C7—H7	119.8	C10—N2—Cr1	118.2 (2)
C6—C7—H7	119.8	C6—N2—Cr1	124.0 (3)
C7—C8—C9	118.9 (4)	C10—N3—C5	112.33 (18)
C7—C8—H8	120.5	C10—N3—C5ⁱ	112.33 (18)
C9—C8—H8	120.5	C5—N3—C5ⁱ	112.4 (3)

N1—C1—C2—C3	−1.4 (4)	C2—C1—N1—Cr1	−178.7 (2)
C1—C2—C3—C4	1.1 (4)	C9—C10—N2—C6	0.000 (1)
C2—C3—C4—C5	0.2 (4)	N3—C10—N2—C6	180.000 (1)
C3—C4—C5—N1	−1.2 (4)	C9—C10—N2—Cr1	180.000 (1)
C3—C4—C5—N3	177.9 (2)	N3—C10—N2—Cr1	0.000 (1)
N2—C6—C7—C8	0.000 (1)	C7—C6—N2—C10	0.000 (1)
C6—C7—C8—C9	0.000 (1)	C7—C6—N2—Cr1	180.000 (1)
N2—C10—C9—C8	0.000 (1)	N2—C10—N3—C5	63.9 (2)
N3—C10—C9—C8	180.000 (1)	C9—C10—N3—C5	−116.1 (2)
C7—C8—C9—C10	0.000 (1)	N2—C10—N3—C5ⁱ	−63.9 (2)
C4—C5—N1—C1	1.0 (4)	C9—C10—N3—C5ⁱ	116.1 (2)
N3—C5—N1—C1	−178.1 (2)	N1—C5—N3—C10	−64.4 (3)
C4—C5—N1—Cr1	−179.9 (2)	C4—C5—N3—C10	116.4 (3)
N3—C5—N1—Cr1	1.0 (3)	N1—C5—N3—C5ⁱ	63.4 (4)
C2—C1—N1—C5	0.3 (4)	C4—C5—N3—C5ⁱ	−115.8 (3)

Symmetry code: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7···N1ⁱⁱ	0.95	2.75	3.578 (5)	146
C7—H7···N1ⁱⁱⁱ	0.95	2.75	3.578 (5)	146
C9—H9···Cl1^iv	0.95	2.82	3.447 (4)	124
C9—H9···Cl1^v	0.95	2.82	3.447 (4)	124
C4—H4···Cl2^vi	0.95	2.77	3.534 (4)	138

Symmetry codes: (ii) x, −y+1/2, z−1; (iii) x, y, z−1; (iv) x+1/2, y, −z+3/2; (v) x+1/2, −y+1/2, −z+3/2; (vi) x+1/2, −y+1/2, −z+5/2.

Acknowledgements

This work was supported by the programs of the Grants-in-Aid for Scientific Research (to TF, No. 23510115) from the Japan Society for the Promotion of Science.

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