Tris(8-quinolinolato-κ²N,O)­chromium(III) ethanol solvate

The title chromium(III) complex, [Cr(C₉H₆NO)₃]·C₂H₆O, is isomorphous with the manganese(III) compound [Xiong et al. (1995). Acta Cryst. C51, 1978–1980]. Three 8-quinolinolate ligands chelate the Cr^III atom to form an approximately octahedral coordination geometry. An ethanol solvent mol­ecule hydrogen bonds to the complex with an O...O distance of 2.758 (5) Å and an O—H...O angle of 167°. The separation distances of 3.426 (19) and 3.368 (4) Å between parallel quinoline rings suggests the existence of π–π stacking between neighboring complex mol­ecules.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.058
• wR factor = 0.162
• Data-to-parameter ratio = 13.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

As part of a series of investigations on π–π-stacking interactions in metal complexes, several 8-quinolinolate–metal complexes have been synthesized in the laboratory.

The structure of the title complex, (I), is shown in Fig. 1. Three 8-quinolinolate ligands chelate to the Cr^III atom in an octahedral coordination geometry. The planar 8-quinolinolate ligands are almost perpendicular to each other, with dihedral angles of 85.84 (10), 85.40 (11) and 81.91 (14)°. The overlapped disposition of neighboring parallel quinoline rings is shown in Fig. 2. The quinoline plane containing atom N21 is separated from the quinoline plane containing N21(-x, −y, 1 − z) by 3.426 (19) Å. Likewise, the plane containing atom 31 and the plane containing N31(-x, −y, −z) are separated by 3.368 (4) Å. These findings strongly suggest the existence of π–π stacking in the crystal structure.

The ethanol solvent molecule is hydrogen bonded to the Cr^III complex, with an O1···O31 distance of 2.758 (5) Å and an O1—H1···O31 angle of 167° (Table 2). Weak C—H···O hydrogen bonding occurs between atom O11 and quinoline atoms C15 and C24.

S2. Experimental

The title complex was prepared by refluxing an ethanol solution (15 ml) containing CrCl₃·6H₂O (0.27 g, 1 mmol), 8-quinolinol (0.29 g, 2 mmol) and imidazole (0.14 g, 2 mmol) for 2 h. The resulting solution was filtered at room temperature. Green single crystals were obtained from the filtrate after 2 weeks.

S3. Refinement

The hydroxyl H atom was located in a difference Fourier map, and included in the final cycles of refinement with fixed positional parameters and displacement parameter U_iso = 0.08 Ų. Other H atoms were placed in calculated positions, with C—H = 0.93–0.97 Å, and included in the final cycles of refinement as riding, with U_iso(H) = 1.2U_eq or 1.5U_eq of the carrier atoms.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. A view of the molecular structure of (I), with 30% probability displacement ellipsoids and the atom-numbering scheme. The dashed line indicates the hydrogen bond between the complex and the solvent molecule.
	Fig. 2. A packing diagram, showing the π–π interactions between neighboring quinoline rings.

(I)

Crystal data

[Cr(C9H6NO)3]·C2H6O	F(000) = 1100
Mr = 530.51	Dx = 1.409 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 8818 reflections
a = 11.2683 (11) Å	θ = 2.5–24.5°
b = 13.2572 (11) Å	µ = 0.50 mm^−1
c = 16.8041 (18) Å	T = 298 K
β = 94.783 (6)°	Prism, green
V = 2501.6 (4) Å^3	0.36 × 0.32 × 0.20 mm
Z = 4

Data collection

Bruker SMART CCD diffractometer	4362 independent reflections
Radiation source: fine-focus sealed tube	3346 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
ω and ϕ scans	θmax = 25.0°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −13→8
Tmin = 0.84, Tmax = 0.91	k = −13→15
8913 measured reflections	l = −19→19

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)] = 0.058	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.162	H-atom parameters constrained
S = 1.10	w = 1/[σ^2(Fo^2) + (0.0725P)^2 + 2.5324P] where P = (Fo^2 + 2Fc^2)/3
4362 reflections	(Δ/σ)max < 0.001
334 parameters	Δρmax = 0.47 e Å^−3
0 restraints	Δρmin = −0.44 e Å^−3

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
Cr	0.06841 (5)	−0.01785 (4)	0.25614 (3)	0.0387 (2)
O11	−0.1047 (2)	−0.00813 (19)	0.26518 (15)	0.0460 (6)
O21	0.0771 (2)	−0.15728 (19)	0.29316 (15)	0.0496 (6)
O31	0.2358 (2)	−0.01254 (19)	0.22972 (14)	0.0465 (6)
N11	0.0461 (2)	0.1328 (2)	0.22680 (17)	0.0412 (7)
N21	0.1125 (3)	0.0116 (2)	0.37607 (17)	0.0413 (7)
N31	0.0427 (3)	−0.0669 (2)	0.14009 (17)	0.0438 (7)
C10	−0.1127 (4)	0.2590 (3)	0.2115 (2)	0.0511 (10)
C12	0.1243 (3)	0.2019 (3)	0.2089 (2)	0.0531 (10)
H12	0.2038	0.1837	0.2076	0.064*
C13	0.0902 (4)	0.3019 (3)	0.1918 (3)	0.0635 (12)
H13	0.1468	0.3491	0.1793	0.076*
C14	−0.0255 (4)	0.3296 (3)	0.1935 (3)	0.0625 (11)
H14	−0.0476	0.3962	0.1827	0.075*
C15	−0.2363 (4)	0.2789 (3)	0.2140 (3)	0.0614 (11)
H15	−0.2654	0.3440	0.2053	0.074*
C16	−0.3117 (4)	0.2026 (4)	0.2292 (3)	0.0632 (12)
H16	−0.3928	0.2160	0.2283	0.076*
C17	−0.2710 (3)	0.1040 (3)	0.2463 (2)	0.0559 (10)
H17	−0.3256	0.0541	0.2569	0.067*
C18	−0.1497 (3)	0.0795 (3)	0.2476 (2)	0.0443 (9)
C19	−0.0724 (3)	0.1603 (3)	0.2284 (2)	0.0407 (8)
C20	0.1518 (3)	−0.0819 (3)	0.5007 (2)	0.0512 (10)
C22	0.1283 (3)	0.0965 (3)	0.4162 (2)	0.0499 (9)
H22	0.1209	0.1572	0.3885	0.060*
C23	0.1558 (4)	0.0993 (3)	0.4989 (2)	0.0571 (11)
H23	0.1658	0.1608	0.5252	0.069*
C24	0.1677 (4)	0.0116 (3)	0.5404 (2)	0.0576 (11)
H24	0.1865	0.0131	0.5954	0.069*
C25	0.1595 (4)	−0.1789 (4)	0.5374 (3)	0.0620 (11)
H25	0.1787	−0.1845	0.5921	0.074*
C26	0.1388 (4)	−0.2627 (4)	0.4927 (3)	0.0630 (12)
H26	0.1439	−0.3252	0.5178	0.076*
C27	0.1098 (3)	−0.2593 (3)	0.4094 (3)	0.0542 (10)
H27	0.0957	−0.3188	0.3808	0.065*
C28	0.1022 (3)	−0.1674 (3)	0.3702 (2)	0.0442 (9)
C29	0.1237 (3)	−0.0785 (3)	0.4173 (2)	0.0407 (8)
C30	0.1548 (4)	−0.1113 (3)	0.0270 (2)	0.0598 (11)
C32	−0.0564 (4)	−0.0946 (3)	0.0987 (2)	0.0580 (11)
H32	−0.1283	−0.0883	0.1217	0.070*
C33	−0.0565 (5)	−0.1331 (4)	0.0210 (3)	0.0720 (13)
H33	−0.1274	−0.1542	−0.0062	0.086*
C34	0.0462 (5)	−0.1396 (4)	−0.0139 (3)	0.0705 (13)
H34	0.0453	−0.1632	−0.0661	0.085*
C35	0.2678 (5)	−0.1146 (4)	−0.0028 (3)	0.0722 (13)
H35	0.2755	−0.1377	−0.0543	0.087*
C36	0.3654 (5)	−0.0839 (4)	0.0436 (3)	0.0759 (15)
H36	0.4390	−0.0855	0.0224	0.091*
C37	0.3600 (4)	−0.0495 (3)	0.1230 (3)	0.0628 (12)
H37	0.4294	−0.0305	0.1531	0.075*
C38	0.2516 (3)	−0.0442 (3)	0.1559 (2)	0.0479 (9)
C39	0.1486 (3)	−0.0749 (3)	0.1065 (2)	0.0447 (9)
O1	0.4443 (4)	0.0801 (4)	0.2883 (3)	0.1187 (16)
C1	0.4784 (10)	0.0899 (8)	0.4279 (6)	0.190 (5)
H1A	0.4724	0.1335	0.4730	0.284*
H1B	0.5602	0.0711	0.4246	0.284*
H1C	0.4315	0.0304	0.4341	0.284*
C2	0.4346 (7)	0.1426 (6)	0.3549 (5)	0.128 (3)
H2A	0.3520	0.1616	0.3581	0.153*
H2B	0.4806	0.2037	0.3492	0.153*
H1	0.3769	0.0487	0.2777	0.080*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cr	0.0394 (3)	0.0414 (4)	0.0352 (3)	0.0015 (2)	0.0024 (2)	−0.0009 (2)
O11	0.0432 (13)	0.0444 (15)	0.0514 (15)	−0.0050 (11)	0.0093 (11)	0.0043 (12)
O21	0.0604 (16)	0.0438 (15)	0.0439 (15)	−0.0010 (12)	0.0011 (12)	−0.0030 (12)
O31	0.0403 (13)	0.0575 (16)	0.0417 (15)	0.0053 (11)	0.0023 (11)	−0.0064 (12)
N11	0.0432 (16)	0.0458 (18)	0.0343 (15)	−0.0015 (14)	0.0023 (12)	0.0005 (13)
N21	0.0401 (16)	0.0473 (18)	0.0367 (16)	0.0002 (13)	0.0050 (12)	−0.0017 (13)
N31	0.0489 (18)	0.0455 (18)	0.0366 (16)	0.0004 (14)	0.0007 (14)	0.0001 (13)
C10	0.060 (2)	0.048 (2)	0.045 (2)	0.0069 (19)	0.0015 (18)	−0.0009 (18)
C12	0.046 (2)	0.061 (3)	0.052 (2)	−0.0109 (19)	0.0050 (17)	−0.003 (2)
C13	0.074 (3)	0.046 (3)	0.071 (3)	−0.014 (2)	0.009 (2)	0.002 (2)
C14	0.081 (3)	0.041 (2)	0.065 (3)	0.004 (2)	0.006 (2)	−0.001 (2)
C15	0.069 (3)	0.056 (3)	0.059 (3)	0.023 (2)	0.006 (2)	0.001 (2)
C16	0.045 (2)	0.081 (3)	0.063 (3)	0.021 (2)	0.0012 (19)	0.001 (2)
C17	0.042 (2)	0.076 (3)	0.050 (2)	−0.001 (2)	0.0078 (17)	0.003 (2)
C18	0.0406 (19)	0.057 (3)	0.0359 (19)	−0.0038 (17)	0.0075 (15)	−0.0014 (17)
C19	0.0433 (19)	0.046 (2)	0.0328 (18)	0.0040 (16)	0.0029 (15)	−0.0022 (15)
C20	0.041 (2)	0.069 (3)	0.044 (2)	0.0023 (18)	0.0053 (16)	0.0053 (19)
C22	0.052 (2)	0.048 (2)	0.050 (2)	−0.0017 (18)	0.0098 (18)	−0.0066 (18)
C23	0.061 (3)	0.067 (3)	0.045 (2)	−0.007 (2)	0.0088 (19)	−0.017 (2)
C24	0.058 (2)	0.078 (3)	0.038 (2)	−0.005 (2)	0.0057 (18)	−0.006 (2)
C25	0.059 (3)	0.078 (3)	0.048 (2)	−0.001 (2)	0.0006 (19)	0.015 (2)
C26	0.058 (2)	0.061 (3)	0.070 (3)	0.001 (2)	0.007 (2)	0.025 (2)
C27	0.052 (2)	0.046 (2)	0.066 (3)	0.0005 (18)	0.0067 (19)	0.0065 (19)
C28	0.0362 (18)	0.047 (2)	0.049 (2)	−0.0004 (16)	0.0035 (16)	0.0013 (17)
C29	0.0329 (17)	0.051 (2)	0.0391 (19)	0.0006 (15)	0.0060 (14)	0.0036 (16)
C30	0.090 (3)	0.049 (2)	0.042 (2)	0.011 (2)	0.018 (2)	0.0030 (18)
C32	0.058 (2)	0.063 (3)	0.051 (2)	−0.007 (2)	−0.0047 (19)	−0.003 (2)
C33	0.078 (3)	0.078 (3)	0.056 (3)	−0.018 (3)	−0.011 (2)	−0.006 (2)
C34	0.100 (4)	0.072 (3)	0.037 (2)	−0.007 (3)	−0.007 (2)	−0.011 (2)
C35	0.094 (4)	0.075 (3)	0.051 (3)	0.014 (3)	0.025 (3)	−0.002 (2)
C36	0.075 (3)	0.082 (4)	0.077 (3)	0.021 (3)	0.044 (3)	0.010 (3)
C37	0.052 (2)	0.068 (3)	0.070 (3)	0.013 (2)	0.016 (2)	0.000 (2)
C38	0.050 (2)	0.043 (2)	0.052 (2)	0.0094 (17)	0.0120 (18)	0.0046 (17)
C39	0.058 (2)	0.037 (2)	0.039 (2)	0.0061 (17)	0.0057 (17)	0.0024 (15)
O1	0.079 (3)	0.131 (4)	0.147 (4)	−0.028 (2)	0.013 (2)	−0.054 (3)
C1	0.281 (14)	0.162 (9)	0.124 (8)	0.051 (8)	0.005 (8)	0.022 (7)
C2	0.125 (6)	0.109 (6)	0.153 (7)	−0.021 (4)	0.038 (5)	−0.060 (5)

Geometric parameters (Å, º)

Cr—O21	1.950 (3)	C22—H22	0.930
Cr—O11	1.974 (3)	C23—C24	1.357 (6)
Cr—O31	1.975 (2)	C23—H23	0.930
Cr—N31	2.053 (3)	C24—H24	0.930
Cr—N11	2.068 (3)	C25—C26	1.350 (6)
Cr—N21	2.072 (3)	C25—H25	0.930
O11—C18	1.292 (5)	C26—C27	1.411 (6)
O21—C28	1.308 (4)	C26—H26	0.930
O31—C38	1.336 (4)	C27—C28	1.385 (5)
N11—C12	1.322 (5)	C27—H27	0.930
N11—C19	1.387 (4)	C28—C29	1.430 (5)
N21—C22	1.317 (5)	C30—C34	1.404 (7)
N21—C29	1.381 (5)	C30—C35	1.407 (6)
N31—C32	1.318 (5)	C30—C39	1.428 (5)
N31—C39	1.365 (5)	C32—C33	1.402 (6)
C10—C19	1.407 (5)	C32—H32	0.930
C10—C14	1.408 (6)	C33—C34	1.343 (7)
C10—C15	1.421 (6)	C33—H33	0.930
C12—C13	1.404 (6)	C34—H34	0.930
C12—H12	0.9300	C35—C36	1.356 (7)
C13—C14	1.358 (6)	C35—H35	0.930
C13—H13	0.930	C36—C37	1.417 (7)
C14—H14	0.930	C36—H36	0.930
C15—C16	1.360 (6)	C37—C38	1.383 (5)
C15—H15	0.930	C37—H37	0.930
C16—C17	1.407 (6)	C38—C39	1.428 (5)
C16—H16	0.930	O1—C2	1.404 (7)
C17—C18	1.403 (5)	O1—H1	0.871
C17—H17	0.930	C1—C2	1.462 (11)
C18—C19	1.434 (5)	C1—H1A	0.960
C20—C24	1.411 (6)	C1—H1B	0.960
C20—C29	1.412 (5)	C1—H1C	0.960
C20—C25	1.426 (6)	C2—H2A	0.970
C22—C23	1.398 (5)	C2—H2B	0.970
O21—Cr—O11	93.51 (11)	C24—C23—H23	120.2
O21—Cr—O31	94.69 (11)	C22—C23—H23	120.2
O11—Cr—O31	169.68 (10)	C23—C24—C20	120.4 (4)
O21—Cr—N31	90.13 (11)	C23—C24—H24	119.8
O11—Cr—N31	91.83 (11)	C20—C24—H24	119.8
O31—Cr—N31	81.91 (11)	C26—C25—C20	120.0 (4)
O21—Cr—N11	173.52 (11)	C26—C25—H25	120.0
O11—Cr—N11	81.62 (11)	C20—C25—H25	120.0
O31—Cr—N11	90.64 (11)	C25—C26—C27	122.8 (4)
N31—Cr—N11	94.28 (12)	C25—C26—H26	118.6
O21—Cr—N21	82.35 (11)	C27—C26—H26	118.6
O11—Cr—N21	94.09 (11)	C28—C27—C26	120.0 (4)
O31—Cr—N21	93.20 (10)	C28—C27—H27	120.0
N31—Cr—N21	170.69 (12)	C26—C27—H27	120.0
N11—Cr—N21	93.69 (12)	O21—C28—C27	124.1 (4)
C18—O11—Cr	114.4 (2)	O21—C28—C29	118.4 (3)
C28—O21—Cr	114.4 (2)	C27—C28—C29	117.5 (3)
C38—O31—Cr	113.7 (2)	N21—C29—C20	121.9 (3)
C12—N11—C19	118.9 (3)	N21—C29—C28	115.5 (3)
C12—N11—Cr	130.8 (3)	C20—C29—C28	122.5 (3)
C19—N11—Cr	110.3 (2)	C34—C30—C35	126.5 (4)
C22—N21—C29	118.6 (3)	C34—C30—C39	116.1 (4)
C22—N21—Cr	132.1 (3)	C35—C30—C39	117.4 (4)
C29—N21—Cr	109.2 (2)	N31—C32—C33	121.8 (4)
C32—N31—C39	119.5 (3)	N31—C32—H32	119.1
C32—N31—Cr	129.4 (3)	C33—C32—H32	119.1
C39—N31—Cr	111.0 (2)	C34—C33—C32	119.8 (4)
C19—C10—C14	116.3 (4)	C34—C33—H33	120.1
C19—C10—C15	117.9 (4)	C32—C33—H33	120.1
C14—C10—C15	125.8 (4)	C33—C34—C30	121.1 (4)
N11—C12—C13	121.6 (4)	C33—C34—H34	119.5
N11—C12—H12	119.2	C30—C34—H34	119.5
C13—C12—H12	119.2	C36—C35—C30	120.1 (4)
C14—C13—C12	119.9 (4)	C36—C35—H35	120.0
C14—C13—H13	120.1	C30—C35—H35	120.0
C12—C13—H13	120.1	C35—C36—C37	122.8 (4)
C13—C14—C10	120.9 (4)	C35—C36—H36	118.6
C13—C14—H14	119.6	C37—C36—H36	118.6
C10—C14—H14	119.6	C38—C37—C36	120.0 (4)
C16—C15—C10	119.8 (4)	C38—C37—H37	120.0
C16—C15—H15	120.1	C36—C37—H37	120.0
C10—C15—H15	120.1	O31—C38—C37	125.2 (4)
C15—C16—C17	122.1 (4)	O31—C38—C39	117.6 (3)
C15—C16—H16	118.9	C37—C38—C39	117.1 (4)
C17—C16—H16	118.9	N31—C39—C30	121.7 (4)
C18—C17—C16	121.2 (4)	N31—C39—C38	115.7 (3)
C18—C17—H17	119.4	C30—C39—C38	122.6 (4)
C16—C17—H17	119.4	C2—O1—H1	108.7
O11—C18—C17	125.1 (4)	C2—C1—H1A	109.5
O11—C18—C19	119.3 (3)	C2—C1—H1B	109.5
C17—C18—C19	115.6 (4)	H1A—C1—H1B	109.5
N11—C19—C10	122.3 (3)	C2—C1—H1C	109.5
N11—C19—C18	114.4 (3)	H1A—C1—H1C	109.5
C10—C19—C18	123.3 (3)	H1B—C1—H1C	109.5
C24—C20—C29	116.8 (4)	O1—C2—C1	110.1 (7)
C24—C20—C25	126.0 (4)	O1—C2—H2A	109.6
C29—C20—C25	117.3 (4)	C1—C2—H2A	109.6
N21—C22—C23	122.7 (4)	O1—C2—H2B	109.6
N21—C22—H22	118.6	C1—C2—H2B	109.6
C23—C22—H22	118.6	H2A—C2—H2B	108.2
C24—C23—C22	119.5 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O31	0.87	1.90	2.758 (5)	167
C15—H15···O11^i	0.93	2.52	3.377 (5)	153
C24—H24···O11^ii	0.93	2.59	3.401 (4)	146

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